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Sample records for weak gravitational lensing

  1. Gravitational Lensing

    SciTech Connect (OSTI)

    Lincoln, Don

    2015-06-24

    In a long line of intellectual triumphs, Einstein’s theory of general relativity was his greatest and most imaginative. It tells us that what we experience as gravity can be most accurately described as the bending of space itself. This idea leads to consequences, including gravitational lensing, which is caused by light traveling in this curved space. This is works in a way analogous to a lens (and hence the name). In this video, Fermilab’s Dr. Don Lincoln explains a little general relativity, a little gravitational lensing, and tells us how this phenomenon allows us to map out the matter of the entire universe, including the otherwise-invisible dark matter.

  2. WEAK GRAVITATIONAL LENSING AS A PROBE OF PHYSICAL PROPERTIES OF SUBSTRUCTURES IN DARK MATTER HALOS

    SciTech Connect (OSTI)

    Shirasaki, Masato

    2015-02-01

    We propose a novel method to select satellite galaxies in outer regions of galaxy groups or clusters using weak gravitational lensing. The method is based on the theoretical expectation that the tangential shear pattern around satellite galaxies would appear with negative values at an offset distance from the center of the main halo. We can thus locate the satellite galaxies statistically with an offset distance of several lensing smoothing scales by using the standard reconstruction of surface mass density maps from weak lensing observation. We test the idea using high-resolution cosmological simulations. We show that subhalos separated from the center of the host halo are successfully located even without assuming the position of the center. For a number of such subhalos, the characteristic mass and offset length can be also estimated on a statistical basis. We perform a Fisher analysis to show how well upcoming weak lensing surveys can constrain the mass density profile of satellite galaxies. In the case of the Large Synoptic Survey Telescope with a sky coverage of 20,000deg{sup 2}, the mass of the member galaxies in the outer region of galaxy clusters can be constrained with an accuracy of ?0.1 dex for galaxy clusters with mass 10{sup 14} h {sup 1} M {sub ?} at z = 0.15. Finally we explore the detectability of tidal stripping features for subhalos having a wide range of masses of 10{sup 11}-10{sup 13} h {sup 1} M {sub ?}.

  3. MEASURING THE GEOMETRY OF THE UNIVERSE FROM WEAK GRAVITATIONAL LENSING BEHIND GALAXY GROUPS IN THE HST COSMOS SURVEY

    SciTech Connect (OSTI)

    Taylor, James E.; Massey, Richard J.; Leauthaud, Alexie; Tanaka, Masayuki; George, Matthew R.; Rhodes, Jason; Ellis, Richard; Scoville, Nick; Kitching, Thomas D.; Capak, Peter; Finoguenov, Alexis; Ilbert, Olivier; Kneib, Jean-Paul; Jullo, Eric; Koekemoer, Anton M.

    2012-04-20

    Gravitational lensing can provide pure geometric tests of the structure of spacetime, for instance by determining empirically the angular diameter distance-redshift relation. This geometric test has been demonstrated several times using massive clusters which produce a large lensing signal. In this case, matter at a single redshift dominates the lensing signal, so the analysis is straightforward. It is less clear how weaker signals from multiple sources at different redshifts can be stacked to demonstrate the geometric dependence. We introduce a simple measure of relative shear which for flat cosmologies separates the effect of lens and source positions into multiplicative terms, allowing signals from many different source-lens pairs to be combined. Applying this technique to a sample of groups and low-mass clusters in the COSMOS survey, we detect a clear variation of shear with distance behind the lens. This represents the first detection of the geometric effect using weak lensing by multiple, low-mass groups. The variation of distance with redshift is measured with sufficient precision to constrain the equation of state of the universe under the assumption of flatness, equivalent to a detection of a dark energy component {Omega}{sub X} at greater than 99% confidence for an equation-of-state parameter -2.5 {<=} w {<=} -0.1. For the case w = -1, we find a value for the cosmological constant density parameter {Omega}{sub {Lambda}} = 0.85{sup +0.044}{sub -}0{sub .19} (68% CL) and detect cosmic acceleration (q{sub 0} < 0) at the 98% CL. We consider the systematic uncertainties associated with this technique and discuss the prospects for applying it in forthcoming weak-lensing surveys.

  4. Tomography and weak lensing statistics

    SciTech Connect (OSTI)

    Munshi, Dipak; Coles, Peter; Kilbinger, Martin E-mail: peter.coles@astro.cf.ac.uk

    2014-04-01

    We provide generic predictions for the lower order cumulants of weak lensing maps, and their correlators for tomographic bins as well as in three dimensions (3D). Using small-angle approximation, we derive the corresponding one- and two-point probability distribution function for the tomographic maps from different bins and for 3D convergence maps. The modelling of weak lensing statistics is obtained by adopting a detailed prescription for the underlying density contrast that involves hierarchal ansatz and lognormal distribution. We study the dependence of our results on cosmological parameters and source distributions corresponding to the realistic surveys such as LSST and DES. We briefly outline how photometric redshift information can be incorporated in our results. We also show how topological properties of convergence maps can be quantified using our results.

  5. Gravitational lensing by rotating naked singularities

    SciTech Connect (OSTI)

    Gyulchev, Galin N.; Yazadjiev, Stoytcho S.

    2008-10-15

    We model massive compact objects in galactic nuclei as stationary, axially symmetric naked singularities in the Einstein-massless scalar field theory and study the resulting gravitational lensing. In the weak deflection limit we study analytically the position of the two weak field images, the corresponding signed and absolute magnifications as well as the centroid up to post-Newtonian order. We show that there are static post-Newtonian corrections to the signed magnification and their sum as well as to the critical curves, which are functions of the scalar charge. The shift of the critical curves as a function of the lens angular momentum is found, and it is shown that they decrease slightly for the weakly naked and vastly for the strongly naked singularities with the increase of the scalar charge. The pointlike caustics drift away from the optical axis and do not depend on the scalar charge. In the strong deflection limit approximation, we compute numerically the position of the relativistic images and their separability for weakly naked singularities. All of the lensing quantities are compared to particular cases as Schwarzschild and Kerr black holes as well as Janis-Newman-Winicour naked singularities.

  6. Lossy compression of weak lensing data

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Vanderveld, R. Ali; Bernstein, Gary M.; Stoughton, Chris; Rhodes, Jason; Massey, Richard; Dobke, Benjamin M.

    2011-07-12

    Future orbiting observatories will survey large areas of sky in order to constrain the physics of dark matter and dark energy using weak gravitational lensing and other methods. Lossy compression of the resultant data will improve the cost and feasibility of transmitting the images through the space communication network. We evaluate the consequences of the lossy compression algorithm of Bernstein et al. (2010) for the high-precision measurement of weak-lensing galaxy ellipticities. This square-root algorithm compresses each pixel independently, and the information discarded is by construction less than the Poisson error from photon shot noise. For simulated space-based images (without cosmicmore » rays) digitized to the typical 16 bits per pixel, application of the lossy compression followed by image-wise lossless compression yields images with only 2.4 bits per pixel, a factor of 6.7 compression. We demonstrate that this compression introduces no bias in the sky background. The compression introduces a small amount of additional digitization noise to the images, and we demonstrate a corresponding small increase in ellipticity measurement noise. The ellipticity measurement method is biased by the addition of noise, so the additional digitization noise is expected to induce a multiplicative bias on the galaxies measured ellipticities. After correcting for this known noise-induced bias, we find a residual multiplicative ellipticity bias of m {approx} -4 x 10-4. This bias is small when compared to the many other issues that precision weak lensing surveys must confront, and furthermore we expect it to be reduced further with better calibration of ellipticity measurement methods.« less

  7. Atmospheric Dispersion Effects in Weak Lensing Measurements

    SciTech Connect (OSTI)

    Plazas, Andrés Alejandro; Bernstein, Gary

    2012-10-01

    The wavelength dependence of atmospheric refraction causes elongation of finite-bandwidth images along the elevation vector, which produces spurious signals in weak gravitational lensing shear measurements unless this atmospheric dispersion is calibrated and removed to high precision. Because astrometric solutions and PSF characteristics are typically calibrated from stellar images, differences between the reference stars' spectra and the galaxies' spectra will leave residual errors in both the astrometric positions (dr) and in the second moment (width) of the wavelength-averaged PSF (dv) for galaxies.We estimate the level of dv that will induce spurious weak lensing signals in PSF-corrected galaxy shapes that exceed the statistical errors of the DES and the LSST cosmic-shear experiments. We also estimate the dr signals that will produce unacceptable spurious distortions after stacking of exposures taken at different airmasses and hour angles. We also calculate the errors in the griz bands, and find that dispersion systematics, uncorrected, are up to 6 and 2 times larger in g and r bands,respectively, than the requirements for the DES error budget, but can be safely ignored in i and z bands. For the LSST requirements, the factors are about 30, 10, and 3 in g, r, and i bands,respectively. We find that a simple correction linear in galaxy color is accurate enough to reduce dispersion shear systematics to insignificant levels in the r band for DES and i band for LSST,but still as much as 5 times than the requirements for LSST r-band observations. More complex corrections will likely be able to reduce the systematic cosmic-shear errors below statistical errors for LSST r band. But g-band effects remain large enough that it seems likely that induced systematics will dominate the statistical errors of both surveys, and cosmic-shear measurements should rely on the redder bands.

  8. Atmospheric Dispersion Effects in Weak Lensing Measurements

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Plazas, Andrés Alejandro; Bernstein, Gary

    2012-10-01

    The wavelength dependence of atmospheric refraction causes elongation of finite-bandwidth images along the elevation vector, which produces spurious signals in weak gravitational lensing shear measurements unless this atmospheric dispersion is calibrated and removed to high precision. Because astrometric solutions and PSF characteristics are typically calibrated from stellar images, differences between the reference stars' spectra and the galaxies' spectra will leave residual errors in both the astrometric positions (dr) and in the second moment (width) of the wavelength-averaged PSF (dv) for galaxies.We estimate the level of dv that will induce spurious weak lensing signals in PSF-corrected galaxy shapes that exceed themore » statistical errors of the DES and the LSST cosmic-shear experiments. We also estimate the dr signals that will produce unacceptable spurious distortions after stacking of exposures taken at different airmasses and hour angles. We also calculate the errors in the griz bands, and find that dispersion systematics, uncorrected, are up to 6 and 2 times larger in g and r bands,respectively, than the requirements for the DES error budget, but can be safely ignored in i and z bands. For the LSST requirements, the factors are about 30, 10, and 3 in g, r, and i bands,respectively. We find that a simple correction linear in galaxy color is accurate enough to reduce dispersion shear systematics to insignificant levels in the r band for DES and i band for LSST,but still as much as 5 times than the requirements for LSST r-band observations. More complex corrections will likely be able to reduce the systematic cosmic-shear errors below statistical errors for LSST r band. But g-band effects remain large enough that it seems likely that induced systematics will dominate the statistical errors of both surveys, and cosmic-shear measurements should rely on the redder bands.« less

  9. Magnified Weak Lensing Cross Correlation Tomography

    SciTech Connect (OSTI)

    Ulmer, Melville P., Clowe, Douglas I.

    2010-11-30

    This project carried out a weak lensing tomography (WLT) measurement around rich clusters of galaxies. This project used ground based photometric redshift data combined with HST archived cluster images that provide the WLT and cluster mass modeling. The technique has already produced interesting results (Guennou et al, 2010,Astronomy & Astrophysics Vol 523, page 21, and Clowe et al, 2011 to be submitted). Guennou et al have validated that the necessary accuracy can be achieved with photometric redshifts for our purposes. Clowe et al titled "The DAFT/FADA survey. II. Tomographic weak lensing signal from 10 high redshift clusters," have shown that for the **first time** via this purely geometrical technique, which does not assume a standard rod or candle, that a cosmological constant is **required** for flat cosmologies. The intent of this project is not to produce the best constraint on the value of the dark energy equation of state, w. Rather, this project is to carry out a sustained effort of weak lensing tomography that will naturally feed into the near term Dark Energy Survey (DES) and to provide invaluable mass calibration for that project. These results will greatly advance a key cosmological method which will be applied to the top-rated ground-based project in the Astro2020 decadal survey, LSST. Weak lensing tomography is one of the key science drivers behind LSST. CO-I Clowe is on the weak lensing LSST committee, and senior scientist on this project, at FNAL James Annis, plays a leading role in the DES. This project has built on successful proposals to obtain ground-based imaging for the cluster sample. By 1 Jan, it is anticipated the project will have accumulated complete 5-color photometry on 30 (or about 1/3) of the targeted cluster sample (public webpage for the survey is available at http://cencos.oamp.fr/DAFT/ and has a current summary of the observational status of various clusters). In all, the project has now been awarded the equivalent of over 60 nights on 4-m class telescopes, which gives concrete evidence of strong community support for this project. The WLT technique is based on the dependence of the gravitational shear signal on the angular diameter distances between the observer, the lens, and the lensed galaxy to measure cosmological parameters. By taking the ratio of measured shears of galaxies with different redshifts around the same lens, one obtains a measurement of the ratios of the angular diameter distances involved. Making these observations over a large range of lenses and background galaxy redshifts will measure the history of the expansion rate of the universe. Because this is a purely geometric measurement, it is insensitive to any form of evolution of objects or the necessity to understand the physics in the early universe. Thus, WLT was identified by the Dark Energy Task Force as perhaps the best method to measure the evolution of DE. To date, however, the conjecture of the DETF has not been experimentally verified, but will be by the proposed project. The primary reason for the lack of tomography measurements is that one must have an exceptional data-set to attempt the measurement. One needs both extremely good seeing (or space observations) in order to minimize the point spread function smearing corrections on weak lensing shear measurements and deep, multi-color data, from B to z, to measure reliable photometric redshifts of the background galaxies being lensed (which are typically too faint to obtain spectroscopic redshifts). Because the entire process from multi-drizzling the HST images, and then creating shear maps, to gathering the necessary ground based observations, to generating photo-zs and then carrying out the tomography is a complicated task, until the creation of our team, nobody has taken the time to connect all the levels of expertise necessary to carry out this project based on HST archival data. Our data are being used in 2 Ph.D. theses. Kellen Murphy, at Ohio University, is using the tomography data along with simulations in a thesis expected to be completed in Jun

  10. Predicting weak lensing statistics from halo mass reconstructions - Final Paper

    SciTech Connect (OSTI)

    Everett, Spencer

    2015-08-20

    As dark matter does not absorb or emit light, its distribution in the universe must be inferred through indirect effects such as the gravitational lensing of distant galaxies. While most sources are only weakly lensed, the systematic alignment of background galaxies around a foreground lens can constrain the mass of the lens which is largely in the form of dark matter. In this paper, I have implemented a framework to reconstruct all of the mass along lines of sight using a best-case dark matter halo model in which the halo mass is known. This framework is then used to make predictions of the weak lensing of 3,240 generated source galaxies through a 324 arcmin field of the Millennium Simulation. The lensed source ellipticities are characterized by the ellipticity-ellipticity and galaxy-mass correlation functions and compared to the same statistic for the intrinsic and ray-traced ellipticities. In the ellipticity-ellipticity correlation function, I and that the framework systematically under predicts the shear power by an average factor of 2.2 and fails to capture correlation from dark matter structure at scales larger than 1 arcminute. The model predicted galaxy-mass correlation function is in agreement with the ray-traced statistic from scales 0.2 to 0.7 arcminutes, but systematically underpredicts shear power at scales larger than 0.7 arcminutes by an average factor of 1.2. Optimization of the framework code has reduced the mean CPU time per lensing prediction by 70% to 24 5 ms. Physical and computational shortcomings of the framework are discussed, as well as potential improvements for upcoming work.

  11. Time delay and magnification centroid due to gravitational lensing by black holes and naked singularities

    SciTech Connect (OSTI)

    Virbhadra, K. S.; Keeton, C. R.

    2008-06-15

    We model the massive dark object at the center of the Galaxy as a Schwarzschild black hole as well as Janis-Newman-Winicour naked singularities, characterized by the mass and scalar charge parameters, and study gravitational lensing (particularly time delay, magnification centroid, and total magnification) by them. We find that the lensing features are qualitatively similar (though quantitatively different) for Schwarzschild black holes, weakly naked, and marginally strongly naked singularities. However, the lensing characteristics of strongly naked singularities are qualitatively very different from those due to Schwarzschild black holes. The images produced by Schwarzschild black hole lenses and weakly naked and marginally strongly naked singularity lenses always have positive time delays. On the other hand, strongly naked singularity lenses can give rise to images with positive, zero, or negative time delays. In particular, for a large angular source position the direct image (the outermost image on the same side as the source) due to strongly naked singularity lensing always has a negative time delay. We also found that the scalar field decreases the time delay and increases the total magnification of images; this result could have important implications for cosmology. As the Janis-Newman-Winicour metric also describes the exterior gravitational field of a scalar star, naked singularities as well as scalar star lenses, if these exist in nature, will serve as more efficient cosmic telescopes than regular gravitational lenses.

  12. Three gravitationally lensed supernovae behind clash galaxy clusters

    Office of Scientific and Technical Information (OSTI)

    (Journal Article) | SciTech Connect Three gravitationally lensed supernovae behind clash galaxy clusters Citation Details In-Document Search Title: Three gravitationally lensed supernovae behind clash galaxy clusters We report observations of three gravitationally lensed supernovae (SNe) in the Cluster Lensing And Supernova survey with Hubble (CLASH) Multi-Cycle Treasury program. These objects, SN CLO12Car (z = 1.28), SN CLN12Did (z = 0.85), and SN CLA11Tib (z = 1.14), are located behind

  13. Origins of weak lensing systematics, and requirements on future...

    Office of Scientific and Technical Information (OSTI)

    Journal Article: Origins of weak lensing systematics, and requirements on future instrumentation (or knowledge of instrumentation) Citation Details In-Document Search Title:...

  14. What is Gravitational Lensing? (LBNL Summer Lecture Series)

    ScienceCinema (OSTI)

    Leauthaud, Alexie; Nakajima, Reiko [Berkeley Center for Cosmological Physics

    2011-04-28

    Summer Lecture Series 2009: Gravitational lensing is explained by Einstein's general theory of relativity: galaxies and clusters of galaxies, which are very massive objects, act on spacetime by causing it to become curved. Alexie Leauthaud and Reiko Nakajima, astrophysicists with the Berkeley Center for Cosmological Physics, will discuss how scientists use gravitational lensing to investigate the nature of dark energy and dark matter in the universe.

  15. What is Gravitational Lensing? (LBNL Summer Lecture Series)

    SciTech Connect (OSTI)

    Leauthaud, Alexie; Nakajima, Reiko

    2009-07-28

    Summer Lecture Series 2009: Gravitational lensing is explained by Einstein's general theory of relativity: galaxies and clusters of galaxies, which are very massive objects, act on spacetime by causing it to become curved. Alexie Leauthaud and Reiko Nakajima, astrophysicists with the Berkeley Center for Cosmological Physics, will discuss how scientists use gravitational lensing to investigate the nature of dark energy and dark matter in the universe.

  16. What is Gravitational Lensing?(LBNL Summer Lecture Series)

    ScienceCinema (OSTI)

    Alexie, Leauthaud; Reiko, Nakajima [Berkeley Center for Cosmological Physics, Berkely, California, United States

    2010-01-08

    July 28, 2009 Berkeley Lab summer lecture: Gravitational lensing is explained by Einstein's general theory of relativity: galaxies and clusters of galaxies, which are very massive objects, act on spacetime by causing it to become curved. Alexie Leauthaud and Reiko Nakajima, astrophysicists with the Berkeley Center for Cosmological Physics, will discuss how scientists use gravitational lensing to investigate the nature of dark energy and dark matter in the universe.

  17. Combining weak-lensing tomography and spectroscopic redshift surveys

    SciTech Connect (OSTI)

    Cai, Yan -Chuan; Bernstein, Gary

    2012-05-11

    Redshift space distortion (RSD) is a powerful way of measuring the growth of structure and testing General Relativity, but it is limited by cosmic variance and the degeneracy between galaxy bias b and the growth rate factor f. The cross-correlation of lensing shear with the galaxy density field can in principle measure b in a manner free from cosmic variance limits, breaking the f-b degeneracy and allowing inference of the matter power spectrum from the galaxy survey. We analyze the growth constraints from a realistic tomographic weak lensing photo-z survey combined with a spectroscopic galaxy redshift survey over the same sky area. For sky coverage fsky = 0.5, analysis of the transverse modes measures b to 2-3% accuracy per Δz = 0.1 bin at z < 1 when ~10 galaxies arcmin–2 are measured in the lensing survey and all halos with M > Mmin = 1013h–1M have spectra. For the gravitational growth parameter parameter γ (f = Ωγm), combining the lensing information with RSD analysis of non-transverse modes yields accuracy σ(γ) ≈ 0.01. Adding lensing information to the RSD survey improves \\sigma(\\gamma) by an amount equivalent to a 3x (10x) increase in RSD survey area when the spectroscopic survey extends down to halo mass 1013.5 (1014) h–1 M. We also find that the σ(γ) of overlapping surveys is equivalent to that of surveys 1.5-2 times larger if they are separated on the sky. This gain is greatest when the spectroscopic mass threshold is 1013 -1014 h–1 M, similar to LRG surveys. The gain of overlapping surveys is reduced for very deep or very shallow spectroscopic surveys, but any practical surveys are more powerful when overlapped than when separated. As a result, the gain of overlapped surveys is larger in the case when the primordial power spectrum normalization is uncertain by > 0.5%.

  18. Combining weak-lensing tomography and spectroscopic redshift surveys

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Cai, Yan -Chuan; Bernstein, Gary

    2012-05-11

    Redshift space distortion (RSD) is a powerful way of measuring the growth of structure and testing General Relativity, but it is limited by cosmic variance and the degeneracy between galaxy bias b and the growth rate factor f. The cross-correlation of lensing shear with the galaxy density field can in principle measure b in a manner free from cosmic variance limits, breaking the f-b degeneracy and allowing inference of the matter power spectrum from the galaxy survey. We analyze the growth constraints from a realistic tomographic weak lensing photo-z survey combined with a spectroscopic galaxy redshift survey over the samemore » sky area. For sky coverage fsky = 0.5, analysis of the transverse modes measures b to 2-3% accuracy per Δz = 0.1 bin at z < 1 when ~10 galaxies arcmin–2 are measured in the lensing survey and all halos with M > Mmin = 1013h–1M⊙ have spectra. For the gravitational growth parameter parameter γ (f = Ωγm), combining the lensing information with RSD analysis of non-transverse modes yields accuracy σ(γ) ≈ 0.01. Adding lensing information to the RSD survey improves \\sigma(\\gamma) by an amount equivalent to a 3x (10x) increase in RSD survey area when the spectroscopic survey extends down to halo mass 1013.5 (1014) h–1 M⊙. We also find that the σ(γ) of overlapping surveys is equivalent to that of surveys 1.5-2 times larger if they are separated on the sky. This gain is greatest when the spectroscopic mass threshold is 1013 -1014 h–1 M⊙, similar to LRG surveys. The gain of overlapping surveys is reduced for very deep or very shallow spectroscopic surveys, but any practical surveys are more powerful when overlapped than when separated. As a result, the gain of overlapped surveys is larger in the case when the primordial power spectrum normalization is uncertain by > 0.5%.« less

  19. Lossy compression of weak lensing data (Journal Article) | SciTech...

    Office of Scientific and Technical Information (OSTI)

    Lossy compression of weak lensing data Citation Details In-Document Search Title: Lossy compression of weak lensing data You are accessing a document from the Department of...

  20. Lossy compression of weak lensing data (Journal Article) | SciTech...

    Office of Scientific and Technical Information (OSTI)

    Journal Article: Lossy compression of weak lensing data Citation Details In-Document Search Title: Lossy compression of weak lensing data Future orbiting observatories will survey...

  1. Cross-correlation of gravitational lensing from DES Science Verification data with SPT and Planck lensing

    SciTech Connect (OSTI)

    Kirk, D.; et al.

    2015-12-14

    We measure the cross-correlation between weak lensing of galaxy images and of the cosmic microwave background (CMB). The effects of gravitational lensing on different sources will be correlated if the lensing is caused by the same mass fluctuations. We use galaxy shape measurements from 139 deg$^{2}$ of the Dark Energy Survey (DES) Science Verification data and overlapping CMB lensing from the South Pole Telescope (SPT) and Planck. The DES source galaxies have a median redshift of $z_{\\rm med} {\\sim} 0.7$, while the CMB lensing kernel is broad and peaks at $z{\\sim}2$. The resulting cross-correlation is maximally sensitive to mass fluctuations at $z{\\sim}0.44$. Assuming the Planck 2015 best-fit cosmology, the amplitude of the DES$\\times$SPT cross-power is found to be $A = 0.88 \\pm 0.30$ and that from DES$\\times$Planck to be $A = 0.86 \\pm 0.39$, where $A=1$ corresponds to the theoretical prediction. These are consistent with the expected signal and correspond to significances of $2.9 \\sigma$ and $2.2 \\sigma$ respectively. We demonstrate that our results are robust to a number of important systematic effects including the shear measurement method, estimator choice, photometric redshift uncertainty and CMB lensing systematics. Significant intrinsic alignment of galaxy shapes would increase the cross-correlation signal inferred from the data; we calculate a value of $A = 1.08 \\pm 0.36$ for DES$\\times$SPT when we correct the observations with a simple IA model. With three measurements of this cross-correlation now existing in the literature, there is not yet reliable evidence for any deviation from the expected LCDM level of cross-correlation, given the size of the statistical uncertainties and the significant impact of systematic errors, particularly IAs. We provide forecasts for the expected signal-to-noise of the combination of the five-year DES survey and SPT-3G.

  2. Sample variance in weak lensing: How many simulations are required?

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Petri, Andrea; May, Morgan; Haiman, Zoltan

    2016-03-24

    Constraining cosmology using weak gravitational lensing consists of comparing a measured feature vector of dimension Nb with its simulated counterpart. An accurate estimate of the Nb × Nb feature covariance matrix C is essential to obtain accurate parameter confidence intervals. When C is measured from a set of simulations, an important question is how large this set should be. To answer this question, we construct different ensembles of Nr realizations of the shear field, using a common randomization procedure that recycles the outputs from a smaller number Ns ≤ Nr of independent ray-tracing N-body simulations. We study parameter confidence intervalsmore » as a function of (Ns, Nr) in the range 1 ≤ Ns ≤ 200 and 1 ≤ Nr ≲ 105. Previous work [S. Dodelson and M. D. Schneider, Phys. Rev. D 88, 063537 (2013)] has shown that Gaussian noise in the feature vectors (from which the covariance is estimated) lead, at quadratic order, to an O(1/Nr) degradation of the parameter confidence intervals. Using a variety of lensing features measured in our simulations, including shear-shear power spectra and peak counts, we show that cubic and quartic covariance fluctuations lead to additional O(1/N2r) error degradation that is not negligible when Nr is only a factor of few larger than Nb. We study the large Nr limit, and find that a single, 240 Mpc/h sized 5123-particle N-body simulation (Ns = 1) can be repeatedly recycled to produce as many as Nr = few × 104 shear maps whose power spectra and high-significance peak counts can be treated as statistically independent. Lastly, a small number of simulations (Ns = 1 or 2) is sufficient to forecast parameter confidence intervals at percent accuracy.« less

  3. Origins of weak lensing systematics, and requirements on future instrumentation (or knowledge of instrumentation)

    SciTech Connect (OSTI)

    Massey, Richard; Hoekstra, Henk; Kitching, Thomas; Rhodes, Jason; Cropper, Mark; Amiaux, Jerome; Harvey, David; Mellier, Yannick; Meneghetti, Massimo; Miller, Lance; Paulin-Henriksson, Stephane; Pires, Sandrine; Scaramella, Roberto; Schrabback, Tim

    2012-12-13

    The first half of this paper explores the origin of systematic biases in the measurement of weak gravitational lensing. Compared to previous work, we expand the investigation of point spread function instability and fold in for the first time the effects of non-idealities in electronic imaging detectors and imperfect galaxy shape measurement algorithms. In addition, these now explain the additive A(?) and multiplicative M(?) systematics typically reported in current lensing measurements. We find that overall performance is driven by a product of a telescope/camera's absolute performance, and our knowledge about its performance.

  4. Gravitational lenses in generalized Einstein-aether theory: The bullet cluster

    SciTech Connect (OSTI)

    Dai, D.-C.; Matsuo, Reijiro; Starkman, Glenn

    2008-11-15

    We study the lensing properties of an asymmetric mass distribution and vector field in generalized Einstein-aether (GEA) theory. As vector-field fluctuations are responsible in GEA for seeding baryonic structure formation, vector-field concentrations can exist independently of baryonic matter. Such concentrations would not be expected to be tied to baryonic matter except gravitationally, and so, like dark matter halos, would become separated from baryonic matter in interacting systems such as the bullet cluster. These vector-field concentrations cause metric deviations that affect weak lensing. Therefore, the distribution of weak lensing deviates from that which would be inferred from the luminous mass distribution, in a way that numerical calculations demonstrate can be consistent with observations. This suggests that MOND-inspired theories can reproduce weak lensing observations, but makes clear the price: the existence of a coherent large-scale fluctuation of a field(s) weakly tied to the baryonic matter, not completely dissimilar to a dark matter halo.

  5. Catastrophic photometric redshift errors: Weak-lensing survey requirements

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Bernstein, Gary; Huterer, Dragan

    2010-01-11

    We study the sensitivity of weak lensing surveys to the effects of catastrophic redshift errors - cases where the true redshift is misestimated by a significant amount. To compute the biases in cosmological parameters, we adopt an efficient linearized analysis where the redshift errors are directly related to shifts in the weak lensing convergence power spectra. We estimate the number Nspec of unbiased spectroscopic redshifts needed to determine the catastrophic error rate well enough that biases in cosmological parameters are below statistical errors of weak lensing tomography. While the straightforward estimate of Nspec is ~106 we find that using onlymore » the photometric redshifts with z ≤ 2.5 leads to a drastic reduction in Nspec to ~ 30,000 while negligibly increasing statistical errors in dark energy parameters. Therefore, the size of spectroscopic survey needed to control catastrophic errors is similar to that previously deemed necessary to constrain the core of the zs – zp distribution. We also study the efficacy of the recent proposal to measure redshift errors by cross-correlation between the photo-z and spectroscopic samples. We find that this method requires ~ 10% a priori knowledge of the bias and stochasticity of the outlier population, and is also easily confounded by lensing magnification bias. In conclusion, the cross-correlation method is therefore unlikely to supplant the need for a complete spectroscopic redshift survey of the source population.« less

  6. Higher-order gravitational lensing reconstruction using Feynman diagrams

    SciTech Connect (OSTI)

    Jenkins, Elizabeth E.; Manohar, Aneesh V.; Yadav, Amit P.S.; Waalewijn, Wouter J. E-mail: amanohar@ucsd.edu E-mail: ayadav@physics.ucsd.edu

    2014-09-01

    We develop a method for calculating the correlation structure of the Cosmic Microwave Background (CMB) using Feynman diagrams, when the CMB has been modified by gravitational lensing, Faraday rotation, patchy reionization, or other distorting effects. This method is used to calculate the bias of the Hu-Okamoto quadratic estimator in reconstructing the lensing power spectrum up to O(?{sup 4}) in the lensing potential ?. We consider both the diagonal noise TT TT, EB EB, etc. and, for the first time, the off-diagonal noise TT TE, TB EB, etc. The previously noted large O(?{sup 4}) term in the second order noise is identified to come from a particular class of diagrams. It can be significantly reduced by a reorganization of the ? expansion. These improved estimators have almost no bias for the off-diagonal case involving only one B component of the CMB, such as EE EB.

  7. Strong gravitational lensing with Gauss-Bonnet correction

    SciTech Connect (OSTI)

    Sadeghi, J.; Vaez, H. E-mail: h.vaez@umz.ac.ir

    2014-06-01

    In this paper we investigate the strong gravitational lensing in a five dimensional background with Gauss-Bonnet gravity, so that in 4-dimensions the Gauss-Bonnet correction disappears. By considering the logarithmic term for deflection angle, we obtain the deflection angle ?-circumflex and corresponding parameters ? and b-bar . Finally, we estimate some properties of relativistic images such as ?{sub ?}, s and r{sub m}.

  8. The DES Science Verification Weak Lensing Shear Catalogs

    SciTech Connect (OSTI)

    Jarvis, M.

    2015-07-20

    We present weak lensing shear catalogs for 139 square degrees of data taken during the Science Verification (SV) time for the new Dark Energy Camera (DECam) being used for the Dark Energy Survey (DES). We describe our object selection, point spread function estimation and shear measurement procedures using two independent shear pipelines, IM3SHAPE and NGMIX, which produce catalogs of 2.12 million and 3.44 million galaxies respectively. We also detail a set of null tests for the shear measurements and find that they pass the requirements for systematic errors at the level necessary for weak lensing science applications using the SV data. Furthermore, we discuss some of the planned algorithmic improvements that will be necessary to produce sufficiently accurate shear catalogs for the full 5-year DES, which is expected to cover 5000 square degrees.

  9. Optimizing weak lensing mass estimates for cluster profile uncertainty

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Gruen, D.; Bernstein, G. M.; Lam, T. Y.; Seitz, S.

    2011-09-11

    Weak lensing measurements of cluster masses are necessary for calibrating mass-observable relations (MORs) to investigate the growth of structure and the properties of dark energy. However, the measured cluster shear signal varies at fixed mass M200m due to inherent ellipticity of background galaxies, intervening structures along the line of sight, and variations in the cluster structure due to scatter in concentrations, asphericity and substructure. We use N-body simulated halos to derive and evaluate a weak lensing circular aperture mass measurement Map that minimizes the mass estimate variance <(Map - M200m)2> in the presence of all these forms of variability. Dependingmore » on halo mass and observational conditions, the resulting mass estimator improves on Map filters optimized for circular NFW-profile clusters in the presence of uncorrelated large scale structure (LSS) about as much as the latter improve on an estimator that only minimizes the influence of shape noise. Optimizing for uncorrelated LSS while ignoring the variation of internal cluster structure puts too much weight on the profile near the cores of halos, and under some circumstances can even be worse than not accounting for LSS at all. As a result, we discuss the impact of variability in cluster structure and correlated structures on the design and performance of weak lensing surveys intended to calibrate cluster MORs.« less

  10. Weak lensing by galaxy troughs in DES Science Verification data

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Gruen, D.; Friedrich, O.; Amara, A.; Bacon, D.; Bonnett, C.; Hartley, W.; Jain, B.; M. Jarvis; Kavprzak, T.; Krause, E.; et al

    2015-11-29

    In this study, we measure the weak lensing shear around galaxy troughs, i.e. the radial alignment of background galaxies relative to underdensities in projections of the foreground galaxy field over a wide range of redshift in Science Verification data from the Dark Energy Survey. Our detection of the shear signal is highly significant (10σ–15σ for the smallest angular scales) for troughs with the redshift range z ϵ [0.2, 0.5] of the projected galaxy field and angular diameters of 10 arcmin…1°. These measurements probe the connection between the galaxy, matter density, and convergence fields. By assuming galaxies are biased tracers ofmore » the matter density with Poissonian noise, we find agreement of our measurements with predictions in a fiducial Λ cold dark matter model. The prediction for the lensing signal on large trough scales is virtually independent of the details of the underlying model for the connection of galaxies and matter. Our comparison of the shear around troughs with that around cylinders with large galaxy counts is consistent with a symmetry between galaxy and matter over- and underdensities. In addition, we measure the two-point angular correlation of troughs with galaxies which, in contrast to the lensing signal, is sensitive to galaxy bias on all scales. The lensing signal of troughs and their clustering with galaxies is therefore a promising probe of the statistical properties of matter underdensities and their connection to the galaxy field.« less

  11. Weak Lensing by Galaxy Troughs in DES Science Verification Data

    SciTech Connect (OSTI)

    Gruen, D.

    2015-09-29

    We measure the weak lensing shear around galaxy troughs, i.e. the radial alignment of background galaxies relative to underdensities in projections of the foreground galaxy field over a wide range of redshift in Science Verification data from the Dark Energy Survey. Our detection of the shear signal is highly significant (10?15? for the smallest angular scales) for troughs with the redshift range z ? [0.2, 0.5] of the projected galaxy field and angular diameters of 10 arcmin1. These measurements probe the connection between the galaxy, matter density, and convergence fields. By assuming galaxies are biased tracers of the matter density with Poissonian noise, we find agreement of our measurements with predictions in a fiducial ? cold dark matter model. Furthermore, the prediction for the lensing signal on large trough scales is virtually independent of the details of the underlying model for the connection of galaxies and matter. Our comparison of the shear around troughs with that around cylinders with large galaxy counts is consistent with a symmetry between galaxy and matter over- and underdensities. In addition, we measure the two-point angular correlation of troughs with galaxies which, in contrast to the lensing signal, is sensitive to galaxy bias on all scales. Finally, the lensing signal of troughs and their clustering with galaxies is therefore a promising probe of the statistical properties of matter underdensities and their connection to the galaxy field.

  12. SPITZER IMAGING OF HERSCHEL-ATLAS GRAVITATIONALLY LENSED SUBMILLIMETER SOURCES

    SciTech Connect (OSTI)

    Hopwood, R.; Negrello, M.; Wardlow, J.; Cooray, A.; Khostovan, A. A.; Kim, S.; Barton, E.; Da Cunha, E.; Cooke, J.; Burgarella, D.; Aretxaga, I.; Auld, R.; Baes, M.; Bertoldi, F.; Bonfield, D. G.; Blundell, R.; Buttiglione, S.; Cava, A.; Dannerbauer, H.

    2011-02-10

    We present physical properties of two submillimeter selected gravitationally lensed sources, identified in the Herschel Astrophysical Terahertz Large Area Survey. These submillimeter galaxies (SMGs) have flux densities >100 mJy at 500 {mu}m, but are not visible in existing optical imaging. We fit light profiles to each component of the lensing systems in Spitzer IRAC 3.6 and 4.5 {mu}m data and successfully disentangle the foreground lens from the background source in each case, providing important constraints on the spectral energy distributions (SEDs) of the background SMG at rest-frame optical-near-infrared wavelengths. The SED fits show that these two SMGs have high dust obscuration with A{sub V} {approx} 4-5 and star formation rates of {approx}100 M{sub sun} yr{sup -1}. They have low gas fractions and low dynamical masses compared with 850 {mu}m selected galaxies.

  13. Gravitational lens equation for embedded lenses; magnification and ellipticity

    SciTech Connect (OSTI)

    Chen, B.; Kantowski, R.; Dai, X.

    2011-10-15

    We give the lens equation for light deflections caused by point mass condensations in an otherwise spatially homogeneous and flat universe. We assume the signal from a distant source is deflected by a single condensation before it reaches the observer. We call this deflector an embedded lens because the deflecting mass is part of the mean density. The embedded lens equation differs from the conventional lens equation because the deflector mass is not simply an addition to the cosmic mean. We prescribe an iteration scheme to solve this new lens equation and use it to compare our results with standard linear lensing theory. We also compute analytic expressions for the lowest order corrections to image amplifications and distortions caused by incorporating the lensing mass into the mean. We use these results to estimate the effect of embedding on strong lensing magnifications and ellipticities and find only small effects, <1%, contrary to what we have found for time delays and for weak lensing, {approx}5%.

  14. Statistical and systematic errors in the measurement of weak-lensing Minkowski functionals: Application to the Canada-France-Hawaii Lensing Survey

    SciTech Connect (OSTI)

    Shirasaki, Masato; Yoshida, Naoki

    2014-05-01

    The measurement of cosmic shear using weak gravitational lensing is a challenging task that involves a number of complicated procedures. We study in detail the systematic errors in the measurement of weak-lensing Minkowski Functionals (MFs). Specifically, we focus on systematics associated with galaxy shape measurements, photometric redshift errors, and shear calibration correction. We first generate mock weak-lensing catalogs that directly incorporate the actual observational characteristics of the Canada-France-Hawaii Lensing Survey (CFHTLenS). We then perform a Fisher analysis using the large set of mock catalogs for various cosmological models. We find that the statistical error associated with the observational effects degrades the cosmological parameter constraints by a factor of a few. The Subaru Hyper Suprime-Cam (HSC) survey with a sky coverage of ?1400 deg{sup 2} will constrain the dark energy equation of the state parameter with an error of ?w {sub 0} ? 0.25 by the lensing MFs alone, but biases induced by the systematics can be comparable to the 1? error. We conclude that the lensing MFs are powerful statistics beyond the two-point statistics only if well-calibrated measurement of both the redshifts and the shapes of source galaxies is performed. Finally, we analyze the CFHTLenS data to explore the ability of the MFs to break degeneracies between a few cosmological parameters. Using a combined analysis of the MFs and the shear correlation function, we derive the matter density ?{sub m0}=0.256{sub 0.046}{sup 0.054}.

  15. Impact of magnification and size bias on the weak lensing power...

    Office of Scientific and Technical Information (OSTI)

    and peak statistics Citation Details In-Document Search Title: Impact of magnification and size bias on the weak lensing power spectrum and peak statistics Authors: Liu J. ...

  16. UP TO 100,000 RELIABLE STRONG GRAVITATIONAL LENSES IN FUTURE DARK ENERGY EXPERIMENTS

    SciTech Connect (OSTI)

    Serjeant, S.

    2014-09-20

    The Euclid space telescope will observe ?10{sup 5} strong galaxy-galaxy gravitational lens events in its wide field imaging survey over around half the sky, but identifying the gravitational lenses from their observed morphologies requires solving the difficult problem of reliably separating the lensed sources from contaminant populations, such as tidal tails, as well as presenting challenges for spectroscopic follow-up redshift campaigns. Here I present alternative selection techniques for strong gravitational lenses in both Euclid and the Square Kilometre Array, exploiting the strong magnification bias present in the steep end of the H? luminosity function and the H I mass function. Around 10{sup 3} strong lensing events are detectable with this method in the Euclid wide survey. While only ?1% of the total haul of Euclid lenses, this sample has ?100% reliability, known source redshifts, high signal-to-noise, and a magnification-based selection independent of assumptions of lens morphology. With the proposed Square Kilometre Array dark energy survey, the numbers of reliable strong gravitational lenses with source redshifts can reach 10{sup 5}.

  17. The Impact of Camera Optical Alignments on Weak Lensing Measures for the

    Office of Scientific and Technical Information (OSTI)

    Dark Energy Survey (Journal Article) | SciTech Connect The Impact of Camera Optical Alignments on Weak Lensing Measures for the Dark Energy Survey Citation Details In-Document Search Title: The Impact of Camera Optical Alignments on Weak Lensing Measures for the Dark Energy Survey Authors: Antonik, Michelle L. ; /University Coll. London ; Bacon, David J. ; /Portsmouth U. ; Bridle, Sarah ; /University Coll. London ; Doel, Peter ; /University Coll. London ; Brooks, David ; /University Coll.

  18. Constraining the neutrino emission of gravitationally lensed Flat-Spectrum Radio Quasars with ANTARES data

    SciTech Connect (OSTI)

    Adrin-Martnez, S.; Ardid, M.; Bou-Cabo, M. [Institut d'Investigaci per a la Gesti Integrada de les Zones Costaneres (IGIC), Universitat Politcnica de Valncia, C/ Paranimf 1, Gandia, 46730 Spain (Spain); Albert, A. [GRPHE - Institut universitaire de technologie de Colmar, 34 rue du Grillenbreit BP 50568, Colmar, 68008 France (France); Andr, M. [Technical University of Catalonia, Laboratory of Applied Bioacoustics, Rambla Exposici, Vilanova i la Geltr, Barcelona, 08800 Spain (Spain); Anton, G. [Friedrich-Alexander-Universitt Erlangen-Nrnberg, Erlangen Centre for Astroparticle Physics, Erwin-Rommel-Str. 1, Erlangen, 91058 Germany (Germany); Aubert, J.-J.; Bertin, V.; Brunner, J.; Busto, J. [Aix Marseille Universit, CNRS/IN2P3, CPPM UMR 7346, Marseille, 13288 France (France); Baret, B. [APC, AstroParticule et Cosmologie, Universit Paris Diderot, CNRS/IN2P3, CEA/Irfu, Observatoire de Paris, Sorbonne Paris Cit, 10, rue Alice Domon et Lonie Duquet, Paris Cedex 13, F-75205 France (France); Barrios-Mart, J. [IFIC - Instituto de Fsica Corpuscular, Edificios Investigacin de Paterna, CSIC - Universitat de Valncia, Apdo de Correos 22085, Valencia, 46071 Spain (Spain); Basa, S. [LAM - Laboratoire d'Astrophysique de Marseille, Ple de l'toile Site de Chteau-Gombert, rue Frdric Joliot-Curie 38, Marseille Cedex 13, 13388 France (France); Biagi, S. [INFN - Sezione di Bologna, Viale Berti-Pichat 6/2, Bologna, 40127 Italy (Italy); Bogazzi, C.; Bormuth, R.; Bouwhuis, M.C.; Bruijn, R. [Nikhef, Science Park 105, Amsterdam, 1098XG The Netherlands (Netherlands); Capone, A. [INFN -Sezione di Roma, P.le Aldo Moro 2, Roma, 00185 Italy (Italy); Caramete, L., E-mail: antares.spokesperson@in2p3.fr [Institute for Space Sciences, Bucharest, M?gurele, R-77125 Romania (Romania); and others

    2014-11-01

    This paper proposes to exploit gravitational lensing effects to improve the sensitivity of neutrino telescopes to the intrinsic neutrino emission of distant blazar populations. This strategy is illustrated with a search for cosmic neutrinos in the direction of four distant and gravitationally lensed Flat-Spectrum Radio Quasars. The magnification factor is estimated for each system assuming a singular isothermal profile for the lens. Based on data collected from 2007 to 2012 by the ANTARES neutrino telescope, the strongest constraint is obtained from the lensed quasar B0218+357, providing a limit on the total neutrino luminosity of this source of 1.08נ10{sup 46}ergs{sup -1}. This limit is about one order of magnitude lower than those previously obtained in the ANTARES standard point source searches with non-lensed Flat-Spectrum Radio Quasars.

  19. COMPARING DENSE GALAXY CLUSTER REDSHIFT SURVEYS WITH WEAK-LENSING MAPS

    SciTech Connect (OSTI)

    Hwang, Ho Seong; Geller, Margaret J.; Zahid, H. Jabran; Diaferio, Antonaldo; Rines, Kenneth J. E-mail: mgeller@cfa.harvard.edu E-mail: diaferio@ph.unito.it

    2014-12-20

    We use dense redshift surveys of nine galaxy clusters at z ∼ 0.2 to compare the galaxy distribution in each system with the projected matter distribution from weak lensing. By combining 2087 new MMT/Hectospec redshifts and the data in the literature, we construct spectroscopic samples within the region of weak-lensing maps of high (70%-89%) and uniform completeness. With these dense redshift surveys, we construct galaxy number density maps using several galaxy subsamples. The shape of the main cluster concentration in the weak-lensing maps is similar to the global morphology of the number density maps based on cluster members alone, mainly dominated by red members. We cross-correlate the galaxy number density maps with the weak-lensing maps. The cross-correlation signal when we include foreground and background galaxies at 0.5z {sub cl} < z < 2z {sub cl} is 10%-23% larger than for cluster members alone at the cluster virial radius. The excess can be as high as 30% depending on the cluster. Cross-correlating the galaxy number density and weak-lensing maps suggests that superimposed structures close to the cluster in redshift space contribute more significantly to the excess cross-correlation signal than unrelated large-scale structure along the line of sight. Interestingly, the weak-lensing mass profiles are not well constrained for the clusters with the largest cross-correlation signal excesses (>20% for A383, A689, and A750). The fractional excess in the cross-correlation signal including foreground and background structures could be a useful proxy for assessing the reliability of weak-lensing cluster mass estimates.

  20. CLASH: Weak-lensing shear-and-magnification analysis of 20 galaxy clusters

    SciTech Connect (OSTI)

    Umetsu, Keiichi; Czakon, Nicole [Institute of Astronomy and Astrophysics, Academia Sinica, P.O. Box 23-141, Taipei 10617, Taiwan (China); Medezinski, Elinor; Lemze, Doron; Ford, Holland [Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States); Nonino, Mario; Balestra, Italo; Biviano, Andrea [INAF-Osservatorio Astronomico di Trieste, via G.B. Tiepolo 11, I-34143 Trieste (Italy); Merten, Julian [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Postman, Marc; Koekemoer, Anton [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21208 (United States); Meneghetti, Massimo [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Donahue, Megan [Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States); Molino, Alberto; Bentez, Narciso [Instituto de Astrofsica de Andaluca (CSIC), E-18008 Granada (Spain); Seitz, Stella; Gruen, Daniel [Universitts-Sternwarte, Mnchen, Scheinerstrasse 1, D-81679 Munich Germany (Germany); Broadhurst, Tom [Ikerbasque, Basque Foundation for Science, Alameda Urquijo, 36-5 Plaza Bizkaia, E-48011 Bilbao (Spain); Grillo, Claudio [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark); Melchior, Peter, E-mail: keiichi@asiaa.sinica.edu.tw [Center for Cosmology and Astro-Particle Physics and Department of Physics, The Ohio State University, Columbus, OH 43210 (United States); and others

    2014-11-10

    We present a joint shear-and-magnification weak-lensing analysis of a sample of 16 X-ray-regular and 4 high-magnification galaxy clusters at 0.19 ? z ? 0.69 selected from the Cluster Lensing And Supernova survey with Hubble (CLASH). Our analysis uses wide-field multi-color imaging, taken primarily with Suprime-Cam on the Subaru Telescope. From a stacked-shear-only analysis of the X-ray-selected subsample, we detect the ensemble-averaged lensing signal with a total signal-to-noise ratio of ? 25 in the radial range of 200-3500 kpc h {sup 1}, providing integrated constraints on the halo profile shape and concentration-mass relation. The stacked tangential-shear signal is well described by a family of standard density profiles predicted for dark-matter-dominated halos in gravitational equilibrium, namely, the Navarro-Frenk-White (NFW), truncated variants of NFW, and Einasto models. For the NFW model, we measure a mean concentration of c{sub 200c}=4.01{sub ?0.32}{sup +0.35} at an effective halo mass of M{sub 200c}=1.34{sub ?0.09}{sup +0.10}10{sup 15} M{sub ?}. We show that this is in excellent agreement with ? cold dark matter (?CDM) predictions when the CLASH X-ray selection function and projection effects are taken into account. The best-fit Einasto shape parameter is ?{sub E}=0.191{sub ?0.068}{sup +0.071}, which is consistent with the NFW-equivalent Einasto parameter of ?0.18. We reconstruct projected mass density profiles of all CLASH clusters from a joint likelihood analysis of shear-and-magnification data and measure cluster masses at several characteristic radii assuming an NFW density profile. We also derive an ensemble-averaged total projected mass profile of the X-ray-selected subsample by stacking their individual mass profiles. The stacked total mass profile, constrained by the shear+magnification data, is shown to be consistent with our shear-based halo-model predictions, including the effects of surrounding large-scale structure as a two-halo term, establishing further consistency in the context of the ?CDM model.

  1. A DETECTION OF WEAK-LENSING MAGNIFICATION USING GALAXY SIZES AND MAGNITUDES

    SciTech Connect (OSTI)

    Schmidt, Fabian; Rhodes, Jason; Leauthaud, Alexie; Tanaka, Masayuki; Massey, Richard; George, Matthew R.; Koekemoer, Anton M.; Finoguenov, Alexis

    2012-01-10

    Weak lensing is commonly measured using shear through galaxy ellipticities or using the effect of magnification bias on galaxy number densities. Here, we report on the first detection of weak-lensing magnification with a new, independent technique using the distribution of galaxy sizes and magnitudes. These data come for free in galaxy surveys designed for measuring shear. We present the magnification estimator and apply it to an X-ray-selected sample of galaxy groups in the COSMOS Hubble Space Telescope survey. The measurement of the projected surface density {Sigma}(r) is consistent with the shear measurements within the uncertainties and has roughly 40% of the signal to noise of the latter. We discuss systematic issues and challenges to realizing the potential of this new probe of weak lensing.

  2. Impact of magnification and size bias on the weak lensing power spectrum

    Office of Scientific and Technical Information (OSTI)

    and peak statistics (Journal Article) | SciTech Connect Impact of magnification and size bias on the weak lensing power spectrum and peak statistics Citation Details In-Document Search Title: Impact of magnification and size bias on the weak lensing power spectrum and peak statistics Authors: Liu J. ; May M. ; Haiman, Z. ; Hui, L. ; Kratochvil, J.M. Publication Date: 2014-01-21 OSTI Identifier: 1132481 Report Number(s): BNL--104426-2014-JA KA3201020 DOE Contract Number: DE-AC02-98CH10886

  3. A NEW APPROACH TO IDENTIFYING THE MOST POWERFUL GRAVITATIONAL LENSING TELESCOPES

    SciTech Connect (OSTI)

    Wong, Kenneth C.; Zabludoff, Ann I.; Ammons, S. Mark; Keeton, Charles R.; Hogg, David W.; Gonzalez, Anthony H.

    2013-05-20

    The best gravitational lenses for detecting distant galaxies are those with the largest mass concentrations and the most advantageous configurations of that mass along the line of sight. Our new method for finding such gravitational telescopes uses optical data to identify projected concentrations of luminous red galaxies (LRGs). LRGs are biased tracers of the underlying mass distribution, so lines of sight with the highest total luminosity in LRGs are likely to contain the largest total mass. We apply this selection technique to the Sloan Digital Sky Survey and identify the 200 fields with the highest total LRG luminosities projected within a 3.'5 radius over the redshift range 0.1 {<=} z {<=} 0.7. The redshift and angular distributions of LRGs in these fields trace the concentrations of non-LRG galaxies. These fields are diverse; 22.5% contain one known galaxy cluster and 56.0% contain multiple known clusters previously identified in the literature. Thus, our results confirm that these LRGs trace massive structures and that our selection technique identifies fields with large total masses. These fields contain two to three times higher total LRG luminosities than most known strong-lensing clusters and will be among the best gravitational lensing fields for the purpose of detecting the highest redshift galaxies.

  4. NOISY WEAK-LENSING CONVERGENCE PEAK STATISTICS NEAR CLUSTERS OF GALAXIES AND BEYOND

    SciTech Connect (OSTI)

    Fan Zuhui; Shan Huanyuan; Liu Jiayi

    2010-08-20

    Taking into account noise from intrinsic ellipticities of source galaxies, in this paper, we study the peak statistics in weak-lensing convergence maps around clusters of galaxies and beyond. We emphasize how the noise peak statistics is affected by the density distribution of nearby clusters, and also how cluster-peak signals are changed by the existence of noise. These are the important aspects to be thoroughly understood in weak-lensing analyses for individual clusters as well as in cosmological applications of weak-lensing cluster statistics. We adopt Gaussian smoothing with the smoothing scale {theta} {sub G} = 0.5arcmin in our analyses. It is found that the noise peak distribution near a cluster of galaxies sensitively depends on the density profile of the cluster. For a cored isothermal cluster with the core radius R{sub c} , the inner region with R {<=} R{sub c} appears noisy containing on average {approx}2.4 peaks with {nu} {>=} 5 for R{sub c} = 1.7arcmin and the true peak height of the cluster {nu} = 5.6, where {nu} denotes the convergence signal-to-noise ratio. For a Navarro-Frenk-White (NFW) cluster of the same mass and the same central {nu}, the average number of peaks with {nu} {>=} 5 within R {<=} R{sub c} is {approx}1.6. Thus a high peak corresponding to the main cluster can be identified more cleanly in the NFW case. In the outer region with R{sub c} < R {<=} 5R{sub c} , the number of high noise peaks is considerably enhanced in comparison with that of the pure noise case without the nearby cluster. For {nu} {>=} 4, depending on the treatment of the mass-sheet degeneracy in weak-lensing analyses, the enhancement factor f is in the range of {approx}5 to {approx}55 for both clusters as their outer density profiles are similar. The properties of the main-cluster-peak identified in convergence maps are also significantly affected by the presence of noise. Scatters as well as a systematic shift for the peak height are present. The height distribution is peaked at {nu} {approx} 6.6, rather than at {nu} = 5.6, corresponding to a shift of {Delta}{nu} {approx} 1, for the isothermal cluster. For the NFW cluster, {Delta}{nu} {approx} 0.8. The existence of noise also causes a location offset for the weak-lensing identified main-cluster-peak with respect to the true center of the cluster. The offset distribution is very broad and extends to R {approx} R{sub c} for the isothermal case. For the NFW cluster, it is relatively narrow and peaked at R {approx} 0.2R{sub c} . We also analyze NFW clusters of different concentrations. It is found that the more centrally concentrated the mass distribution of a cluster is, the less its weak-lensing signal is affected by noise. Incorporating these important effects and the mass function of NFW dark matter halos, we further present a model calculating the statistical abundances of total convergence peaks, true and false ones, over a large field beyond individual clusters. The results are in good agreement with those from numerical simulations. The model then allows us to probe cosmologies with the convergence peaks directly without the need of expensive follow-up observations to differentiate true and false peaks.

  5. GALAXIES IN X-RAY GROUPS. II. A WEAK LENSING STUDY OF HALO CENTERING

    SciTech Connect (OSTI)

    George, Matthew R.; Ma, Chung-Pei; Leauthaud, Alexie; Bundy, Kevin; Finoguenov, Alexis; Rykoff, Eli S.; Tinker, Jeremy L.; Wechsler, Risa H.; Massey, Richard; Mei, Simona

    2012-09-20

    Locating the centers of dark matter halos is critical for understanding the mass profiles of halos, as well as the formation and evolution of the massive galaxies that they host. The task is observationally challenging because we cannot observe halos directly, and tracers such as bright galaxies or X-ray emission from hot plasma are imperfect. In this paper, we quantify the consequences of miscentering on the weak lensing signal from a sample of 129 X-ray-selected galaxy groups in the COSMOS field with redshifts 0 < z < 1 and halo masses in the range 10{sup 13}-10{sup 14} M{sub Sun }. By measuring the stacked lensing signal around eight different candidate centers (such as the brightest member galaxy, the mean position of all member galaxies, or the X-ray centroid), we determine which candidates best trace the center of mass in halos. In this sample of groups, we find that massive galaxies near the X-ray centroids trace the center of mass to {approx}< 75 kpc, while the X-ray position and centroids based on the mean position of member galaxies have larger offsets primarily due to the statistical uncertainties in their positions (typically {approx}50-150 kpc). Approximately 30% of groups in our sample have ambiguous centers with multiple bright or massive galaxies, and some of these groups show disturbed mass profiles that are not well fit by standard models, suggesting that they are merging systems. We find that halo mass estimates from stacked weak lensing can be biased low by 5%-30% if inaccurate centers are used and the issue of miscentering is not addressed.

  6. ELLIPTICAL WEIGHTED HOLICs FOR WEAK LENSING SHEAR MEASUREMENT. III. THE EFFECT OF RANDOM COUNT NOISE ON IMAGE MOMENTS IN WEAK LENSING ANALYSIS

    SciTech Connect (OSTI)

    Okura, Yuki; Futamase, Toshifumi E-mail: tof@astr.tohoku.ac.jp

    2013-07-01

    This is the third paper on the improvement of systematic errors in weak lensing analysis using an elliptical weight function, referred to as E-HOLICs. In previous papers, we succeeded in avoiding errors that depend on the ellipticity of the background image. In this paper, we investigate the systematic error that depends on the signal-to-noise ratio of the background image. We find that the origin of this error is the random count noise that comes from the Poisson noise of sky counts. The random count noise makes additional moments and centroid shift error, and those first-order effects are canceled in averaging, but the second-order effects are not canceled. We derive the formulae that correct this systematic error due to the random count noise in measuring the moments and ellipticity of the background image. The correction formulae obtained are expressed as combinations of complex moments of the image, and thus can correct the systematic errors caused by each object. We test their validity using a simulated image and find that the systematic error becomes less than 1% in the measured ellipticity for objects with an IMCAT significance threshold of {nu} {approx} 11.7.

  7. NEW DEVELOPMENTS ON INVERSE POLYGON MAPPING TO CALCULATE GRAVITATIONAL LENSING MAGNIFICATION MAPS: OPTIMIZED COMPUTATIONS

    SciTech Connect (OSTI)

    Mediavilla, E.; Lopez, P.; Gonzalez-Morcillo, C.; Jimenez-Vicente, J.

    2011-11-01

    We derive an exact solution (in the form of a series expansion) to compute gravitational lensing magnification maps. It is based on the backward gravitational lens mapping of a partition of the image plane in polygonal cells (inverse polygon mapping, IPM), not including critical points (except perhaps at the cell boundaries). The zeroth-order term of the series expansion leads to the method described by Mediavilla et al. The first-order term is used to study the error induced by the truncation of the series at zeroth order, explaining the high accuracy of the IPM even at this low order of approximation. Interpreting the Inverse Ray Shooting (IRS) method in terms of IPM, we explain the previously reported N {sup -3/4} dependence of the IRS error with the number of collected rays per pixel. Cells intersected by critical curves (critical cells) transform to non-simply connected regions with topological pathologies like auto-overlapping or non-preservation of the boundary under the transformation. To define a non-critical partition, we use a linear approximation of the critical curve to divide each critical cell into two non-critical subcells. The optimal choice of the cell size depends basically on the curvature of the critical curves. For typical applications in which the pixel of the magnification map is a small fraction of the Einstein radius, a one-to-one relationship between the cell and pixel sizes in the absence of lensing guarantees both the consistence of the method and a very high accuracy. This prescription is simple but very conservative. We show that substantially larger cells can be used to obtain magnification maps with huge savings in computation time.

  8. Strong gravitational lensing as a tool to investigate the structure of jets at high energies

    SciTech Connect (OSTI)

    Barnacka, Anna; Geller, Margaret J.; Benbow, Wystan; Dell'antonio, Ian P.

    2014-06-20

    The components of blazar jets that emit radiation span a factor of 10{sup 10} in scale. The spatial structure of these emitting regions depends on the observed energy. Photons emitted at different sites cross the lens plane at different distances from the mass-weighted center of the lens. Thus there are differences in magnification ratios and time delays between the images of lensed blazars observed at different energies. When the lens structure and redshift are known from optical observations, these constraints can elucidate the structure of the source at high energies. At these energies, current technology is inadequate to resolve these sources, and the observed light curve is thus the sum of the images. Durations of ?-ray flares are short compared with typical time delays; thus both the magnification ratio and the time delay can be measured for the delayed counterparts. These measurements are a basis for localizing the emitting region along the jet. To demonstrate the power of strong gravitational lensing, we build a toy model based on the best studied and the nearest relativistic jet M87.

  9. Mask effects on cosmological studies with weak-lensing peak statistics

    SciTech Connect (OSTI)

    Liu, Xiangkun; Pan, Chuzhong; Fan, Zuhui; Wang, Qiao

    2014-03-20

    With numerical simulations, we analyze in detail how the bad data removal, i.e., the mask effect, can influence the peak statistics of the weak-lensing convergence field reconstructed from the shear measurement of background galaxies. It is found that high peak fractions are systematically enhanced because of the presence of masks; the larger the masked area is, the higher the enhancement is. In the case where the total masked area is about 13% of the survey area, the fraction of peaks with signal-to-noise ratio ? ? 3 is ?11% of the total number of peaks, compared with ?7% of the mask-free case in our considered cosmological model. This can have significant effects on cosmological studies with weak-lensing convergence peak statistics, inducing a large bias in the parameter constraints if the effects are not taken into account properly. Even for a survey area of 9 deg{sup 2}, the bias in (? {sub m}, ?{sub 8}) is already intolerably large and close to 3?. It is noted that most of the affected peaks are close to the masked regions. Therefore, excluding peaks in those regions in the peak statistics can reduce the bias effect but at the expense of losing usable survey areas. Further investigations find that the enhancement of the number of high peaks around the masked regions can be largely attributed to the smaller number of galaxies usable in the weak-lensing convergence reconstruction, leading to higher noise than that of the areas away from the masks. We thus develop a model in which we exclude only those very large masks with radius larger than 3' but keep all the other masked regions in peak counting statistics. For the remaining part, we treat the areas close to and away from the masked regions separately with different noise levels. It is shown that this two-noise-level model can account for the mask effect on peak statistics very well, and the bias in cosmological parameters is significantly reduced if this model is applied in the parameter fitting.

  10. Self-calibration of photometric redshift scatter in weak-lensing surveys

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Zhang, Pengjie; Pen, Ue -Li; Bernstein, Gary

    2010-06-11

    Photo-z errors, especially catastrophic errors, are a major uncertainty for precision weak lensing cosmology. We find that the shear-(galaxy number) density and density-density cross correlation measurements between photo-z bins, available from the same lensing surveys, contain valuable information for self-calibration of the scattering probabilities between the true-z and photo-z bins. The self-calibration technique we propose does not rely on cosmological priors nor parameterization of the photo-z probability distribution function, and preserves all of the cosmological information available from shear-shear measurement. We estimate the calibration accuracy through the Fisher matrix formalism. We find that, for advanced lensing surveys such as themore » planned stage IV surveys, the rate of photo-z outliers can be determined with statistical uncertainties of 0.01-1% for z < 2 galaxies. Among the several sources of calibration error that we identify and investigate, the galaxy distribution bias is likely the most dominant systematic error, whereby photo-z outliers have different redshift distributions and/or bias than non-outliers from the same bin. This bias affects all photo-z calibration techniques based on correlation measurements. As a result, galaxy bias variations of O(0.1) produce biases in photo-z outlier rates similar to the statistical errors of our method, so this galaxy distribution bias may bias the reconstructed scatters at several-σ level, but is unlikely to completely invalidate the self-calibration technique.« less

  11. Impact of spurious shear on cosmological parameter estimates from weak lensing observables

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Petri, Andrea; May, Morgan; Haiman, Zoltán; Kratochvil, Jan M.

    2014-12-30

    We research, residual errors in shear measurements, after corrections for instrument systematics and atmospheric effects, can impact cosmological parameters derived from weak lensing observations. Here we combine convergence maps from our suite of ray-tracing simulations with random realizations of spurious shear. This allows us to quantify the errors and biases of the triplet (Ωm,w,σ8) derived from the power spectrum (PS), as well as from three different sets of non-Gaussian statistics of the lensing convergence field: Minkowski functionals (MFs), low-order moments (LMs), and peak counts (PKs). Our main results are as follows: (i) We find an order of magnitude smaller biasesmore » from the PS than in previous work. (ii) The PS and LM yield biases much smaller than the morphological statistics (MF, PK). (iii) For strictly Gaussian spurious shear with integrated amplitude as low as its current estimate of σsys2 ≈ 10-7, biases from the PS and LM would be unimportant even for a survey with the statistical power of Large Synoptic Survey Telescope. However, we find that for surveys larger than ≈ 100 deg2, non-Gaussianity in the noise (not included in our analysis) will likely be important and must be quantified to assess the biases. (iv) The morphological statistics (MF, PK) introduce important biases even for Gaussian noise, which must be corrected in large surveys. The biases are in different directions in (Ωm,w,σ8) parameter space, allowing self-calibration by combining multiple statistics. Our results warrant follow-up studies with more extensive lensing simulations and more accurate spurious shear estimates.« less

  12. Impact of spurious shear on cosmological parameter estimates from weak lensing observables

    SciTech Connect (OSTI)

    Petri, Andrea; May, Morgan; Haiman, Zoltn; Kratochvil, Jan M.

    2014-12-30

    We research, residual errors in shear measurements, after corrections for instrument systematics and atmospheric effects, can impact cosmological parameters derived from weak lensing observations. Here we combine convergence maps from our suite of ray-tracing simulations with random realizations of spurious shear. This allows us to quantify the errors and biases of the triplet (?m,w,?8) derived from the power spectrum (PS), as well as from three different sets of non-Gaussian statistics of the lensing convergence field: Minkowski functionals (MFs), low-order moments (LMs), and peak counts (PKs). Our main results are as follows: (i) We find an order of magnitude smaller biases from the PS than in previous work. (ii) The PS and LM yield biases much smaller than the morphological statistics (MF, PK). (iii) For strictly Gaussian spurious shear with integrated amplitude as low as its current estimate of ?sys2 ? 10-7, biases from the PS and LM would be unimportant even for a survey with the statistical power of Large Synoptic Survey Telescope. However, we find that for surveys larger than ? 100 deg2, non-Gaussianity in the noise (not included in our analysis) will likely be important and must be quantified to assess the biases. (iv) The morphological statistics (MF, PK) introduce important biases even for Gaussian noise, which must be corrected in large surveys. The biases are in different directions in (?m,w,?8) parameter space, allowing self-calibration by combining multiple statistics. Our results warrant follow-up studies with more extensive lensing simulations and more accurate spurious shear estimates.

  13. Impact of spurious shear on cosmological parameter estimates from weak lensing observables

    SciTech Connect (OSTI)

    Petri, Andrea; May, Morgan; Haiman, Zoltán; Kratochvil, Jan M.

    2014-12-30

    We research, residual errors in shear measurements, after corrections for instrument systematics and atmospheric effects, can impact cosmological parameters derived from weak lensing observations. Here we combine convergence maps from our suite of ray-tracing simulations with random realizations of spurious shear. This allows us to quantify the errors and biases of the triplet (Ωm,w,σ8) derived from the power spectrum (PS), as well as from three different sets of non-Gaussian statistics of the lensing convergence field: Minkowski functionals (MFs), low-order moments (LMs), and peak counts (PKs). Our main results are as follows: (i) We find an order of magnitude smaller biases from the PS than in previous work. (ii) The PS and LM yield biases much smaller than the morphological statistics (MF, PK). (iii) For strictly Gaussian spurious shear with integrated amplitude as low as its current estimate of σsys2 ≈ 10-7, biases from the PS and LM would be unimportant even for a survey with the statistical power of Large Synoptic Survey Telescope. However, we find that for surveys larger than ≈ 100 deg2, non-Gaussianity in the noise (not included in our analysis) will likely be important and must be quantified to assess the biases. (iv) The morphological statistics (MF, PK) introduce important biases even for Gaussian noise, which must be corrected in large surveys. The biases are in different directions in (Ωm,w,σ8) parameter space, allowing self-calibration by combining multiple statistics. Our results warrant follow-up studies with more extensive lensing simulations and more accurate spurious shear estimates.

  14. Self-calibration of photometric redshift scatter in weak-lensing surveys

    SciTech Connect (OSTI)

    Zhang, Pengjie; Pen, Ue -Li; Bernstein, Gary

    2010-06-11

    Photo-z errors, especially catastrophic errors, are a major uncertainty for precision weak lensing cosmology. We find that the shear-(galaxy number) density and density-density cross correlation measurements between photo-z bins, available from the same lensing surveys, contain valuable information for self-calibration of the scattering probabilities between the true-z and photo-z bins. The self-calibration technique we propose does not rely on cosmological priors nor parameterization of the photo-z probability distribution function, and preserves all of the cosmological information available from shear-shear measurement. We estimate the calibration accuracy through the Fisher matrix formalism. We find that, for advanced lensing surveys such as the planned stage IV surveys, the rate of photo-z outliers can be determined with statistical uncertainties of 0.01-1% for z < 2 galaxies. Among the several sources of calibration error that we identify and investigate, the galaxy distribution bias is likely the most dominant systematic error, whereby photo-z outliers have different redshift distributions and/or bias than non-outliers from the same bin. This bias affects all photo-z calibration techniques based on correlation measurements. As a result, galaxy bias variations of O(0.1) produce biases in photo-z outlier rates similar to the statistical errors of our method, so this galaxy distribution bias may bias the reconstructed scatters at several-? level, but is unlikely to completely invalidate the self-calibration technique.

  15. Redshift Distributions of Galaxies in the DES Science Verification Shear Catalogue and Implications for Weak Lensing

    SciTech Connect (OSTI)

    Bonnett, C.

    2015-07-21

    We present photometric redshift estimates for galaxies used in the weak lensing analysis of the Dark Energy Survey Science Verification (DES SV) data. Four model- or machine learning-based photometric redshift methods { annz2, bpz calibrated against BCC-U fig simulations, skynet, and tpz { are analysed. For training, calibration, and testing of these methods, we also construct a catalogue of spectroscopically confirmed galaxies matched against DES SV data. The performance of the methods is evalu-ated against the matched spectroscopic catalogue, focusing on metrics relevant for weak lensing analyses, with additional validation against COSMOS photo-zs. From the galaxies in the DES SV shear catalogue, which have mean redshift 0.72 0.01 over the range 0:3 < z < 1:3, we construct three tomographic bins with means of z = {0.45; 0.67,1.00g}. These bins each have systematic uncertainties ?z ? 0.05 in the mean of the fiducial skynet photo-z n(z). We propagate the errors in the redshift distributions through to their impact on cosmological parameters estimated with cosmic shear, and find that they cause shifts in the value of ?8 of approx. 3%. This shift is within the one sigma statistical errors on ?8 for the DES SV shear catalog. We also found that further study of the potential impact of systematic differences on the critical surface density, ?crit, contained levels of bias safely less than the statistical power of DES SV data. We recommend a final Gaussian prior for the photo-z bias in the mean of n(z) of width 0:05 for each of the three tomographic bins, and show that this is a sufficient bias model for the corresponding cosmology analysis.

  16. Cosmology Constraints from the Weak Lensing Peak Counts and the Power Spectrum in CFHTLenS

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Liu, Jia; May, Morgan; Petri, Andrea; Haiman, Zoltan; Hui, Lam; Kratochvil, Jan M.

    2015-03-04

    Lensing peaks have been proposed as a useful statistic, containing cosmological information from non-Gaussianities that is inaccessible from traditional two-point statistics such as the power spectrum or two-point correlation functions. Here we examine constraints on cosmological parameters from weak lensing peak counts, using the publicly available data from the 154 deg2 CFHTLenS survey. We utilize a new suite of ray-tracing N-body simulations on a grid of 91 cosmological models, covering broad ranges of the three parameters Ωm, σ8, and w, and replicating the galaxy sky positions, redshifts, and shape noise in the CFHTLenS observations. We then build an emulator thatmore » interpolates the power spectrum and the peak counts to an accuracy of ≤ 5%, and compute the likelihood in the three-dimensional parameter space (Ωm, σ8, w) from both observables. We find that constraints from peak counts are comparable to those from the power spectrum, and somewhat tighter when different smoothing scales are combined. Neither observable can constrain w without external data. When the power spectrum and peak counts are combined, the area of the error “banana” in the (Ωm, σ8) plane reduces by a factor of ≈ two, compared to using the power spectrum alone. For a flat Λ cold dark matter model, combining both statistics, we obtain the constraint σ8(Ωm/0.27)0.63 = 0.85+0.03-0.03.« less

  17. Cosmology Constraints from the Weak Lensing Peak Counts and the Power Spectrum in CFHTLenS

    SciTech Connect (OSTI)

    Liu, Jia; May, Morgan; Petri, Andrea; Haiman, Zoltan; Hui, Lam; Kratochvil, Jan M.

    2015-03-04

    Lensing peaks have been proposed as a useful statistic, containing cosmological information from non-Gaussianities that is inaccessible from traditional two-point statistics such as the power spectrum or two-point correlation functions. Here we examine constraints on cosmological parameters from weak lensing peak counts, using the publicly available data from the 154 deg2 CFHTLenS survey. We utilize a new suite of ray-tracing N-body simulations on a grid of 91 cosmological models, covering broad ranges of the three parameters Ωm, σ8, and w, and replicating the galaxy sky positions, redshifts, and shape noise in the CFHTLenS observations. We then build an emulator that interpolates the power spectrum and the peak counts to an accuracy of ≤ 5%, and compute the likelihood in the three-dimensional parameter space (Ωm, σ8, w) from both observables. We find that constraints from peak counts are comparable to those from the power spectrum, and somewhat tighter when different smoothing scales are combined. Neither observable can constrain w without external data. When the power spectrum and peak counts are combined, the area of the error “banana” in the (Ωm, σ8) plane reduces by a factor of ≈ two, compared to using the power spectrum alone. For a flat Λ cold dark matter model, combining both statistics, we obtain the constraint σ8m/0.27)0.63 = 0.85+0.03-0.03.

  18. TESTING GRAVITATIONAL LENSING AS THE SOURCE OF ENHANCED STRONG Mg II ABSORPTION TOWARD GAMMA-RAY BURSTS

    SciTech Connect (OSTI)

    Rapoport, Sharon; Onken, Christopher A.; Schmidt, Brian P.; Tucker, Brad E.; Wyithe, J. Stuart B.; Levan, Andrew J.

    2012-08-01

    Sixty percent of gamma-ray bursts (GRBs) reveal strong Mg II absorbing systems, which is a factor of {approx}2 times the rate seen along lines of sight to quasars. Previous studies argue that the discrepancy in the strong Mg II covering factor is most likely to be the result of either quasars being obscured due to dust or the consequence of many GRBs being strongly gravitationally lensed. We analyze observations of quasars that show strong foreground Mg II absorption. We find that GRB lines of sight pass closer to bright galaxies than would be expected for random lines of sight within the impact parameter expected for strong Mg II absorption. While this cannot be explained by obscuration in the GRB sample, it is a natural consequence of gravitational lensing. Upon examining the particular configurations of galaxies near a sample of GRBs with strong Mg II absorption, we find several intriguing lensing candidates. Our results suggest that lensing provides a viable contribution to the observed enhancement of strong Mg II absorption along lines of sight to GRBs, and we outline the future observations required to test this hypothesis conclusively.

  19. Shape profiles and orientation bias for weak and strong lensing cluster halos

    SciTech Connect (OSTI)

    Groener, A. M.; Goldberg, D. M.

    2014-11-10

    We study the intrinsic shape and alignment of isodensities of galaxy cluster halos extracted from the MultiDark MDR1 cosmological simulation. We find that the simulated halos are extremely prolate on small scales and increasingly spherical on larger ones. Due to this trend, analytical projection along the line of sight produces an overestimation of the concentration index as a decreasing function of radius, which we quantify by using both the intrinsic distribution of three-dimensional concentrations (c {sub 200}) and isodensity shape on weak and strong lensing scales. We find this difference to be ?18% (?9%) for low- (medium-)mass cluster halos with intrinsically low concentrations (c {sub 200} = 1-3), while we find virtually no difference for halos with intrinsically high concentrations. Isodensities are found to be fairly well aligned throughout the entirety of the radial scale of each halo population. However, major axes of individual halos have been found to deviate by as much as ?30. We also present a value-added catalog of our analysis results, which we have made publicly available to download.

  20. Atmospheric PSF Interpolation for Weak Lensing in Short Exposure Imaging Data

    SciTech Connect (OSTI)

    Chang, C.; Marshall, P.J.; Jernigan, J.G.; Peterson, J.R.; Kahn, S.M.; Gull, S.F.; AlSayyad, Y.; Ahmad, Z.; Bankert, J.; Bard, D.; Connolly, A.; Gibson, R.R.; Gilmore, K.; Grace, E.; Hannel, M.; Hodge, M.A.; Jones, L.; Krughoff, S.; Lorenz, S.; Marshall, S.; Meert, A.

    2012-09-19

    A main science goal for the Large Synoptic Survey Telescope (LSST) is to measure the cosmic shear signal from weak lensing to extreme accuracy. One difficulty, however, is that with the short exposure time ({approx_equal}15 seconds) proposed, the spatial variation of the Point Spread Function (PSF) shapes may be dominated by the atmosphere, in addition to optics errors. While optics errors mainly cause the PSF to vary on angular scales similar or larger than a single CCD sensor, the atmosphere generates stochastic structures on a wide range of angular scales. It thus becomes a challenge to infer the multi-scale, complex atmospheric PSF patterns by interpolating the sparsely sampled stars in the field. In this paper we present a new method, psfent, for interpolating the PSF shape parameters, based on reconstructing underlying shape parameter maps with a multi-scale maximum entropy algorithm. We demonstrate, using images from the LSST Photon Simulator, the performance of our approach relative to a 5th-order polynomial fit (representing the current standard) and a simple boxcar smoothing technique. Quantitatively, psfent predicts more accurate PSF models in all scenarios and the residual PSF errors are spatially less correlated. This improvement in PSF interpolation leads to a factor of 3.5 lower systematic errors in the shear power spectrum on scales smaller than {approx} 13, compared to polynomial fitting. We estimate that with psfent and for stellar densities greater than {approx_equal}1/arcmin{sup 2}, the spurious shear correlation from PSF interpolation, after combining a complete 10-year dataset from LSST, is lower than the corresponding statistical uncertainties on the cosmic shear power spectrum, even under a conservative scenario.

  1. A Measurement of Gravitational Lensing of the Cosmic Microwave Background by Galaxy Clusters Using Data from the South Pole Telescope

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Baxter, E. J.; Keisler, R.; Dodelson, S.; Aird, K. A.; Allen, S. W.; Ashby, M. L.N.; Bautz, M.; Bayliss, M.; Benson, B. A.; Bleem, L. E.; et al

    2015-06-22

    Clusters of galaxies are expected to gravitationally lens the cosmic microwave background (CMB) and thereby generate a distinct signal in the CMB on arcminute scales. Measurements of this effect can be used to constrain the masses of galaxy clusters with CMB data alone. Here we present a measurement of lensing of the CMB by galaxy clusters using data from the South Pole Telescope (SPT). We also develop a maximum likelihood approach to extract the CMB cluster lensing signal and validate the method on mock data. We quantify the effects on our analysis of several potential sources of systematic error andmore » find that they generally act to reduce the best-fit cluster mass. It is estimated that this bias to lower cluster mass is roughly 0.85σ in units of the statistical error bar, although this estimate should be viewed as an upper limit. Furthermore, we apply our maximum likelihood technique to 513 clusters selected via their Sunyaev–Zeldovich (SZ) signatures in SPT data, and rule out the null hypothesis of no lensing at 3.1σ. The lensing-derived mass estimate for the full cluster sample is consistent with that inferred from the SZ flux: M200,lens = 0.83+0.38-0.37 M200,SZ (68% C.L., statistical error only).« less

  2. Mapping all the mass in the universe (with weak gravitational lensing) - Oral Presentation

    SciTech Connect (OSTI)

    Everett, Spencer

    2015-08-13

    Recent discoveries have shown that most of the universe is made of an exotic dark matter that behaves much differently than the normal matter that we experience in everyday life. As we cannot detect dark matter directly, we must infer its location in the universe by indirect effects, such as the distortion of light from distant galaxies as it travels through large clouds of dark matter. While the degree of distortion should be proportional to the amount of dark matter present, we don't know the original shape of the galaxy so the distortion is difficult to quantify. If we had a model of how dark matter is linked to galaxies, and thus be able predict the amount of distortion that should occur, we could apply the model to galaxy surveys to map out the dark matter in our universe. In this research, I attach a spherical 'halo' of dark matter to each galaxy in a simulated universe to approximate its known complex dark matter structure. I then predict how the halos distort the light from distant galaxies generated behind the halos. As the data is simulated, the true distortion of the light is known which is compared to the halo-predicted distortion. I find that, on average, the model under-predicts the degree of distortion on all scales and fails to capture distortions from large-scale dark matter structure. These issues are likely due to missing features in the model, as the halo model is a greatly simplified version of the actual distribution of dark matter. Potential improvements to the model for future work are discussed.

  3. ACCOUNTING FOR COSMIC VARIANCE IN STUDIES OF GRAVITATIONALLY LENSED HIGH-REDSHIFT GALAXIES IN THE HUBBLE FRONTIER FIELD CLUSTERS

    SciTech Connect (OSTI)

    Robertson, Brant E.; Stark, Dan P.; Ellis, Richard S.; Dunlop, James S.; McLure, Ross J.; McLeod, Derek

    2014-12-01

    Strong gravitational lensing provides a powerful means for studying faint galaxies in the distant universe. By magnifying the apparent brightness of background sources, massive clusters enable the detection of galaxies fainter than the usual sensitivity limit for blank fields. However, this gain in effective sensitivity comes at the cost of a reduced survey volume and, in this Letter, we demonstrate that there is an associated increase in the cosmic variance uncertainty. As an example, we show that the cosmic variance uncertainty of the high-redshift population viewed through the Hubble Space Telescope Frontier Field cluster Abell 2744 increases from ?35% at redshift z ? 7 to ? 65% at z ? 10. Previous studies of high-redshift galaxies identified in the Frontier Fields have underestimated the cosmic variance uncertainty that will affect the ultimate constraints on both the faint-end slope of the high-redshift luminosity function and the cosmic star formation rate density, key goals of the Frontier Field program.

  4. DETECTION OF SUBSTRUCTURE IN THE GRAVITATIONALLY LENSED QUASAR MG0414+0534 USING MID-INFRARED AND RADIO VLBI OBSERVATIONS

    SciTech Connect (OSTI)

    MacLeod, Chelsea L. [Physics Department, United States Naval Academy, Annapolis, MD 21403 (United States); Jones, Ramsey; Agol, Eric [Astronomy Department, University of Washington, Seattle, WA 98195 (United States); Kochanek, Christopher S., E-mail: macleod@usna.edu [Department of Astronomy and the Center for Cosmology and Astroparticle Physics, Ohio State University, Columbus, OH 43210 (United States)

    2013-08-10

    We present 11.2 {mu}m observations of the gravitationally lensed, radio-loud z{sub s} = 2.64 quasar MG0414+0534, obtained using the Michelle camera on Gemini North. We find a flux ratio anomaly of A2/A1 = 0.93 {+-} 0.02 for the quasar images A1 and A2. When combined with the 11.7 {mu}m measurements from Minezaki et al., the A2/A1 flux ratio is nearly 5{sigma} from the expected ratio for a model based on the two visible lens galaxies. The mid-IR flux ratio anomaly can be explained by a satellite (substructure), 0.''3 northeast of image A2, as can the detailed very long baseline interferometry (VLBI) structures of the jet produced by the quasar. When we combine the mid-IR flux ratios with high-resolution VLBI measurements, we find a best-fit mass between 10{sup 6.2} and 10{sup 7.5} M{sub Sun} inside the Einstein radius for a satellite substructure modeled as a singular isothermal sphere at the redshift of the main lens (z{sub l} = 0.96). We are unable to set an interesting limit on the mass to light ratio due to its proximity to the quasar image A2. While the observations used here were technically difficult, surveys of flux anomalies in gravitational lenses with the James Webb Space Telescope will be simple, fast, and should well constrain the abundance of substructure in dark matter halos.

  5. Higgs gravitational interaction, weak boson scattering, and Higgs inflation in Jordan and Einstein frames

    SciTech Connect (OSTI)

    Ren, Jing; Xianyu, Zhong-Zhi; He, Hong-Jian E-mail: xianyuzhongzhi@gmail.com

    2014-06-01

    We study gravitational interaction of Higgs boson through the unique dimension-4 operator ?H{sup }HR, with H the Higgs doublet and R the Ricci scalar curvature. We analyze the effect of this dimensionless nonminimal coupling ? on weak gauge boson scattering in both Jordan and Einstein frames. We explicitly establish the longitudinal-Goldstone equivalence theorem with nonzero ? coupling in both frames, and analyze the unitarity constraints. We study the ?-induced weak boson scattering cross sections at O(1?30) TeV scales, and propose to probe the Higgs-gravity coupling via weak boson scattering experiments at the LHC (14 TeV) and the next generation pp colliders (50-100 TeV). We further extend our study to Higgs inflation, and quantitatively derive the perturbative unitarity bounds via coupled channel analysis, under large field background at the inflation scale. We analyze the unitarity constraints on the parameter space in both the conventional Higgs inflation and the improved models in light of the recent BICEP2 data.

  6. Comparison of galaxy clusters selected by weak-lensing, optical spectroscopy, and X-rays in the deep lens survey F2 field

    SciTech Connect (OSTI)

    Starikova, Svetlana; Jones, Christine; Forman, William R.; Vikhlinin, Alexey; Kurtz, Michael J.; Fabricant, Daniel G.; Murray, Stephen S.; Geller, Margaret J.; Dell'Antonio, Ian P.

    2014-05-10

    We compare galaxy clusters selected in Chandra and XMM-Newton X-ray observations of the 4 deg{sup 2} Deep Lens Survey (DLS) F2 field to the cluster samples previously selected in the same field from a sensitive weak-lensing shear map derived from the DLS and from a detailed galaxy redshift surveythe Smithsonian Hectospec Lensing Survey (SHELS). Our Chandra and XMM-Newton observations cover 1.6 deg{sup 2} of the DLS F2 field, including all 12 weak-lensing peaks above a signal-to-noise ratio of 3.5, along with 16 of the 20 SHELS clusters with published velocity dispersions >500 km s{sup 1}. We detect 26 extended X-ray sources in this area and confirm 23 of them as galaxy clusters using the optical imaging. Approximately 75% of clusters detected in either X-ray or spectroscopic surveys are found in both; these follow the previously established scaling relations between velocity dispersion, L {sub X}, and T {sub X}. A lower percentage, 60%, of clusters are in common between X-ray and DLS samples. With the exception of a high false-positive rate in the DLS weak-lensing search (5 out of 12 DLS candidates appear to be false), differences between the three cluster detection methods can be attributed primarily to observational uncertainties and intrinsic scatter between different observables and cluster mass.

  7. Discovery of two gravitationally lensed quasars in the Dark Energy Survey

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Agnello, A.

    2015-10-01

    In this study, we present spectroscopic confirmation of two new lensed quasars via data obtained at the 6.5m Magellan/Baade Telescope. The lens candidates have been selected from the Dark Energy Survey (DES) and WISE based on their multi-band photometry and extended morphology in DES images. Images of DES J0115-5244 show two blue point sources at either side of a red galaxy. Our long-slit data confirm that both point sources are images of the same quasar at zs = 1.64. The Einstein Radius estimated from the DES images is 0.51''. DES J2146-0047 is in the area of overlap between DES andmore » the Sloan Digital Sky Survey (SDSS). Two blue components are visible in the DES and SDSS images. The SDSS fiber spectrum shows a quasar component at zs = 2.38 and absorption compatible with Mg II and Fe II at zl = 0.799, which we tentatively associate with the foreground lens galaxy. The long-slit Magellan spectra show that the blue components are resolved images of the same quasar. Furthermore, the Einstein Radius is 0.68'' corresponding to an enclosed mass of 1.6 × 1011 M⊙. Three other candidates were observed and rejected, two being low-redshift pairs of starburst galaxies, and one being a quasar behind a blue star. These first confirmation results provide an important empirical validation of the data-mining and model-based selection that is being applied to the entire DES dataset.« less

  8. Discovery of two gravitationally lensed quasars in the Dark Energy Survey

    SciTech Connect (OSTI)

    Agnello, A.

    2015-10-01

    In this study, we present spectroscopic confirmation of two new lensed quasars via data obtained at the 6.5m Magellan/Baade Telescope. The lens candidates have been selected from the Dark Energy Survey (DES) and WISE based on their multi-band photometry and extended morphology in DES images. Images of DES J0115-5244 show two blue point sources at either side of a red galaxy. Our long-slit data confirm that both point sources are images of the same quasar at zs = 1.64. The Einstein Radius estimated from the DES images is 0.51''. DES J2146-0047 is in the area of overlap between DES and the Sloan Digital Sky Survey (SDSS). Two blue components are visible in the DES and SDSS images. The SDSS fiber spectrum shows a quasar component at zs = 2.38 and absorption compatible with Mg II and Fe II at zl = 0.799, which we tentatively associate with the foreground lens galaxy. The long-slit Magellan spectra show that the blue components are resolved images of the same quasar. Furthermore, the Einstein Radius is 0.68'' corresponding to an enclosed mass of 1.6 1011 M?. Three other candidates were observed and rejected, two being low-redshift pairs of starburst galaxies, and one being a quasar behind a blue star. These first confirmation results provide an important empirical validation of the data-mining and model-based selection that is being applied to the entire DES dataset.

  9. CAN THE MASSES OF ISOLATED PLANETARY-MASS GRAVITATIONAL LENSES BE MEASURED BY TERRESTRIAL PARALLAX?

    SciTech Connect (OSTI)

    Freeman, M.; Botzler, C. S.; Bray, J. C.; Cherrie, J. M.; Rattenbury, N. J.; Philpott, L. C.; Abe, F.; Muraki, Y.; Albrow, M. D.; Bennett, D. P.; Bond, I. A.; Christie, G. W.; Natusch, T.; Dionnet, Z.; Gould, A.; Han, C.; Heyrovský, D.; McCormick, J. M.; Skowron, J.; and others

    2015-02-01

    Recently Sumi et al. reported evidence for a large population of planetary-mass objects (PMOs) that are either unbound or orbit host stars in orbits ≥10 AU. Their result was deduced from the statistical distribution of durations of gravitational microlensing events observed by the MOA collaboration during 2006 and 2007. Here we study the feasibility of measuring the mass of an individual PMO through microlensing by examining a particular event, MOA-2011-BLG-274. This event was unusual as the duration was short, the magnification high, the source-size effect large, and the angular Einstein radius small. Also, it was intensively monitored from widely separated locations under clear skies at low air masses. Choi et al. concluded that the lens of the event may have been a PMO but they did not attempt a measurement of its mass. We report here a re-analysis of the event using re-reduced data. We confirm the results of Choi et al. and attempt a measurement of the mass and distance of the lens using the terrestrial parallax effect. Evidence for terrestrial parallax is found at a 3σ level of confidence. The best fit to the data yields the mass and distance of the lens as 0.80 ± 0.30 M {sub J} and 0.80 ± 0.25 kpc respectively. We exclude a host star to the lens out to a separation ∼40 AU. Drawing on our analysis of MOA-2011-BLG-274 we propose observational strategies for future microlensing surveys to yield sharper results on PMOs including those down to super-Earth mass.

  10. The serendipitous observation of a gravitationally lensed galaxy at z = 0.9057 from the Blanco Cosmology Survey: The Elliot Arc

    SciTech Connect (OSTI)

    Buckley-Geer, E J; Lin, H; Drabek, E R; Allam, S S; Tucker, D L; Armstrong, R; Barkhouse, W A; Bertin, E; Brodwin, M; Desai, S; Frieman, J A

    2011-11-03

    We report on the serendipitous discovery in the Blanco Cosmology Survey (BCS) imaging data of a z = 0.9057 galaxy that is being strongly lensed by a massive galaxy cluster at a redshift of z = 0.3838. The lens (BCS J2352-5452) was discovered while examining i- and z-band images being acquired in October 2006 during a BCS observing run. Follow-up spectroscopic observations with the GMOS instrument on the Gemini South 8m telescope confirmed the lensing nature of this system. Using weak plus strong lensing, velocity dispersion, cluster richness N200, and fitting to an NFW cluster mass density profile, we have made three independent estimates of the mass M200 which are all very consistent with each other. The combination of the results from the three methods gives M200 = (5.1 x 1.3) x 1014 circle_dot, which is fully consistent with the individual measurements. The final NFW concentration c200 from the combined fit is c200 = 5.4-1.1+1.4. We have compared our measurements of M200 and c200 with predictions for (a) clusters from ?CDM simulations, (b) lensing selected clusters from simulations, and (c) a real sample of cluster lenses. We find that we are most compatible with the predictions for ?CDM simulations for lensing clusters, and we see no evidence based on this one system for an increased concentration compared to ?CDM. Finally, using the flux measured from the [OII]3727 line we have determined the star formation rate (SFR) of the source galaxy and find it to be rather modest given the assumed lens magnification.

  11. The serendipitous observation of a gravitationally lensed galaxy at z = 0.9057 from the Blanco Cosmology Survey: the Elliot Arc

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Buckley-Geer, E. J.; Lin, H.; Drabek, E. R.; Allam, S. S.; Tucker, D. L.; Armstrong, R.; Barkhouse, W. A.; Bertin, E.; Brodwin, M.; Desai, S.; et al

    2011-11-03

    We report on the serendipitous discovery in the Blanco Cosmology Survey (BCS) imaging data of a z = 0.9057 galaxy that is being strongly lensed by a massive galaxy cluster at a redshift of z = 0.3838. The lens (BCS J2352-5452) was discovered while examining i- and z-band images being acquired in October 2006 during a BCS observing run. Follow-up spectroscopic observations with the GMOS instrument on the Gemini South 8m telescope confirmed the lensing nature of this system. Using weak plus strong lensing, velocity dispersion, cluster richness N200, and fitting to an NFW cluster mass density profile, we havemore » made three independent estimates of the mass M200 which are all very consistent with each other. The combination of the results from the three methods gives M200 = (5.1 x 1.3) x 1014 circle_dot, which is fully consistent with the individual measurements. The final NFW concentration c200 from the combined fit is c200 = 5.4-1.1+1.4. We have compared our measurements of M200 and c200 with predictions for (a) clusters from λCDM simulations, (b) lensing selected clusters from simulations, and (c) a real sample of cluster lenses. We find that we are most compatible with the predictions for λCDM simulations for lensing clusters, and we see no evidence based on this one system for an increased concentration compared to λCDM. Finally, using the flux measured from the [OII]3727 line we have determined the star formation rate (SFR) of the source galaxy and find it to be rather modest given the assumed lens magnification.« less

  12. JOINT ANALYSIS OF CLUSTER OBSERVATIONS. II. CHANDRA/XMM-NEWTON X-RAY AND WEAK LENSING SCALING RELATIONS FOR A SAMPLE OF 50 RICH CLUSTERS OF GALAXIES

    SciTech Connect (OSTI)

    Mahdavi, Andisheh [Department of Physics and Astronomy, San Francisco State University, San Francisco, CA 94131 (United States); Hoekstra, Henk [Leiden Observatory, Leiden University, Niels Bohrweg 2, NL-2333 CA Leiden (Netherlands); Babul, Arif; Bildfell, Chris [Department of Physics and Astronomy, University of Victoria, Victoria, BC V8W 3P6 (Canada); Jeltema, Tesla [Santa Cruz Institute for Particle Physics, UC Santa Cruz, 1156 High Street, Santa Cruz, CA 95064 (United States); Henry, J. Patrick [Institute for Astronomy, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States)

    2013-04-20

    We present a study of multiwavelength X-ray and weak lensing scaling relations for a sample of 50 clusters of galaxies. Our analysis combines Chandra and XMM-Newton data using an energy-dependent cross-calibration. After considering a number of scaling relations, we find that gas mass is the most robust estimator of weak lensing mass, yielding 15% {+-} 6% intrinsic scatter at r{sub 500}{sup WL} (the pseudo-pressure Y{sub X} yields a consistent scatter of 22% {+-} 5%). The scatter does not change when measured within a fixed physical radius of 1 Mpc. Clusters with small brightest cluster galaxy (BCG) to X-ray peak offsets constitute a very regular population whose members have the same gas mass fractions and whose even smaller (<10%) deviations from regularity can be ascribed to line of sight geometrical effects alone. Cool-core clusters, while a somewhat different population, also show the same (<10%) scatter in the gas mass-lensing mass relation. There is a good correlation and a hint of bimodality in the plane defined by BCG offset and central entropy (or central cooling time). The pseudo-pressure Y{sub X} does not discriminate between the more relaxed and less relaxed populations, making it perhaps the more even-handed mass proxy for surveys. Overall, hydrostatic masses underestimate weak lensing masses by 10% on the average at r{sub 500}{sup WL}; but cool-core clusters are consistent with no bias, while non-cool-core clusters have a large and constant 15%-20% bias between r{sub 2500}{sup WL} and r{sub 500}{sup WL}, in agreement with N-body simulations incorporating unthermalized gas. For non-cool-core clusters, the bias correlates well with BCG ellipticity. We also examine centroid shift variance and power ratios to quantify substructure; these quantities do not correlate with residuals in the scaling relations. Individual clusters have for the most part forgotten the source of their departures from self-similarity.

  13. Mass calibration of galaxy clusters at redshift 0.1–1.0 using weak lensing in the Sloan Digital Sky Survey Stripe 82 co-add

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Wiesner, Matthew P.; Lin, Huan; Soares-Santos, Marcelle

    2015-07-08

    We present galaxy cluster mass–richness relations found in the Sloan Digital Sky Survey Stripe 82 co-add using clusters found using a Voronoi tessellation cluster finder. These relations were found using stacked weak lensing shear observed in a large sample of galaxy clusters. These mass–richness relations are presented for four redshift bins, 0.1 < z ≤ 0.4, 0.4 < z ≤ 0.7, 0.7 < z ≤ 1.0 and 0.1 < z ≤ 1.0. We describe the sample of galaxy clusters and explain how these clusters were found using a Voronoi tessellation cluster finder. We fit a Navarro-Frenk-White profile to the stackedmore » weak lensing shear signal in redshift and richness bins in order to measure virial mass (M200). We describe several effects that can bias weak lensing measurements, including photometric redshift bias, the effect of the central BCG, halo miscentering, photometric redshift uncertainty and foreground galaxy contamination. We present mass–richness relations using richness measure NVT with each of these effects considered separately as well as considered altogether. We also examine redshift evolution of the mass–richness relation. As a result, we present measurements of the mass coefficient (M200|20) and the power-law slope (α) for power-law fits to the mass and richness values in each of the redshift bins. We find values of the mass coefficient of 8.49 ± 0.526, 14.1 ± 1.78, 30.2 ± 8.74 and 9.23 ± 0.525 × 1013 h–1 M⊙ for each of the four redshift bins, respectively. As a result, we find values of the power-law slope of 0.905 ± 0.0585, 0.948 ± 0.100, 1.33 ± 0.260 and 0.883 ± 0.0500, respectively.« less

  14. Mass calibration of galaxy clusters at redshift 0.11.0 using weak lensing in the Sloan Digital Sky Survey Stripe 82 co-add

    SciTech Connect (OSTI)

    Wiesner, Matthew P.; Lin, Huan; Soares-Santos, Marcelle

    2015-07-08

    We present galaxy cluster massrichness relations found in the Sloan Digital Sky Survey Stripe 82 co-add using clusters found using a Voronoi tessellation cluster finder. These relations were found using stacked weak lensing shear observed in a large sample of galaxy clusters. These massrichness relations are presented for four redshift bins, 0.1 < z ? 0.4, 0.4 < z ? 0.7, 0.7 < z ? 1.0 and 0.1 < z ? 1.0. We describe the sample of galaxy clusters and explain how these clusters were found using a Voronoi tessellation cluster finder. We fit a Navarro-Frenk-White profile to the stacked weak lensing shear signal in redshift and richness bins in order to measure virial mass (M200). We describe several effects that can bias weak lensing measurements, including photometric redshift bias, the effect of the central BCG, halo miscentering, photometric redshift uncertainty and foreground galaxy contamination. We present massrichness relations using richness measure NVT with each of these effects considered separately as well as considered altogether. We also examine redshift evolution of the massrichness relation. As a result, we present measurements of the mass coefficient (M200|20) and the power-law slope (?) for power-law fits to the mass and richness values in each of the redshift bins. We find values of the mass coefficient of 8.49 0.526, 14.1 1.78, 30.2 8.74 and 9.23 0.525 1013 h1 M? for each of the four redshift bins, respectively. As a result, we find values of the power-law slope of 0.905 0.0585, 0.948 0.100, 1.33 0.260 and 0.883 0.0500, respectively.

  15. HerMES: A DEFICIT IN THE SURFACE BRIGHTNESS OF THE COSMIC INFRARED BACKGROUND DUE TO GALAXY CLUSTER GRAVITATIONAL LENSING

    SciTech Connect (OSTI)

    Zemcov, M.; Cooray, A.; Bock, J.; Dowell, C. D.; Nguyen, H. T.; Blain, A.; Bethermin, M.; Conley, A.; Glenn, J.; Conversi, L.; Farrah, D.; Oliver, S. J.; Roseboom, I. G.; Griffin, M.; Halpern, M.; Marsden, G.; Jullo, E.; Kneib, J.-P.; Richard, J.; and others

    2013-06-01

    We have observed four massive galaxy clusters with the SPIRE instrument on the Herschel Space Observatory and measure a deficit of surface brightness within their central region after removing detected sources. We simulate the effects of instrumental sensitivity and resolution, the source population, and the lensing effect of the clusters to estimate the shape and amplitude of the deficit. The amplitude of the central deficit is a strong function of the surface density and flux distribution of the background sources. We find that for the current best fitting faint end number counts, and excellent lensing models, the most likely amplitude of the central deficit is the full intensity of the cosmic infrared background (CIB). Our measurement leads to a lower limit to the integrated total intensity of the CIB of I{sub 250{mu}m}>0.69{sub -0.03}{sup +0.03}(stat.){sub -0.06}{sup +0.11}(sys.) MJy sr{sup -1}, with more CIB possible from both low-redshift sources and from sources within the target clusters. It should be possible to observe this effect in existing high angular resolution data at other wavelengths where the CIB is bright, which would allow tests of models of the faint source component of the CIB.

  16. TYPE Ia SUPERNOVA REMNANT SHELL AT z = 3.5 SEEN IN THE THREE SIGHTLINES TOWARD THE GRAVITATIONALLY LENSED QSO B1422+231

    SciTech Connect (OSTI)

    Hamano, Satoshi; Kobayashi, Naoto [Institute of Astronomy, University of Tokyo, 2-21-1 Osawa, Mitaka, Tokyo 181-0015 (Japan); Kondo, Sohei [Koyama Astronomical Observatory, Kyoto-Sangyo University, Motoyama, Kamigamo, Kita-Ku, Kyoto 603-8555 (Japan); Tsujimoto, Takuji [National Astronomical Observatory of Japan and Department of Astronomical Science, Graduate University for Advanced Studies, 2-21-1 Osawa, Mitaka, Tokyo 181-0015 (Japan); Okoshi, Katsuya [Faculty of Industrial Science and Technology, Tokyo University of Science, 102-1 Tomino, Oshamanbe, Hokkaido 049-3514 (Japan); Shigeyama, Toshikazu, E-mail: hamano@ioa.s.u-tokyo.ac.jp [Research Center for the Early Universe, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033 (Japan)

    2012-08-01

    Using the Subaru 8.2 m Telescope with the IRCS Echelle spectrograph, we obtained high-resolution (R = 10,000) near-infrared (1.01-1.38 {mu}m) spectra of images A and B of the gravitationally lensed QSO B1422+231 (z = 3.628) consisting of four known lensed images. We detected Mg II absorption lines at z = 3.54, which show a large variance of column densities ({approx}0.3 dex) and velocities ({approx}10 km s{sup -1}) between sightlines A and B with a projected separation of only 8.4h{sup -1}{sub 70} pc at that redshift. This is the smallest spatial structure of the high-z gas clouds ever detected after Rauch et al. found a 20 pc scale structure for the same z = 3.54 absorption system using optical spectra of images A and C. The observed systematic variances imply that the system is an expanding shell as originally suggested by Rauch et al. By combining the data for three sightlines, we managed to constrain the radius and expansion velocity of the shell ({approx}50-100 pc, 130 km s{sup -1}), concluding that the shell is truly a supernova remnant (SNR) rather than other types of shell objects, such as a giant H II region. We also detected strong Fe II absorption lines for this system, but with much broader Doppler width than that of {alpha}-element lines. We suggest that this Fe II absorption line originates in a localized Fe II-rich gas cloud that is not completely mixed with plowed ambient interstellar gas clouds showing other {alpha}-element low-ion absorption lines. Along with the Fe richness, we conclude that the SNR is produced by an SN Ia explosion.

  17. NEW CONSTRAINTS ON THE FAINT END OF THE UV LUMINOSITY FUNCTION AT z ? 7-8 USING THE GRAVITATIONAL LENSING OF THE HUBBLE FRONTIER FIELDS CLUSTER A2744

    SciTech Connect (OSTI)

    Atek, Hakim; Kneib, Jean-Paul; Richard, Johan; Clement, Benjamin; Jauzac, Mathilde; Schaerer, Daniel; Limousin, Marceau; Jullo, Eric; Natarajan, Priyamvada; Egami, Eiichi; Ebeling, Harald

    2015-02-10

    Exploiting the power of gravitational lensing, the Hubble Frontier Fields (HFF) program aims at observing six massive galaxy clusters to explore the distant universe far beyond the limits of blank field surveys. Using the complete Hubble Space Telescope observations of the first HFF cluster A2744, we report the detection of 50 galaxy candidates at z ? 7 and eight candidates at z ? 8 in a total survey area of 0.96arcmin{sup 2} in the source plane. Three of these galaxies are multiply imaged by the lensing cluster. Using an updated model of the mass distribution in the cluster we were able to calculate the magnification factor and the effective survey volume for each galaxy in order to compute the ultraviolet galaxy luminosity function (LF) at both redshifts 7 and 8. Our new measurements reliably extend the z ? 7 UV LF down to an absolute magnitude of M {sub UV} ? 15.5. We find a characteristic magnitude of M{sub UV}{sup ?}=?20.90{sub ?0.73}{sup +0.90}mag and a faint-end slope ?=?2.01{sub ?0.28}{sup +0.20}, close to previous determinations in blank fields. We show here for the first time that this slope remains steep down to very faint luminosities of 0.01 L {sup *}. Although prone to large uncertainties, our results at z ? 8 also seem to confirm a steep faint-end slope below 0.1 L {sup *}. The HFF program is therefore providing an extremely efficient way to study the faintest galaxy populations at z > 7 that would otherwise be inaccessible with current instrumentation. The full sample of six galaxy clusters will provide even better constraints on the buildup of galaxies at early epochs and their contribution to cosmic reionization.

  18. Magnification relations for Kerr lensing and testing cosmic censorship

    SciTech Connect (OSTI)

    Werner, M. C.; Petters, A. O.

    2007-09-15

    A Kerr black hole with mass parameter m and angular momentum parameter a acting as a gravitational lens gives rise to two images in the weak field limit. We study the corresponding magnification relations, namely, the signed and absolute magnification sums and the centroid up to post-Newtonian order. We show that there are post-Newtonian corrections to the total absolute magnification and centroid proportional to a/m, which is in contrast to the spherically symmetric case where such corrections vanish. Hence we also propose a new set of lensing observables for the two images involving these corrections, which should allow measuring a/m with gravitational lensing. In fact, the resolution capabilities needed to observe this for the Galactic black hole should in principle be accessible to current and near-future instrumentation. Since a/m>1 indicates a naked singularity, a most interesting application would be a test of the cosmic censorship conjecture. The technique used to derive the image properties is based on the degeneracy of the Kerr lens and a suitably displaced Schwarzschild lens at post-Newtonian order. A simple physical explanation for this degeneracy is also given.

  19. Lensing duct

    DOE Patents [OSTI]

    Beach, Raymond J. , Benett

    1994-01-01

    A lensing duct to condense (intensify) light using a combination of front surface lensing and reflective waveguiding. The duct tapers down from a wide input side to a narrow output side, with the input side being lens-shaped and coated with an antireflective coating for more efficient transmission into the duct. The four side surfaces are uncoated, preventing light from escaping by total internal reflection as it travels along the duct (reflective waveguiding). The duct has various applications for intensifying light, such as in the coupling of diode array pump light to solid state lasing materials, and can be fabricated from inexpensive glass and plastic.

  20. Galaxy cluster lensing masses in modified lensing potentials

    SciTech Connect (OSTI)

    Barreira, Alexandre; Li, Baojiu; Jennings, Elise; Merten, Julian; King, Lindsay; Baugh, Carlton M.; Pascoli, Silvia

    2015-10-28

    In this study, we determine the concentration–mass relation of 19 X-ray selected galaxy clusters from the Cluster Lensing and Supernova Survey with Hubble survey in theories of gravity that directly modify the lensing potential. We model the clusters as Navarro–Frenk–White haloes and fit their lensing signal, in the Cubic Galileon and Nonlocal gravity models, to the lensing convergence profiles of the clusters. We discuss a number of important issues that need to be taken into account, associated with the use of non-parametric and parametric lensing methods, as well as assumptions about the background cosmology. Our results show that the concentration and mass estimates in the modified gravity models are, within the error bars, the same as in Λ cold dark matter. This result demonstrates that, for the Nonlocal model, the modifications to gravity are too weak at the cluster redshifts, and for the Galileon model, the screening mechanism is very efficient inside the cluster radius. However, at distances ~ [2–20] Mpc/h from the cluster centre, we find that the surrounding force profiles are enhanced by ~ 20–40% in the Cubic Galileon model. This has an impact on dynamical mass estimates, which means that tests of gravity based on comparisons between lensing and dynamical masses can also be applied to the Cubic Galileon model.

  1. Galaxy cluster lensing masses in modified lensing potentials

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Barreira, Alexandre; Li, Baojiu; Jennings, Elise; Merten, Julian; King, Lindsay; Baugh, Carlton M.; Pascoli, Silvia

    2015-10-28

    In this study, we determine the concentration–mass relation of 19 X-ray selected galaxy clusters from the Cluster Lensing and Supernova Survey with Hubble survey in theories of gravity that directly modify the lensing potential. We model the clusters as Navarro–Frenk–White haloes and fit their lensing signal, in the Cubic Galileon and Nonlocal gravity models, to the lensing convergence profiles of the clusters. We discuss a number of important issues that need to be taken into account, associated with the use of non-parametric and parametric lensing methods, as well as assumptions about the background cosmology. Our results show that the concentrationmore » and mass estimates in the modified gravity models are, within the error bars, the same as in Λ cold dark matter. This result demonstrates that, for the Nonlocal model, the modifications to gravity are too weak at the cluster redshifts, and for the Galileon model, the screening mechanism is very efficient inside the cluster radius. However, at distances ~ [2–20] Mpc/h from the cluster centre, we find that the surrounding force profiles are enhanced by ~ 20–40% in the Cubic Galileon model. This has an impact on dynamical mass estimates, which means that tests of gravity based on comparisons between lensing and dynamical masses can also be applied to the Cubic Galileon model.« less

  2. MEASURING LENSING MAGNIFICATION OF QUASARS BY LARGE SCALE STRUCTURE USING

    Office of Scientific and Technical Information (OSTI)

    THE VARIABILITY-LUMINOSITY RELATION (Journal Article) | SciTech Connect MEASURING LENSING MAGNIFICATION OF QUASARS BY LARGE SCALE STRUCTURE USING THE VARIABILITY-LUMINOSITY RELATION Citation Details In-Document Search Title: MEASURING LENSING MAGNIFICATION OF QUASARS BY LARGE SCALE STRUCTURE USING THE VARIABILITY-LUMINOSITY RELATION We introduce a technique to measure gravitational lensing magnification using the variability of type I quasars. Quasars' variability amplitudes and luminosities

  3. Formalism for testing theories of gravity using lensing by compact objects: Static, spherically symmetric case

    SciTech Connect (OSTI)

    Keeton, Charles R.; Petters, A.O.

    2005-11-15

    We are developing a general, unified, and rigorous analytical framework for using gravitational lensing by compact objects to test different theories of gravity beyond the weak-deflection limit. In this paper we present the formalism for computing corrections to lensing observables for static, spherically symmetric gravity theories in which the corrections to the weak-deflection limit can be expanded as a Taylor series in one parameter, namely, the gravitational radius of the lens object. We take care to derive coordinate-independent expressions and compute quantities that are directly observable. We compute series expansions for the observables that are accurate to second order in the ratio {epsilon}={theta} /{theta}{sub E} of the angle subtended by the lens's gravitational radius to the weak-deflection Einstein radius, which scales with mass as {epsilon}{proportional_to}M {sup 1/2}. The positions, magnifications, and time delays of the individual images have corrections at both first and second order in {epsilon}, as does the differential time delay between the two images. Interestingly, we find that the first-order corrections to the total magnification and centroid position vanish in all gravity theories that agree with general relativity in the weak-deflection limit, but they can remain nonzero in modified theories that disagree with general relativity in the weak-deflection limit. For the Reissner-Nordstroem metric and a related metric from heterotic string theory, our formalism reveals an intriguing connection between lensing observables and the condition for having a naked singularity, which could provide an observational method for testing the existence of such objects. We apply our formalism to the galactic black hole and predict that the corrections to the image positions are at the level of 10 {mu}arc s (microarcseconds), while the correction to the time delay is a few hundredths of a second. These corrections would be measurable today if a pulsar were found to be lensed by the galactic black hole, and they should be readily detectable with planned missions like MAXIM.

  4. Maps of CMB lensing deflection from N-body simulations in Coupled Dark Energy Cosmologies

    SciTech Connect (OSTI)

    Carbone, Carmelita; Baldi, Marco; Baccigalupi, Carlo E-mail: marco.baldi5@unibo.it E-mail: bacci@sissa.it

    2013-09-01

    We produce lensing potential and deflection-angle maps in order to simulate the weak gravitational lensing of the Cosmic Microwave Background (CMB) via ray-tracing through the COupled Dark Energy Cosmological Simulations (CoDECS), the largest suite of N-body simulations to date for interacting Dark Energy cosmologies. The constructed maps faithfully reflect the N-body cosmic structures on a range of scales going from the arcminute to the degree scale, limited only by the resolution and extension of the simulations. We investigate the variation of the lensing pattern due to the underlying Dark Energy (DE) dynamics, characterised by different background and perturbation behaviours as a consequence of the interaction between the DE field and Cold Dark Matter (CDM). In particular, we study in detail the results from three cosmological models differing in the background and perturbations evolution at the epoch in which the lensing cross section is most effective, corresponding to a redshift of ∼ 1, with the purpose to isolate their imprints in the lensing observables, regardless of the compatibility of these models with present constraints. The scenarios investigated here include a reference ΛCDM cosmology, a standard coupled DE (cDE) scenario, and a ''bouncing'' cDE scenario. For the standard cDE scenario, we find that typical differences in the lensing potential result from two effects: the enhanced growth of linear CDM density fluctuations with respect to the ΛCDM case, and the modified nonlinear dynamics of collapsed structures induced by the DE-CDM interaction. As a consequence, CMB lensing highlights the DE impact in the cosmological expansion, even in the degenerate case where the amplitude of the linear matter density perturbations, parametrised through σ{sub 8}, is the same in both the standard cDE and ΛCDM cosmologies. For the ''bouncing'' scenario, we find that the two opposite behaviours of the lens density contrast and of the matter abundance lead to a counter-intuitive effect, making the power of the lensing signal in this model lower by 10% than in the ΛCDM scenario. Moreover, we compare the behaviour of CDM and baryons in CoDECS separately, in order to isolate effects coming from the coupling with the DE component. We find that, in the bouncing scenario, baryons show an opposite trend with respect to CDM, due to the coupling of the latter with the DE component. These results confirm the relevance of CMB lensing as a probe for DE at the early stages of cosmic acceleration, and demonstrate the reliability of N-body based large scale CMB lensing simulations in the context of DE studies.

  5. Wide-field lensing mass maps from Dark Energy Survey science verification data: Methodology and detailed analysis

    SciTech Connect (OSTI)

    Vikram, V.; Sheldon, E.; Chang, C.; Jain, B.; Bacon, D.; Amara, A.; Becker, M. R.; Bernstein, G.; Bonnett, C.; Bridle, S.; Brout, D.; Busha, M.; Frieman, J.; Gaztanaga, E.; Hartley, W.; Jarvis, M.; Kacprzak, T.; Kovacs, A.; Lahav, O.; Leistedt, B.; Lin, H.; Melchior, P.; Peiris, H.; Rozo, E.; Rykoff, E.; Sanchez, C.; Sheldon, E.; Troxel, M. A.; Wechsler, R.; Zuntz, J.; Abbott, T.; Abdalla, F. B.; Armstrong, R.; Banerji, M.; Bauer, A. H.; Benoit-Levy, A.; Bertin, E.; Brooks, D.; Buckley-Geer, E.; Burke, D. L.; Capozzi, D.; Carnero Rosell, A.; Kind, M. Carrasco; Castander, F. J.; Crocce, M.; Cunha, C. E.

    2015-07-29

    Weak gravitational lensing allows one to reconstruct the spatial distribution of the projected mass density across the sky. These mass maps provide a powerful tool for studying cosmology as they probe both luminous and dark matter. In this paper, we present a weak lensing mass map reconstructed from shear measurements in a 139 deg2 area from the Dark Energy Survey science verification data. We compare the distribution of mass with that of the foreground distribution of galaxies and clusters. The overdensities in the reconstructed map correlate well with the distribution of optically detected clusters. We demonstrate that candidate superclusters and voids along the line of sight can be identified, exploiting the tight scatter of the cluster photometric redshifts. We cross-correlate the mass map with a foreground magnitude-limited galaxy sample from the same data. Our measurement gives results consistent with mock catalogs from N-body simulations that include the primary sources of statistical uncertainties in the galaxy, lensing, and photo-z catalogs. The statistical significance of the cross-correlation is at the 6.8? level with 20 arcminute smoothing. We find that the contribution of systematics to the lensing mass maps is generally within measurement uncertainties. We analyze less than 3% of the final area that will be mapped by the DES; the tools and analysis techniques developed in this paper can be applied to forthcoming larger data sets from the survey.

  6. Wide-field lensing mass maps from Dark Energy Survey science verification data: Methodology and detailed analysis

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Vikram, V.

    2015-07-29

    Weak gravitational lensing allows one to reconstruct the spatial distribution of the projected mass density across the sky. These “mass maps” provide a powerful tool for studying cosmology as they probe both luminous and dark matter. In this paper, we present a weak lensing mass map reconstructed from shear measurements in a 139 deg2 area from the Dark Energy Survey (DES) science verification data. We compare the distribution of mass with that of the foreground distribution of galaxies and clusters. The overdensities in the reconstructed map correlate well with the distribution of optically detected clusters. We demonstrate that candidate superclustersmore » and voids along the line of sight can be identified, exploiting the tight scatter of the cluster photometric redshifts. We cross-correlate the mass map with a foreground magnitude-limited galaxy sample from the same data. Our measurement gives results consistent with mock catalogs from N-body simulations that include the primary sources of statistical uncertainties in the galaxy, lensing, and photo-z catalogs. The statistical significance of the cross-correlation is at the 6.8σ level with 20 arcminute smoothing. We find that the contribution of systematics to the lensing mass maps is generally within measurement uncertainties. In this study, we analyze less than 3% of the final area that will be mapped by the DES; the tools and analysis techniques developed in this paper can be applied to forthcoming larger data sets from the survey.« less

  7. Wide-field lensing mass maps from Dark Energy Survey science verification data: Methodology and detailed analysis

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Vikram, V.; Sheldon, E.; Chang, C.; Jain, B.; Bacon, D.; Amara, A.; Becker, M. R.; Bernstein, G.; Bonnett, C.; Bridle, S.; et al

    2015-07-29

    Weak gravitational lensing allows one to reconstruct the spatial distribution of the projected mass density across the sky. These mass maps provide a powerful tool for studying cosmology as they probe both luminous and dark matter. In this paper, we present a weak lensing mass map reconstructed from shear measurements in a 139 deg2 area from the Dark Energy Survey science verification data. We compare the distribution of mass with that of the foreground distribution of galaxies and clusters. The overdensities in the reconstructed map correlate well with the distribution of optically detected clusters. We demonstrate that candidate superclusters andmorevoids along the line of sight can be identified, exploiting the tight scatter of the cluster photometric redshifts. We cross-correlate the mass map with a foreground magnitude-limited galaxy sample from the same data. Our measurement gives results consistent with mock catalogs from N-body simulations that include the primary sources of statistical uncertainties in the galaxy, lensing, and photo-z catalogs. The statistical significance of the cross-correlation is at the 6.8? level with 20 arcminute smoothing. We find that the contribution of systematics to the lensing mass maps is generally within measurement uncertainties. We analyze less than 3% of the final area that will be mapped by the DES; the tools and analysis techniques developed in this paper can be applied to forthcoming larger data sets from the survey.less

  8. Wide-field lensing mass maps from Dark Energy Survey science verification data: Methodology and detailed analysis

    SciTech Connect (OSTI)

    Vikram, V.

    2015-07-29

    Weak gravitational lensing allows one to reconstruct the spatial distribution of the projected mass density across the sky. These mass maps provide a powerful tool for studying cosmology as they probe both luminous and dark matter. In this paper, we present a weak lensing mass map reconstructed from shear measurements in a 139 deg2 area from the Dark Energy Survey (DES) science verification data. We compare the distribution of mass with that of the foreground distribution of galaxies and clusters. The overdensities in the reconstructed map correlate well with the distribution of optically detected clusters. We demonstrate that candidate superclusters and voids along the line of sight can be identified, exploiting the tight scatter of the cluster photometric redshifts. We cross-correlate the mass map with a foreground magnitude-limited galaxy sample from the same data. Our measurement gives results consistent with mock catalogs from N-body simulations that include the primary sources of statistical uncertainties in the galaxy, lensing, and photo-z catalogs. The statistical significance of the cross-correlation is at the 6.8? level with 20 arcminute smoothing. We find that the contribution of systematics to the lensing mass maps is generally within measurement uncertainties. In this study, we analyze less than 3% of the final area that will be mapped by the DES; the tools and analysis techniques developed in this paper can be applied to forthcoming larger data sets from the survey.

  9. Wide-Field Lensing Mass Maps from DES Science Verification Data

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Chang, C.; Vikram, V.; Jain, B.

    2015-07-29

    We present a mass map reconstructed from weak gravitational lensing shear measurements over 139 deg2 from the Dark Energy Survey (DES) Science Verification data. The mass map probes both luminous and dark matter, thus providing a tool for studying cosmology. We find good agreement between the mass map and the distribution of massive galaxy clusters identified using a red-sequence cluster finder. Potential candidates for super-clusters and voids are identified using these maps. We measure the cross-correlation between the mass map and a magnitude-limited foreground galaxy sample and find a detection at the 6.8? level with 20 arcminute smoothing. These measurementsmoreare consistent with simulated galaxy catalogs based on ?CDM Nbody simulations, suggesting low systematics uncertainties in the map. We summarize our key findings in this letter; the detailed methodology and tests for systematics are presented in a companion paper.less

  10. LENSING NOISE IN MILLIMETER-WAVE GALAXY CLUSTER SURVEYS

    SciTech Connect (OSTI)

    Hezaveh, Yashar; Vanderlinde, Keith; Holder, Gilbert; De Haan, Tijmen

    2013-08-01

    We study the effects of gravitational lensing by galaxy clusters of the background of dusty star-forming galaxies (DSFGs) and the cosmic microwave background (CMB), and examine the implications for Sunyaev-Zel'dovich-based (SZ) galaxy cluster surveys. At the locations of galaxy clusters, gravitational lensing modifies the probability distribution of the background flux of the DSFGs as well as the CMB. We find that, in the case of a single-frequency 150 GHz survey, lensing of DSFGs leads both to a slight increase ({approx}10%) in detected cluster number counts (due to a {approx}50% increase in the variance of the DSFG background, and hence an increased Eddington bias) and a rare (occurring in {approx}2% of clusters) 'filling-in' of SZ cluster signals by bright strongly lensed background sources. Lensing of the CMB leads to a {approx}55% reduction in CMB power at the location of massive galaxy clusters in a spatially matched single-frequency filter, leading to a net decrease in detected cluster number counts. We find that the increase in DSFG power and decrease in CMB power due to lensing at cluster locations largely cancel, such that the net effect on cluster number counts for current SZ surveys is subdominant to Poisson errors.

  11. Probing gravitational dark matter

    SciTech Connect (OSTI)

    Ren, Jing; He, Hong-Jian

    2015-03-27

    So far all evidences of dark matter (DM) come from astrophysical and cosmological observations, due to the gravitational interactions of DM. It is possible that the true DM particle in the universe joins gravitational interactions only, but nothing else. Such a Gravitational DM (GDM) may act as a weakly interacting massive particle (WIMP), which is conceptually simple and attractive. In this work, we explore this direction by constructing the simplest scalar GDM particle χ{sub s}. It is a ℤ{sub 2} odd singlet under the standard model (SM) gauge group, and naturally joins the unique dimension-4 interaction with Ricci curvature, ξ{sub s}χ{sub s}{sup 2}R, where ξ{sub s} is the dimensionless nonminimal coupling. We demonstrate that this gravitational interaction ξ{sub s}χ{sub s}{sup 2}R, together with Higgs-curvature nonminimal coupling term ξ{sub h}H{sup †}HR, induces effective couplings between χ{sub s}{sup 2} and SM fields, and can account for the observed DM thermal relic abundance. We analyze the annihilation cross sections of GDM particles and derive the viable parameter space for realizing the DM thermal relic density. We further study the direct/indirect detections and the collider signatures of such a scalar GDM. These turn out to be highly predictive and testable.

  12. Gravitational waves from gravitational collapse

    SciTech Connect (OSTI)

    Fryer, Christopher L; New, Kimberly C

    2008-01-01

    Gravitational wave emission from stellar collapse has been studied for nearly four decades. Current state-of-the-art numerical investigations of collapse include those that use progenitors with more realistic angular momentum profiles, properly treat microphysics issues, account for general relativity, and examine non-axisymmetric effects in three dimensions. Such simulations predict that gravitational waves from various phenomena associated with gravitational collapse could be detectable with ground-based and space-based interferometric observatories. This review covers the entire range of stellar collapse sources of gravitational waves: from the accretion induced collapse of a white dwarf through the collapse down to neutron stars or black holes of massive stars to the collapse of supermassive stars.

  13. The Impact of Camera Optical Alignments on Weak Lensing Measures...

    Office of Scientific and Technical Information (OSTI)

    London ; Roodman, Aaron ; SLAC ; Walker, Alistair R. ; Cerro-Tololo InterAmerican Obs. less Publication Date: 2013-03-18 OSTI Identifier: 1074241 Report Number(s): ...

  14. Hollow lensing duct

    DOE Patents [OSTI]

    Beach, Raymond J.; Honea, Eric C.; Bibeau, Camille; Mitchell, Scott; Lang, John; Maderas, Dennis; Speth, Joel; Payne, Stephen A.

    2000-01-01

    A hollow lensing duct to condense (intensify) light using a combination of focusing using a spherical or cylindrical lens followed by reflective waveguiding. The hollow duct tapers down from a wide input side to a narrow output side, with the input side consisting of a lens that may be coated with an antireflective coating for more efficient transmission into the duct. The inside surfaces of the hollow lens duct are appropriately coated to be reflective, preventing light from escaping by reflection as it travels along the duct (reflective waveguiding). The hollow duct has various applications for intensifying light, such as in the coupling of diode array pump light to solid state lasing materials.

  15. RHIC electron lenses upgrades

    SciTech Connect (OSTI)

    Gu, X.; Altinbas, Z.; Bruno, D.; Binello, S.; Costanzo, M.; Drees, A.; Fischer, W.; Gassner, D. M.; Hock, J.; Hock, K.; Harvey, M.; Luo, Y.; Marusic, A.; Mi, C.; Mernick, K.; Minty, M.; Michnoff, R.; Miller, T. A.; Pikin, A. I.; Robert-Demolaize, G.; Samms, T.; Shrey, T. C.; Schoefer, V.; Tan, Y.; Than, R.; Thieberger, P.; White, S. M.

    2015-05-03

    In the Relativistic Heavy Ion Collider (RHIC) 100 GeV polarized proton run in 2015, two electron lenses were used to partially compensate for the head-on beam-beam effect for the first time. Here, we describe the design of the current electron lens, detailing the hardware modifications made after the 2014 commissioning run with heavy ions. A new electron gun with 15-mm diameter cathode is characterized. The electron beam transverse profile was measured using a YAG screen and fitted with a Gaussian distribution. During operation, the overlap of the electron and proton beams was achieved using the electron backscattering detector in conjunction with an automated orbit control program.

  16. Analytic models of plausible gravitational lens potentials

    SciTech Connect (OSTI)

    Baltz, Edward A.; Marshall, Phil; Oguri, Masamune, E-mail: eabaltz@slac.stanford.edu, E-mail: pjm@physics.ucsb.edu, E-mail: oguri@slac.stanford.edu [Kavli Institute for Particle Astrophysics and Cosmology, Stanford University, PO Box 20450, MS29, Stanford, CA 94309 (United States)] [Kavli Institute for Particle Astrophysics and Cosmology, Stanford University, PO Box 20450, MS29, Stanford, CA 94309 (United States)

    2009-01-15

    Gravitational lenses on galaxy scales are plausibly modelled as having ellipsoidal symmetry and a universal dark matter density profile, with a Sersic profile to describe the distribution of baryonic matter. Predicting all lensing effects requires knowledge of the total lens potential: in this work we give analytic forms for that of the above hybrid model. Emphasising that complex lens potentials can be constructed from simpler components in linear combination, we provide a recipe for attaining elliptical symmetry in either projected mass or lens potential. We also provide analytic formulae for the lens potentials of Sersic profiles for integer and half-integer index. We then present formulae describing the gravitational lensing effects due to smoothly-truncated universal density profiles in cold dark matter model. For our isolated haloes the density profile falls off as radius to the minus fifth or seventh power beyond the tidal radius, functional forms that allow all orders of lens potential derivatives to be calculated analytically, while ensuring a non-divergent total mass. We show how the observables predicted by this profile differ from that of the original infinite-mass NFW profile. Expressions for the gravitational flexion are highlighted. We show how decreasing the tidal radius allows stripped haloes to be modelled, providing a framework for a fuller investigation of dark matter substructure in galaxies and clusters. Finally we remark on the need for finite mass halo profiles when doing cosmological ray-tracing simulations, and the need for readily-calculable higher order derivatives of the lens potential when studying catastrophes in strong lenses.

  17. Discovery of Four Gravitationally Lensed Quasarsfrom the Sloan...

    Office of Scientific and Technical Information (OSTI)

    Resource Type: Journal Article Resource Relation: Journal Name: The Astronimical Journal Research Org: Stanford Linear Accelerator Center (SLAC) Sponsoring Org: USDOE...

  18. Three gravitationally lensed supernovae behind clash galaxy clusters...

    Office of Scientific and Technical Information (OSTI)

    Using multi-color light-curve fits to determine a standardized SN Ia luminosity distance, ... Subject: 79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; BRIGHTNESS; CLASSIFICATION; COLOR; ...

  19. Weak Interactions

    DOE R&D Accomplishments [OSTI]

    Lee, T. D.

    1957-06-01

    Experimental results on the non-conservation of parity and charge conservation in weak interactions are reviewed. The two-component theory of the neutrino is discussed. Lepton reactions are examined under the assumption of the law of conservation of leptons and that the neutrino is described by a two- component theory. From the results of this examination, the universal Fermi interactions are analyzed. Although reactions involving the neutrino can be described, the same is not true of reactions which do not involve the lepton, as the discussion of the decay of K mesons and hyperons shows. The question of the invariance of time reversal is next examined. (J.S.R.)

  20. CMB ISW-lensing bispectrum from cosmic strings

    SciTech Connect (OSTI)

    Yamauchi, Daisuke; Sendouda, Yuuiti; Takahashi, Keitaro E-mail: sendouda@cc.hirosaki-u.ac.jp

    2014-02-01

    We study the effect of weak lensing by cosmic (super-)strings on the higher-order statistics of the cosmic microwave background (CMB). A cosmic string segment is expected to cause weak lensing as well as an integrated Sachs-Wolfe (ISW) effect, the so-called Gott-Kaiser-Stebbins (GKS) effect, to the CMB temperature fluctuation, which are thus naturally cross-correlated. We point out that, in the presence of such a correlation, yet another kind of the post-recombination CMB temperature bispectra, the ISW-lensing bispectra, will arise in the form of products of the auto- and cross-power spectra. We first present an analytic method to calculate the autocorrelation of the temperature fluctuations induced by the strings, and the cross-correlation between the temperature fluctuation and the lensing potential both due to the string network. In our formulation, the evolution of the string network is assumed to be characterized by the simple analytic model, the velocity-dependent one scale model, and the intercommutation probability is properly incorporated in order to characterize the possible superstringy nature. Furthermore, the obtained power spectra are dominated by the Poisson-distributed string segments, whose correlations are assumed to satisfy the simple relations. We then estimate the signal-to-noise ratios of the string-induced ISW-lensing bispectra and discuss the detectability of such CMB signals from the cosmic string network. It is found that in the case of the smaller string tension, G? << 10{sup -7}, the ISW-lensing bispectrum induced by a cosmic string network can constrain the string-model parameters even more tightly than the purely GKS-induced bispectrum in the ongoing and future CMB observations on small scales.

  1. Wide-Field Lensing Mass Maps from Dark Energy Survey Science Verification Data

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Chang, C.

    2015-07-29

    We present a mass map reconstructed from weak gravitational lensing shear measurements over 139 deg2 from the Dark Energy Survey science verification data. The mass map probes both luminous and dark matter, thus providing a tool for studying cosmology. We also find good agreement between the mass map and the distribution of massive galaxy clusters identified using a red-sequence cluster finder. Potential candidates for superclusters and voids are identified using these maps. We measure the cross-correlation between the mass map and a magnitude-limited foreground galaxy sample and find a detection at the 6.8σ level with 20 arc min smoothing. Thesemore » measurements are consistent with simulated galaxy catalogs based on N-body simulations from a cold dark matter model with a cosmological constant. This suggests low systematics uncertainties in the map. Finally, we summarize our key findings in this Letter; the detailed methodology and tests for systematics are presented in a companion paper.« less

  2. Wide-Field Lensing Mass Maps from Dark Energy Survey Science Verification Data

    SciTech Connect (OSTI)

    Chang, C.

    2015-07-29

    We present a mass map reconstructed from weak gravitational lensing shear measurements over 139 deg2 from the Dark Energy Survey science verification data. The mass map probes both luminous and dark matter, thus providing a tool for studying cosmology. We also find good agreement between the mass map and the distribution of massive galaxy clusters identified using a red-sequence cluster finder. Potential candidates for superclusters and voids are identified using these maps. We measure the cross-correlation between the mass map and a magnitude-limited foreground galaxy sample and find a detection at the 6.8? level with 20 arc min smoothing. These measurements are consistent with simulated galaxy catalogs based on N-body simulations from a cold dark matter model with a cosmological constant. This suggests low systematics uncertainties in the map. Finally, we summarize our key findings in this Letter; the detailed methodology and tests for systematics are presented in a companion paper.

  3. Relativistic images in Randall-Sundrum II braneworld lensing

    SciTech Connect (OSTI)

    Bin-Nun, Amitai Y.

    2010-06-15

    In this paper, we explore the properties of gravitational lensing by black holes in the Randall-Sundrum II braneworld. We use numerical techniques to calculate lensing observables using the tidal Reissner-Nordstrom (TRN) and Garriga-Tanaka metrics to examine supermassive black holes and primordial black holes. We introduce a new way to parametrize tidal charge in the TRN metric which results in a large increase in image magnifications for braneworld primordial black holes compared to their 4-dimensional analogs. Finally, we offer a mathematical analysis that allows us to assess the validity of the logarithmic approximation of the bending angle for any static, spherically symmetric metric. We apply this to the TRN metric and show that it is valid for any amount of tidal charge.

  4. The M31 pixel lensing plan campaign: MACHO lensing and self-lensing signals

    SciTech Connect (OSTI)

    Calchi Novati, S.; Scarpetta, G.; Bozza, V.; Bruni, I.; Gualandi, R.; Dall'Ora, M.; De Paolis, F.; Ingrosso, G.; Nucita, A.; Strafella, F.; Dominik, M.; Jetzer, Ph.; Mancini, L.; Safonova, M.; Subramaniam, A.; Sereno, M.; Gould, A.; Collaboration: PLAN Collaboration

    2014-03-10

    We present the final analysis of the observational campaign carried out by the PLAN (Pixel Lensing Andromeda) collaboration to detect a dark matter signal in form of MACHOs through the microlensing effect. The campaign consists of about 1 month/year observations carried out over 4 years (2007-2010) at the 1.5 m Cassini telescope in Loiano (Astronomical Observatory of BOLOGNA, OAB) plus 10 days of data taken in 2010 at the 2 m Himalayan Chandra Telescope monitoring the central part of M31 (two fields of about 13' 12.'6). We establish a fully automated pipeline for the search and the characterization of microlensing flux variations. As a result, we detect three microlensing candidates. We evaluate the expected signal through a full Monte Carlo simulation of the experiment completed by an analysis of the detection efficiency of our pipeline. We consider both 'self lensing' and 'MACHO lensing' lens populations, given by M31 stars and dark matter halo MACHOs, in M31 and the Milky Way, respectively. The total number of events is consistent with the expected self-lensing rate. Specifically, we evaluate an expected signal of about two self-lensing events. As for MACHO lensing, for full 0.5(10{sup 2}) M {sub ?} MACHO halos, our prediction is for about four (seven) events. The comparatively small number of expected MACHO versus self-lensing events, together with the small number statistics at our disposal, do not enable us to put strong constraints on that population. Rather, the hypothesis, suggested by a previous analysis, on the MACHO nature of OAB-07-N2, one of the microlensing candidates, translates into a sizeable lower limit for the halo mass fraction in form of the would-be MACHO population, f, of about 15% for 0.5 M {sub ?} MACHOs.

  5. Tevatron Electron Lenses: Design and Operation

    SciTech Connect (OSTI)

    Shiltsev, Vladimir; Bishofberger, Kip; Kamerdzhiev, Vsevolod; Kozub, Sergei; Kufer, Matthew; Kuznetsov, Gennady; Martinez, Alexander; Olson, Marvin; Pfeffer, Howard; Saewert, Greg; Scarpine, Vic; /Fermilab /SLAC /Fermilab /Serpukhov, IHEP /Novosibirsk, IYF /Serpukhov, IHEP /Fermilab

    2008-08-01

    The beam-beam effects have been the dominating sources of beam loss and lifetime limitations in the Tevatron proton-antiproton collider [1]. Electron lenses were originally proposed for compensation of electromagnetic long-range and head-on beam-beam interactions of proton and antiproton beams [2]. Results of successful employment of two electron lenses built and installed in the Tevatron are reported in [3,4,5]. In this paper we present design features of the Tevatron electron lenses (TELs), discuss the generation of electron beams, describe different modes of operation and outline the technical parameters of various subsystems.

  6. Weak Interaction | Jefferson Lab

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Weak Interaction Weak Interaction February 22, 2011 Jefferson Lab has an accelerator designed to do incisive medium energy physics. This program is dominated by experiments aimed at developing our understanding of the strong interaction. This is the force which generates much of the complexity in the world around us. On the finest distance scales, the strong interaction acts between quarks and quarks, quarks and gluons, gluons and gluons. The mass of the proton (which is built of quarks and

  7. 3C 220.3: A radio galaxy lensing a submillimeter galaxy

    SciTech Connect (OSTI)

    Haas, Martin; Westhues, Christian; Chini, Rolf; Leipski, Christian; Klaas, Ulrich; Meisenheimer, Klaus; Barthel, Peter; Koopmans, Lon V. E.; Wilkes, Belinda J.; Bussmann, R. Shane; Willner, S. P.; Ashby, Matthew L. N.; Kuraszkiewicz, Joanna; Vegetti, Simona; Clements, David L.; Fassnacht, Christopher D.; Horesh, Assaf; Lagattuta, David J.; Stern, Daniel; Wylezalek, Dominika

    2014-07-20

    Herschel Space Observatory photometry and extensive multiwavelength follow-up have revealed that the powerful radio galaxy (PRG) 3C 220.3 at z = 0.685 acts as a gravitational lens for a background submillimeter galaxy (SMG) at z = 2.221. At an observed wavelength of 1 mm, the SMG is lensed into three distinct images. In the observed near infrared, these images are connected by an arc of ?1''.8 radius forming an Einstein half-ring centered near the radio galaxy. In visible light, only the arc is apparent. 3C 220.3 is the only known instance of strong galaxy-scale lensing by a PRG not located in a galaxy cluster and therefore it offers the potential to probe the dark matter content of the radio galaxy host. Lens modeling rejects a single lens, but two lenses centered on the radio galaxy host A and a companion B, separated by 1''.5, provide a fit consistent with all data and reveal faint candidates for the predicted fourth and fifth images. The model does not require an extended common dark matter halo, consistent with the absence of extended bright X-ray emission on our Chandra image. The projected dark matter fractions within the Einstein radii of A (1''.02) and B (0''.61) are about 0.4 0.3 and 0.55 0.3. The mass to i-band light ratios of A and B, M/L{sub i}?84 M{sub ?} L{sub ?}{sup ?1}, appear comparable to those of radio-quiet lensing galaxies at the same redshift in the CfA-Arizona Space Telescope LEns Survey, Lenses Structure and Dynamics, and Strong Lenses in the Legacy Survey samples. The lensed SMG is extremely bright with observed f(250 ?m) = 440 mJy owing to a magnification factor ? ? 10. The SMG spectrum shows luminous, narrow C IV ?1549 emission, revealing that the SMG houses a hidden quasar in addition to a violent starburst. Multicolor image reconstruction of the SMG indicates a bipolar morphology of the emitted ultraviolet (UV) light suggestive of cones through which UV light escapes a dust-enshrouded nucleus.

  8. Fabrication of wedged multilayer Laue lenses

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Prasciolu, M.; Leontowich, A. F. G.; Krzywinski, J.; Andrejczuk, A.; Chapman, H. N.; Bajt, S.

    2015-01-01

    We present a new method to fabricate wedged multilayer Laue lenses, in which the angle of diffracting layers smoothly varies in the lens to achieve optimum diffracting efficiency across the entire pupil of the lens. This was achieved by depositing a multilayer onto a flat substrate placed in the penumbra of a straight-edge mask. The distance between the mask and the substrate was calibrated and the multilayer Laue lens was cut in a position where the varying layer thickness and the varying layer tilt simultaneously satisfy the Fresnel zone plate condition and Bragg’s law for all layers in the stack.more » This method can be used to extend the achievable numerical aperture of multilayer Laue lenses to reach considerably smaller focal spot sizes than achievable with lenses composed of parallel layers.« less

  9. Fabrication of wedged multilayer Laue lenses

    SciTech Connect (OSTI)

    Prasciolu, M.; Leontowich, A. F. G.; Krzywinski, J.; Andrejczuk, A.; Chapman, H. N.; Bajt, S.

    2015-01-01

    We present a new method to fabricate wedged multilayer Laue lenses, in which the angle of diffracting layers smoothly varies in the lens to achieve optimum diffracting efficiency across the entire pupil of the lens. This was achieved by depositing a multilayer onto a flat substrate placed in the penumbra of a straight-edge mask. The distance between the mask and the substrate was calibrated and the multilayer Laue lens was cut in a position where the varying layer thickness and the varying layer tilt simultaneously satisfy the Fresnel zone plate condition and Braggs law for all layers in the stack. This method can be used to extend the achievable numerical aperture of multilayer Laue lenses to reach considerably smaller focal spot sizes than achievable with lenses composed of parallel layers.

  10. A redshift survey of the strong-lensing cluster ABELL 383

    SciTech Connect (OSTI)

    Geller, Margaret J.; Hwang, Ho Seong; Kurtz, Michael J.; Diaferio, Antonaldo; Coe, Dan; Rines, Kenneth J. E-mail: hhwang@cfa.harvard.edu E-mail: diaferio@ph.unito.it E-mail: kenneth.rines@wwu.edu

    2014-03-01

    Abell 383 is a famous rich cluster (z = 0.1887) imaged extensively as a basis for intensive strong- and weak-lensing studies. Nonetheless, there are few spectroscopic observations. We enable dynamical analyses by measuring 2360 new redshifts for galaxies with r {sub Petro} ≤ 20.5 and within 50' of the Brightest Cluster Galaxy (BCG; R.A.{sub 2000} = 42.°014125, decl.{sub 2000} = –03.°529228). We apply the caustic technique to identify 275 cluster members within 7 h {sup –1} Mpc of the hierarchical cluster center. The BCG lies within –11 ± 110 km s{sup –1} and 21 ± 56 h {sup –1} kpc of the hierarchical cluster center; the velocity dispersion profile of the BCG appears to be an extension of the velocity dispersion profile based on cluster members. The distribution of cluster members on the sky corresponds impressively with the weak-lensing contours of Okabe et al. especially when the impact of foreground and background structure is included. The values of R {sub 200} = 1.22 ± 0.01 h {sup –1} Mpc and M {sub 200} = (5.07 ± 0.09) × 10{sup 14} h {sup –1} M {sub ☉} obtained by application of the caustic technique agree well with recent completely independent lensing measures. The caustic estimate extends direct measurement of the cluster mass profile to a radius of ∼5 h {sup –1} Mpc.

  11. Gravitational properties of antimatter

    SciTech Connect (OSTI)

    Goldman, T.; Nieto, M.M.

    1985-01-01

    Quantum gravity is at the forefront of modern particle physics, yet there are no direct tests, for antimatter, of even the principle of equivalence. We note that modern descriptions of gravity, such as fibre bundles and higher dimensional spacetimes, allow violations of the commonly stated form of the principle of equivalence, and of CPT. We review both indirect arguments and experimental tests of the expected gravitational properties of CPT-conjugate states. We conclude that a direct experimental test of the gravitational properties of antimatter, at the 1% (or better) level, would be of great value. We identify some experimental reasons which make the antiproton a prime candidate for this test, and we strongly urge that such an experiment be done at LEAR. 21 references.

  12. Searching for Novel Gravitational Effects

    ScienceCinema (OSTI)

    Christopher Stubb

    2010-09-01

    Stubbs, Chair of the Physics Department at Harvard University, discusses experiments that search for novel gravitational effect and scientific observations about it.

  13. Weakly broken galileon symmetry

    SciTech Connect (OSTI)

    Pirtskhalava, David; Santoni, Luca; Trincherini, Enrico; Vernizzi, Filippo

    2015-09-01

    Effective theories of a scalar ϕ invariant under the internal galileon symmetryϕ→ϕ+b{sub μ}x{sup μ} have been extensively studied due to their special theoretical and phenomenological properties. In this paper, we introduce the notion of weakly broken galileon invariance, which characterizes the unique class of couplings of such theories to gravity that maximally retain their defining symmetry. The curved-space remnant of the galileon’s quantum properties allows to construct (quasi) de Sitter backgrounds largely insensitive to loop corrections. We exploit this fact to build novel cosmological models with interesting phenomenology, relevant for both inflation and late-time acceleration of the universe.

  14. THE FAINTEST RADIO SOURCE YET: EXPANDED VERY LARGE ARRAY OBSERVATIONS OF THE GRAVITATIONAL LENS SDSS J1004+4112

    SciTech Connect (OSTI)

    Jackson, N.

    2011-09-20

    We present new radio observations of the large-separation gravitationally lensed quasar SDSS J1004+4112, taken in a total of 6 hr of observations with the Expanded Very Large Array. The maps reach a thermal noise level of approximately 4 {mu}Jy. We detect four of the five lensed images at the 15-35 {mu}Jy level, representing a source of intrinsic flux density, after allowing for lensing magnification, of about 1 {mu}Jy, intrinsically probably the faintest radio source yet detected. This reinforces the utility of gravitational lensing in potentially allowing us to study nJy-level sources before the advent of the Square Kilometre Array. In an optical observation taken three months after the radio observation, image C is the brightest image, whereas the radio map shows flux density ratios consistent with previous optical observations. Future observations separated by a time delay will give the intrinsic flux ratios of the images in this source.

  15. Automation Enhancement of Multilayer Laue Lenses

    SciTech Connect (OSTI)

    Lauer K. R.; Conley R.

    2010-12-01

    X-ray optics fabrication at Brookhaven National Laboratory has been facilitated by a new, state of the art magnetron sputtering physical deposition system. With its nine magnetron sputtering cathodes and substrate carrier that moves on a linear rail via a UHV brushless linear servo motor, the system is capable of accurately depositing the many thousands of layers necessary for multilayer Laue lenses. I have engineered a versatile and automated control program from scratch for the base system and many subsystems. Its main features include a custom scripting language, a fully customizable graphical user interface, wireless and remote control, and a terminal-based interface. This control system has already been successfully used in the creation of many types of x-ray optics, including several thousand layer multilayer Laue lenses.Before reaching the point at which a deposition can be run, stencil-like masks for the sputtering cathodes must be created to ensure the proper distribution of sputtered atoms. Quality of multilayer Laue lenses can also be difficult to measure, given the size of the thin film layers. I employ my knowledge of software and algorithms to further ease these previously painstaking processes with custom programs. Additionally, I will give an overview of an x-ray optic simulator package I helped develop during the summer of 2010. In the interest of keeping my software free and open, I have worked mostly with the multiplatform Python and the PyQt application framework, utilizing C and C++ where necessary.

  16. STRONG GRAVITATIONAL LENSING BY THE SUPER-MASSIVE cD GALAXY IN...

    Office of Scientific and Technical Information (OSTI)

    Authors: Carrasco, E. R. ; Gomez, P. L. ; Lee, H. ; Diaz, R. ; Bergmann, M. ; Turner, J. E. H. ; Miller, B. W. ; West, M. J. 1 ; Verdugo, T. 2 + Show Author Affiliations Gemini ...

  17. Spherical gravitational collapse in N dimensions

    SciTech Connect (OSTI)

    Goswami, Rituparno; Joshi, Pankaj S.

    2007-10-15

    We investigate here spherically symmetric gravitational collapse in a space-time with an arbitrary number of dimensions and with a general type I matter field, which is a broad class that includes most of the physically reasonable matter forms. We show that given the initial data for matter in terms of the initial density and pressure profiles at an initial surface t=t{sub i} from which the collapse evolves, there exist the rest of the initial data functions and classes of solutions of Einstein equations which we construct here, such that the space-time evolution goes to a final state which is either a black hole or a naked singularity, depending on the nature of initial data and evolutions chosen, and subject to validity of the weak energy condition. The results are discussed and analyzed in the light of the cosmic censorship hypothesis in black hole physics. The formalism here combines the earlier results on gravitational collapse in four dimensions in a unified treatment. Also the earlier work is generalized to higher-dimensional space-times to allow a study of the effect of the number of dimensions on the possible final outcome of the collapse in terms of either a black hole or naked singularity. No restriction is adopted on the number of dimensions, and other limiting assumptions such as self-similarity of space-time are avoided, in order to keep the treatment general. Our methodology allows us to consider to an extent the genericity and stability aspects related to the occurrence of naked singularities in gravitational collapse.

  18. On possible use of electron lenses in LHC

    SciTech Connect (OSTI)

    Shiltsev, V.; /Fermilab

    2006-10-01

    We present basic facts about electron lenses used in high-energy accelerators and discuss their possible application in the LHC. Four proposals are presented: (a) electron lenses for compensation of head-on beam-beam effects; (b) electron lens as tune-spreader for better beam stability; (c) as electromagnetic primary collimator for ions and protons; (d) satellite bunch cleaning by electron lenses. Main requirements are discussed.

  19. A RECIPE TO PROBE ALTERNATIVE THEORIES OF GRAVITATION VIA N-BODY NUMERICAL SIMULATIONS. I. SPIRAL GALAXIES

    SciTech Connect (OSTI)

    Brandao, C. S. S.; De Araujo, J. C. N., E-mail: claudiosoriano.uesc@gmail.com, E-mail: jcarlos.dearaujo@inpe.br [Divisao de Astrofisica, Instituto Nacional de Pesquisas Espaciais, S. J. Campos, SP 12227-010 (Brazil)

    2012-05-01

    A way to probe alternative theories of gravitation is to study if they could account for the structures of the universe. We therefore modified the well-known Gadget-2 code to probe alternative theories of gravitation through galactic dynamics. As an application, we simulate the evolution of spiral galaxies to probe alternative theories of gravitation whose weak field limits have a Yukawa-like gravitational potential. These simulations show that galactic dynamics can be used to constrain the parameters associated with alternative theories of gravitation. It is worth stressing that the recipe given in this study can be applied to any other alternative theory of gravitation in which the superposition principle is valid.

  20. Tevatron Electron Lenses: Design and Operation

    SciTech Connect (OSTI)

    Shiltsev, Vladimir; Bishofberger, Kip; Kamerdzhiev, Vsevolod; Kozub, Sergei; Kufer, Matthew; Kuznetsov, Gennady; Martinez, Alexander; Olson, Marvin; Pfeffer, Howard; Saewert, Greg; Scarpine, Vic; Seryi, Andrei; Solyak, Nikolai; Sytnik, Veniamin; Tiunov, Mikhail; Tkachenko, Leonid; Wildman, David; Wolff, Daniel; Zhang, Xiao-Long; /Fermilab

    2011-09-12

    Fermilab's Tevatron is currently the world's highest energy accelerator in which tightly focused beams of 980 GeV protons and antiprotons collide at two dedicated interaction points (IPs). Both beams share the same beam pipe and magnet aperture and, in order to avoid multiple detrimental head-on collisions, the beams are placed on separated orbits everywhere except the main IPs by using high-voltage (HV) electrostatic separators. The electromagnetic beam-beam interaction at the main IPs together with the long-range interactions between separated beams adversely affect the collider performance, reducing the luminosity integral per store (period of continuous collisions) by 10-30%. Tuning the collider operation for optimal performance becomes more and more cumbersome as the beam intensities and luminosity increase. The long-range effects which (besides being nonlinear) vary from bunch to bunch are particularly hard to mitigate. A comprehensive review of the beam-beam effects in the Tevatron Collider Run II can be found in Ref. [1]. The beam-beam effects have been the dominating sources of beam loss and lifetime limitations in the Tevatron proton-antiproton collider [1]. Electron lenses were originally proposed for compensation of electromagnetic long-range and head-on beam-beam interactions of proton and antiproton beams [2]. Results of successful employment of two electron lenses built and installed in the Tevatron are reported in [3,4,5]. In this paper we present design features of the Tevatron electron lenses (TELs), discuss the generation of electron beams, describe different modes of operation and outline the technical parameters of various subsystems.

  1. Construction progress of the RHIC electron lenses

    SciTech Connect (OSTI)

    Fischer W.; Altinbas, Z.; Anerella, M.; Beebe, E.; et al

    2012-05-20

    In polarized proton operation the RHIC performance is limited by the head-on beam-beam effect. To overcome this limitation two electron lenses are under construction. We give an overview of the construction progress. Guns, collectors and the warm electron beam transport solenoids with their power supplies have been constructed. The superconducting solenoids that guide the electron beam during the interaction with the proton beam are near completion. A test stand has been set up to verify the performance of the gun, collector and some of the instrumentation. The infrastructure is being prepared for installation, and simulations continue to optimize the performance.

  2. Electron beam generation in Tevatron electron lenses

    SciTech Connect (OSTI)

    Kamerdzhiev, V.; Kuznetsov, G.; Shiltsev, V.; Solyak, N.; Tiunov, M.; /Novosibirsk, IYF

    2006-08-01

    New type of high perveance electron guns with convex cathode has been developed. Three guns described in this article are built to provide transverse electron current density distributions needed for Electron Lenses for beam-beam compensation in the Tevatron collider. The current distribution can be controlled either by the gun geometry or by voltage on a special control electrode located near cathode. We present the designs of the guns and report results of beam measurements on the test bench. Because of their high current density and low transverse temperature of electrons, electron guns of this type can be used in electron cooling and beam-beam compensation devices.

  3. Compound Refractive Lenses for Thermal Neutron Applications

    SciTech Connect (OSTI)

    Gary, Charles K.

    2013-11-12

    This project designed and built compound refractive lenses (CRLs) that are able to focus, collimate and image using thermal neutrons. Neutrons are difficult to manipulate compared to visible light or even x rays; however, CRLs can provide a powerful tool for focusing, collimating and imaging neutrons. Previous neutron CRLs were limited to long focal lengths, small fields of view and poor resolution due to the materials available and manufacturing techniques. By demonstrating a fabrication method that can produce accurate, small features, we have already dramatically improved the focal length of thermal neutron CRLs, and the manufacture of Fresnel lens CRLs that greatly increases the collection area, and thus efficiency, of neutron CRLs. Unlike a single lens, a compound lens is a row of N lenslets that combine to produce an N-fold increase in the refraction of neutrons. While CRLs can be made from a variety of materials, we have chosen to mold Teflon lenses. Teflon has excellent neutron refraction, yet can be molded into nearly arbitrary shapes. We designed, fabricated and tested Teflon CRLs for neutrons. We demonstrated imaging at wavelengths as short as 1.26 ? with large fields of view and achieved resolution finer than 250 ?m which is better than has been previously shown. We have also determined designs for Fresnel CRLs that will greatly improve performance.

  4. MODELING OF THE HERMES SUBMILLIMETER SOURCE LENSED BY A DARK MATTER DOMINATED FOREGROUND GROUP OF GALAXIES

    SciTech Connect (OSTI)

    Gavazzi, R.; Cooray, A.; Conley, A.; Aguirre, J. E.; Amblard, A.; Auld, R.; Beelen, A.; Blain, A.; Bock, J.; Bradford, C. M.; Bridge, C.; Djorgovski, S. G.; Blundell, R.; Brisbin, D.; Burgarella, D.; Chanial, P.; Christopher, N.; Clements, D. L.; Cox, P.

    2011-09-10

    We present the results of a gravitational lensing analysis of the bright z{sub s} = 2.957 submillimeter galaxy (SMG) HERMES found in the Herschel/SPIRE science demonstration phase data from the Herschel Multi-tiered Extragalactic Survey (HerMES) project. The high-resolution imaging available in optical and near-IR channels, along with CO emission obtained with the Plateau de Bure Interferometer, allows us to precisely estimate the intrinsic source extension and hence estimate the total lensing magnification to be {mu} = 10.9 {+-} 0.7. We measure the half-light radius R{sub eff} of the source in the rest-frame near-UV and V bands that characterize the unobscured light coming from stars and find R{sub eff,*} = [2.0 {+-} 0.1] kpc, in good agreement with recent studies on the SMG population. This lens model is also used to estimate the size of the gas distribution (R{sub eff,gas} = [1.1 {+-} 0.5] kpc) by mapping back in the source plane the CO (J = 5 {yields} 4) transition line emission. The lens modeling yields a relatively large Einstein radius R{sub Ein} = 4.''10 {+-} 0.''02, corresponding to a deflector velocity dispersion of [483 {+-} 16] km s{sup -1}. This shows that HERMES is lensed by a galaxy group-size dark matter halo at redshift z{sub l} {approx} 0.6. The projected dark matter contribution largely dominates the mass budget within the Einstein radius with f{sub dm}(< R{sub Ein}) {approx} 80%. This fraction reduces to f{sub dm}(< R{sub eff,G1} {approx_equal} 4.5 kpc) {approx} 47% within the effective radius of the main deflecting galaxy of stellar mass M{sub *,G1} = [8.5 {+-} 1.6] x 10{sup 11} M{sub sun}. At this smaller scale the dark matter fraction is consistent with results already found for massive lensing ellipticals at z {approx} 0.2 from the Sloan Lens ACS Survey.

  5. Constraints on axion inflation from the weak gravity conjecture

    SciTech Connect (OSTI)

    Rudelius, Tom

    2015-09-08

    We derive constraints facing models of axion inflation based on decay constant alignment from a string-theoretic and quantum gravitational perspective. In particular, we investigate the prospects for alignment and ‘anti-alignment’ of C{sub 4} axion decay constants in type IIB string theory, deriving a strict no-go result in the latter case. We discuss the relationship of axion decay constants to the weak gravity conjecture and demonstrate agreement between our string-theoretic constraints and those coming from the ‘generalized’ weak gravity conjecture. Finally, we consider a particular model of decay constant alignment in which the potential of C{sub 4} axions in type IIB compactifications on a Calabi-Yau three-fold is dominated by contributions from D7-branes, pointing out that this model evades some of the challenges derived earlier in our paper but is highly constrained by other geometric considerations.

  6. MEASURING MICROLENSING USING SPECTRA OF MULTIPLY LENSED QUASARS

    SciTech Connect (OSTI)

    Motta, V.; Mediavilla, E.; Munoz, J. A. E-mail: emg@iac.es E-mail: jmunoz@uv.es

    2012-08-10

    We report on a program of spectroscopic observations of gravitationally lensed QSOs with multiple images. We seek to establish whether microlensing is occurring in each QSO image using only single-epoch observations. We calculate flux ratios for the cores of emission lines in image pairs to set a baseline for no microlensing. The offset of the continuum flux ratios relative to this baseline yields the microlensing magnification free from extinction, as extinction affects the continuum and the lines equally. When we find chromatic microlensing, we attempt to constrain the size of the QSO accretion disk. SDSSJ1004+4112 and HE1104-1805 show chromatic microlensing with amplitudes 0.2 < |{Delta}m| < 0.6 and 0.2 < |{Delta}m| < 0.4 mag, respectively. Modeling the accretion disk with a Gaussian source (I{proportional_to}exp (- R{sup 2}/2r{sup 2}{sub s})) of size r{sub s} {proportional_to}{lambda}{sup p} and using magnification maps to simulate microlensing, we find r{sub s} ({lambda}3363) = 7 {+-} 3 lt-day(18.1 {+-} 7.8 Multiplication-Sign 10{sup 15} cm) and p = 1.1 {+-} 0.4 for SDSS1004+4112, and r{sub s} ({lambda}3363) = 6 {+-} 2 lt-day(15.5 {+-} 5.2 Multiplication-Sign 10{sup 15} cm) and p = 0.7 {+-} 0.1 for HE1104-1805. For SDSSJ1029+2623, we find strong chromaticity of {approx}0.4 mag in the continuum flux ratio, which probably arises from microlensing, although not all the available data fit within this explanation. For Q0957+561, we measure B - A magnitude differences of 0.4 mag, much greater than the {approx}0.05 mag amplitude usually inferred from light-curve variability. It may substantially modify the current interpretations of microlensing in this system, likely favoring the hypothesis of smaller sources and/or larger microdeflectors. For HS0818+1227, our data yield possible evidence of microlensing.

  7. Lensing reconstruction from a patchwork of polarization maps

    SciTech Connect (OSTI)

    Namikawa, Toshiya; Nagata, Ryo E-mail: rnagata@post.kek.jp

    2014-09-01

    The lensing signals involved in CMB polarization maps have already been measured with ground-based experiments such as SPTpol and POLARBEAR, and would become important as a probe of cosmological and astrophysical issues in the near future. Sizes of polarization maps from ground-based experiments are, however, limited by contamination of long wavelength modes of observational noise. To further extract the lensing signals, we explore feasibility of measuring lensing signals from a collection of small sky maps each of which is observed separately by a ground-based large telescope, i.e., lensing reconstruction from a patchwork map of large sky coverage organized from small sky patches. We show that, although the B-mode power spectrum obtained from the patchwork map is biased due to baseline uncertainty, bias on the lensing potential would be negligible if the B-mode on scales larger than the blowup scale of 1/f noise is removed in the lensing reconstruction. As examples of cosmological applications, we also show 1) the cross-correlations between the reconstructed lensing potential and full-sky temperature/polarization maps from satellite missions such as PLANCK and LiteBIRD, and 2) the use of the reconstructed potential for delensing B-mode polarization of LiteBIRD observation.

  8. Coupling effect on the proton optics from the electron lenses

    SciTech Connect (OSTI)

    Luo, Y.; Gu, X.; Fischer, W.

    2010-08-01

    In this note we calculate the effect of the electron lense solenoids on the proton optics. Electron lenses (e-lenses) are to be used for head-on beam-beam compensation in the Relativistic Heavy Ion Collider (RHIC). Electron lenses are to be used for head-on beam-beam compensation in the polarized proton (pp) runs to compensate the large tune spread generated by the head-on proton-proton beam-beam interactions at IP6 and IP8 in the Relativistic Heavy Ion Collider (RHIC). The main part of an electron lens is a superconducting solenoid with a longitudinal magnetic field up to 6 T. In this report, we will estimate the e-elenses effects on the {beta} and dispersion functions with 100 GeV and 250 GeV pp run lattices. Table 1 lists some lattice and beam parameters to be used in the following study.

  9. Quantum discord with weak measurements

    SciTech Connect (OSTI)

    Singh, Uttam Pati, Arun Kumar

    2014-04-15

    Weak measurements cause small change to quantum states, thereby opening up the possibility of new ways of manipulating and controlling quantum systems. We ask, can weak measurements reveal more quantum correlation in a composite quantum state? We prove that the weak measurement induced quantum discord, called as the super quantum discord, is always larger than the quantum discord captured by the strong measurement. Moreover, we prove the monotonicity of the super quantum discord as a function of the measurement strength and in the limit of strong projective measurement the super quantum discord becomes the normal quantum discord. We find that unlike the normal discord, for pure entangled states, the super quantum discord can exceed the quantum entanglement. Our results provide new insights on the nature of quantum correlation and suggest that the notion of quantum correlation is not only observer dependent but also depends on how weakly one perturbs the composite system. We illustrate the key results for pure as well as mixed entangled states. -- Highlights: Introduced the role of weak measurements in quantifying quantum correlation. We have introduced the notion of the super quantum discord (SQD). For pure entangled state, we show that the SQD exceeds the entanglement entropy. This shows that quantum correlation depends not only on observer but also on measurement strength.

  10. Gravitational wave background from Standard Model physics: qualitative features

    SciTech Connect (OSTI)

    Ghiglieri, J.; Laine, M.

    2015-07-16

    Because of physical processes ranging from microscopic particle collisions to macroscopic hydrodynamic fluctuations, any plasma in thermal equilibrium emits gravitational waves. For the largest wavelengths the emission rate is proportional to the shear viscosity of the plasma. In the Standard Model at T>160 GeV, the shear viscosity is dominated by the most weakly interacting particles, right-handed leptons, and is relatively large. We estimate the order of magnitude of the corresponding spectrum of gravitational waves. Even though at small frequencies (corresponding to the sub-Hz range relevant for planned observatories such as eLISA) this background is tiny compared with that from non-equilibrium sources, the total energy carried by the high-frequency part of the spectrum is non-negligible if the production continues for a long time. We suggest that this may constrain (weakly) the highest temperature of the radiation epoch. Observing the high-frequency part directly sets a very ambitious goal for future generations of GHz-range detectors.

  11. Apparatus and method for measurement of weak optical absorptions by thermally induced laser pulsing

    DOE Patents [OSTI]

    Cremers, D.A.; Keller, R.A.

    1985-10-01

    The thermal lensing phenomenon is used as the basis for measurement of weak optical absorptions when a cell containing the sample to be investigated is inserted into a normally continuous-wave operation laser-pumped dye laser cavity for which the output coupler is deliberately tilted relative to intracavity circulating laser light, and pulsed laser output ensues, the pulsewidth of which can be related to the sample absorptivity by a simple algorithm or calibration curve. A minimum detection limit of less than 10[sup [minus]5] cm[sup [minus]1] has been demonstrated using this technique. 6 figs.

  12. Apparatus and method for measurement of weak optical absorptions by thermally induced laser pulsing

    DOE Patents [OSTI]

    Cremers, D.A.; Keller, R.A.

    1982-06-08

    The thermal lensing phenomenon is used as the basis for measurement of weak optical absorptions when a cell containing the sample to be investigated is inserted into a normally continuous-wave operation laser-pumped dye laser cavity for which the output coupler is deliberately tilted relative to intracavity circulating laser light, and pulsed laser output ensues, the pulsewidth of which can be rlated to the sample absorptivity by a simple algorithm or calibration curve. A minimum detection limit of less than 10/sup -5/ cm/sup -1/ has been demonstrated using this technique.

  13. Gravitational effects on inflaton decay

    SciTech Connect (OSTI)

    Ema, Yohei; Jinno, Ryusuke; Mukaida, Kyohei; Nakayama, Kazunori

    2015-05-22

    We point out that the inflaton inevitably couples to all non-conformally coupled matters gravitationally through an oscillation in the Hubble parameter or the cosmic scale factor. It leads to particle production during the inflaton oscillation regime, which is most efficient just after inflation. Moreover, the analysis is extended to the model with non-minimal inflaton couplings to gravity, in which the Hubble parameter oscillates more violently. We apply our results to the graviton production by the inflaton: gravitons are also produced just after inflation, but the non-minimal coupling does not induce inflaton decay into the graviton pair.

  14. Stabilization of weak ferromagnetism by

    Office of Scientific and Technical Information (OSTI)

    Stabilization of weak ferromagnetism by strong magnetic response to epitaxial strain in multiferroic BiFeO3 7 * 7 * 7 2 1 Hemant Dixit' , Jun Hee Lee ' , Jaron T. Krogel ' , Satoshi Okamoto and Valentino R. Cooper1' * 1. Materials Science and Technology Division, Oak Ridge National Lab, Oak Ridge, TN 37830' USA 2. Center for Nanophase Materials Science, Oak Ridge National Lab, Oak Ridge, TN 37830, USA *Email: dixithm@ornl.gov. leei@ornl.gov. coopervr@ornl.gov Abstract: Multiferroic BiFeO3

  15. Weak interactions at the SSC

    SciTech Connect (OSTI)

    Chanowitz, M.S.

    1986-03-01

    Prospects for the study of standard model weak interactions at the SSC are reviewed, with emphasis on the unique capability of the SSC to study the mechanism of electroweak symmetry breaking whether the associated new quanta are at the TeV scale or higher. Symmetry breaking by the minimal Higgs mechanism and by related strong interaction dynamical variants is summarized. A set of measurements is outlined that would calibrate the proton structure functions and the backgrounds to new physics. The ability to measure the three weak gauge boson vertex is found to complement LEP II, with measurements extending to larger Q/sup 2/ at a comparable statistical level in detectable decays. B factory physics is briefly reviewed as one example of a possible broad program of high statistics studies of sub-TeV scale phenomena. The largest section of the talk is devoted to the possible manifestations of symmetry breaking in the WW and ZZ production cross sections. Some new results are presented bearing on the ability to detect high mass WW and ZZ pairs. The principal conclusion is that although nonstandard model scenarios are typically more forgiving, the capability to study symmetry breaking in the standard model (and in related strong interaction dynamical variants) requires achieving the SSC design goals of ..sqrt.. s,L = 40Tev, 10/sup 33/cm/sup -2/sec/sup -1/. 28 refs., 5 figs.

  16. Critical condition in gravitational shock wave collision and...

    Office of Scientific and Technical Information (OSTI)

    Critical condition in gravitational shock wave collision and heavy ion collisions Citation Details In-Document Search Title: Critical condition in gravitational shock wave ...

  17. Grazing collisions of gravitational shock waves and entropy production...

    Office of Scientific and Technical Information (OSTI)

    Grazing collisions of gravitational shock waves and entropy production in heavy ion collisions Citation Details In-Document Search Title: Grazing collisions of gravitational shock ...

  18. A STUDY OF GRAVITATIONAL LENS CHROMATICITY WITH THE HUBBLE SPACE TELESCOPE

    SciTech Connect (OSTI)

    Munoz, J. A.; Mosquera, A. M.; Mediavilla, E.; Kochanek, C. S.; Falco, E. E.

    2011-12-01

    We report Hubble Space Telescope observations of six gravitational lenses with the Advanced Camera for Surveys. We measured the flux ratios between the lensed images in seven filters from 8140 #Angstrom# to 2200 #Angstrom#. In three of the systems, HE0512-3329, B1600+434, and H1413+117, we were able to construct UV extinction curves partially overlapping the 2175 #Angstrom# feature and characterize the properties of the dust relative to the Galaxy and the Magellanic Clouds. In HE1104-1804, we detect chromatic microlensing and use it to study the physical properties of the quasar accretion disk. For a Gaussian model of the disk exp (- r{sup 2}/2r{sup 2}{sub s}), scaling with wavelength as r{sub s} {proportional_to}{lambda}{sup p}, we estimate r{sub s} ({lambda}3363) = 4{sup +4}{sub -2} (7 {+-} 4) light days and p = 1.1 {+-} 0.6 (1.0 {+-} 0.6) for a logarithmic (linear) prior on r{sub s} . The remaining two systems, FBQ0951+2635 and SBS1520+530, yielded no useful estimates of extinction or chromatic microlensing.

  19. Novel Nanoparticle Production Method Could Lead to Better Lights, Lenses,

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Solar Cells Nanoparticle Production Method Could Lead to Better Lights, Lenses, Solar Cells - Sandia Energy Energy Search Icon Sandia Home Locations Contact Us Employee Locator Energy & Climate Secure & Sustainable Energy Future Stationary Power Energy Conversion Efficiency Solar Energy Wind Energy Water Power Supercritical CO2 Geothermal Natural Gas Safety, Security & Resilience of the Energy Infrastructure Energy Storage Nuclear Power & Engineering Grid Modernization

  20. Combining Galaxy-Galaxy Lensing and Galaxy Clustering

    SciTech Connect (OSTI)

    Park, Youngsoo; Krause, Elisabeth; Dodelson, Scott; Jain, Bhuvnesh; Amara, Adam; Becker, Matt; Bridle, Sarah; Clampitt, Joseph; Crocce, Martin; Honscheid, Klaus; Gaztanaga, Enrique; Sanchez, Carles; Wechsler, Risa

    2015-01-01

    Combining galaxy-galaxy lensing and galaxy clustering is a promising method for inferring the growth rate of large scale structure, a quantity that will shed light on the mechanism driving the acceleration of the Universe. The Dark Energy Survey (DES) is a prime candidate for such an analysis, with its measurements of both the distribution of galaxies on the sky and the tangential shears of background galaxies induced by these foreground lenses. By constructing an end-to-end analysis that combines large-scale galaxy clustering and small-scale galaxy-galaxy lensing, we also forecast the potential of a combined probes analysis on DES datasets. In particular, we develop a practical approach to a DES combined probes analysis by jointly modeling the assumptions and systematics affecting the different components of the data vector, employing a shared halo model, HOD parametrization, photometric redshift errors, and shear measurement errors. Furthermore, we study the effect of external priors on different subsets of these parameters. We conclude that DES data will provide powerful constraints on the evolution of structure growth in the universe, conservatively/ optimistically constraining the growth function to 8%/4.9% with its first-year data covering 1000 square degrees, and to 4%/2.3% with its full five-year data covering 5000 square degrees.

  1. DYNAMICAL STRUCTURE OF THE MOLECULAR INTERSTELLAR MEDIUM IN AN EXTREMELY BRIGHT, MULTIPLY LENSED z {approx_equal} 3 SUBMILLIMETER GALAXY DISCOVERED WITH HERSCHEL

    SciTech Connect (OSTI)

    Riechers, Dominik A.; Cooray, A.; Carpenter, J. M.; Bock, J.; Omont, A.; Neri, R.; Cox, P.; Harris, A. I.; Baker, A. J.; Frayer, D. T.; Auld, R.; Aussel, H.; Chanial, P.; Blundell, R.; Brisbin, D.; Burgarella, D.; Chapman, S. C.; Clements, D. L.

    2011-05-20

    We report the detection of CO(J = 5 {yields} 4), CO(J = 3 {yields} 2), and CO(J = 1 {yields} 0) emission in the strongly lensed, Herschel/SPIRE-selected submillimeter galaxy (SMG) HERMES J105751.1+573027 at z = 2.9574 {+-} 0.0001, using the Plateau de Bure Interferometer, the Combined Array for Research in Millimeter-wave Astronomy, and the Green Bank Telescope. The observations spatially resolve the molecular gas into four lensed images with a maximum separation of {approx}9'' and reveal the internal gas dynamics in this system. We derive lensing-corrected CO line luminosities of L'{sub CO(1-0)} = (4.17 {+-} 0.41), L'{sub CO(3-2)} = (3.96 {+-} 0.20), and L'{sub CO(5-4)} = (3.45 {+-} 0.20) x 10{sup 10} ({mu}{sub L}/10.9){sup -1} K km s{sup -1} pc{sup 2}, corresponding to luminosity ratios of r{sub 31} = 0.95 {+-} 0.10, r{sub 53} = 0.87 {+-} 0.06, and r{sub 51} = 0.83 {+-} 0.09. This suggests a total molecular gas mass of M{sub gas} = 3.3x10{sup 10} ({alpha}{sub CO}/0.8) ({mu}{sub L}/10.9){sup -1} M{sub sun}. The gas mass, gas mass fraction, gas depletion timescale, star formation efficiency, and specific star formation rate are typical for an SMG. The velocity structure of the gas reservoir suggests that the brightest two lensed images are dynamically resolved projections of the same dust-obscured region in the galaxy that are kinematically offset from the unresolved fainter images. The resolved kinematics appear consistent with the complex velocity structure observed in major, 'wet' (i.e., gas-rich) mergers. Major mergers are commonly observed in SMGs and are likely to be responsible for fueling their intense starbursts at high gas consumption rates. This study demonstrates the level of detail to which galaxies in the early universe can be studied by utilizing the increase in effective spatial resolution and sensitivity provided by gravitational lensing.

  2. Fundamentals of the relativistic theory of gravitation

    SciTech Connect (OSTI)

    Logunov, A.A.; Mestvirishvili, M.A.

    1986-01-01

    An extended exposition of the relativistic theory of gravitation (RTG) proposed by Logunov, Vlasov, and Mestvirishvili is presented. The RTG was constructed uniquely on the basis of the relativity principle and the geometrization principle by regarding the gravitational field as a physical field in the spirit of Faraday and Maxwell possessing energy, momentum, and spins 2 and 0. In the theory, conservation laws for the energy, momentum, and angular momentum for the matter and gravitational field taken together are strictly satisfied. The theory explains all the existing gravitational experiments. When the evolution of the universe is analyzed, the theory leads to the conclusion that the universe is infinite and flat, and it is predicted to contain a large amount of hidden mass. This missing mass exceeds by almost 40 times the amount of matter currently observed in the universe. The RTG predicts that gravitational collapse, which for a comoving observer occurs after a finite proper time, does not lead to infinite compression of matter but is halted at a certain finite density of the collapsing body. Therefore, according to the RTG there cannot be any objects in nature in which the gravitational contraction of matter to infinite density occurs, i.e., there are no black holes.

  3. The Third Image of the Large-Separation Lensed Quasar SDSS J1029+2623

    SciTech Connect (OSTI)

    Oguri, Masamune; Ofek, Eran O.; Inada, Naohisa; Morokuma, Tomoki; Falco, Emilio E.; Kochanek, Christopher S.; Kayo, Issha; Broadhurst, Tom; Richards, Gordon T.

    2008-02-22

    We identify a third image in the unique quasar lens SDSS J1029+2623, the second known quasar lens produced by a massive cluster of galaxies. The spectrum of the third image shows similar emission and absorption features, but has a redder continuum than the other two images which can be explained by differential extinction or microlensing. We also identify several lensed arcs. Our observations suggest a complicated structure of the lens cluster at z {approx} 0.6. We argue that the three lensed images are produced by a naked cusp on the basis of successful mass models, the distribution of cluster member galaxies, and the shapes and locations of the lensed arcs. Lensing by a naked cusp is quite rare among galaxy-scale lenses but is predicted to be common among large-separation lensed quasars. Thus the discovery can be viewed as support for an important theoretical prediction of the standard cold dark matter model.

  4. Plans for Deployment of Hollow Electron Lenses at the LHC for Enhanced Beam

    Office of Scientific and Technical Information (OSTI)

    Collimation (Conference) | SciTech Connect Plans for Deployment of Hollow Electron Lenses at the LHC for Enhanced Beam Collimation Citation Details In-Document Search Title: Plans for Deployment of Hollow Electron Lenses at the LHC for Enhanced Beam Collimation Hollow electron lenses are considered as a possible means to improve the LHC beam collimation system, providing active control of halo diffusion rates and suppressing the population of transverse halos. After a very successful

  5. NALCAL

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Erin Sheldon, Brookhaven National Laboratory Title: Weak Gravitational Lensing of Galaxy Clusters 3:30 DIRECTOR'S COFFEE BREAK 2nd Flr X-Over 4:00 All Experimenters' Meeting...

  6. Plans for Deployment of Hollow Electron Lenses at the LHC for...

    Office of Scientific and Technical Information (OSTI)

    Hollow electron lenses are considered as a possible means to improve the LHC beam collimation system, providing active control of halo diffusion rates and suppressing the ...

  7. Gravitational wave extraction in simulations of rotating stellar core collapse

    SciTech Connect (OSTI)

    Reisswig, C.; Ott, C. D.; Sperhake, U.; Schnetter, E.

    2011-03-15

    We perform simulations of general relativistic rotating stellar core collapse and compute the gravitational waves (GWs) emitted in the core-bounce phase of three representative models via multiple techniques. The simplest technique, the quadrupole formula (QF), estimates the GW content in the spacetime from the mass-quadrupole tensor only. It is strictly valid only in the weak-field and slow-motion approximation. For the first time, we apply GW extraction methods in core collapse that are fully curvature based and valid for strongly radiating and highly relativistic sources. These techniques are not restricted to weak-field and slow-motion assumptions. We employ three extraction methods computing (i) the Newman-Penrose (NP) scalar {Psi}{sub 4}, (ii) Regge-Wheeler-Zerilli-Moncrief master functions, and (iii) Cauchy-characteristic extraction (CCE) allowing for the extraction of GWs at future null infinity, where the spacetime is asymptotically flat and the GW content is unambiguously defined. The latter technique is the only one not suffering from residual gauge and finite-radius effects. All curvature-based methods suffer from strong nonlinear drifts. We employ the fixed-frequency integration technique as a high-pass waveform filter. Using the CCE results as a benchmark, we find that finite-radius NP extraction yields results that agree nearly perfectly in phase, but differ in amplitude by {approx}1%-7% at core bounce, depending on the model. Regge-Wheeler-Zerilli-Moncrief waveforms, while, in general, agreeing in phase, contain spurious high-frequency noise of comparable amplitudes to those of the relatively weak GWs emitted in core collapse. We also find remarkably good agreement of the waveforms obtained from the QF with those obtained from CCE. The results from QF agree very well in phase and systematically underpredict peak amplitudes by {approx}5%-11%, which is comparable to the NP results and is certainly within the uncertainties associated with core collapse physics.

  8. CP Violation, Neutral Currents, and Weak Equivalence

    DOE R&D Accomplishments [OSTI]

    Fitch, V. L.

    1972-03-23

    Within the past few months two excellent summaries of the state of our knowledge of the weak interactions have been presented. Correspondingly, we will not attempt a comprehensive review but instead concentrate this discussion on the status of CP violation, the question of the neutral currents, and the weak equivalence principle.

  9. Weak rigidity in the PPN formalism

    SciTech Connect (OSTI)

    del Olmo, V.; Olivert, J.

    1987-04-01

    The influence of the concept of weakly rigid almost-thermodynamic material schemes on the classical deformations is analyzed. The methods of the PPN approximation are considered. In this formalism, the equations that characterize the weak rigidity are expressed. As a consequence of that, an increase of two orders of magnitude in the strain rate tensor is obtained.

  10. Q-weak Experiment Determines Proton's Weak Charge | U.S. DOE...

    Office of Science (SC) Website

    result will offer a stringent experimental test of the Standard Model and will provide ... Related Links Q-weak: A Precision Test of the Standard Model and Determination of the Weak ...

  11. Optical loss due to diffraction by concentrator Fresnel lenses

    SciTech Connect (OSTI)

    Hornung, Thorsten Nitz, Peter

    2014-09-26

    Fresnel lenses are widely used in concentrating photovoltaic (CPV) systems as a primary optical element. They focus sunlight on small solar cells or on the entrance apertures of secondary optical elements. A Fresnel lens consists of several prism rings and diffraction by these prism rings is unavoidable. Some of the light that would reach a designated target area according to geometric optics will miss it due to diffraction. This diffraction loss may be of relevant magnitude for CPV applications. The results of published analytical calculations are evaluated, discussed, and compared to computer simulations and measurements.

  12. Steven Weinberg, Weak Interactions, and Electromagnetic Interactions

    Office of Scientific and Technical Information (OSTI)

    Conceptual Foundations of the Unified Theory of Weak and Electromagnetic Interactions; Review of Modern Physics, Vol. 52, Issue 3: 515-523, July 1980 (Nobel Lecture) 100 years of ...

  13. Probing the Proton's Weak Side | Jefferson Lab

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    such as those that may be produced by the Large Hadron Collider at CERN in Europe. "The weak charge for the proton is exquisitely, accurately predicted by the Standard Model. ...

  14. Proton's Weak Charge Determined for First Time | Jefferson Lab

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Proton's Weak Charge Determined for First Time Proton's Weak Charge Determined for First Time Q-weak at Jefferson Lab has measured the proton's weak charge Q-weak at Jefferson Lab has measured the proton's weak charge. NEWPORT NEWS, VA, Sept. 17, 2013 - Researchers have made the first experimental determination of the weak charge of the proton in research carried out at the Department of Energy's Thomas Jefferson National Accelerator Facility (Jefferson Lab). The results, accepted for

  15. RESOLVING THE BARYON-FRACTION PROFILE IN LENSING GALAXIES

    SciTech Connect (OSTI)

    Leier, Dominik; Ferreras, Ignacio; Saha, Prasenjit; Falco, Emilio E.

    2011-10-20

    The study of the distribution of baryonic matter within dark halos enriches our understanding of galaxy formation. We show the radial dependence of stellar baryon-fraction curves derived for 21 lensing galaxies from the CfA-Arizona Space Telescope LEns Survey (CASTLES) by means of stellar population synthesis and pixel-based mass reconstruction. The sample covers a stellar mass range of M{sub s} {approx_equal} 2 x 10{sup 9}-3 x 10{sup 11} M{sub sun} (solar masses) which corresponds to a total enclosed mass range of M{sub L} {approx_equal} 7 x 10{sup 9}-3 x 10{sup 12} M{sub sun} on radial scales from 0.25R{sub e} to 5R{sub e} (effective radii). By examining the M{sub s} and M{sub L} dependence on radial distance to the center of each galaxy, we find that there are pairs of lenses on small to intermediate mass scales which approach at large radii the same values for their enclosed total mass but exhibit very different stellar masses and stellar baryon fractions. This peculiar behavior subsides for the most massive lensing galaxies. All the baryon-fraction profiles show that the dark matter halo overtakes the stellar content between 1.5 and 2.5R{sub e}. At 3R{sub e} most of the stellar component is enclosed. We find evidence for a stellar baryon fraction steadily declining over the full mass range. Furthermore, we shed light on the Fundamental Plane puzzle by showing that the slope of the M{sub L} (< R)-to-M{sub s} (< R) relation approaches the mass-to-light relation of recent Fundamental Plane studies at large radii. We also introduce novel concentration indices c = R90/R50 for stellar and total mass profiles (i.e., the ratio of radii enclosing 90% and 50% of the stellar or total mass). We show that the value c = 2.6 originally determined by light profiles which separates early-type galaxies from late-type galaxies also holds for stellar mass. In particular, less massive dark matter halos turn out to be influenced by the distribution of stellar matter on resolved scales below 10 kpc. The ongoing study of resolved baryon-fraction profiles will make it possible to evaluate the validity of star formation models as well as adiabatic contraction prescriptions commonly used in simulations.

  16. A NOVEL APPROACH IN THE WEAKLY INTERACTING MASSIVE PARTICLE QUEST: CROSS-CORRELATION OF GAMMA-RAY ANISOTROPIES AND COSMIC SHEAR

    SciTech Connect (OSTI)

    Camera, Stefano; Fornasa, Mattia; Fornengo, Nicolao; Regis, Marco

    2013-07-01

    Both cosmic shear and cosmological gamma-ray emission stem from the presence of dark matter (DM) in the universe: DM structures are responsible for the bending of light in the weak-lensing regime and those same objects can emit gamma rays, either because they host astrophysical sources (active galactic nuclei or star-forming galaxies) or directly by DM annihilations (or decays, depending on the properties of the DM particle). Such gamma rays should therefore exhibit strong correlation with the cosmic shear signal. In this Letter, we compute the cross-correlation angular power spectrum of cosmic shear and gamma rays produced by the annihilation/decay of weakly interacting massive particle DM, as well as by astrophysical sources. We show that this observable provides novel information on the composition of the extragalactic gamma-ray background (EGB), since the amplitude and shape of the cross-correlation signal strongly depend on which class of sources is responsible for the gamma-ray emission. If the DM contribution to the EGB is significant (at least in a definite energy range), although compatible with current observational bounds, its strong correlation with the cosmic shear makes such signal potentially detectable by combining Fermi Large Area Telescope data with forthcoming galaxy surveys, like the Dark Energy Survey and Euclid. At the same time, the same signal would demonstrate that the weak-lensing observables are indeed due to particle DM matter and not to possible modifications of general relativity.

  17. Prolate spheroidal harmonic expansion of gravitational field

    SciTech Connect (OSTI)

    Fukushima, Toshio

    2014-06-01

    As a modification of the oblate spheroidal case, a recursive method is developed to compute the point value and a few low-order derivatives of the prolate spheroidal harmonics of the second kind, Q{sub nm} (y), namely the unnormalized associated Legendre function (ALF) of the second kind with its argument in the domain, 1 < y < ∞. They are required in evaluating the prolate spheroidal harmonic expansion of the gravitational field in addition to the point value and the low-order derivatives of P-bar {sub nm}(t), the 4π fully normalized ALF of the first kind with its argument in the domain, |t| ≤ 1. The new method will be useful in the gravitational field computation of elongated celestial objects.

  18. Gravitational radiation from a cylindrical naked singularity

    SciTech Connect (OSTI)

    Nakao, Ken-ichi; Morisawa, Yoshiyuki

    2005-06-15

    We construct an approximate solution which describes the gravitational emission from a naked singularity formed by the gravitational collapse of a cylindrical thick shell composed of dust. The assumed situation is that the collapsing speed of the dust is very large. In this situation, the metric variables are obtained approximately by a kind of linear perturbation analysis in the background Morgan solution which describes the motion of cylindrical null dust. The most important problem in this study is what boundary conditions for metric and matter variables should be imposed at the naked singularity. We find a boundary condition that all the metric and matter variables are everywhere finite at least up to the first order approximation. This implies that the spacetime singularity formed by this high-speed dust collapse is very similar to that formed by the null dust and the final singularity will be a conical one. Weyl curvature is completely released from the collapsed dust.

  19. Core and filament formation in magnetized, self-gravitating isothermal layers

    SciTech Connect (OSTI)

    Van Loo, Sven; Keto, Eric; Zhang, Qizhou

    2014-07-01

    We examine the role of the gravitational instability in an isothermal, self-gravitating layer threaded by magnetic fields on the formation of filaments and dense cores. Using a numerical simulation, we follow the non-linear evolution of a perturbed equilibrium layer. The linear evolution of such a layer is described in the analytic work of Nagai et al. We find that filaments and dense cores form simultaneously. Depending on the initial magnetic field, the resulting filaments form either a spiderweb-like network (for weak magnetic fields) or a network of parallel filaments aligned perpendicular to the magnetic field lines (for strong magnetic fields). Although the filaments are radially collapsing, the density profile of their central region (up to the thermal scale height) can be approximated by a hydrodynamical equilibrium density structure. Thus, the magnetic field does not play a significant role in setting the density distribution of the filaments. The density distribution outside of the central region deviates from the equilibrium. The radial column density distribution is then flatter than the expected power law of r {sup 4} and similar to filament profiles observed with Herschel. Our results do not explain the near constant filament width of ?0.1pc. However, our model does not include turbulent motions. It is expected that the accretion-driven amplification of these turbulent motions provides additional support within the filaments against gravitational collapse. Finally, we interpret the filamentary network of the massive star forming complex G14.225-0.506 in terms of the gravitational instability model and find that the properties of the complex are consistent with being formed out of an unstable layer threaded by a strong, parallel magnetic field.

  20. Metal Nanostructure Formation on Graphene: Weak versus Strong...

    Office of Scientific and Technical Information (OSTI)

    Metal Nanostructure Formation on Graphene: Weak versus Strong Bonding Citation Details In-Document Search Title: Metal Nanostructure Formation on Graphene: Weak versus Strong...

  1. T-728: Apache Tomcat HTTP DIGEST Authentication Weaknesses Let...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    8: Apache Tomcat HTTP DIGEST Authentication Weaknesses Let Remote Users Conduct Bypass Attacks T-728: Apache Tomcat HTTP DIGEST Authentication Weaknesses Let Remote Users Conduct...

  2. Theory and Modeling of Weakly Bound/Physisorbed Materials for...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Theory and Modeling of Weakly BoundPhysisorbed Materials for Hydrogen Storage Theory and Modeling of Weakly BoundPhysisorbed Materials for Hydrogen Storage Presentation on the...

  3. Guide for 3D WARP simulations of hollow electron beam lenses...

    Office of Scientific and Technical Information (OSTI)

    test stand Citation Details In-Document Search Title: Guide for 3D WARP simulations of hollow electron beam lenses. Practical explanation on basis of Tevatron electron lens test ...

  4. Galaxy-Galaxy Lensing in the DES Science Verification Data (Journal...

    Office of Scientific and Technical Information (OSTI)

    Dividing the lenses into three redshift bins, we find no evidence for evolution in the ... cosmological and galaxy evolution studies with the DES data and redMaGiC galaxy samples. ...

  5. High resolution x-ray and gamma ray imaging using diffraction lenses with

    Office of Scientific and Technical Information (OSTI)

    mechanically bent crystals (Patent) | DOEPatents High resolution x-ray and gamma ray imaging using diffraction lenses with mechanically bent crystals Title: High resolution x-ray and gamma ray imaging using diffraction lenses with mechanically bent crystals A method for high spatial resolution imaging of a plurality of sources of x-ray and gamma-ray radiation is provided. High quality mechanically bent diffracting crystals of 0.1 mm radial width are used for focusing the radiation and

  6. Durability of Poly(Methyl Methacrylate) Lenses Used in Concentrating Photovoltaic Technology (Revised) (Presentation)

    SciTech Connect (OSTI)

    Miller, D. C.; Carloni, J. D.; Pankow, J. W.; Gjersing, E. L.; To, B.; Packard, C. E.; Kennedy, C. E.; Kurtz, S. R.

    2012-01-01

    Concentrating photovoltaic (CPV) technology recently gained interest based on its expected low levelized cost of electricity, high efficiency, and scalability. Many CPV systems employ Fresnel lenses composed of poly(methyl methacrylate) (PMMA) to obtain a high optical flux density on the cell. The optical and mechanical durability of these lenses, however, is not well established relative to the desired surface life of 30 years. Our research aims to quantify the expected lifetime of PMMA in key market locations (FL, AZ, and CO).

  7. THE MASS-RICHNESS RELATION OF MaxBCG CLUSTERS FROM QUASAR LENSING

    Office of Scientific and Technical Information (OSTI)

    MAGNIFICATION USING VARIABILITY (Journal Article) | SciTech Connect THE MASS-RICHNESS RELATION OF MaxBCG CLUSTERS FROM QUASAR LENSING MAGNIFICATION USING VARIABILITY Citation Details In-Document Search Title: THE MASS-RICHNESS RELATION OF MaxBCG CLUSTERS FROM QUASAR LENSING MAGNIFICATION USING VARIABILITY Accurate measurement of galaxy cluster masses is an essential component not only in studies of cluster physics but also for probes of cosmology. However, different mass measurement

  8. TIME DELAY AND ACCRETION DISK SIZE MEASUREMENTS IN THE LENSED QUASAR SBS 0909+532 FROM MULTIWAVELENGTH MICROLENSING ANALYSIS

    SciTech Connect (OSTI)

    Hainline, Laura J.; Morgan, Christopher W.; MacLeod, Chelsea L.; Landaal, Zachary D. [Department of Physics, United States Naval Academy, 572C Holloway Rd, Annapolis, MD 21402 (United States); Kochanek, C. S. [Department of Astronomy, The Ohio State University, 140 West 18th Ave, Columbus, OH 43210 (United States); Harris, Hugh C.; Tilleman, Trudy [United States Naval Observatory, Flagstaff Station, 10391 West Naval Observatory Road, Flagstaff, AZ 86001-8521 (United States); Goicoechea, L. J.; Shalyapin, V. N. [Facultad de Ciencias, Universidad de Cantabria, Avda. de Los Castros s/n, E-39005 Santander (Spain); Falco, Emilio E., E-mail: hainline@usna.edu, E-mail: cmorgan@usna.edu, E-mail: macleod@usna.edu, E-mail: m123894@usna.edu, E-mail: ckochanek@astronomy.ohio-state.edu, E-mail: hch@nofs.navy.mil, E-mail: trudy@nofs.navy.mil, E-mail: goicol@unican.es, E-mail: vshal@ukr.net, E-mail: falco@cfa.harvard.edu [Harvard-Smithsonian Center for Astrophysics, 60 Garden St, Cambridge, MA 02138 (United States)

    2013-09-01

    We present three complete seasons and two half-seasons of Sloan Digital Sky Survey (SDSS) r-band photometry of the gravitationally lensed quasar SBS 0909+532 from the U.S. Naval Observatory, as well as two seasons each of SDSS g-band and r-band monitoring from the Liverpool Robotic Telescope. Using Monte Carlo simulations to simultaneously measure the system's time delay and model the r-band microlensing variability, we confirm and significantly refine the precision of the system's time delay to {Delta}t{sub AB} = 50{sub -4}{sup +2} days, where the stated uncertainties represent the bounds of the formal 1{sigma} confidence interval. There may be a conflict between the time delay measurement and a lens consisting of a single galaxy. While models based on the Hubble Space Telescope astrometry and a relatively compact stellar distribution can reproduce the observed delay, the models have somewhat less dark matter than we would typically expect. We also carry out a joint analysis of the microlensing variability in the r and g bands to constrain the size of the quasar's continuum source at these wavelengths, obtaining log {l_brace}(r{sub s,r}/cm)[cos i/0.5]{sup 1/2}{r_brace} = 15.3 {+-} 0.3 and log {l_brace}(r{sub s,g}/cm)[cos i/0.5]{sup 1/2}{r_brace} = 14.8 {+-} 0.9, respectively. Our current results do not formally constrain the temperature profile of the accretion disk but are consistent with the expectations of standard thin disk theory.

  9. General properties of the gravitational wave spectrum from phase

    Office of Scientific and Technical Information (OSTI)

    transitions (Journal Article) | SciTech Connect General properties of the gravitational wave spectrum from phase transitions Citation Details In-Document Search Title: General properties of the gravitational wave spectrum from phase transitions In this paper we discuss some general aspects of the gravitational wave background arising from postinflationary short-lasting cosmological events such as phase transitions. We concentrate on the physics which determines the shape and the peak

  10. Gravitational Instability of a Nonrotating Galaxy (Conference) | SciTech

    Office of Scientific and Technical Information (OSTI)

    Connect Gravitational Instability of a Nonrotating Galaxy Citation Details In-Document Search Title: Gravitational Instability of a Nonrotating Galaxy Gravitational instability of the distribution of stars in a galaxy is a well-known phenomenon in astrophysics. This report is an attempt to analyze this phenomenon by applying standard tools developed in accelerator physics. It is found that a nonrotating galaxy would become unstable if its size exceeds a certain limit that depends on its mass

  11. Critical condition in gravitational shock wave collision and heavy ion

    Office of Scientific and Technical Information (OSTI)

    collisions (Journal Article) | SciTech Connect Critical condition in gravitational shock wave collision and heavy ion collisions Citation Details In-Document Search Title: Critical condition in gravitational shock wave collision and heavy ion collisions In this paper, we derive a critical condition for matter equilibration in heavy ion collisions using a holographic approach. Gravitational shock waves with infinite transverse extension are used to model an infinite nucleus. We construct the

  12. Weak measurement and Bohmian conditional wave functions

    SciTech Connect (OSTI)

    Norsen, Travis; Struyve, Ward

    2014-11-15

    It was recently pointed out and demonstrated experimentally by Lundeen etal. that the wave function of a particle (more precisely, the wave function possessed by each member of an ensemble of identically-prepared particles) can be directly measured using weak measurement. Here it is shown that if this same technique is applied, with appropriate post-selection, to one particle from a perhaps entangled multi-particle system, the result is precisely the so-called conditional wave function of Bohmian mechanics. Thus, a plausibly operationalist method for defining the wave function of a quantum mechanical sub-system corresponds to the natural definition of a sub-system wave function which Bohmian mechanics uniquely makes possible. Similarly, a weak-measurement-based procedure for directly measuring a sub-systems density matrix should yield, under appropriate circumstances, the Bohmian conditional density matrix as opposed to the standard reduced density matrix. Experimental arrangements to demonstrate this behaviorand also thereby reveal the non-local dependence of sub-system state functions on distant interventionsare suggested and discussed. - Highlights: We study a direct measurement protocol for wave functions and density matrices. Weakly measured states of entangled particles correspond to Bohmian conditional states. Novel method of observing quantum non-locality is proposed.

  13. CMB lensing tomography with the DES Science Verification galaxies

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Giannantonio, T.

    2016-01-07

    We measure the cross-correlation between the galaxy density in the Dark Energy Survey (DES) Science Verification data and the lensing of the cosmic microwave background (CMB) as reconstructed with the Planck satellite and the South Pole Telescope (SPT). When using the DES main galaxy sample over the full redshift range 0.2 < zphot < 1.2, a cross-correlation signal is detected at 6σ and 4σ with SPT and Planck respectively. We then divide the DES galaxies into five photometric redshift bins, finding significant (>2σ) detections in all bins. Comparing to the fiducial Planck cosmology, we find the redshift evolution of themore » signal matches expectations, although the amplitude is consistently lower than predicted across redshift bins. We test for possible systematics that could affect our result and find no evidence for significant contamination. Finally, we demonstrate how these measurements can be used to constrain the growth of structure across cosmic time. We find the data are fit by a model in which the amplitude of structure in the z < 1.2 universe is 0.73 ± 0.16 times as large as predicted in the LCDM Planck cosmology, a 1.7σ deviation.« less

  14. Unitarity check in gravitational Higgs mechanism (Journal Article...

    Office of Scientific and Technical Information (OSTI)

    Journal Article: Unitarity check in gravitational Higgs mechanism Citation Details ... OSTI Identifier: 21537616 Resource Type: Journal Article Resource Relation: Journal Name: ...

  15. Standing gravitational waves from domain walls

    SciTech Connect (OSTI)

    Gogberashvili, Merab; Myrzakul, Shynaray; Singleton, Douglas

    2009-07-15

    We construct a plane symmetric, standing gravitational wave for a domain wall plus a massless scalar field. The scalar field can be associated with a fluid which has the properties of 'stiff' matter, i.e., matter in which the speed of sound equals the speed of light. Although domain walls are observationally ruled out in the present era, the solution has interesting features which might shed light on the character of exact nonlinear wave solutions to Einstein's equations. Additionally this solution may act as a template for higher dimensional 'brane-world' model standing waves.

  16. PLASMA EMISSION BY WEAK TURBULENCE PROCESSES

    SciTech Connect (OSTI)

    Ziebell, L. F.; Gaelzer, R.; Yoon, P. H.; Pavan, J. E-mail: rudi.gaelzer@ufrgs.br E-mail: joel.pavan@ufpel.edu.br

    2014-11-10

    The plasma emission is the radiation mechanism responsible for solar type II and type III radio bursts. The first theory of plasma emission was put forth in the 1950s, but the rigorous demonstration of the process based upon first principles had been lacking. The present Letter reports the first complete numerical solution of electromagnetic weak turbulence equations. It is shown that the fundamental emission is dominant and unless the beam speed is substantially higher than the electron thermal speed, the harmonic emission is not likely to be generated. The present findings may be useful for validating reduced models and for interpreting particle-in-cell simulations.

  17. Boson Hubbard model with weakly coupled fermions

    SciTech Connect (OSTI)

    Lutchyn, Roman M.; Tewari, Sumanta; Das Sarma, S.

    2008-12-01

    Using an imaginary-time path integral approach, we develop the perturbation theory suited to the boson Hubbard model and apply it to calculate the effects of a dilute gas of spin-polarized fermions weakly interacting with the bosons. The full theory captures both the static and the dynamic effects of the fermions on the generic superfluid-insulator phase diagram. We find that, in a homogenous system described by a single-band boson Hubbard Hamiltonian, the intrinsic perturbative effect of the fermions is to generically suppress the insulating lobes and to enhance the superfluid phase.

  18. HERSCHEL-ATLAS: TOWARD A SAMPLE OF {approx}1000 STRONGLY LENSED GALAXIES

    SciTech Connect (OSTI)

    Gonzalez-Nuevo, J.; Lapi, A.; Bressan, S.; Danese, L.; De Zotti, G.; Cai, Z.-Y.; Fan, L.; Fleuren, S.; Sutherland, W.; Negrello, M.; Baes, M.; Baker, A. J.; Clements, D. L.; Cooray, A.; Dannerbauer, H.; Dunne, L.; Dye, S.; Eales, S.; Frayer, D. T.; Harris, A. I.; and others

    2012-04-10

    While the selection of strongly lensed galaxies (SLGs) with 500 {mu}m flux density S{sub 500} > 100 mJy has proven to be rather straightforward, for many applications it is important to analyze samples larger than the ones obtained when confining ourselves to such a bright limit. Moreover, only by probing to fainter flux densities is it possible to exploit strong lensing to investigate the bulk of the high-z star-forming galaxy population. We describe HALOS (the Herschel-ATLAS Lensed Objects Selection), a method for efficiently selecting fainter candidate SLGs, reaching a surface density of {approx_equal} 1.5-2 deg{sup -2}, i.e., a factor of about 4-6 higher than that at the 100 mJy flux limit. HALOS will allow the selection of up to {approx}1000 candidate SLGs (with amplifications {mu} {approx}> 2) over the full H-ATLAS survey area. Applying HALOS to the H-ATLAS Science Demonstration Phase field ({approx_equal} 14.4 deg{sup 2}) we find 31 candidate SLGs, whose candidate lenses are identified in the VIKING near-infrared catalog. Using the available information on candidate sources and candidate lenses we tentatively estimate a {approx_equal} 72% purity of the sample. As expected, the purity decreases with decreasing flux density of the sources and with increasing angular separation between candidate sources and lenses. The redshift distribution of the candidate lensed sources is close to that reported for most previous surveys for lensed galaxies, while that of candidate lenses extends to redshifts substantially higher than found in the other surveys. The counts of candidate SLGs are also in good agreement with model predictions. Even though a key ingredient of the method is the deep near-infrared VIKING photometry, we show that H-ATLAS data alone allow the selection of a similarly deep sample of candidate SLGs with an efficiency close to 50%; a slightly lower surface density ({approx_equal} 1.45 deg{sup -2}) can be reached with a {approx}70% efficiency.

  19. THE IMPACT OF THERMODYNAMICS ON GRAVITATIONAL COLLAPSE: FILAMENT FORMATION AND MAGNETIC FIELD AMPLIFICATION

    SciTech Connect (OSTI)

    Peters, Thomas; Klessen, Ralf S.; Federrath, Christoph; Smith, Rowan J.; Schleicher, Dominik R. G.; Banerjee, Robi; Sur, Sharanya

    2012-12-01

    Stars form by the gravitational collapse of interstellar gas. The thermodynamic response of the gas can be characterized by an effective equation of state. It determines how gas heats up or cools as it gets compressed, and hence plays a key role in regulating the process of stellar birth on virtually all scales, ranging from individual star clusters up to the galaxy as a whole. We present a systematic study of the impact of thermodynamics on gravitational collapse in the context of high-redshift star formation, but argue that our findings are also relevant for present-day star formation in molecular clouds. We consider a polytropic equation of state, P = k{rho}{sup {Gamma}}, with both sub-isothermal exponents {Gamma} < 1 and super-isothermal exponents {Gamma} > 1. We find significant differences between these two cases. For {Gamma} > 1, pressure gradients slow down the contraction and lead to the formation of a virialized, turbulent core. Weak magnetic fields are strongly tangled and efficiently amplified via the small-scale turbulent dynamo on timescales corresponding to the eddy-turnover time at the viscous scale. For {Gamma} < 1, on the other hand, pressure support is not sufficient for the formation of such a core. Gravitational contraction proceeds much more rapidly and the flow develops very strong shocks, creating a network of intersecting sheets and extended filaments. The resulting magnetic field lines are very coherent and exhibit a considerable degree of order. Nevertheless, even under these conditions we still find exponential growth of the magnetic energy density in the kinematic regime.

  20. The effects of the RHIC E-lenses magnetic structure layout on the proton beam trajectory

    SciTech Connect (OSTI)

    Gu, X.; Pikin, A.; Luo, Y.; Okamura, M.; Fischer, W.; Gupta, R.; Hock, J.; Raparia, D.

    2011-03-28

    We are designing two electron lenses (E-lens) to compensate for the large beam-beam tune spread from proton-proton interactions at IP6 and IP8 in the Relativistic Heavy Ion Collider (RHIC). They will be installed in RHIC IR10. First, the layout of these two E-lenses is introduced. Then the effects of e-lenses on proton beam are discussed. For example, the transverse fields of the e-lens bending solenoids and the fringe field of the main solenoids will shift the proton beam. For the effects of the e-lens on proton beam trajectory, we calculate the transverse kicks that the proton beam receives in the electron lens via Opera at first. Then, after incorporating the simplified E-lens lattice in the RHIC lattice, we obtain the closed orbit effect with the Simtrack Code.

  1. On the Unreasonable Effectiveness of post-Newtonian Theory in Gravitational-Wave Physics

    ScienceCinema (OSTI)

    Clifford M. Will

    2010-01-08

    The first indirect detection of gravitational waves involved a binary system of neutron stars.  In the future, the first direct detection may also involve binary systems -- inspiralling and merging binary neutron stars or black holes. This means that it is essential to understand in full detail the two-body system in general relativity, a notoriously difficult problem with a long history. Post-Newtonian approximation methods are thought to work only under slow motion and weak field conditions, while numerical solutions of Einstein's equations are thought to be limited to the final merger phase.  Recent results have shown that post-Newtonian approximations seem to remain unreasonably valid well into the relativistic regime, while advances in numerical relativity now permit solutions for numerous orbits before merger.  It is now possible to envision linking post-Newtonian theory and numerical relativity to obtain a complete ``solution'' of the general relativistic two-body problem.  These solutions will play a central role in detecting and understanding gravitational wave signals received by interferometric observatories on Earth and in space.

  2. GRAVITATIONAL WAVE SIGNATURES OF HYPERACCRETING COLLAPSAR DISKS

    SciTech Connect (OSTI)

    Kotake, Kei; Takiwaki, Tomoya; Harikae, Seiji

    2012-08-20

    By performing two-dimensional special relativistic (SR) magnetohydrodynamic simulations, we study possible signatures of gravitational waves (GWs) in the context of the collapsar model for long-duration gamma-ray bursts. In our SR simulations, the central black hole is treated as an absorbing boundary. By doing so, we focus on the GWs generated by asphericities in neutrino emission and matter motions in the vicinity of the hyperaccreting disks. We compute nine models by adding initial angular momenta and magnetic fields parametrically to a precollapse core of a 35 M{sub Sun} progenitor star. As for the microphysics, a realistic equation of state is employed and the neutrino cooling is taken into account via a multi-flavor neutrino leakage scheme. To accurately estimate GWs produced by anisotropic neutrino emission, we perform a ray-tracing analysis in general relativity by a post-processing procedure. By employing a stress formula that includes contributions from both magnetic fields and SR corrections, we also study the effects of magnetic fields on the gravitational waveforms. We find that the GW amplitudes from anisotropic neutrino emission show a monotonic increase with time, whose amplitudes are much larger than those from matter motions of the accreting material. We show that the increasing trend of the neutrino GWs stems from the excess of neutrino emission in the direction near parallel to the spin axis illuminated from the hyperaccreting disks. We point out that a recently proposed future space-based interferometer like Fabry-Perot-type DECIGO would permit the detection of these GW signals within Almost-Equal-To 100 Mpc.

  3. Correcting Quadrupole Roll in Magnetic Lenses with Skew Quadrupoles

    SciTech Connect (OSTI)

    Walstrom, Peter Lowell

    2014-11-10

    Quadrupole rolls (i.e. rotation around the magnet axis) are known to be a significant source of image blurring in magnetic quadrupole lenses. These rolls may be caused by errors in mechanical mounting of quadrupoles, by uneven radiation-induced demagnetization of permanent-magnet quadrupoles, etc. Here a four-quadrupole 10 lens with so-called Russian or A -B B-A symmetry is used as a model problem. Existing SLAC 1/2 in. bore high-gradient quadrupoles are used in the design. The dominant quadrupole roll effect is changes in the first-order part of the transfer map (the R matrix) from the object to the image plane (Note effects on the R matrix can be of first order in rotation angle for some R-matrix elements and second order in rotation angle for other elements, as shown below). It is possible to correct roll-induced image blur by mechanically adjusting the roll angle of one or more of the quadrupoles. Usually, rotation of one quadrupole is sufficient to correct most of the combined effect of rolls in all four quadrupoles. There are drawbacks to this approach, however, since mechanical roll correction requires multiple entries into experimental area to make the adjustments, which are made according to their effect on images. An alternative is to use a single electromagnetic skew quadrupole corrector placed either between two of the quadrupoles or after the fourth quadrupole (so-called non-local correction). The basic feasibility of skew quadrupole correction of quadrupole roll effects is demonstrated here. Rolls of the third lens quadrupole of up to about 1 milliradian can be corrected with a 15 cm long skew quadrupole with a gradient of up to 1 T/m. Since the effect of rolls of the remaining three lens quadrupoles are lower, a weaker skew quadrupole can be used to correct them. Non-local correction of quadrupole roll effects by skew quadrupoles is shown to be about one-half as effective as local correction (i.e. rotating individual quadrupoles to zero roll angle or placing skew quadrupole correctors in the bores of main quadrupoles).

  4. Weak interactions of supersymmetric staus at high energies (Journal

    Office of Scientific and Technical Information (OSTI)

    Article) | SciTech Connect Weak interactions of supersymmetric staus at high energies Citation Details In-Document Search Title: Weak interactions of supersymmetric staus at high energies Neutrino telescopes may have the potential to detect the quasistable staus predicted by some supersymmetric models. Detection depends on stau electromagnetic energy loss and weak interactions. We present results for the weak interactions contribution to the energy loss of high energy staus as they pass

  5. Effect of the electron lenses on the RHIC proton beam closed orbit

    SciTech Connect (OSTI)

    Gu, X.; Luo, Y.; Pikin, A.; Okamura, M.; Fischer, W.; Montag, C.; Gupta, R.; Hock, J.; Jain, A.; Raparia, D.

    2011-02-01

    We are designing two electron lenses (E-lens) to compensate for the large beam-beam tune spread from proton-proton interactions at IP6 and IP8 in the Relativistic Heavy Ion Collider (RHIC). They will be installed at RHIC IR10. The transverse fields of the E-lenses bending solenoids and the fringe field of the main solenoids will shift the proton beam. We calculate the transverse kicks that the proton beam receives in the electron lens via Opera. Then, after incorporating the simplified E-lens lattice in the RHIC lattice, we obtain the closed orbit effect with the Simtrack Code.

  6. Observable induced gravitational waves from an early matter phase

    SciTech Connect (OSTI)

    Alabidi, Laila; Sasaki, Misao; Kohri, Kazunori; Sendouda, Yuuiti E-mail: kohri@post.kek.jp E-mail: sendouda@cc.hirosaki-u.ac.jp

    2013-05-01

    Assuming that inflation is succeeded by a phase of matter domination, which corresponds to a low temperature of reheating T{sub r} < 10{sup 9}GeV, we evaluate the spectra of gravitational waves induced in the post-inflationary universe. We work with models of hilltop-inflation with an enhanced primordial scalar spectrum on small scales, which can potentially lead to the formation of primordial black holes. We find that a lower reheat temperature leads to the production of gravitational waves with energy densities within the ranges of both space and earth based gravitational wave detectors.

  7. Electron lenses for compensation of beam-beam effects: Tevatron, RHIC, LHC

    SciTech Connect (OSTI)

    Shiltsev, V.; /Fermilab

    2007-12-01

    Since previous BEAM'06 workshop a year ago, significant progress has been made in the field of beam-beam compensation (BBC)--it has been experimentally demonstrated that both Tevatron Electron Lenses (TEL) significantly improve proton and luminosity lifetimes in high-luminosity stores. This article summarizes these results and discusses prospects of the BBC in Tevatron, RHIC and LHC.

  8. Gravitational waves from phase transitions at the electroweak scale and

    Office of Scientific and Technical Information (OSTI)

    beyond (Journal Article) | SciTech Connect waves from phase transitions at the electroweak scale and beyond Citation Details In-Document Search Title: Gravitational waves from phase transitions at the electroweak scale and beyond If there was a first-order phase transition in the early universe, there should be an associated stochastic background of gravitational waves. In this paper, we point out that the characteristic frequency of the spectrum due to phase transitions which took place in

  9. Grazing collisions of gravitational shock waves and entropy production in

    Office of Scientific and Technical Information (OSTI)

    heavy ion collisions (Journal Article) | SciTech Connect Grazing collisions of gravitational shock waves and entropy production in heavy ion collisions Citation Details In-Document Search Title: Grazing collisions of gravitational shock waves and entropy production in heavy ion collisions AdS/CFT correspondence is now widely used for the study of strongly coupled plasmas, such as those produced in ultrarelativistic heavy ion collisions at the Relativistic Heavy Ion Collider. While properties

  10. Gravitational radiation from magnetically funneled supernova fallback onto a magnetar

    SciTech Connect (OSTI)

    Melatos, A.; Priymak, M., E-mail: amelatos@unimelb.edu.au, E-mail: m.priymak@pgrad.unimelb.edu.au [School of Physics, University of Melbourne, Parkville, VIC 3010 (Australia)

    2014-10-20

    Protomagnetars spun up to millisecond rotation periods by supernova fallback are predicted to radiate gravitational waves via hydrodynamic instabilities for ?10{sup 2} s before possibly collapsing to form a black hole. It is shown that magnetic funneling of the accretion flow (1) creates a magnetically confined polar mountain, which boosts the gravitational wave signal, and (2) 'buries' the magnetic dipole moment, delaying the propeller phase and assisting black hole formation.

  11. New Sources of Gravitational Waves During Inflation (Technical Report) |

    Office of Scientific and Technical Information (OSTI)

    SciTech Connect Technical Report: New Sources of Gravitational Waves During Inflation Citation Details In-Document Search Title: New Sources of Gravitational Waves During Inflation We point out that detectable inflationary tensor modes can be generated by particle or string sources produced during inflation, consistently with the requirements for inflation and constraints from scalar fluctuations. We show via examples that this effect can dominate over the contribution from quantum

  12. Critical condition in gravitational shock wave collision and heavy ion

    Office of Scientific and Technical Information (OSTI)

    collisions (Journal Article) | SciTech Connect SciTech Connect Search Results Journal Article: Critical condition in gravitational shock wave collision and heavy ion collisions Citation Details In-Document Search Title: Critical condition in gravitational shock wave collision and heavy ion collisions Authors: Lin, Shu ; Shuryak, Edward Publication Date: 2011-02-23 OSTI Identifier: 1099912 Type: Publisher's Accepted Manuscript Journal Name: Physical Review D Additional Journal Information:

  13. Critical condition in gravitational shock wave collision and heavy ion

    Office of Scientific and Technical Information (OSTI)

    collisions (Journal Article) | DOE PAGES Critical condition in gravitational shock wave collision and heavy ion collisions « Prev Next » Title: Critical condition in gravitational shock wave collision and heavy ion collisions Authors: Lin, Shu ; Shuryak, Edward Publication Date: 2011-02-23 OSTI Identifier: 1099912 Type: Publisher's Accepted Manuscript Journal Name: Physical Review D Additional Journal Information: Journal Volume: 83; Journal Issue: 4; Journal ID: ISSN 1550-7998 Publisher:

  14. Princeton physicists share in excitement of gravitational waves Einstein

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    predicted | Princeton Plasma Physics Lab Princeton physicists share in excitement of gravitational waves Einstein predicted By Catherine Zandonella, Office of the Dean for Research February 12, 2016 Tweet Widget Google Plus One Share on Facebook The collision of two black holes - an event detected for the first time ever by the Laser Interferometer Gravitational-Wave Observatory, or LIGO - is seen in this still from a computer simulation. (Image by SXS) The collision of two black holes - an

  15. Gravitational waves from global second order phase transitions

    SciTech Connect (OSTI)

    Jr, John T. Giblin; Price, Larry R.; Siemens, Xavier; Vlcek, Brian E-mail: larryp@caltech.edu E-mail: bvlcek@uwm.edu

    2012-11-01

    Global second-order phase transitions are expected to produce scale-invariant gravitational wave spectra. In this manuscript we explore the dynamics of a symmetry-breaking phase transition using lattice simulations. We explicitly calculate the stochastic gravitational wave background produced during the transition and subsequent self-ordering phase. We comment on this signal as it compares to the scale-invariant spectrum produced during inflation.

  16. Anisotropies in the gravitational-wave stochastic background

    SciTech Connect (OSTI)

    Ölmez, S.; Mandic, V.; Siemens, X. E-mail: mandic@physics.umn.edu

    2012-07-01

    We consider anisotropies in the stochastic background of gravitational-waves (SBGW) arising from random fluctuations in the number of gravitational-wave sources. We first develop the general formalism which can be applied to different cosmological or astrophysical scenarios. We then apply this formalism to calculate the anisotropies of SBGW associated with the fluctuations in the number of cosmic string loops, considering both cosmic string cusps and kinks. We calculate the anisotropies as a function of angle and frequency.

  17. Inflationary gravitational waves and the evolution of the early universe

    SciTech Connect (OSTI)

    Jinno, Ryusuke; Moroi, Takeo; Nakayama, Kazunori E-mail: moroi@hep-th.phys.s.u-tokyo.ac.jp

    2014-01-01

    We study the effects of various phenomena which may have happened in the early universe on the spectrum of inflationary gravitational waves. The phenomena include phase transitions, entropy productions from non-relativistic matter, the production of dark radiation, and decoupling of dark matter/radiation from thermal bath. These events can create several characteristic signatures in the inflationary gravitational wave spectrum, which may be direct probes of the history of the early universe and the nature of high-energy physics.

  18. Princeton physicists share in excitement of gravitational waves Einstein

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    predicted | Princeton Plasma Physics Lab Princeton physicists share in excitement of gravitational waves Einstein predicted By Catherine andonella, Office of the Dean for Research February 12, 2016 Tweet Widget Google Plus One Share on Facebook The collision of two black holes - an event detected for the first time ever by the Laser Interferometer Gravitational-Wave Observatory, or LIGO - is seen in this still from a computer simulation. (Image by SXS) The collision of two black holes - an

  19. Gravitational waves found, black-hole models led the way

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Survey and the Baryon Oscillation Spectroscopic Survey (Journal Article) | DOE PAGES Gravitational Redshift of Galaxies in Clusters from the Sloan Digital Sky Survey and the Baryon Oscillation Spectroscopic Survey Title: Gravitational Redshift of Galaxies in Clusters from the Sloan Digital Sky Survey and the Baryon Oscillation Spectroscopic Survey Authors: Sadeh, Iftach ; Feng, Low Lerh ; Lahav, Ofer Publication Date: 2015-02-20 OSTI Identifier: 1181622 Type: Publisher's Accepted Manuscript

  20. A DETAILED GRAVITATIONAL LENS MODEL BASED ON SUBMILLIMETER ARRAY AND KECK ADAPTIVE OPTICS IMAGING OF A HERSCHEL-ATLAS SUBMILLIMETER GALAXY AT z = 4.243 {sup ,} {sup ,}

    SciTech Connect (OSTI)

    Bussmann, R. S.; Gurwell, M. A.; Fu Hai; Cooray, A.; Smith, D. J. B.; Bonfield, D.; Dunne, L.; Dye, S.; Eales, S.; Auld, R.; Baes, M.; Fritz, J.; Baker, A. J.; Cava, A.; Clements, D. L.; Dariush, A.; Coppin, K.; Dannerbauer, H.; De Zotti, G.; Hopwood, R.; and others

    2012-09-10

    We present high-spatial resolution imaging obtained with the Submillimeter Array (SMA) at 880 {mu}m and the Keck adaptive optics (AO) system at the K{sub S}-band of a gravitationally lensed submillimeter galaxy (SMG) at z = 4.243 discovered in the Herschel Astrophysical Terahertz Large Area Survey. The SMA data (angular resolution Almost-Equal-To 0.''6) resolve the dust emission into multiple lensed images, while the Keck AO K{sub S}-band data (angular resolution Almost-Equal-To 0.''1) resolve the lens into a pair of galaxies separated by 0.''3. We present an optical spectrum of the foreground lens obtained with the Gemini-South telescope that provides a lens redshift of z{sub lens} = 0.595 {+-} 0.005. We develop and apply a new lens modeling technique in the visibility plane that shows that the SMG is magnified by a factor of {mu} = 4.1 {+-} 0.2 and has an intrinsic infrared (IR) luminosity of L{sub IR} = (2.1 {+-} 0.2) Multiplication-Sign 10{sup 13} L{sub Sun }. We measure a half-light radius of the background source of r{sub s} = 4.4 {+-} 0.5 kpc which implies an IR luminosity surface density of {Sigma}{sub IR} (3.4 {+-} 0.9) Multiplication-Sign 10{sup 11} L{sub Sun} kpc{sup -2}, a value that is typical of z > 2 SMGs but significantly lower than IR luminous galaxies at z {approx} 0. The two lens galaxies are compact (r{sub lens} Almost-Equal-To 0.9 kpc) early-types with Einstein radii of {theta}{sub E1} 0.57 {+-} 0.01 and {theta}{sub E2} = 0.40 {+-} 0.01 that imply masses of M{sub lens1} = (7.4 {+-} 0.5) Multiplication-Sign 10{sup 10} M{sub Sun} and M{sub lens2} = (3.7 {+-} 0.3) Multiplication-Sign 10{sup 10} M{sub Sun }. The two lensing galaxies are likely about to undergo a dissipationless merger, and the mass and size of the resultant system should be similar to other early-type galaxies at z {approx} 0.6. This work highlights the importance of high spatial resolution imaging in developing models of strongly lensed galaxies discovered by Herschel.

  1. Dust magneto-gravitational drift wave in gB configuration

    SciTech Connect (OSTI)

    Salahshoor, M. Niknam, A. R.

    2014-11-15

    The dispersion relation of electrostatic waves in a magnetized complex plasma under gravity is presented. It is assumed that the waves propagate perpendicular to the external fields. The effects of weak electric field, neutral drag force, and ion drag force are also taken into account. The dispersion relation is numerically examined in an appropriate parameter space in which the gravity plays the dominant role in the dynamics of magnetized microparticles. The numerical results show that an unstable low frequency drift wave can be developed in the long wavelength limit. This unstable mode is transformed into an aperiodic stationary structure at a cut-off wavenumber. Furthermore, the influence of the external fields on the dispersion properties is analyzed. It is shown that the instability is essentially due to the EB drift motion of plasma particles. However, in the absence of weak electric field, the gB drift motion of microparticles can cause the instability in a wide range of wavenumbers. It is also found that by increasing the magnetic field strength, the wave frequency is first increased and then decreased. This behaviour is explained by the existence of an extremum point in the dust magneto-gravitational drift velocity.

  2. Corrigendum and addendum. Modeling weakly nonlinear acoustic wave

    Office of Scientific and Technical Information (OSTI)

    propagation (Journal Article) | SciTech Connect Corrigendum and addendum. Modeling weakly nonlinear acoustic wave propagation Citation Details In-Document Search Title: Corrigendum and addendum. Modeling weakly nonlinear acoustic wave propagation This article presents errors, corrections, and additions to the research outlined in the following citation: Christov, I., Christov, C. I., & Jordan, P. M. (2007). Modeling weakly nonlinear acoustic wave propagation. The Quarterly Journal of

  3. Neutron Beta Decay as a Probe of Weak Interactions (Conference...

    Office of Scientific and Technical Information (OSTI)

    Citation Details In-Document Search Title: Neutron Beta Decay as a Probe of Weak Interactions Authors: Saunders, Alexander 1 + Show Author Affiliations Los Alamos National ...

  4. Direct Measurement of the Neutral Weak Dipole Moments of the...

    Office of Scientific and Technical Information (OSTI)

    Visit OSTI to utilize additional information resources in energy science and technology. A ... We present direct measurements of the neutral weak anomalous magnetic dipole moment, asub ...

  5. Gravitational wave hotspots: Ranking potential locations of single-source gravitational wave emission

    SciTech Connect (OSTI)

    Simon, Joseph; Polin, Abigail; Lommen, Andrea; Christy, B; Stappers, Ben; Finn, Lee Samuel; Jenet, F. A.

    2014-03-20

    The steadily improving sensitivity of pulsar timing arrays (PTAs) suggests that gravitational waves (GWs) from supermassive black hole binary (SMBHB) systems in the nearby universe will be detectable sometime during the next decade. Currently, PTAs assume an equal probability of detection from every sky position, but as evidence grows for a non-isotropic distribution of sources, is there a most likely sky position for a detectable single source of GWs? In this paper, a collection of Galactic catalogs is used to calculate various metrics related to the detectability of a single GW source resolvable above a GW background, assuming that every galaxy has the same probability of containing an SMBHB. Our analyses of these data reveal small probabilities that one of these sources is currently in the PTA band, but as sensitivity is improved regions of consistent probability density are found in predictable locations, specifically around local galaxy clusters.

  6. The mass distribution of the strong lensing cluster SDSS J1531+3414

    SciTech Connect (OSTI)

    Sharon, Keren; Johnson, Traci L. [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109 (United States); Gladders, Michael D. [Kavli Institute for Cosmological Physics, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 (United States); Rigby, Jane R. [Observational Cosmology Lab, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Wuyts, Eva [Max-Planck-Institut fr extraterrestrische Physik, Giessenbachstr. 1, D-85741 Garching (Germany); Bayliss, Matthew B. [Department of Physics, Harvard University, 17 Oxford Street, Cambridge, MA 02138 (United States); Florian, Michael K. [Department of Astronomy and Astrophysics, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 (United States); Dahle, Hkon, E-mail: kerens@umich.edu [Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029, Blindern, N-0315 Oslo (Norway)

    2014-11-01

    We present the mass distribution at the core of SDSS J1531+3414, a strong-lensing cluster at z = 0.335. We find that the mass distribution is well described by two cluster-scale halos with a contribution from cluster-member galaxies. New Hubble Space Telescope observations of SDSS J1531+3414 reveal a signature of ongoing star formation associated with the two central galaxies at the core of the cluster, in the form of a chain of star forming regions at the center of the cluster. Using the lens model presented here, we place upper limits on the contribution of a possible lensed image to the flux at the central region, and rule out that this emission is coming from a background source.

  7. Three-point galaxy-galaxy lensing as a probe of dark matter halo shapes

    SciTech Connect (OSTI)

    Adhikari, Susmita; Chue, Chun Yin Ricky; Dalal, Neal E-mail: chue2@illinois.edu

    2015-01-01

    We propose a method to measure the ellipticities of dark matter halos using the lens-shear-shear 3-point correlation function. This method is immune to effects of galaxy-halo misalignments that can potentially limit 2-point galaxy-galaxy lensing measurements of halo anisotropy. Using a simple model for the projected mass distributions of dark matter halos, we construct an ellipticity estimator that sums over all possible triangular configurations of the 3-point function. By applying our estimator to halos from N-body simulations, we find that systematic errors in the recovered ellipticity will be at the ?<5% fractional level. We estimate that future imaging surveys like LSST will have sufficient statistics to detect halo ellipticities using 3-point lensing.

  8. Optics solutions for pp operation with electron lenses at 100 GeV

    SciTech Connect (OSTI)

    White, S.; Fischer, W.; Luo, Y.

    2014-07-12

    Electron lenses for head-on compensation are currently under commissioning and foreseen to be operational for the 2015 polarized proton run. These devices will provide a partial compensation of head-on beam-beam effects and allow to double the RHIC proton luminosity. This note reviews the optics constraints related to beam-beam compensation and summarizes the current lattice options for proton operation at 100 GeV.

  9. GRAVITATIONAL WAVES OF JET PRECESSION IN GAMMA-RAY BURSTS

    SciTech Connect (OSTI)

    Sun Mouyuan; Liu Tong; Gu Weimin; Lu Jufu

    2012-06-10

    The physical nature of gamma-ray bursts (GRBs) is believed to involve an ultra-relativistic jet. The observed complex structure of light curves motivates the idea of jet precession. In this work, we study the gravitational waves of jet precession based on neutrino-dominated accretion disks around black holes, which may account for the central engine of GRBs. In our model, the jet and the inner part of the disk may precess along with the black hole, which is driven by the outer part of the disk. Gravitational waves are therefore expected to be significant from this black-hole-inner-disk precession system. By comparing our numerical results with the sensitivity of some detectors, we find that it is possible for DECIGO and BBO to detect such gravitational waves, particularly for GRBs in the Local Group.

  10. Gravitational-wave generation in hybrid quintessential inflationary models

    SciTech Connect (OSTI)

    Sa, Paulo M.; Henriques, Alfredo B.

    2010-06-15

    We investigate the generation of gravitational waves in the hybrid quintessential inflationary model. The full gravitational-wave energy spectrum is calculated using the method of continuous Bogoliubov coefficients. The postinflationary kination period, characteristic of quintessential inflationary models, leaves a clear signature on the spectrum, namely, a peak at high frequencies. The maximum of the peak is firmly located at the megahertz-gigahertz region of the spectrum and corresponds to {Omega}{sub GW{approx_equal}}10{sup -12}. This peak is substantially smaller than the one appearing in the gravitational-wave energy spectrum of the original quintessential inflationary model, therefore avoiding any conflict with the nucleosynthesis constraint on {Omega}{sub GW}.

  11. Studying inflation with future space-based gravitational wave detectors

    SciTech Connect (OSTI)

    Jinno, Ryusuke; Moroi, Takeo; Takahashi, Tomo E-mail: moroi@phys.s.u-tokyo.ac.jp

    2014-12-01

    Motivated by recent progress in our understanding of the B-mode polarization of cosmic microwave background (CMB), which provides important information about the inflationary gravitational waves (IGWs), we study the possibility to acquire information about the early universe using future space-based gravitational wave (GW) detectors. We perform a detailed statistical analysis to estimate how well we can determine the reheating temperature after inflation as well as the amplitude, the tensor spectral index, and the running of the inflationary gravitational waves. We discuss how the accuracies depend on noise parameters of the detector and the minimum frequency available in the analysis. Implication of such a study on the test of inflation models is also discussed.

  12. Chromatic-aberration-corrected diffractive lenses for ultra-broadband focusing

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Wang, Peng; Mohammad, Nabil; Menon, Rajesh

    2016-02-12

    We exploit the inherent dispersion in diffractive optics to demonstrate planar chromatic-aberration-corrected lenses. Specifically, we designed, fabricated and characterized cylindrical diffractive lenses that efficiently focus the entire visible band (450 nm to 700 nm) onto a single line. These devices are essentially pixelated, multi-level microstructures. Experiments confirm an average optical efficiency of 25% for a three-wavelength apochromatic lens whose chromatic focus shift is only 1.3 μm and 25 μm in the lateral and axial directions, respectively. Super-achromatic performance over the continuous visible band is also demonstrated with averaged lateral and axial focus shifts of only 1.65 μm and 73.6 μm,more » respectively. These lenses are easy to fabricate using single-step grayscale lithography and can be inexpensively replicated. Furthermore, these devices are thin (<3 μm), error tolerant, has low aspect ratio (<1:1) and offer polarization-insensitive focusing, all significant advantages compared to alternatives that rely on metasurfaces. Lastly, our design methodology offers high design flexibility in numerical aperture and focal length, and is readily extended to 2D.« less

  13. Joint Analysis of Galaxy-Galaxy Lensing and Galaxy Clustering: Methodology and Forecasts for DES

    SciTech Connect (OSTI)

    Park, Y.

    2015-07-19

    The joint analysis of galaxy-galaxy lensing and galaxy clustering is a promising method for inferring the growth function of large scale structure. Our analysis will be carried out on data from the Dark Energy Survey (DES), with its measurements of both the distribution of galaxies and the tangential shears of background galaxies induced by these foreground lenses. We develop a practical approach to modeling the assumptions and systematic effects affecting small scale lensing, which provides halo masses, and large scale galaxy clustering. Introducing parameters that characterize the halo occupation distribution (HOD), photometric redshift uncertainties, and shear measurement errors, we study how external priors on different subsets of these parameters affect our growth constraints. Degeneracies within the HOD model, as well as between the HOD and the growth function, are identified as the dominant source of complication, with other systematic effects sub-dominant. The impact of HOD parameters and their degeneracies necessitate the detailed joint modeling of the galaxy sample that we employ. Finally, we conclude that DES data will provide powerful constraints on the evolution of structure growth in the universe, conservatively/optimistically constraining the growth function to 7.9%/4.8% with its first-year data that covered over 1000 square degrees, and to 3.9%/2.3% with its full five-year data that will survey 5000 square degrees, including both statistical and systematic uncertainties.

  14. Viscous gravitational aether and the cosmological constant problem

    SciTech Connect (OSTI)

    Kuang, Xiaomei; Ling, Yi E-mail: yling@ncu.edu.cn

    2009-10-01

    Recently a notion of gravitational aether is advocated to solve the cosmological constant problem. Through the modification of the source of gravity one finds that the effective Newton's constant is source dependent so as to provide a simple but consistent way to decouple gravity from the vacuum energy. However, in the original paper the ratio of the effective Newton's constants for pressureless dust and radiation has an upper bound which is 0.75. In this paper we propose a scheme to loose this bound by introducing a bulk viscosity for the gravitational aether, and expect this improvement will provide more space for matching predictions from this theoretical programm with observational constraints.

  15. Unitarity check in gravitational Higgs mechanism (Journal Article) |

    Office of Scientific and Technical Information (OSTI)

    SciTech Connect Unitarity check in gravitational Higgs mechanism Citation Details In-Document Search Title: Unitarity check in gravitational Higgs mechanism The effective field theory of massive gravity has long been formulated in a generally covariant way [N. Arkani-Hamed, H. Georgi, and M. D. Schwartz, Ann. Phys. (N.Y.) 305, 96 (2003).]. Using this formalism, it has been found recently that there exists a class of massive nonlinear theories that are free of the Boulware-Deser ghosts, at

  16. COLLOQUIUM: The Observation of Gravitational Waves from a Binary Black Hole

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Merger | Princeton Plasma Physics Lab 5, 2016, 4:15pm to 5:30pm Colloquia MBG Auditorium, PPPL (284 cap.) COLLOQUIUM: The Observation of Gravitational Waves from a Binary Black Hole Merger Dr. Duncan Brown Syracuse University On September 14, 2015 the the two detectors of the Laser Interferometer Gravitational-Wave Observatory (LIGO) simultaneously observed gravitational waves from a binary black hole merger. The gravitational waves observed match the waveform predicted by general relativity

  17. Ultra-weak sector, Higgs boson mass, and the dilaton

    SciTech Connect (OSTI)

    Allison, Kyle; Hill, Christopher T.; Ross, Graham G.

    2014-11-01

    The Higgs boson mass may arise from a portal coupling to a singlet field $\\sigma$ which has a very large VEV $f \\gg m_\\text{Higgs}$. This requires a sector of "ultra-weak" couplings $\\zeta_i$, where $\\zeta_i \\lesssim m_\\text{Higgs}^2 / f^2$. Ultra-weak couplings are technically naturally small due to a custodial shift symmetry of $\\sigma$ in the $\\zeta_i \\rightarrow 0$ limit. The singlet field $\\sigma$ has properties similar to a pseudo-dilaton. We engineer explicit breaking of scale invariance in the ultra-weak sector via a Coleman-Weinberg potential, which requires hierarchies amongst the ultra-weak couplings.

  18. Evidence for a Weak Iron Core at Earth's Center

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Evidence for a Weak Iron Core at Earth's Center Print Seismic waves that pass through the center of the Earth travel faster going from pole to pole than along the equatorial...

  19. Ultra-weak sector, Higgs boson mass, and the dilaton

    SciTech Connect (OSTI)

    Allison, Kyle; Hill, Christopher T.; Ross, Graham G.

    2014-09-26

    The Higgs boson mass may arise from a portal coupling to a singlet field $\\sigma$ which has a very large VEV $f \\gg m_\\text{Higgs}$. This requires a sector of "ultra-weak" couplings $\\zeta_i$, where $\\zeta_i \\lesssim m_\\text{Higgs}^2 / f^2$. Ultra-weak couplings are technically naturally small due to a custodial shift symmetry of $\\sigma$ in the $\\zeta_i \\rightarrow 0$ limit. The singlet field $\\sigma$ has properties similar to a pseudo-dilaton. We engineer explicit breaking of scale invariance in the ultra-weak sector via a Coleman-Weinberg potential, which requires hierarchies amongst the ultra-weak couplings.

  20. Ultra-weak sector, Higgs boson mass, and the dilaton

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Allison, Kyle; Hill, Christopher T.; Ross, Graham G.

    2014-09-26

    The Higgs boson mass may arise from a portal coupling to a singlet fieldmore » $$\\sigma$$ which has a very large VEV $$f \\gg m_\\text{Higgs}$$. This requires a sector of "ultra-weak" couplings $$\\zeta_i$$, where $$\\zeta_i \\lesssim m_\\text{Higgs}^2 / f^2$$. Ultra-weak couplings are technically naturally small due to a custodial shift symmetry of $$\\sigma$$ in the $$\\zeta_i \\rightarrow 0$$ limit. The singlet field $$\\sigma$$ has properties similar to a pseudo-dilaton. We engineer explicit breaking of scale invariance in the ultra-weak sector via a Coleman-Weinberg potential, which requires hierarchies amongst the ultra-weak couplings.« less

  1. Stabilization of weak ferromagnetism by strong magnetic response to

    Office of Scientific and Technical Information (OSTI)

    epitaxial strain in multiferroic BiFeO3 (Journal Article) | SciTech Connect Stabilization of weak ferromagnetism by strong magnetic response to epitaxial strain in multiferroic BiFeO3 Citation Details In-Document Search Title: Stabilization of weak ferromagnetism by strong magnetic response to epitaxial strain in multiferroic BiFeO3 Multiferroic BiFeO3 exhibits excellent magnetoelectric coupling critical for magnetic information processing with minimal power consumption. Thus, the degenerate

  2. Consistent analysis of one-nucleon spectroscopic factors involving weakly-

    Office of Scientific and Technical Information (OSTI)

    and strongly-bound nucleons (Journal Article) | SciTech Connect Consistent analysis of one-nucleon spectroscopic factors involving weakly- and strongly-bound nucleons Citation Details In-Document Search Title: Consistent analysis of one-nucleon spectroscopic factors involving weakly- and strongly-bound nucleons Authors: Okołowicz, J. ; Lam, Y. H. ; Płoszajczak, M. ; Macchiavelli, A. O. ; Smirnova, N. A. Publication Date: 2016-04-01 OSTI Identifier: 1246192 Grant/Contract Number:

  3. HISTORY OF WEAK INTERACTIONS. (Technical Report) | SciTech Connect

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    HISTORY OF WEAK INTERACTIONS. Citation Details In-Document Search Title: HISTORY OF WEAK INTERACTIONS. × You are accessing a document from the Department of Energy's (DOE) SciTech Connect. This site is a product of DOE's Office of Scientific and Technical Information (OSTI) and is provided as a public service. Visit OSTI to utilize additional information resources in energy science and technology. A paper copy of this document is also available for sale to the public from the National Technical

  4. A comparison of weak-turbulence and particle-in-cell simulations of weak electron-beam plasma interaction

    SciTech Connect (OSTI)

    Ratcliffe, H. Brady, C. S.; Che Rozenan, M. B.; Nakariakov, V. M.

    2014-12-15

    Quasilinear theory has long been used to treat the problem of a weak electron beam interacting with plasma and generating Langmuir waves. Its extension to weak-turbulence theory treats resonant interactions of these Langmuir waves with other plasma wave modes, in particular, ion-sound waves. These are strongly damped in plasma of equal ion and electron temperatures, as sometimes seen in, for example, the solar corona and wind. Weak turbulence theory is derived in the weak damping limit, with a term describing ion-sound wave damping then added. In this paper, we use the EPOCH particle-in-cell code to numerically test weak turbulence theory for a range of electron-ion temperature ratios. We find that in the cold ion limit, the results agree well, but for increasing ion temperature the three-wave resonance becomes broadened in proportion to the ion-sound wave damping rate. Additionally, we establish lower limits on the number of simulation particles needed to accurately reproduce the electron and wave distributions in their saturated states and to reproduce their intermediate states and time evolution. These results should be taken into consideration in, for example, simulations of plasma wave generation in the solar corona of Type III solar radio bursts from the corona to the solar wind and in weak turbulence investigations of ion-acoustic lines in the ionosphere.

  5. Generalized crossing states in the interacting case: The uniform gravitational field

    SciTech Connect (OSTI)

    Villanueva, Anthony D.; Galapon, Eric A.

    2010-11-15

    We reconsider Baute et al.'s free crossing states [Phys. Rev. A 61, 022118 (2000)] and show that if we require a generalization in the interacting case that goes in complete parallel with the free-particle case, then this generalized crossing state cannot be arbitrary but is determined by the null space of the particle's quantum time-of-arrival operator. Nonetheless, the free crossing states appear as the leading term in the asymptotic expansion of our generalized crossing state in the limit of large momentum. We then examine the quantum time-of-arrival problem of a spinless particle in a uniform gravitational field. Mass-dependent time-of-arrival probability distributions emerge, signifying quantum departures from the weak equivalence principle. However, in the classical limit of large mass and vanishing uncertainty in position, the mass dependence of the quantum time-of-arrival distribution becomes exponentially small and the mean quantum time of arrival reduces to the classical time of arrival.

  6. Triangular lattice of carbon nanotube arrays for negative index of refraction and subwavelength lensing effect

    SciTech Connect (OSTI)

    Wang, Y.; Wang, X.; Rybczynski, J.; Wang, D.Z.; Kempa, K.; Ren, Z.F.

    2005-04-11

    Self-assembly of polystyrene microspheres has been utilized in a two-step masking technique to prepare triangular lattices of catalytic nanodots at low cost. Subsequent triangular lattices of aligned carbon nanotubes on a silicon substrate are achieved by plasma-enhanced chemical vapor deposition. Nickel is used both in the nanodots and in the secondary mask. The triangular lattices of carbon nanotube arrays as two-dimensional photonic crystals show higher geometrical symmetry than the hexagonal lattices previously reported, enabling broader applications including negative index of refraction and subwavelength lensing effect.

  7. Short spatial filters with spherical lenses for high-power pulsed lasers

    SciTech Connect (OSTI)

    Burdonov, K F; Soloviev, A A; Shaikin, A A; Potemkin, A K; Egorov, A S

    2013-11-30

    We report possible employment of short spatial filters based on spherical lenses in a pulsed laser source (neodymium glass, 300 J, 1 ns). The influence of the spherical aberration on the quality of output radiation and coefficient of conversion to the second harmonics is studied. The ultra-short aberration spatial filter of length 1.9 m with an aperture of 122 mm is experimentally tested. A considerable shortening of multi-cascade pump lasers for modern petawatt laser systems is demonstrated by the employment of short spatial filters without expensive aspherical optics. (elements of laser systems)

  8. Resurgence and holomorphy: From weak to strong coupling

    SciTech Connect (OSTI)

    Cherman, Aleksey; Koroteev, Peter; Ünsal, Mithat

    2015-05-15

    We analyze the resurgence properties of finite-dimensional exponential integrals which are prototypes for partition functions in quantum field theories. In these simple examples, we demonstrate that perturbation theory, even at arbitrarily weak coupling, fails as the argument of the coupling constant is varied. It is well-known that perturbation theory also fails at stronger coupling. We show that these two failures are actually intimately related. The formalism of resurgent transseries, which takes into account global analytic continuation properties, fixes both problems and provides an arbitrarily accurate description of exact result for any value of coupling. This means that strong coupling results can be deduced by using merely weak coupling data. Finally, we give another perspective on resurgence theory by showing that the monodromy properties of the weak coupling results are in precise agreement with the monodromy properties of the strong-coupling expansions, obtained using analysis of the holomorphy structure of Picard-Fuchs equations.

  9. Variance control in weak-value measurement pointers

    SciTech Connect (OSTI)

    Parks, A. D.; Gray, J. E.

    2011-07-15

    The variance of an arbitrary pointer observable is considered for the general case that a complex weak value is measured using a complex valued pointer state. For the typical cases where the pointer observable is either its position or momentum, the associated expressions for the pointer's variance after the measurement contain a term proportional to the product of the weak value's imaginary part with the rate of change of the third central moment of position relative to the initial pointer state just prior to the time of the measurement interaction when position is the observable--or with the initial pointer state's third central moment of momentum when momentum is the observable. These terms provide a means for controlling pointer position and momentum variance and identify control conditions which, when satisfied, can yield variances that are smaller after the measurement than they were before the measurement. Measurement sensitivities which are useful for estimating weak-value measurement accuracies are also briefly discussed.

  10. First upper limits from LIGO on gravitational wave bursts

    SciTech Connect (OSTI)

    B. Abbott et al.

    2004-03-09

    We report on a search for gravitational wave bursts using data from the first science run of the LIGO detectors. Our search focuses on bursts with durations ranging from 4 ms to 100 ms, and with significant power in the LIGO sensitivity band of 150 to 3000 Hz. We bound the rate for such detected bursts at less than 1.6 events per day at 90% confidence level. This result is interpreted in terms of the detection efficiency for ad hoc waveforms (Gaussians and sine-Gaussians) as a function of their root-sum-square strain h{sub rss}; typical sensitivities lie in the range h{sub rss} {approx} 10{sup -19} - 10{sup -17} strain/{radical}Hz, depending on waveform. We discuss improvements in the search method that will be applied to future science data from LIGO and other gravitational wave detectors.

  11. Massive gravitational waves in Chern-Simons modified gravity

    SciTech Connect (OSTI)

    Myung, Yun Soo; Moon, Taeyoon E-mail: tymoon@inje.ac.kr

    2014-10-01

    We consider the nondynamical Chern-Simons (nCS) modified gravity, which is regarded as a parity-odd theory of massive gravity in four dimensions. We first find polarization modes of gravitational waves for θ=x/μ in nCS modified gravity by using the Newman-Penrose formalism where the null complex tetrad is necessary to specify gravitational waves. We show that in the Newman–Penrose formalism, the number of polarization modes is one in addition to an unspecified Ψ{sub 4}, implying three degrees of freedom for θ=x/μ. This compares with two for a canonical embedding of θ=t/μ. Also, if one introduces the Ricci tensor formalism to describe a massive graviton arising from the nCS modified gravity, one finds one massive mode after making second-order wave equations, which is compared to five found from the parity-even Einstein–Weyl gravity.

  12. Evidence for a Weak Iron Core at Earth's Center

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Evidence for a Weak Iron Core at Earth's Center Evidence for a Weak Iron Core at Earth's Center Print Wednesday, 30 April 2014 00:00 Seismic waves that pass through the center of the Earth travel faster going from pole to pole than along the equatorial plane-why? One theory is that the grains of iron that make up most of the solid inner core could be aligned in a way that transmits waves more efficiently in one direction than the other. Recent evidence for this "texturing" of iron

  13. The quantum gravitational back-reaction on inflation

    SciTech Connect (OSTI)

    Tsamis, N.C. |; Woodard, R.P.

    1995-02-01

    We describe our recent calculation of the dominant late time behavior of the expectation value of the metric at two loops in a locally de Sitter background on the manifold T{sup 3} {times} {Re}. If correct, our result proves that quantum gravitational effects slow the rate of inflation by an amount which becomes non-perturbatively large at late times. 11 refs., 9 figs., 11 tabs.

  14. Motion of gravitationally interacting particles in Born-Infeld electrodynamics

    SciTech Connect (OSTI)

    Shkolnik, N.; Mallett, R.L.

    1986-12-15

    The motion of charged particles in the framework of the Einstein-Infeld-Hoffmann method is examined. The Born-Infeld energy-momentum tensor is used on the right-hand side of the gravitational field equations. It is shown that this results in a modified behavior of charged particles. In particular, it leads to a modification of Coulomb's law at small distances. It is also shown that a stable system of two charged particles is possible.

  15. Transverse profile of the electron beam for the RHIC electron lenses

    SciTech Connect (OSTI)

    Gu, X.; Altinbas, Z.; Costanzo, M.; Fischer, W.; Gassner, D. M.; Hock, J.; Luo, Y.; Miller, T.; Tan, Y.; Thieberger, P.; Montag, C.; Pikin, A. I.

    2015-07-10

    To compensate for the beam-beam effects from the proton-proton interactions at the two interaction points IP6 and IP8 in the Relativistic Heavy Ion Collider (RHIC), we are constructing two electron lenses (e-lenses) that we plan to install in the interaction region IR10. Before installing them, the electron gun, collector, instrumentation were tested and the electron beam properties were qualified on an electron lens test bench. We will present the test results and discuss our measurement of the electron beam current and of the electron gun perveance. We achieved a maximum current of 1 A with 5 kV energy for both the pulsed- and the DC-beam (which is a long turn-by-turn pulse beam). We measured beam transverse profiles with an Yttrium Aluminum Garnet (YAG) screen and pinhole detector, and compared those to simulated beam profiles. Measurements of the pulsed electron beam stability were obtained by measuring the modulator voltage.

  16. Strong lensing probability in TeVeS (tensor-vector-scalar) theory

    SciTech Connect (OSTI)

    Chen Daming

    2008-01-15

    We recalculate the strong lensing probability as a function of the image separation in TeVeS (tensor-vector-scalar) cosmology, which is a relativistic version of MOND (MOdified Newtonian Dynamics). The lens is modeled by the Hernquist profile. We assume an open cosmology with {Omega}{sub b} = 0.04 and {Omega}{sub {Lambda}} = 0.5 and three different kinds of interpolating functions. Two different galaxy stellar mass functions (GSMF) are adopted: PHJ (Panter, Heavens and Jimenez 2004 Mon. Not. R. Astron. Soc. 355 764) determined from SDSS data release 1 and Fontana (Fontana et al 2006 Astron. Astrophys. 459 745) from GOODS-MUSIC catalog. We compare our results with both the predicted probabilities for lenses from singular isothermal sphere galaxy halos in LCDM (Lambda cold dark matter) with a Schechter-fit velocity function, and the observational results for the well defined combined sample of the Cosmic Lens All-Sky Survey (CLASS) and Jodrell Bank/Very Large Array Astrometric Survey (JVAS). It turns out that the interpolating function {mu}(x) = x/(1+x) combined with Fontana GSMF matches the results from CLASS/JVAS quite well.

  17. Transverse profile of the electron beam for the RHIC electron lenses

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Gu, X.; Altinbas, Z.; Costanzo, M.; Fischer, W.; Gassner, D. M.; Hock, J.; Luo, Y.; Miller, T.; Tan, Y.; Thieberger, P.; et al

    2015-07-10

    To compensate for the beam-beam effects from the proton-proton interactions at the two interaction points IP6 and IP8 in the Relativistic Heavy Ion Collider (RHIC), we are constructing two electron lenses (e-lenses) that we plan to install in the interaction region IR10. Before installing them, the electron gun, collector, instrumentation were tested and the electron beam properties were qualified on an electron lens test bench. We will present the test results and discuss our measurement of the electron beam current and of the electron gun perveance. We achieved a maximum current of 1 A with 5 kV energy for bothmore » the pulsed- and the DC-beam (which is a long turn-by-turn pulse beam). We measured beam transverse profiles with an Yttrium Aluminum Garnet (YAG) screen and pinhole detector, and compared those to simulated beam profiles. Measurements of the pulsed electron beam stability were obtained by measuring the modulator voltage.« less

  18. COSMOLOGICAL DEPENDENCE OF THE MEASUREMENTS OF LUMINOSITY FUNCTION, PROJECTED CLUSTERING AND GALAXY-GALAXY LENSING SIGNAL

    SciTech Connect (OSTI)

    More, Surhud

    2013-11-10

    Observables such as the galaxy luminosity function, ?(M), projected galaxy clustering, w {sub p}(r {sub p}), and the galaxy-galaxy lensing signal, ??(r {sub p}), are often measured from galaxy redshift surveys assuming a fiducial cosmological model for calculating distances to, and between galaxies. There are a growing number of studies that perform joint analyses of these measurements and constrain cosmological parameters. We quantify the amount by which such measurements systematically vary as the fiducial cosmology used for the measurements is changed, and show that these effects can be significant at high redshifts (z ? 0.5). Cosmological analyses (or halo occupation distribution analyses) that use the luminosity function, clustering and the galaxy-galaxy lensing signal but ignore such systematic effects may bias the inference of the parameters. We present a simple way to account for the differences in the cosmological model used for the measurements and those used for the prediction of observables, thus allowing a fair comparison between models and data.

  19. SPINDOWN OF ISOLATED NEUTRON STARS: GRAVITATIONAL WAVES OR MAGNETIC BRAKING?

    SciTech Connect (OSTI)

    Staff, Jan E.; Jaikumar, Prashanth; Chan, Vincent; Ouyed, Rachid

    2012-05-20

    We study the spindown of isolated neutron stars from initially rapid rotation rates, driven by two factors: (1) gravitational wave emission due to r-modes and (2) magnetic braking. In the context of isolated neutron stars, we present the first study including self-consistently the magnetic damping of r-modes in the spin evolution. We track the spin evolution employing the RNS code, which accounts for the rotating structure of neutron stars for various equations of state. We find that, despite the strong damping due to the magnetic field, r-modes alter the braking rate from pure magnetic braking for B {<=} 10{sup 13} G. For realistic values of the saturation amplitude {alpha}{sub sat}, the r-mode can also decrease the time to reach the threshold central density for quark deconfinement. Within a phenomenological model, we assess the gravitational waveform that would result from r-mode-driven spindown of a magnetized neutron star. To contrast with the persistent signal during the spindown phase, we also present a preliminary estimate of the transient gravitational wave signal from an explosive quark-hadron phase transition, which can be a signal for the deconfinement of quarks inside neutron stars.

  20. GRAVITATIONAL WAVE SIGNATURES IN BLACK HOLE FORMING CORE COLLAPSE

    SciTech Connect (OSTI)

    Cerd-Durn, Pablo; DeBrye, Nicolas; Aloy, Miguel A.; Font, Jos A.; Obergaulinger, Martin

    2013-12-20

    We present general relativistic numerical simulations of collapsing stellar cores. Our initial model consists of a low metallicity rapidly-rotating progenitor which is evolved in axisymmetry with the latest version of our general relativistic code CoCoNuT, which allows for black hole formation and includes the effects of a microphysical equation of state (LS220) and a neutrino leakage scheme to account for radiative losses. The motivation of our study is to analyze in detail the emission of gravitational waves in the collapsar scenario of long gamma-ray bursts. Our simulations show that the phase during which the proto-neutron star (PNS) survives before ultimately collapsing to a black hole is particularly optimal for gravitational wave emission. The high-amplitude waves last for several seconds and show a remarkable quasi-periodicity associated with the violent PNS dynamics, namely during the episodes of convection and the subsequent nonlinear development of the standing-accretion shock instability (SASI). By analyzing the spectrogram of our simulations we are able to identify the frequencies associated with the presence of g-modes and with the SASI motions at the PNS surface. We note that the gravitational waves emitted reach large enough amplitudes to be detected with third-generation detectors such as the Einstein Telescope within a Virgo Cluster volume at rates ? 0.1yr{sup 1}.

  1. Microoptic lenses

    DOE Patents [OSTI]

    Snyder, J.J.

    1993-01-19

    The present invention provides several novel diffraction limited microlens configurations which are especially valuable for use in conjunction with laser diodes, and optical fibers. Collimators, circularizers and focusers (couplers) are provided.

  2. Microoptic lenses

    DOE Patents [OSTI]

    Snyder, James J. (San Jose, CA)

    1993-01-01

    The present invention provides several novel diffraction limited microlens configurations which are especially valuable for use in conjunction with laser diodes, and optical fibers. Collimators, circularizers and focusers (couplers) are provided.

  3. Corrigendum and addendum. Modeling weakly nonlinear acoustic wave propagation

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Christov, Ivan; Christov, C. I.; Jordan, P. M.

    2014-12-18

    This article presents errors, corrections, and additions to the research outlined in the following citation: Christov, I., Christov, C. I., & Jordan, P. M. (2007). Modeling weakly nonlinear acoustic wave propagation. The Quarterly Journal of Mechanics and Applied Mathematics, 60(4), 473-495.

  4. A COMPREHENSIVE VIEW OF A STRONGLY LENSED PLANCK-ASSOCIATED SUBMILLIMETER GALAXY

    SciTech Connect (OSTI)

    Fu Hai; Cooray, A.; Jullo, E.; Bussmann, R. S.; Ivison, R. J.; Perez-Fournon, I.; Djorgovski, S. G.; Scoville, N.; Yan, L.; Riechers, D. A.; Bradford, M.; Aguirre, J.; Auld, R.; Baes, M.; Baker, A. J.; Cava, A.; Clements, D. L.; Dannerbauer, H.; Dariush, A.; De Zotti, G.; and others

    2012-07-10

    We present high-resolution maps of stars, dust, and molecular gas in a strongly lensed submillimeter galaxy (SMG) at z = 3.259. HATLAS J114637.9-001132 is selected from the Herschel-Astrophysical Terahertz Large Area Survey (H-ATLAS) as a strong lens candidate mainly based on its unusually high 500 {mu}m flux density ({approx}300 mJy). It is the only high-redshift Planck detection in the 130 deg{sup 2} H-ATLAS Phase-I area. Keck Adaptive Optics images reveal a quadruply imaged galaxy in the K band while the Submillimeter Array and the Jansky Very Large Array show doubly imaged 880 {mu}m and CO(1{yields}0) sources, indicating differentiated distributions of the various components in the galaxy. In the source plane, the stars reside in three major kpc-scale clumps extended over {approx}1.6 kpc, the dust in a compact ({approx}1 kpc) region {approx}3 kpc north of the stars, and the cold molecular gas in an extended ({approx}7 kpc) disk {approx}5 kpc northeast of the stars. The emissions from the stars, dust, and gas are magnified by {approx}17, {approx}8, and {approx}7 times, respectively, by four lensing galaxies at z {approx} 1. Intrinsically, the lensed galaxy is a warm (T{sub dust} {approx} 40-65 K), hyper-luminous (L{sub IR} {approx} 1.7 Multiplication-Sign 10{sup 13} L{sub Sun }; star formation rate (SFR) {approx}2000 M{sub Sun} yr{sup -1}), gas-rich (M{sub gas}/M{sub baryon} {approx} 70%), young (M{sub stellar}/SFR {approx} 20 Myr), and short-lived (M{sub gas}/SFR {approx} 40 Myr) starburst. With physical properties similar to unlensed z > 2 SMGs, HATLAS J114637.9-001132 offers a detailed view of a typical SMG through a powerful cosmic microscope.

  5. Gravitational Waves from Coalescing Binary Black Holes: Theoretical and Experimental Challenges

    ScienceCinema (OSTI)

    None

    2011-10-06

    A network of ground-based interferometric gravitational wave detectors (LIGO/VIRGO/GEO/...) is currently taking data near its planned sensitivity. Coalescing black hole binaries are among the most promising, and most exciting, gravitational wave sources for these detectors. The talk will review the theoretical and experimental challenges that must be met in order to successfully detect gravitational waves from coalescing black hole binaries, and to be able to reliably measure the physical parameters of the source (masses, spins, ...).

  6. Compound refractive lenses as prefocusing optics for X-ray FEL radiation

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Heimann, Philip; MacDonald, Michael; Nagler, Bob; Lee, Hae Ja; Galtier, Eric; Arnold, Brice; Xing, Zhou

    2016-01-27

    The performance of X-ray free-electron laser beamlines may be limited by the angular aperture. Compound refractive lenses (CRLs) can be employed to prefocus the X-ray beam, thereby increasing the beamline transmission. A prefocusing CRL was implemented in the X-ray transport of the Matter under Extreme Conditions Instrument at the Linac Coherent Light Source. A significant improvement in the beamline transmission was calculated over the 3–10 keV photon energy range. At 5 keV, the relative X-ray intensity was measured and a factor of four increase was seen in the beamline transmission. As a result, the X-ray focus was also determined bymore » the ablation imprint method.« less

  7. DISCOVERY OF A STRONG LENSING GALAXY EMBEDDED IN A CLUSTER AT z = 1.62

    SciTech Connect (OSTI)

    Wong, Kenneth C.; Suyu, Sherry H.; Tran, Kim-Vy H.; Papovich, Casey J.; Momcheva, Ivelina G.; Brammer, Gabriel B.; Koekemoer, Anton M.; Brodwin, Mark; Gonzalez, Anthony H.; Kacprzak, Glenn G.; Rudnick, Gregory H.; Halkola, Aleksi

    2014-07-10

    We identify a strong lensing galaxy in the cluster IRC 0218 (also known as XMM-LSS J0218205102) that is spectroscopically confirmed to be at z = 1.62, making it the highest-redshift strong lens galaxy known. The lens is one of the two brightest cluster galaxies and lenses a background source galaxy into an arc and a counterimage. With Hubble Space Telescope (HST) grism and Keck/LRIS spectroscopy, we measure the source redshift to be z {sub S} = 2.26. Using HST imaging in ACS/F475W, ACS/F814W, WFC3/F125W, and WFC3/F160W, we model the lens mass distribution with an elliptical power-law profile and account for the effects of the cluster halo and nearby galaxies. The Einstein radius is ?{sub E}=0.38{sub ?0.01}{sup +0.02} arcsec (3.2{sub ?0.1}{sup +0.2} kpc) and the total enclosed mass is M {sub tot}(

  8. The dark side of galaxy colour: evidence from new SDSS measurements of galaxy clustering and lensing

    SciTech Connect (OSTI)

    Hearin, Andrew P.; Watson, Douglas F.; Becker, Matthew R.; Reyes, Reinabelle; Berlind, Andreas A.; Zentner, Andrew R.

    2014-08-12

    The age matching model has recently been shown to predict correctly the luminosity L and g-r color of galaxies residing within dark matter halos. The central tenet of the model is intuitive: older halos tend to host galaxies with older stellar populations. In this paper, we demonstrate that age matching also correctly predicts the g-r color trends exhibited in a wide variety of statistics of the galaxy distribution for stellar mass M* threshold samples. In particular, we present new measurements of the galaxy two-point correlation function and the galaxy-galaxy lensing signal as a function of M* and g-r color from the Sloan Digital Sky Survey, and show that age matching exhibits remarkable agreement with these and other statistics of low-redshift galaxies. In so doing, we also demonstrate good agreement between the galaxy-galaxy lensing observed by SDSS and the signal predicted by abundance matching, a new success of this model. We describe how age matching is a specific example of a larger class of Conditional Abundance Matching models (CAM), a theoretical framework we introduce here for the first time. CAM provides a general formalism to study correlations at fixed mass between any galaxy property and any halo property. The striking success of our simple implementation of CAM provides compelling evidence that this technique has the potential to describe the same set of data as alternative models, but with a dramatic reduction in the required number of parameters. CAM achieves this reduction by exploiting the capability of contemporary N-body simulations to determine dark matter halo properties other than mass alone, which distinguishes our model from conventional approaches to the galaxy-halo connection.

  9. Weak and strong coupling equilibration in nonabelian gauge theories

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Keegan, Liam; Kurkela, Aleksi; Romatschke, Paul; van der Schee, Wilke; Zhu, Yan

    2016-04-06

    In this study, we present a direct comparison studying equilibration through kinetic theory at weak coupling and through holography at strong coupling in the same set-up. The set-up starts with a homogeneous thermal state, which then smoothly transitions through an out-of-equilibrium phase to an expanding system undergoing boost-invariant flow. This first apples-to-apples comparison of equilibration provides a benchmark for similar equilibration processes in heavy-ion collisions, where the equilibration mechanism is still under debate. We find that results at weak and strong coupling can be smoothly connected by simple, empirical power-laws for the viscosity, equilibration time and entropy production of themore » system.« less

  10. How does pressure gravitate? Cosmological constant problem confronts observational cosmology

    SciTech Connect (OSTI)

    Narimani, Ali; Scott, Douglas; Afshordi, Niayesh E-mail: nafshordi@pitp.ca

    2014-08-01

    An important and long-standing puzzle in the history of modern physics is the gross inconsistency between theoretical expectations and cosmological observations of the vacuum energy density, by at least 60 orders of magnitude, otherwise known as the cosmological constant problem. A characteristic feature of vacuum energy is that it has a pressure with the same amplitude, but opposite sign to its energy density, while all the precision tests of General Relativity are either in vacuum, or for media with negligible pressure. Therefore, one may wonder whether an anomalous coupling to pressure might be responsible for decoupling vacuum from gravity. We test this possibility in the context of the Gravitational Aether proposal, using current cosmological observations, which probe the gravity of relativistic pressure in the radiation era. Interestingly, we find that the best fit for anomalous pressure coupling is about half-way between General Relativity (GR), and Gravitational Aether (GA), if we include Planck together with WMAP and BICEP2 polarization cosmic microwave background (CMB) observations. Taken at face value, this data combination excludes both GR and GA at around the 3 σ level. However, including higher resolution CMB observations (''highL'') or baryonic acoustic oscillations (BAO) pushes the best fit closer to GR, excluding the Gravitational Aether solution to the cosmological constant problem at the 4- 5 σ level. This constraint effectively places a limit on the anomalous coupling to pressure in the parametrized post-Newtonian (PPN) expansion, ζ{sub 4} = 0.105 ± 0.049 (+highL CMB), or ζ{sub 4} = 0.066 ± 0.039 (+BAO). These represent the most precise measurement of this parameter to date, indicating a mild tension with GR (for ΛCDM including tensors, with 0ζ{sub 4}=), and also among different data sets.

  11. ORBITAL MIGRATION OF PROTOPLANETS IN A MARGINALLY GRAVITATIONALLY UNSTABLE DISK

    SciTech Connect (OSTI)

    Boss, Alan P.

    2013-02-20

    Core accretion and disk instability require giant protoplanets to form in the presence of disk gas. Protoplanet migration models generally assume disk masses low enough that the disk's self-gravity can be neglected. However, disk instability requires a disk massive enough to be marginally gravitationally unstable (MGU). Even for core accretion, an FU Orionis outburst may require a brief MGU disk phase. We present a new set of three-dimensional, gravitational radiation hydrodynamics models of MGU disks with multiple protoplanets, which interact gravitationally with the disk and with each other, including disk gas mass accretion. Initial protoplanet masses are 0.01 to 10 M {sub Circled-Plus} for core accretion models, and 0.1 to 3 M {sub Jup} for Nice scenario models, starting on circular orbits with radii of 6, 8, 10, or 12 AU, inside a 0.091 M {sub Sun} disk extending from 4 to 20 AU around a 1 M {sub Sun} protostar. Evolutions are followed for up to {approx}4000 yr and involve phases of relative stability (e {approx} 0.1) interspersed with chaotic phases (e {approx} 0.4) of orbital interchanges. The 0.01 to 10 M {sub Circled-Plus} cores can orbit stably for {approx}1000 yr: monotonic inward or outward orbital migration of the type seen in low mass disks does not occur. A system with giant planet masses similar to our solar system (1.0, 0.33, 0.1, 0.1 M {sub Jup}) was stable for over 1000 yr, and a Jupiter-Saturn-like system was stable for over 3800 yr, implying that our giant planets might well survive an MGU disk phase.

  12. Gauge and averaging in gravitational self-force

    SciTech Connect (OSTI)

    Gralla, Samuel E.

    2011-10-15

    A difficulty with previous treatments of the gravitational self-force is that an explicit formula for the force is available only in a particular gauge (Lorenz gauge), where the force in other gauges must be found through a transformation law once the Lorenz-gauge force is known. For a class of gauges satisfying a 'parity condition' ensuring that the Hamiltonian center of mass of the particle is well-defined, I show that the gravitational self-force is always given by the angle average of the bare gravitational force. To derive this result I replace the computational strategy of previous work with a new approach, wherein the form of the force is first fixed up to a gauge-invariant piece by simple manipulations, and then that piece is determined by working in a gauge designed specifically to simplify the computation. This offers significant computational savings over the Lorenz gauge, since the Hadamard expansion is avoided entirely and the metric perturbation takes a very simple form. I also show that the rest mass of the particle does not evolve due to first-order self-force effects. Finally, I consider the 'mode sum regularization' scheme for computing the self-force in black hole background spacetimes, and use the angle-average form of the force to show that the same mode-by-mode subtraction may be performed in all parity-regular gauges. It appears plausible that suitably modified versions of the Regge-Wheeler and radiation gauges (convenient to Schwarzschild and Kerr, respectively) are in this class.

  13. Tsung-Dao Lee, Weak Interactions, and Nonconservation of Parity

    Office of Scientific and Technical Information (OSTI)

    Tsung-Dao Lee, Weak Interactions, and Nonconservation of Parity Resources with Additional Information Tsung-Dao Lee Courtesy of Brookhaven National Laboratory T. D. Lee "has devoted his long career to the study of the theoretical aspects of particle and nuclear physics. In 1957, Lee and Chen Ning Yang won the Nobel Prize in physics for disproving a tenet of physics known as the conservation of parity. Their finding was based on research carried out at Brookhaven's particle accelerator, the

  14. Weak-interaction processes in core-collapse supernovae

    SciTech Connect (OSTI)

    Langanke, K.

    2015-02-24

    Weak interaction processes play an important role for the dynamics of a core-collapse supernova. Due to progress of nuclear modeling and constrained by data it has been possible to improve the rates of these processes for supernova conditions decisively. This manuscript describes the recent advances and the current status in deriving electron capture rates on nuclei and of inelastic neutrino-nucleus scattering for applications in supernova simulations and briefly discusses their impact on such studies.

  15. Weakly Turbulent Magnetohydrodynamic Waves in Compressible Low-{beta} Plasmas

    SciTech Connect (OSTI)

    Chandran, Benjamin D. G.

    2008-12-05

    In this Letter, weak-turbulence theory is used to investigate interactions among Alfven waves and fast and slow magnetosonic waves in collisionless low-{beta} plasmas. The wave kinetic equations are derived from the equations of magnetohydrodynamics, and extra terms are then added to model collisionless damping. These equations are used to provide a quantitative description of a variety of nonlinear processes, including parallel and perpendicular energy cascade, energy transfer between wave types, 'phase mixing', and the generation of backscattered Alfven waves.

  16. Approximations of very weak solutions to boundary-value problems.

    SciTech Connect (OSTI)

    Berggren, Martin Olof

    2003-03-01

    Standard weak solutions to the Poisson problem on a bounded domain have square-integrable derivatives, which limits the admissible regularity of inhomogeneous data. The concept of solution may be further weakened in order to define solutions when data is rough, such as for inhomogeneous Dirichlet data that is only square-integrable over the boundary. Such very weak solutions satisfy a nonstandard variational form (u, v) = G(v). A Galerkin approximation combined with an approximation of the right-hand side G defines a finite-element approximation of the very weak solution. Applying conforming linear elements leads to a discrete solution equivalent to the text-book finite-element solution to the Poisson problem in which the boundary data is approximated by L{sub 2}-projections. The L{sub 2} convergence rate of the discrete solution is O(h{sub s}) for some s {element_of} (0,1/2) that depends on the shape of the domain, asserting a polygonal (two-dimensional) or polyhedral (three-dimensional) domain without slits and (only) square-integrable boundary data.

  17. GRAVITATIONAL INSTABILITY OF ROTATING, PRESSURE-CONFINED, POLYTROPIC GAS DISKS WITH VERTICAL STRATIFICATION

    SciTech Connect (OSTI)

    Kim, Jeong-Gyu; Kim, Woong-Tae; Seo, Young Min; Hong, Seung Soo E-mail: wkim@astro.snu.ac.kr E-mail: sshong@astro.snu.ac.kr

    2012-12-20

    We investigate the gravitational instability (GI) of rotating, vertically stratified, pressure-confined, polytropic gas disks using a linear stability analysis as well as analytic approximations. The disks are initially in vertical hydrostatic equilibrium and bounded by a constant external pressure. We find that the GI of a pressure-confined disk is in general a mixed mode of the conventional Jeans and distortional instabilities, and is thus an unstable version of acoustic-surface-gravity waves. The Jeans mode dominates in weakly confined disks or disks with rigid boundaries. On the other hand, when the disk has free boundaries and is strongly pressure confined, the mixed GI is dominated by the distortional mode that is surface-gravity waves driven unstable under their own gravity and thus incompressible. We demonstrate that the Jeans mode is gravity-modified acoustic waves rather than inertial waves and that inertial waves are almost unaffected by self-gravity. We derive an analytic expression for the effective sound speed c{sub eff} of acoustic-surface-gravity waves. We also find expressions for the gravity reduction factors relative to a razor-thin counterpart that are appropriate for the Jeans and distortional modes. The usual razor-thin dispersion relation, after correcting for c{sub eff} and the reduction factors, closely matches the numerical results obtained by solving a full set of linearized equations. The effective sound speed generalizes the Toomre stability parameter of the Jeans mode to allow for the mixed GI of vertically stratified, pressure-confined disks.

  18. Precession effect of the gravitational self-force in a Schwarzschild spacetime and the effective one-body formalism

    SciTech Connect (OSTI)

    Barack, Leor; Damour, Thibault; Sago, Norichika

    2010-10-15

    Using a recently presented numerical code for calculating the Lorenz-gauge gravitational self-force (GSF), we compute the O(m) conservative correction to the precession rate of the small-eccentricity orbits of a particle of mass m moving around a Schwarzschild black hole of mass M>>m. Specifically, we study the gauge-invariant function {rho}(x), where {rho} is defined as the O(m) part of the dimensionless ratio ({Omega}-circumflex{sub r}/{Omega}-circumflex{sub {phi}}){sup 2} between the squares of the radial and azimuthal frequencies of the orbit, and where x=[Gc{sup -3}(M+m){Omega}-circumflex{sub {phi}}]{sup 2/3} is a gauge-invariant measure of the dimensionless gravitational potential (mass over radius) associated with the mean circular orbit. Our GSF computation of the function {rho}(x) in the interval 0weak-field regime (small x) with the 3rd post-Newtonian (PN) expansion of the EOB results, and that this agreement is improved when taking into account the analytic values of some of the logarithmic-running terms occurring at higher PN orders. Furthermore, we demonstrate that GSF data give access to higher-order PN terms of {rho}(x) and can be used to set useful new constraints on the values of yet-undetermined EOB parameters. Most significantly, we observe that an excellent global representation of {rho}(x) can be obtained using a simple '2-point' Pade approximant which combines 3PN knowledge at x=0 with GSF information at a single strong-field point (say, x=1/6).

  19. MEASURING THE MASS DISTRIBUTION IN GALAXY CLUSTERS

    SciTech Connect (OSTI)

    Geller, Margaret J.; Diaferio, Antonaldo; Rines, Kenneth J.; Serra, Ana Laura E-mail: diaferio@ph.unito.it E-mail: serra@to.infn.it

    2013-02-10

    Cluster mass profiles are tests of models of structure formation. Only two current observational methods of determining the mass profile, gravitational lensing, and the caustic technique are independent of the assumption of dynamical equilibrium. Both techniques enable the determination of the extended mass profile at radii beyond the virial radius. For 19 clusters, we compare the mass profile based on the caustic technique with weak lensing measurements taken from the literature. This comparison offers a test of systematic issues in both techniques. Around the virial radius, the two methods of mass estimation agree to within {approx}30%, consistent with the expected errors in the individual techniques. At small radii, the caustic technique overestimates the mass as expected from numerical simulations. The ratio between the lensing profile and the caustic mass profile at these radii suggests that the weak lensing profiles are a good representation of the true mass profile. At radii larger than the virial radius, the extrapolated Navarro, Frenk and White fit to the lensing mass profile exceeds the caustic mass profile. Contamination of the lensing profile by unrelated structures within the lensing kernel may be an issue in some cases; we highlight the clusters MS0906+11 and A750, superposed along the line of sight, to illustrate the potential seriousness of contamination of the weak lensing signal by these unrelated structures.

  20. HYPERCRITICAL ACCRETION, INDUCED GRAVITATIONAL COLLAPSE, AND BINARY-DRIVEN HYPERNOVAE

    SciTech Connect (OSTI)

    Fryer, Chris L. [CCS-2, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Rueda, Jorge A.; Ruffini, Remo [ICRANet, Piazza della Repubblica 10, I-65122 Pescara (Italy)

    2014-10-01

    The induced gravitational collapse (IGC) paradigm has been successfully applied to the explanation of the concomitance of gamma-ray bursts (GRBs) with supernovae (SNe) Ic. The progenitor is a tight binary system composed of a carbon-oxygen (CO) core and a neutron star (NS) companion. The explosion of the SN leads to hypercritical accretion onto the NS companion, which reaches the critical mass, hence inducing its gravitational collapse to a black hole (BH) with consequent emission of the GRB. The first estimates of this process were based on a simplified model of the binary parameters and the Bondi-Hoyle-Lyttleton accretion rate. We present here the first full numerical simulations of the IGC phenomenon. We simulate the core-collapse and SN explosion of CO stars to obtain the density and ejection velocity of the SN ejecta. We follow the hydrodynamic evolution of the accreting material falling into the Bondi-Hoyle surface of the NS all the way up to its incorporation in the NS surface. The simulations go up to BH formation when the NS reaches the critical mass. For appropriate binary parameters, the IGC occurs in short timescales ?10{sup 2}-10{sup 3} s owing to the combined effective action of the photon trapping and the neutrino cooling near the NS surface. We also show that the IGC scenario leads to a natural explanation for why GRBs are associated only with SNe Ic with totally absent or very little helium.

  1. Large-amplitude solitons in gravitationally balanced quantum plasmas

    SciTech Connect (OSTI)

    Akbari-Moghanjoughi, M.

    2014-08-15

    Using the quantum fluid model for self-gravitating quantum plasmas with the Bernoulli pseudopotential method and taking into account the relativistic degeneracy effect, it is shown that gravity-induced large-amplitude density rarefaction solitons can exist in gravitationally balanced quantum plasmas. These nonlinear solitons are generated due to the force imbalance between the gravity and the quantum fluid pressure via local density perturbations, similar to that on shallow waters. It is found that both the fluid mass-density and the atomic-number of the constituent ions have significant effect on the amplitude and width of these solitonic profiles. Existence of a large-scale gravity-induced solitonic activities on neutron-star surface, for instance, can be a possible explanation for the recently proposed resonant shattering mechanism [D. Tsang et al., Phys. Rev. Lett. 108, 011102 (2012)] causing the intense short gamma ray burst phenomenon, in which release of ?10{sup 46}10{sup 47} ergs would be possible from the surface. The resonant shattering of the crust in a neutron star has been previously attributed to the crust-core interface mode and the tidal surface tensions. We believe that current model can be a more natural explanation for the energy liberation by solitonic activities on the neutron star surfaces, without a requirement for external mergers like other neutron stars or black holes for the crustal shatter.

  2. Gravitational waves from individual supermassive black hole binaries in circular orbits: limits from the North American nanohertz observatory for gravitational waves

    SciTech Connect (OSTI)

    Arzoumanian, Z.; Brazier, A.; Chatterjee, S.; Cordes, J. M.; Dolch, T.; Lam, M. T.; Burke-Spolaor, S.; Chamberlin, S. J.; Ellis, J. A.; Demorest, P. B.; Deng, X.; Koop, M.; Ferdman, R. D.; Kaspi, V. M.; Garver-Daniels, N.; Lorimer, D. R.; Jenet, F.; Jones, G.; Lazio, T. J. W.; Lommen, A. N.; Collaboration: NANOGrav Collaboration; and others

    2014-10-20

    We perform a search for continuous gravitational waves from individual supermassive black hole binaries using robust frequentist and Bayesian techniques. We augment standard pulsar timing models with the addition of time-variable dispersion measure and frequency variable pulse shape terms. We apply our techniques to the Five Year Data Release from the North American Nanohertz Observatory for Gravitational Waves. We find that there is no evidence for the presence of a detectable continuous gravitational wave; however, we can use these data to place the most constraining upper limits to date on the strength of such gravitational waves. Using the full 17 pulsar data set we place a 95% upper limit on the strain amplitude of h {sub 0} ? 3.0 10{sup 14} at a frequency of 10 nHz. Furthermore, we place 95% sky-averaged lower limits on the luminosity distance to such gravitational wave sources, finding that d{sub L} ? 425 Mpc for sources at a frequency of 10 nHz and chirp mass 10{sup 10} M {sub ?}. We find that for gravitational wave sources near our best timed pulsars in the sky, the sensitivity of the pulsar timing array is increased by a factor of ?four over the sky-averaged sensitivity. Finally we place limits on the coalescence rate of the most massive supermassive black hole binaries.

  3. Evidence for a Weak Iron Core at Earth's Center

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Evidence for a Weak Iron Core at Earth's Center Print Seismic waves that pass through the center of the Earth travel faster going from pole to pole than along the equatorial plane-why? One theory is that the grains of iron that make up most of the solid inner core could be aligned in a way that transmits waves more efficiently in one direction than the other. Recent evidence for this "texturing" of iron grains in the Earth's inner core comes from x-ray spectroscopy and diffraction

  4. Evidence for a Weak Iron Core at Earth's Center

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Evidence for a Weak Iron Core at Earth's Center Print Seismic waves that pass through the center of the Earth travel faster going from pole to pole than along the equatorial plane-why? One theory is that the grains of iron that make up most of the solid inner core could be aligned in a way that transmits waves more efficiently in one direction than the other. Recent evidence for this "texturing" of iron grains in the Earth's inner core comes from x-ray spectroscopy and diffraction

  5. Evidence for a Weak Iron Core at Earth's Center

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Evidence for a Weak Iron Core at Earth's Center Print Seismic waves that pass through the center of the Earth travel faster going from pole to pole than along the equatorial plane-why? One theory is that the grains of iron that make up most of the solid inner core could be aligned in a way that transmits waves more efficiently in one direction than the other. Recent evidence for this "texturing" of iron grains in the Earth's inner core comes from x-ray spectroscopy and diffraction

  6. Evidence for a Weak Iron Core at Earth's Center

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Evidence for a Weak Iron Core at Earth's Center Print Seismic waves that pass through the center of the Earth travel faster going from pole to pole than along the equatorial plane-why? One theory is that the grains of iron that make up most of the solid inner core could be aligned in a way that transmits waves more efficiently in one direction than the other. Recent evidence for this "texturing" of iron grains in the Earth's inner core comes from x-ray spectroscopy and diffraction

  7. Evidence for a Weak Iron Core at Earth's Center

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Evidence for a Weak Iron Core at Earth's Center Print Seismic waves that pass through the center of the Earth travel faster going from pole to pole than along the equatorial plane-why? One theory is that the grains of iron that make up most of the solid inner core could be aligned in a way that transmits waves more efficiently in one direction than the other. Recent evidence for this "texturing" of iron grains in the Earth's inner core comes from x-ray spectroscopy and diffraction

  8. Evidence for a Weak Iron Core at Earth's Center

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Evidence for a Weak Iron Core at Earth's Center Print Seismic waves that pass through the center of the Earth travel faster going from pole to pole than along the equatorial plane-why? One theory is that the grains of iron that make up most of the solid inner core could be aligned in a way that transmits waves more efficiently in one direction than the other. Recent evidence for this "texturing" of iron grains in the Earth's inner core comes from x-ray spectroscopy and diffraction

  9. Merging weak and QCD showers with matrix elements

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Christiansen, Jesper Roy; Prestel, Stefan

    2016-01-22

    In this study, we present a consistent way of combining associated weak boson radiation in hard dijet events with hard QCD radiation in Drell–Yan-like scatterings. This integrates multiple tree-level calculations with vastly different cross sections, QCD- and electroweak parton-shower resummation into a single framework. The new merging strategy is implemented in the P ythia event generator and predictions are confronted with LHC data. Improvements over the previous strategy are observed. Results of the new electroweak-improved merging at a future 100 TeV proton collider are also investigated.

  10. Dark-Matter-Induced Violation of the Weak Equivalence Principle

    SciTech Connect (OSTI)

    Carroll, Sean M.; Mantry, Sonny [California Institute of Technology, Pasadena, California 91125 (United States); Ramsey-Musolf, Michael J. [University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); California Institute of Technology, Pasadena, California 91125 (United States); Stubbs, Christoper W. [Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts 02138 (United States)

    2009-07-03

    A long-range fifth force coupled to dark matter can induce a coupling to ordinary matter if the dark matter interacts with standard model fields. We consider constraints on such a scenario from both astrophysical observations and laboratory experiments. We also examine the case where the dark matter is a weakly interacting massive particle, and derive relations between the coupling to dark matter and the coupling to ordinary matter for different models. Currently, this scenario is most tightly constrained by galactic dynamics, but improvements in Eoetvoes experiments can probe unconstrained regions of parameter space.

  11. REDSHIFT DETERMINATION AND CO LINE EXCITATION MODELING FOR THE MULTIPLY LENSED GALAXY HLSW-01

    SciTech Connect (OSTI)

    Scott, K. S.; Lupu, R. E.; Aguirre, J. E.; Auld, R.; Eales, S.; Aussel, H.; Chanial, P.; Beelen, A.; Bock, J.; Bradford, C. M.; Carpenter, J. M.; Cooray, A.; Dowell, C. D.; Brisbin, D.; Burgarella, D.; Chapman, S. C.; Clements, D. L.; Conley, A.; Cox, P.

    2011-05-20

    We report on the redshift measurement and CO line excitation of HERMES J105751.1+573027 (HLSW-01), a strongly lensed submillimeter galaxy discovered in Herschel/SPIRE observations as part of the Herschel Multi-tiered Extragalactic Survey (HerMES). HLSW-01 is an ultra-luminous galaxy with an intrinsic far-infrared luminosity of L{sub FIR} = 1.4 x 10{sup 13} L{sub sun}, and is lensed by a massive group of galaxies into at least four images with a total magnification of {mu} = 10.9 {+-} 0.7. With the 100 GHz instantaneous bandwidth of the Z-Spec instrument on the Caltech Submillimeter Observatory, we robustly identify a redshift of z = 2.958 {+-} 0.007 for this source, using the simultaneous detection of four CO emission lines (J = 7 {yields} 6, J = 8 {yields} 7, J = 9 {yields} 8, and J = 10 {yields} 9). Combining the measured line fluxes for these high-J transitions with the J = 1 {yields} 0, J = 3 {yields} 2, and J = 5 {yields} 4 line fluxes measured with the Green Bank Telescope, the Combined Array for Research in Millimeter Astronomy, and the Plateau de Bure Interferometer, respectively, we model the physical properties of the molecular gas in this galaxy. We find that the full CO spectral line energy distribution is described well by warm, moderate-density gas with T{sub kin} = 86-235 K and n{sub H{sub 2}} = (1.1-3.5) x 10{sup 3} cm{sup -3}. However, it is possible that the highest-J transitions are tracing a small fraction of very dense gas in molecular cloud cores, and two-component models that include a warm/dense molecular gas phase with T{sub kin} {approx} 200 K, n{sub H{sub 2}}{approx}10{sup 5} cm{sup -3} are also consistent with these data. Higher signal-to-noise measurements of the J{sub up} {>=} 7 transitions with high spectral resolution, combined with high spatial resolution CO maps, are needed to improve our understanding of the gas excitation, morphology, and dynamics of this interesting high-redshift galaxy.

  12. The emergence of weakly twisted magnetic fields in the sun

    SciTech Connect (OSTI)

    Archontis, V.; Hood, A. W.; Tsinganos, K.

    2013-11-20

    We have studied the emergence of a weakly twisted magnetic flux tube from the upper convection zone into the solar atmosphere. It is found that the rising magnetized plasma does not undergo the classical, single ?-shaped loop emergence, but it becomes unstable in two places, forming two magnetic lobes that are anchored in small-scale bipolar structures at the photosphere, between the two main flux concentrations. The two magnetic lobes rise and expand into the corona, forming an overall undulating magnetic flux system. The dynamical interaction of the lobes results in the triggering of high-speed and hot jets and the formation of successive cool and hot loops that coexist in the emerging flux region. Although the initial emerging field is weakly twisted, a highly twisted magnetic flux rope is formed at the low atmosphere, due to shearing and reconnection. The new flux rope (hereafter post-emergence flux rope) does not erupt. It remains confined by the overlying field. Although there is no ejective eruption of the post-emergence rope, it is found that a considerable amount of axial and azimuthal flux is transferred into the solar atmosphere during the emergence of the magnetic field.

  13. Gravitational waves from gamma-ray pulsar glitches

    SciTech Connect (OSTI)

    Stopnitzky, Elan; Profumo, Stefano

    2014-06-01

    We use data from pulsar gamma-ray glitches recorded by the Fermi Large Area Telescope as input to theoretical models of gravitational wave signals the glitches might generate. We find that the typical peak amplitude of the gravity wave signal from gamma-ray pulsar glitches lies between 10{sup 23} and 10{sup 35} in dimensionless units, with peak frequencies in the range of 1 to 1000 Hz, depending on the model. We estimate the signal-to-noise ratio (S/N) for all gamma-ray glitches, and discuss detectability with current gravity wave detectors. Our results indicate that the strongest predicted signals are potentially within reach of current detectors, and that pulsar gamma-ray glitches are promising targets for gravity wave searches by current and next-generation detectors.

  14. Instability of black hole formation in gravitational collapse

    SciTech Connect (OSTI)

    Joshi, Pankaj S.; Malafarina, Daniele

    2011-01-15

    We consider here the classic scenario given by Oppenheimer, Snyder, and Datt, for the gravitational collapse of a massive matter cloud, and examine its stability under the introduction of small tangential stresses. We show, by offering an explicit class of physically valid tangential stress perturbations, that an introduction of tangential pressure, however small, can qualitatively change the final fate of collapse from a black hole final state to a naked singularity. This shows instability of black hole formation in collapse and sheds important light on the nature of cosmic censorship hypothesis and its possible formulations. The key effect of these perturbations is to alter the trapped surface formation pattern within the collapsing cloud and the apparent horizon structure. This allows the singularity to be visible, and implications are discussed.

  15. Gravitationally collapsing shells in (2+1) dimensions

    SciTech Connect (OSTI)

    Mann, Robert B.; Oh, John J.

    2006-12-15

    We study gravitationally collapsing models of pressureless dust, fluids with pressure, and the generalized Chaplygin gas (GCG) shell in (2+1)-dimensional spacetimes. Various collapse scenarios are investigated under a variety of the background configurations such as anti-de Sitter (AdS) black hole, de Sitter (dS) space, flat and AdS space with a conical deficit. As with the case of a disk of dust, we find that the collapse of a dust shell coincides with the Oppenheimer-Snyder type collapse to a black hole provided the initial density is sufficiently large. We also find - for all types of shell - that collapse to a naked singularity is possible under a broad variety of initial conditions. For shells with pressure this singularity can occur for a finite radius of the shell. We also find that GCG shells exhibit diverse collapse scenarios, which can be easily demonstrated by an effective potential analysis.

  16. 5-dimensional braneworld with gravitating NambuGoto matching conditions

    SciTech Connect (OSTI)

    Kofinas, Georgios; Zarikas, Vasilios

    2014-12-15

    We continue the investigation of a recent proposal on alternative matching conditions for self-gravitating defects which generalize the standard matching conditions. The reasoning for this study is the need for consistency of the various codimension defects and the existence of a meaningful equation of motion at the probe limit, things that seem to lack from the standard approach. These matching conditions arise by varying the branebulk action with respect to the brane embedding fields (and not with respect to the bulk metric at the brane position) in a way that takes into account the gravitational back-reaction of the brane to the bulk. They always possess a NambuGoto probe limit and any codimension defect is seemingly consistent for any second order bulk gravity theory. Here, we consider in detail the case of a codimension-1 brane in five-dimensional Einstein gravity, derive the generic alternative junction conditions and find the Z{sub 2}-symmetric braneworld cosmology, as well as its bulk extension. Compared to the standard braneworld cosmology, the new one has an extra integration constant which accounts for the today matter and dark energy contents, therefore, there is more freedom for accommodating the observed cosmic features. One branch of the solution possesses the asymptotic linearized LFRW regime. We have constrained the parameters so that to have a recent passage from a long deceleration era to a small today acceleration epoch and we have computed the age of the universe, consistent with current data, and the time-varying dark energy equation of state. For a range of the parameters it is possible for the presented cosmology to provide a large acceleration in the high energy regime.

  17. Durability of Poly(Methyl Methacrylate) Lenses Used in Concentrating Photovoltaic Modules: Preprint

    SciTech Connect (OSTI)

    Miller, D. C.; Gedvilas, L. M.; To, B.; Kennedy, C. E.; Kurtz, S. R.

    2010-08-01

    Concentrating photovoltaic (CPV) technology has recently gained interest based on their expected low levelized cost of electricity, high efficiency, and scalability. Many CPV systems use Fresnel lenses made of poly(methyl methacrylate)(PMMA) to obtain a high optical flux density. The optical and mechanical durability of such components, however, are not well established relative to the desired service life of 30 years. Specific reliability issues may include: reduced optical transmittance, discoloration, hazing, surface erosion, embrittlement, crack growth, physical aging, shape setting (warpage), and soiling. The initial results for contemporary lens- and material-specimens aged cumulatively to 6 months are presented. The study here uses an environmental chamber equipped with a xenon-arc lamp to age specimens at least 8x the nominal field rate. A broad range in the affected characteristics (including optical transmittance, yellowness index, mass loss, and contact angle) has been observed to date, depending on the formulation of PMMA used. The most affected specimens are further examined in terms of their visual appearance, surface roughness (examined via atomic force microscopy), and molecular structure (via Fourier transform infrared spectroscopy).

  18. Magic Lenses for RHIC: Compensating Beam-beam Interaction (488th Brookhaven Lecture)

    SciTech Connect (OSTI)

    Luo, Yun

    2013-07-17

    Scientists at Brookhaven Lab’s Relativistic Heavy Ion Collider (RHIC) smash atomic particles together to understand more about why the physical world works the way it does. Increasing rates of particle collisions, or luminosity, at RHIC is no small challenge, but the results—more data for better clues—are crucial for scientists trying answer big questions about the origins of matter and mass. When scientists at RHIC collide protons, they don’t hope for a head-on crash by focusing only two particles roaring toward each other from opposite directions. For all intents and purposes, that would be impossible. The scientists can smash protons because they significantly increase the likelihood of collisions by steering hundreds of billions clumped into bunches, which at RHIC are about 3.5 meters long and less than 1 millimeter tall. The particles of these bunches are all positively charged, so when they interact, they repel outwardly—think how magnets repel when their same poles are pushed together. Although this decreases the density of each bunch, reducing luminosity, scientists in Brookhaven Lab’s Collider-Accelerator Department (C-AD) have a solution. After more than seven years of development, the scientists have designed an electron-lens system that uses electrons’ negative charges to attract positively charged proton bunches and minimize their repelling tendencies. Combined with other upgrades to the RHIC accelerator complex, these lenses are important components in efforts towards the major task of doubling the luminosity for proton-proton collisions.

  19. PROTOSTELLAR DISK FORMATION ENABLED BY WEAK, MISALIGNED MAGNETIC FIELDS

    SciTech Connect (OSTI)

    Krumholz, Mark R.; Crutcher, Richard M.; Hull, Charles L. H.

    2013-04-10

    The gas from which stars form is magnetized, and strong magnetic fields can efficiently transport angular momentum. Most theoretical models of this phenomenon find that it should prevent formation of large (>100 AU), rotationally supported disks around most protostars, even when non-ideal magnetohydrodynamic (MHD) effects that allow the field and gas to decouple are taken into account. Using recent observations of magnetic field strengths and orientations in protostellar cores, we show that this conclusion is incorrect. The distribution of magnetic field strengths is very broad, and alignments between fields and angular momentum vectors within protostellar cores are essentially random. By combining the field strength and misalignment data with MHD simulations showing that disk formation is expected for both weak and misaligned fields, we show that these observations imply that we should expect disk fractions of {approx}10%-50% even when protostars are still deeply embedded in their parent cores, and even if the gas is governed by ideal MHD.

  20. Candidate gravitational microlensing events for future direct lens imaging

    SciTech Connect (OSTI)

    Henderson, C. B.; Gould, A.; Gaudi, B. S.; Park, H.; Han, C.; Sumi, T.; Koshimoto, N.; Udalski, A.; Tsapras, Y.; Bozza, V.; Abe, F.; Fukunaga, D.; Itow, Y.; Masuda, K.; Bennett, D. P.; Bond, I. A.; Ling, C. H.; Botzler, C. S.; Freeman, M.; Fukui, A.; Collaboration: MOA Collaboration; OGLE Collaboration; μFUN Collaboration; RoboNet Collaboration; and others

    2014-10-10

    The mass of the lenses giving rise to Galactic microlensing events can be constrained by measuring the relative lens-source proper motion and lens flux. The flux of the lens can be separated from that of the source, companions to the source, and unrelated nearby stars with high-resolution images taken when the lens and source are spatially resolved. For typical ground-based adaptive optics (AO) or space-based observations, this requires either inordinately long time baselines or high relative proper motions. We provide a list of microlensing events toward the Galactic bulge with high relative lens-source proper motion that are therefore good candidates for constraining the lens mass with future high-resolution imaging. We investigate all events from 2004 to 2013 that display detectable finite-source effects, a feature that allows us to measure the proper motion. In total, we present 20 events with μ ≳ 8 mas yr{sup –1}. Of these, 14 were culled from previous analyses while 6 are new, including OGLE-2004-BLG-368, MOA-2005-BLG-36, OGLE-2012-BLG-0211, OGLE-2012-BLG-0456, MOA-2012-BLG-532, and MOA-2013-BLG-029. In ≲12 yr from the time of each event the lens and source of each event will be sufficiently separated for ground-based telescopes with AO systems or space telescopes to resolve each component and further characterize the lens system. Furthermore, for the most recent events, comparison of the lens flux estimates from images taken immediately to those estimated from images taken when the lens and source are resolved can be used to empirically check the robustness of the single-epoch method currently being used to estimate lens masses for many events.

  1. Gravitational waves from the collision of tidally disrupted stars with massive black holes

    SciTech Connect (OSTI)

    East, William E.

    2014-11-10

    We use simulations of hydrodynamics coupled with full general relativity to investigate the gravitational waves produced by a star colliding with a massive black hole when the star's tidal disruption radius lies far outside of the black hole horizon. We consider both main-sequence and white-dwarf compaction stars, and nonspinning black holes, as well as those with near-extremal spin. We study the regime in between where the star can be accurately modeled by a point particle, and where tidal effects completely suppress the gravitational wave signal. We find that nonnegligible gravitational waves can be produced even when the star is strongly affected by tidal forces, as well as when it collides with large angular momentum. We discuss the implications that these results have for the potential observation of gravitational waves from these sources with future detectors.

  2. Implication of Tsallis entropy in the ThomasFermi model for self-gravitating fermions

    SciTech Connect (OSTI)

    Ourabah, Kamel; Tribeche, Mouloud

    2014-03-15

    The ThomasFermi approach for self-gravitating fermions is revisited within the theoretical framework of the q-statistics. Starting from the q-deformation of the FermiDirac distribution function, a generalized ThomasFermi equation is derived. It is shown that the Tsallis entropy preserves a scaling property of this equation. The q-statistical approach to Jeans instability in a system of self-gravitating fermions is also addressed. The dependence of the Jeans wavenumber (or the Jeans length) on the parameter q is traced. It is found that the q-statistics makes the Fermionic system unstable at scales shorter than the standard Jeans length. -- Highlights: ThomasFermi approach for self-gravitating fermions. A generalized ThomasFermi equation is derived. Nonextensivity preserves a scaling property of this equation. Nonextensive approach to Jeans instability of self-gravitating fermions. It is found that nonextensivity makes the Fermionic system unstable at shorter scales.

  3. Gravitational Redshift of Galaxies in Clusters from the Sloan Digital Sky

    Office of Scientific and Technical Information (OSTI)

    Survey and the Baryon Oscillation Spectroscopic Survey (Journal Article) | SciTech Connect Gravitational Redshift of Galaxies in Clusters from the Sloan Digital Sky Survey and the Baryon Oscillation Spectroscopic Survey Citation Details In-Document Search Title: Gravitational Redshift of Galaxies in Clusters from the Sloan Digital Sky Survey and the Baryon Oscillation Spectroscopic Survey Authors: Sadeh, Iftach ; Feng, Low Lerh ; Lahav, Ofer Publication Date: 2015-02-20 OSTI Identifier:

  4. Gravitational wave generation from bubble collisions in first-order phase

    Office of Scientific and Technical Information (OSTI)

    transitions: An analytic approach (Journal Article) | SciTech Connect wave generation from bubble collisions in first-order phase transitions: An analytic approach Citation Details In-Document Search Title: Gravitational wave generation from bubble collisions in first-order phase transitions: An analytic approach Gravitational wave production from bubble collisions was calculated in the early 1990s using numerical simulations. In this paper, we present an alternative analytic estimate,

  5. Gravitational waves and the scale of inflation (Journal Article) | SciTech

    Office of Scientific and Technical Information (OSTI)

    Connect Gravitational waves and the scale of inflation Citation Details In-Document Search Title: Gravitational waves and the scale of inflation Authors: Mirbabayi, Mehrdad ; Senatore, Leonardo ; Silverstein, Eva ; Zaldarriaga, Matias Publication Date: 2015-03-12 OSTI Identifier: 1180012 Grant/Contract Number: FG02-12ER41854; AC03-76SF00515 Type: Publisher's Accepted Manuscript Journal Name: Physical Review D Additional Journal Information: Journal Volume: 91; Journal Issue: 6; Journal ID:

  6. Kinetic model for an auroral double layer that spans many gravitational

    Office of Scientific and Technical Information (OSTI)

    scale heights (Journal Article) | SciTech Connect Kinetic model for an auroral double layer that spans many gravitational scale heights Citation Details In-Document Search Title: Kinetic model for an auroral double layer that spans many gravitational scale heights The electrostatic potential profile and the particle densities of a simplified auroral double layer are found using a relaxation method to solve Poisson's equation in one dimension. The electron and ion distribution functions for

  7. Gravitational Redshift of Galaxies in Clusters from the Sloan Digital Sky

    Office of Scientific and Technical Information (OSTI)

    Survey and the Baryon Oscillation Spectroscopic Survey (Journal Article) | SciTech Connect Gravitational Redshift of Galaxies in Clusters from the Sloan Digital Sky Survey and the Baryon Oscillation Spectroscopic Survey Citation Details In-Document Search Title: Gravitational Redshift of Galaxies in Clusters from the Sloan Digital Sky Survey and the Baryon Oscillation Spectroscopic Survey Authors: Sadeh, Iftach ; Feng, Low Lerh ; Lahav, Ofer Publication Date: 2015-02-20 OSTI Identifier:

  8. Gravitational Redshift of Galaxies in Clusters from the Sloan Digital Sky

    Office of Scientific and Technical Information (OSTI)

    Survey and the Baryon Oscillation Spectroscopic Survey (Journal Article) | DOE PAGES Gravitational Redshift of Galaxies in Clusters from the Sloan Digital Sky Survey and the Baryon Oscillation Spectroscopic Survey Title: Gravitational Redshift of Galaxies in Clusters from the Sloan Digital Sky Survey and the Baryon Oscillation Spectroscopic Survey Authors: Sadeh, Iftach ; Feng, Low Lerh ; Lahav, Ofer Publication Date: 2015-02-20 OSTI Identifier: 1181622 Type: Publisher's Accepted Manuscript

  9. Natural Scherk-Schwarz theories of the weak scale

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    García, Isabel Garcia; Howe, Kiel; March-Russell, John

    2015-12-01

    Natural supersymmetric theories of the weak scale are under growing pressure given present LHC constraints, raising the question of whether untuned supersymmetric (SUSY) solutions to the hierarchy problem are possible. In this paper, we explore a class of 5-dimensional natural SUSY theories in which SUSY is broken by the Scherk-Schwarz mechanism. We pedagogically explain how Scherk-Schwarz elegantly solves the traditional problems of 4-dimensional SUSY theories (based on the MSSM and its many variants) that usually result in an unsettling level of fine-tuning. The minimal Scherk-Schwarz set up possesses novel phenomenology, which we briefly outline. In this study, we show thatmore » achieving the observed physical Higgs mass motivates extra structure that does not significantly affect the level of tuning (always better than ~10%) and we explore three qualitatively different extensions: the addition of extra matter that couples to the Higgs, an extra U(1)' gauge group under which the Higgs is charged and an NMSSM-like solution to the Higgs mass problem.« less

  10. Natural Scherk-Schwarz theories of the weak scale

    SciTech Connect (OSTI)

    García, Isabel Garcia; Howe, Kiel; March-Russell, John

    2015-12-01

    Natural supersymmetric theories of the weak scale are under growing pressure given present LHC constraints, raising the question of whether untuned supersymmetric (SUSY) solutions to the hierarchy problem are possible. In this paper, we explore a class of 5-dimensional natural SUSY theories in which SUSY is broken by the Scherk-Schwarz mechanism. We pedagogically explain how Scherk-Schwarz elegantly solves the traditional problems of 4-dimensional SUSY theories (based on the MSSM and its many variants) that usually result in an unsettling level of fine-tuning. The minimal Scherk-Schwarz set up possesses novel phenomenology, which we briefly outline. In this study, we show that achieving the observed physical Higgs mass motivates extra structure that does not significantly affect the level of tuning (always better than ~10%) and we explore three qualitatively different extensions: the addition of extra matter that couples to the Higgs, an extra U(1)' gauge group under which the Higgs is charged and an NMSSM-like solution to the Higgs mass problem.

  11. Photoexcited energy transfer in a weakly coupled dimer

    SciTech Connect (OSTI)

    Hernandez, Laura Alfonso; Nelson, Tammie; Tretiak, Sergei; Fernandez-Alberti, Sebastian

    2015-01-08

    Nonadiabatic excited-state molecular dynamics (NA-ESMD) simulations have been performed in order to study the time-dependent exciton localization during energy transfer between two chromophore units of the weakly coupled anthracene dimer dithia-anthracenophane (DTA). Simulations are done at both low temperature (10 K) and room temperature (300 K). The initial photoexcitation creates an exciton which is primarily localized on a single monomer unit. Subsequently, the exciton experiences an ultrafast energy transfer becoming localized on either one monomer unit or the other, whereas delocalization between both monomers never occurs. In half of the trajectories, the electronic transition density becomes completely localized on the same monomer as the initial excitation, while in the other half, it becomes completely localized on the opposite monomer. In this article, we present an analysis of the energy transfer dynamics and the effect of thermally induced geometry distortions on the exciton localization. Finally, simulated fluorescence anisotropy decay curves for both DTA and the monomer unit dimethyl anthracene (DMA) are compared. As a result, our analysis reveals that changes in the transition density localization caused by energy transfer between two monomers in DTA is not the only source of depolarization and exciton relaxation within a single DTA monomer unit can also cause reorientation of the transition dipole.

  12. Photoexcited energy transfer in a weakly coupled dimer

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Hernandez, Laura Alfonso; Nelson, Tammie; Tretiak, Sergei; Fernandez-Alberti, Sebastian

    2015-01-08

    Nonadiabatic excited-state molecular dynamics (NA-ESMD) simulations have been performed in order to study the time-dependent exciton localization during energy transfer between two chromophore units of the weakly coupled anthracene dimer dithia-anthracenophane (DTA). Simulations are done at both low temperature (10 K) and room temperature (300 K). The initial photoexcitation creates an exciton which is primarily localized on a single monomer unit. Subsequently, the exciton experiences an ultrafast energy transfer becoming localized on either one monomer unit or the other, whereas delocalization between both monomers never occurs. In half of the trajectories, the electronic transition density becomes completely localized on themore » same monomer as the initial excitation, while in the other half, it becomes completely localized on the opposite monomer. In this article, we present an analysis of the energy transfer dynamics and the effect of thermally induced geometry distortions on the exciton localization. Finally, simulated fluorescence anisotropy decay curves for both DTA and the monomer unit dimethyl anthracene (DMA) are compared. As a result, our analysis reveals that changes in the transition density localization caused by energy transfer between two monomers in DTA is not the only source of depolarization and exciton relaxation within a single DTA monomer unit can also cause reorientation of the transition dipole.« less

  13. Collisional disruption of gravitational aggregates in the tidal environment

    SciTech Connect (OSTI)

    Hyodo, Ryuki; Ohtsuki, Keiji

    2014-05-20

    The degree of disruption in collisions in free space is determined by specific impact energy, and the mass fraction of the largest remnant is a monotonically decreasing function of impact energy. However, it has not been shown whether such a relationship is applicable to collisions under the influence of a planet's tidal force, which is important in ring dynamics and satellite accretion. Here we examine the collisional disruption of gravitational aggregates in the tidal environment by using local N-body simulations. We find that outcomes of such a collision largely depend on the impact velocity, the direction of impact, and the radial distance from the planet. In the case of a strong tidal field corresponding to Saturn's F ring, collisions in the azimuthal direction are much more destructive than those in the radial direction. Numerical results of collisions sensitively depend on the impact velocity, and a complete disruption of aggregates can occur even in impacts with velocity much lower than their escape velocity. In such low-velocity collisions, the deformation of colliding aggregates plays an essential role in determining collision outcomes, because the physical size of the aggregate is comparable to its Hill radius. On the other hand, the dependence of collision outcomes on impact velocity becomes similar to the case in free space when the distance from the planet is sufficiently large. Our results are consistent with Cassini observations of the F ring, which suggest ongoing creation and disruption of aggregates within the ring.

  14. Rotation-dependent catastrophic disruption of gravitational aggregates

    SciTech Connect (OSTI)

    Ballouz, Ronald-Louis; Richardson, Derek C.; Schwartz, Stephen R.; Michel, Patrick

    2014-07-10

    We carry out a systematic exploration of the effect of pre-impact rotation on the outcomes of low-speed collisions between planetesimals modeled as gravitational aggregates. We use pkdgrav, a cosmology code adapted to collisional problems and recently enhanced with a new soft-sphere collision algorithm that includes more realistic contact forces. A rotating body has lower effective surface gravity than a non-rotating one and therefore might suffer more mass loss as the result of a collision. What is less well understood, however, is whether rotation systematically increases mass loss on average regardless of the impact trajectory. This has important implications for the efficiency of planet formation via planetesimal growth, and also more generally for the determination of the impact energy threshold for catastrophic disruption (leading to the largest remnant retaining 50% of the original mass), as this has generally only been evaluated for non-spinning bodies. We find that for most collision scenarios, rotation lowers the threshold energy for catastrophic dispersal. For head-on collisions, we develop a semi-analytic description of the change in the threshold description as a function of the target's pre-impact rotation rate, and find that these results are consistent with the 'universal law' of catastrophic disruption developed by Leinhardt and Stewart. Using this approach, we introduce re-scaled catastrophic disruption variables that take into account the interacting mass fraction of the target and the projectile in order to translate oblique impacts into equivalent head-on collisions.

  15. Observational constraints on holographic dark energy with varying gravitational constant

    SciTech Connect (OSTI)

    Lu, Jianbo; Xu, Lixin; Saridakis, Emmanuel N.; Setare, M.R. E-mail: msaridak@phys.uoa.gr E-mail: lxxu@dlut.edu.cn

    2010-03-01

    We use observational data from Type Ia Supernovae (SN), Baryon Acoustic Oscillations (BAO), Cosmic Microwave Background (CMB) and observational Hubble data (OHD), and the Markov Chain Monte Carlo (MCMC) method, to constrain the cosmological scenario of holographic dark energy with varying gravitational constant. We consider both flat and non-flat background geometry, and we present the corresponding constraints and contour-plots of the model parameters. We conclude that the scenario is compatible with observations. In 1? we find ?{sub ?0} = 0.72{sup +0.03}{sub ?0.03}, ?{sub k0} = ?0.0013{sup +0.0130}{sub ?0.0040}, c = 0.80{sup +0.19}{sub ?0.14} and ?{sub G}?G'/G = ?0.0025{sup +0.0080}{sub ?0.0050}, while for the present value of the dark energy equation-of-state parameter we obtain w{sub 0} = ?1.04{sup +0.15}{sub ?0.20}.

  16. Final fate of spherically symmetric gravitational collapse of a dust cloud in Einstein-Gauss-Bonnet gravity

    SciTech Connect (OSTI)

    Maeda, Hideki

    2006-05-15

    We give a model of the higher-dimensional spherically symmetric gravitational collapse of a dust cloud including the perturbative effects of quantum gravity. The n({>=}5)-dimensional action with the Gauss-Bonnet term for gravity is considered and a simple formulation of the basic equations is given for the spacetime M{approx_equal}M{sup 2}xK{sup n-2} with a perfect fluid and a cosmological constant. This is a generalization of the Misner-Sharp formalism of the four-dimensional spherically symmetric spacetime with a perfect fluid in general relativity. The whole picture and the final fate of the gravitational collapse of a dust cloud differ greatly between the cases with n=5 and n{>=}6. There are two families of solutions, which we call plus-branch and the minus-branch solutions. A plus-branch solution can be attached to the outside vacuum region which is asymptotically anti-de Sitter in spite of the absence of a cosmological constant. Bounce inevitably occurs in the plus-branch solution for n{>=}6, and consequently singularities cannot be formed. Since there is no trapped surface in the plus-branch solution, the singularity formed in the case of n=5 must be naked. On the other hand, a minus-branch solution can be attached to the outside asymptotically flat vacuum region. We show that naked singularities are massless for n{>=}6, while massive naked singularities are possible for n=5. In the homogeneous collapse represented by the flat Friedmann-Robertson-Walker solution, the singularity formed is spacelike for n{>=}6, while it is ingoing-null for n=5. In the inhomogeneous collapse with smooth initial data, the strong cosmic censorship hypothesis holds for n{>=}10 and for n=9 depending on the parameters in the initial data, while a naked singularity is always formed for 5{<=}n{<=}8. These naked singularities can be globally naked when the initial surface radius of the dust cloud is fine-tuned, and then the weak cosmic censorship hypothesis is violated.

  17. Weakly Ionized Plasmas in Hypersonics: Fundamental Kinetics and Flight Applications

    SciTech Connect (OSTI)

    Macheret, Sergey

    2005-05-16

    The paper reviews some of the recent studies of applications of weakly ionized plasmas to supersonic/hypersonic flight. Plasmas can be used simply as means of delivering energy (heating) to the flow, and also for electromagnetic flow control and magnetohydrodynamic (MHD) power generation. Plasma and MHD control can be especially effective in transient off-design flight regimes. In cold air flow, nonequilibrium plasmas must be created, and the ionization power budget determines design, performance envelope, and the very practicality of plasma/MHD devices. The minimum power budget is provided by electron beams and repetitive high-voltage nanosecond pulses, and the paper describes theoretical and computational modeling of plasmas created by the beams and repetitive pulses. The models include coupled equations for non-local and unsteady electron energy distribution function (modeled in forward-back approximation), plasma kinetics, and electric field. Recent experimental studies at Princeton University have successfully demonstrated stable diffuse plasmas sustained by repetitive nanosecond pulses in supersonic air flow, and for the first time have demonstrated the existence of MHD effects in such plasmas. Cold-air hypersonic MHD devices are shown to permit optimization of scramjet inlets at Mach numbers higher than the design value, while operating in self-powered regime. Plasma energy addition upstream of the inlet throat can increase the thrust by capturing more air (Virtual Cowl), or it can reduce the flow Mach number and thus eliminate the need for an isolator duct. In the latter two cases, the power that needs to be supplied to the plasma would be generated by an MHD generator downstream of the combustor, thus forming the 'reverse energy bypass' scheme. MHD power generation on board reentry vehicles is also discussed.

  18. The cross correlation between the 21-cm radiation and the CMB lensing field: a new cosmological signal

    SciTech Connect (OSTI)

    Vallinotto, Alberto

    2011-01-01

    The measurement of Baryon Acoustic Oscillations through the 21-cm intensity mapping technique at redshift z {<=} 4 has the potential to tightly constrain the evolution of dark energy. Crucial to this experimental effort is the determination of the biasing relation connecting fluctuations in the density of neutral hydrogen (HI) with the ones of the underlying dark matter field. In this work I show how the HI bias relevant to these 21-cm intensity mapping experiments can successfully be measured by cross-correlating their signal with the lensing signal obtained from CMB observations. In particular I show that combining CMB lensing maps from Planck with 21-cm field measurements carried out with an instrument similar to the Cylindrical Radio Telescope, this cross-correlation signal can be detected with a signal-to-noise (S/N) ratio of more than 5. Breaking down the signal arising from different redshift bins of thickness {Delta}z = 0.1, this signal leads to constraining the large scale neutral hydrogen bias and its evolution to 4{sigma} level.

  19. GREEN BANK TELESCOPE ZPECTROMETER CO(1-0) OBSERVATIONS OF THE STRONGLY LENSED SUBMILLIMETER GALAXIES FROM THE HERSCHEL ATLAS

    SciTech Connect (OSTI)

    Frayer, D. T.; Maddalena, R.; Harris, A. I.; Baker, A. J.; Ivison, R. J.; Smail, Ian; Negrello, M.; Aretxaga, I.; Baes, M.; Birkinshaw, M.; Bonfield, D. G.; Burgarella, D.; Buttiglione, S.; Cava, A.; Cooray, A.; Dannerbauer, H.

    2011-01-10

    The Herschel Astrophysical Terahertz Large Area Survey (H-ATLAS) has uncovered a population of strongly lensed submillimeter galaxies (SMGs). The Zpectrometer instrument on the Green Bank Telescope (GBT) was used to measure the redshifts and constrain the masses of the cold molecular gas reservoirs for two candidate high-redshift lensed sources. We derive CO(1-0) redshifts of z = 3.042 {+-} 0.001 and z = 2.625 {+-} 0.001, and measure molecular gas masses of (1-3) x10{sup 10} M{sub sun}, corrected for lens amplification and assuming a conversion factor of {alpha} = 0.8 M{sub sun}( K km s{sup -1} pc{sup 2}){sup -1}. We find typical L(IR)/L'(CO) ratios of 120 {+-} 40 and 140 {+-} 50 L{sub sun}( K km s{sup -1} pc{sup 2}){sup -1}, which are consistent with those found for local ultraluminous infrared galaxies (ULIRGs) and other high-redshift SMGs. From analysis of published data, we find no evidence for enhanced L(IR)/L'(CO(1-0)) ratios for the SMG population in comparison to local ULIRGs. The GBT results highlight the power of using the CO lines to derive blind redshifts, which is challenging for the SMGs at optical wavelengths given their high obscuration.

  20. V-234: EMC RSA Archer GRC Open Redirection Weakness and Security Bypass

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Security Issue | Department of Energy 4: EMC RSA Archer GRC Open Redirection Weakness and Security Bypass Security Issue V-234: EMC RSA Archer GRC Open Redirection Weakness and Security Bypass Security Issue September 4, 2013 - 6:00am Addthis PROBLEM: A weakness and a security issue have been reported in EMC RSA Archer GRC PLATFORM: EMC RSA Archer GRC 5.x ABSTRACT: This fixes multiple vulnerabilities, which can be exploited to bypass certain security restrictions and to conduct spoofing

  1. GRAVITATIONAL INFALL ONTO MOLECULAR FILAMENTS. II. EXTERNALLY PRESSURIZED CYLINDERS

    SciTech Connect (OSTI)

    Heitsch, Fabian

    2013-10-10

    Two aspects of the evolution of externally pressurized, hydrostatic filaments are discussed. (1) The free-fall accretion of gas onto such a filament will lead to filament parameters (specifically, FWHM-column-density relations) inconsistent with the observations of Arzoumanian et al., except for two cases: for low-mass, isothermal filaments, agreement is found as in the analysis by Fischera and Martin. Magnetized cases, for which the field scales weakly with the density as B?n {sup 1/2}, also reproduce observed parameters. (2) Realistically, the filaments will be embedded not only in gas of non-zero pressure, but also of non-zero density. Thus, the appearance of sheet-embedded filaments is explored. Generating a grid of filament models and comparing the resulting column density ratios and profile shapes with observations suggests that the three-dimensional filament profiles are intrinsically flatter than isothermal, beyond projection and evolution effects.

  2. Cosmological constraints on the gravitational interactions of matter and dark matter

    SciTech Connect (OSTI)

    Bai, Yang; Salvado, Jordi; Stefanek, Ben A.

    2015-10-13

    Although there is overwhelming evidence of dark matter from its gravitational interaction, we still do not know its precise gravitational interaction strength or whether it obeys the equivalence principle. Using the latest available cosmological data and working within the framework of ΛCDM, we first update the measurement of the multiplicative factor of cosmology-relevant Newton’s constant over the standard laboratory-based value and find that it is consistent with one. In general relativity, dark matter equivalence principle breaking can be mimicked by a long-range dark matter force mediated by an ultra light scalar field. Using the Planck three year data, we find that the dark matter “fifth-force” strength is constrained to be weaker than 10{sup −4} of the gravitational force. We also introduce a phenomenological, post-Newtonian two-fluid description to explicitly break the equivalence principle by introducing a difference between dark matter inertial and gravitational masses. Depending on the decoupling time of the dark matter and ordinary matter fluids, the ratio of the dark matter gravitational mass to inertial mass is constrained to be unity at the 10{sup −6} level.

  3. Results of the IGEC-2 search for gravitational wave bursts during 2005

    SciTech Connect (OSTI)

    Astone, P.; Babusci, D.; Giordano, G.; Marini, A.; Modestino, G.; Quintieri, L.; Ronga, F.; Baggio, L.; Bassan, M.; Fafone, V.; Moleti, A.; Bignotto, M.; Cerdonio, M.; Conti, L.; Drago, M.; Liguori, N.; Bonaldi, M.; Falferi, P.; Vinante, A.; Camarda, M.

    2007-11-15

    The network of resonant bar detectors of gravitational waves resumed coordinated observations within the International Gravitational Event Collaboration (IGEC-2). Four detectors are taking part in this Collaboration: ALLEGRO, AURIGA, EXPLORER and NAUTILUS. We present here the results of the search for gravitational wave bursts over 6 months during 2005, when IGEC-2 was the only gravitational wave observatory in operation. The implemented network data analysis is based on a time coincidence search among AURIGA, EXPLORER and NAUTILUS; ALLEGRO data was reserved for follow-up studies. The network amplitude sensitivity to bursts improved by a factor {approx_equal}3 over the 1997-2000 IGEC observations; the wider sensitive band also allowed the analysis to be tuned over a larger class of waveforms. Given the higher single-detector duty factors, the analysis was based on threefold coincidence, to ensure the identification of any single candidate of gravitational waves with high statistical confidence. The false detection rate was as low as 1 per century. No candidates were found.

  4. A Bayesian approach to multi-messenger astronomy: identification of gravitational-wave host galaxies

    SciTech Connect (OSTI)

    Fan, XiLong; Messenger, Christopher; Heng, Ik Siong

    2014-11-01

    We present a general framework for incorporating astrophysical information into Bayesian parameter estimation techniques used by gravitational wave data analysis to facilitate multi-messenger astronomy. Since the progenitors of transient gravitational wave events, such as compact binary coalescences, are likely to be associated with a host galaxy, improvements to the source sky location estimates through the use of host galaxy information are explored. To demonstrate how host galaxy properties can be included, we simulate a population of compact binary coalescences and show that for ?8.5% of simulations within 200 Mpc, the top 10 most likely galaxies account for a ?50% of the total probability of hosting a gravitational wave source. The true gravitational wave source host galaxy is in the top 10 galaxy candidates ?10% of the time. Furthermore, we show that by including host galaxy information, a better estimate of the inclination angle of a compact binary gravitational wave source can be obtained. We also demonstrate the flexibility of our method by incorporating the use of either the B or K band into our analysis.

  5. Existence of global weak solution for a reduced gravity two and a half layer model

    SciTech Connect (OSTI)

    Guo, Zhenhua Li, Zilai Yao, Lei

    2013-12-15

    We investigate the existence of global weak solution to a reduced gravity two and a half layer model in one-dimensional bounded spatial domain or periodic domain. Also, we show that any possible vacuum state has to vanish within finite time, then the weak solution becomes a unique strong one.

  6. Applications of Laminar Weak-Link Mechanisms for Ultraprecision Synchrotron Radiation Instruments

    SciTech Connect (OSTI)

    Shu, D.; Toellner, T. S.; Alp, E. E.; Maser, J.; Ilavsky, J.; Shastri, S. D.; Lee, P. L.; Narayanan, S.; Long, G. G. [Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439 (United States)

    2007-01-19

    Unlike traditional kinematic flexure mechanisms, laminar overconstrained weak-link mechanisms provide much higher structure stiffness and stability. Using a laminar structure configured and manufactured by chemical etching and lithography techniques, we are able to design and build linear and rotary weak-link mechanisms with ultrahigh positioning sensitivity and stability for synchrotron radiation applications. Applications of laminar rotary weak-link mechanism include: high-energy-resolution monochromators for inelastic x-ray scattering and x-ray analyzers for ultra-small-angle scattering and powder-diffraction experiments. Applications of laminar linear weak-link mechanism include high-stiffness piezo-driven stages with subnanometer resolution for an x-ray microscope. In this paper, we summarize the recent designs and applications of the laminar weak-link mechanisms at the Advanced Photon Source.

  7. CONVERGENCE STUDIES OF MASS TRANSPORT IN DISKS WITH GRAVITATIONAL INSTABILITIES. I. THE CONSTANT COOLING TIME CASE

    SciTech Connect (OSTI)

    Michael, Scott; Steiman-Cameron, Thomas Y.; Durisen, Richard H. [Astronomy Department, Indiana University, Bloomington, IN 47405 (United States); Boley, Aaron C., E-mail: scamicha@astro.indiana.edu, E-mail: tomsc@astro.indiana.edu, E-mail: durisen@astro.indiana.edu, E-mail: aaron.boley@gmail.com [Department of Astronomy, University of Florida, Gainesville, FL 32611 (United States)

    2012-02-10

    We conduct a convergence study of a protostellar disk, subject to a constant global cooling time and susceptible to gravitational instabilities (GIs), at a time when heating and cooling are roughly balanced. Our goal is to determine the gravitational torques produced by GIs, the level to which transport can be represented by a simple {alpha}-disk formulation, and to examine fragmentation criteria. Four simulations are conducted, identical except for the number of azimuthal computational grid points used. A Fourier decomposition of non-axisymmetric density structures in cos (m{phi}), sin (m{phi}) is performed to evaluate the amplitudes A{sub m} of these structures. The A{sub m} , gravitational torques, and the effective Shakura and Sunyaev {alpha} arising from gravitational stresses are determined for each resolution. We find nonzero A{sub m} for all m-values and that A{sub m} summed over all m is essentially independent of resolution. Because the number of measurable m-values is limited to half the number of azimuthal grid points, higher-resolution simulations have a larger fraction of their total amplitude in higher-order structures. These structures act more locally than lower-order structures. Therefore, as the resolution increases the total gravitational stress decreases as well, leading higher-resolution simulations to experience weaker average gravitational torques than lower-resolution simulations. The effective {alpha} also depends upon the magnitude of the stresses, thus {alpha}{sub eff} also decreases with increasing resolution. Our converged {alpha}{sub eff} is consistent with predictions from an analytic local theory for thin disks by Gammie, but only over many dynamic times when averaged over a substantial volume of the disk.

  8. Dust gravitational drift wave in complex plasma under gravity

    SciTech Connect (OSTI)

    Salahshoor, M. Niknam, A. R.

    2014-12-15

    The dispersion relation of electrostatic waves in a complex plasma under gravity is presented. It is assumed that the waves propagate parallel to the external fields. The effects of weak electric field, neutral drag force, and ion drag force are also taken into account. The dispersion relation is numerically examined in an appropriate parameter space in which the gravity plays the dominant role in the dynamics of microparticles. The numerical results show that, in the low pressure complex plasma under gravity, a low frequency drift wave can be developed in the long wavelength limit. The stability state of this wave is switched at a certain critical wavenumber in such a way that the damped mode is transformed into a growing one. Furthermore, the influence of the external fields on the dispersion properties is analyzed. It is shown that the wave instability is essentially due to the electrostatic streaming of plasma particles. It is also found that by increasing the electric field strength, the stability switching occurs at smaller wavenumbers.

  9. Effect of thermal gravitational convection on flame propagation over a fuel surface

    SciTech Connect (OSTI)

    Samsonov, V.P.

    1985-03-01

    The effect of thermal gravitational convection on flame propagation velocity and stability was determined by comparison of experimental results obtained by changing gravitational conditions while maintaining other external conditions constant. The fuel materials used were series BF glues. Interferograms were produced to study the alcohol vapor concentration field above the drying glue surface. Under conditions of normal gravity, flame behavior changes markedly. The flame loses stability and its structure becomes complex and strictly periodically repetitive. Experiments under conditions of weightlessness revealed that in the absence of gravity, relaxation combustion is impossible.

  10. Compact dark matter objects, asteroseismology, and gravitational waves radiated by sun

    SciTech Connect (OSTI)

    Pokrovsky, Yu. E.

    2015-12-15

    The solar surface oscillations observed by Crimean Astrophysical Observatory and Solar Helioseismic Observatory are considered to be excited by a small fraction of Dark Matter in form of Compact Dark Matter Objects (CDMO) in the solar structure. Gravitational Waves (GW) radiated by these CDMO are predicted to be the strongest at the Earth and are easily detectable by European Laser Interferometer Space Antenna or by Gravitational-Wave Observatory “Dulkyn” which can solve two the most challenging tasks in the modern physics: direct detection of GW and DM.

  11. Gravitational waves from domain walls in the next-to-minimal supersymmetric standard model

    SciTech Connect (OSTI)

    Kadota, Kenji; Kawasaki, Masahiro; Saikawa, Ken’ichi

    2015-10-16

    The next-to-minimal supersymmetric standard model predicts the formation of domain walls due to the spontaneous breaking of the discrete Z{sub 3}-symmetry at the electroweak phase transition, and they collapse before the epoch of big bang nucleosynthesis if there exists a small bias term in the potential which explicitly breaks the discrete symmetry. Signatures of gravitational waves produced from these unstable domain walls are estimated and their parameter dependence is investigated. It is shown that the amplitude of gravitational waves becomes generically large in the decoupling limit, and that their frequency is low enough to be probed in future pulsar timing observations.

  12. Method and apparatus for evaluating structural weakness in polymer matrix composites

    DOE Patents [OSTI]

    Wachter, Eric A.; Fisher, Walter G.

    1996-01-01

    A method and apparatus for evaluating structural weaknesses in polymer matrix composites is described. An object to be studied is illuminated with laser radiation and fluorescence emanating therefrom is collected and filtered. The fluorescence is then imaged and the image is studied to determine fluorescence intensity over the surface of the object being studied and the wavelength of maximum fluorescent intensity. Such images provide a map of the structural integrity of the part being studied and weaknesses, particularly weaknesses created by exposure of the object to heat, are readily visible in the image.

  13. Method and apparatus for evaluating structural weakness in polymer matrix composites

    DOE Patents [OSTI]

    Wachter, E.A.; Fisher, W.G.

    1996-01-09

    A method and apparatus for evaluating structural weaknesses in polymer matrix composites is described. An object to be studied is illuminated with laser radiation and fluorescence emanating therefrom is collected and filtered. The fluorescence is then imaged and the image is studied to determine fluorescence intensity over the surface of the object being studied and the wavelength of maximum fluorescent intensity. Such images provide a map of the structural integrity of the part being studied and weaknesses, particularly weaknesses created by exposure of the object to heat, are readily visible in the image. 6 figs.

  14. Naked singularities in non-self-similar gravitational collapse of radiation shells

    SciTech Connect (OSTI)

    Joshi, P.S.; Dwivedi, I.H. )

    1992-03-15

    Non-self-similar gravitational collapse of imploding radiation is shown to give rise to a strong curvature naked singularity. The conditions are specified for the singularity to be globally naked and the strength of the same is examined along nonspacelike curves and along all the families of nonspacelike geodesics terminating at the singularity in the past.

  15. The effects of charge transfer inefficiency (CTI) on galaxy shape

    Office of Scientific and Technical Information (OSTI)

    measurements (Journal Article) | SciTech Connect SciTech Connect Search Results Journal Article: The effects of charge transfer inefficiency (CTI) on galaxy shape measurements Citation Details In-Document Search Title: The effects of charge transfer inefficiency (CTI) on galaxy shape measurements We examine the effects of charge transfer inefficiency (CTI) during CCD readout on the demanding galaxy shape measurements required by studies of weak gravitational lensing. We simulate a CCD

  16. Process for loading weak-acid ion exchange resin with uranium

    DOE Patents [OSTI]

    Notz, Karl J.

    1976-01-01

    A method for loading ion exchange resins is described. The process comprises contacting a weak acid cation exchange resin in the ammonium form with a uranyl fluoride salt solution.

  17. A Story of Q-weak at Jefferson Lab (On YouTube) | Jefferson Lab

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    A Story of Q-weak at Jefferson Lab (On YouTube) External Link: http://www.youtube.com/watch?v=WhYb53Kkl9k By jlab_admin on Sun, 2012-02-05

  18. V-234: EMC RSA Archer GRC Open Redirection Weakness and Security...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    V-234: EMC RSA Archer GRC Open Redirection Weakness and Security Bypass Security Issue ... Vendor recommends updating to version 5.4 Addthis Related Articles V-084: RSA Archer eGRC ...

  19. Theory and Modeling of Weakly Bound/Physisorbed Materials for Hydrogen Storage

    Broader source: Energy.gov [DOE]

    Presentation on the Theory and Modeling of Weakly Bound/Physisorbed Materials for Hydrogen Storage given at the DOE Theory Focus Session on Hydrogen Storage Materials on May 18, 2006.

  20. Structure solution with weak anomalous data (Technical Report) | SciTech

    Office of Scientific and Technical Information (OSTI)

    Connect Structure solution with weak anomalous data Citation Details In-Document Search Title: Structure solution with weak anomalous data Authors: Terwilliger, Thomas C. [1] + Show Author Affiliations Los Alamos National Laboratory Publication Date: 2014-10-21 OSTI Identifier: 1133759 Report Number(s): LA-UR-14-24209 DOE Contract Number: AC52-06NA25396 Resource Type: Technical Report Research Org: Los Alamos National Laboratory (LANL) Sponsoring Org: NIH Country of Publication: United

  1. Method of Control o Multiple Contraction in the volume of Weakly Ionized

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Plasma by Standing Acoustic Wave Excitation. | Princeton Plasma Physics Lab Method of Control o Multiple Contraction in the volume of Weakly Ionized Plasma by Standing Acoustic Wave Excitation. This invention is a process that uses a standing acoustic wave in the volume of weakly ionized plasma to control the initiation of contraction (transition to arc) in certain designated places - the antimodes of the standing wave. No.: M-876 Inventor(s): Igor Kaganovich

  2. Weak charge form factor and radius of 208Pb through parity violation in electron scattering

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Horowitz, C. J.; Ahmed, Z.; Jen, C. -M.; Rakhman, A.; Souder, P. A.; Dalton, M. M.; Liyanage, N.; Paschke, K. D.; Saenboonruang, K.; Silwal, R.; et al

    2012-03-26

    We use distorted wave electron scattering calculations to extract the weak charge form factor FW(more » $$\\bar{q}$$), the weak charge radius RW, and the point neutron radius Rn, of 208Pb from the PREX parity violating asymmetry measurement. The form factor is the Fourier transform of the weak charge density at the average momentum transfer $$\\bar{q}$$ = 0.475 fm-1. We find FW($$\\bar{q}$$) = 0.204 ± 0.028(exp) ± 0.001(model). We use the Helm model to infer the weak radius from FW($$\\bar{q}$$). We find RW = 5.826 ± 0.181(exp) ± 0.027(model) fm. Here the exp error includes PREX statistical and systematic errors, while the model error describes the uncertainty in RW from uncertainties in the surface thickness σ of the weak charge density. The weak radius is larger than the charge radius, implying a 'weak charge skin' where the surface region is relatively enriched in weak charges compared to (electromagnetic) charges. We extract the point neutron radius Rn = 5.751 ± 0.175 (exp) ± 0.026(model) ± 0.005(strange) fm, from RW. Here there is only a very small error (strange) from possible strange quark contributions. We find Rn to be slightly smaller than RW because of the nucleon's size. As a result, we find a neutron skin thickness of Rn-Rp = 0.302 ± 0.175 (exp) ± 0.026 (model) ± 0.005 (strange) fm, where Rp is the point proton radius.« less

  3. Upper bounds on sparticle masses from naturalness or how to disprove weak

    Office of Scientific and Technical Information (OSTI)

    scale supersymmetry (Journal Article) | SciTech Connect Upper bounds on sparticle masses from naturalness or how to disprove weak scale supersymmetry Citation Details In-Document Search This content will become publicly available on February 15, 2017 Title: Upper bounds on sparticle masses from naturalness or how to disprove weak scale supersymmetry Authors: Baer, Howard ; Barger, Vernon ; Savoy, Michael Publication Date: 2016-02-16 OSTI Identifier: 1238092 Type: Publisher's Accepted

  4. Van der Waals Metal-Semiconductor Junction: Weak Fermi Level Pinning

    Office of Scientific and Technical Information (OSTI)

    Enables Effective Tuning of Schottky Barrier (Journal Article) | SciTech Connect Van der Waals Metal-Semiconductor Junction: Weak Fermi Level Pinning Enables Effective Tuning of Schottky Barrier Citation Details In-Document Search This content will become publicly available on April 1, 2017 Title: Van der Waals Metal-Semiconductor Junction: Weak Fermi Level Pinning Enables Effective Tuning of Schottky Barrier Two-dimensional (2D) semiconductors have shown great potential for electronic and

  5. Primordial massive gravitational waves from Einstein-Chern-Simons-Weyl gravity

    SciTech Connect (OSTI)

    Myung, Yun Soo; Moon, Taeyoon E-mail: tymoon@inje.ac.kr

    2014-08-01

    We investigate the evolution of cosmological perturbations during de Sitter inflation in the Einstein-Chern-Simons-Weyl gravity. Primordial massive gravitational waves are composed of one scalar, two vector and four tensor circularly polarized modes. We show that the vector power spectrum decays quickly like a transversely massive vector in the superhorizon limit z?0. In this limit, the power spectrum coming from massive tensor modes decays quickly, leading to the conventional tensor power spectrum. Also, we find that in the limit of m{sup 2}?0 (keeping the Weyl-squared term only), the vector and tensor power spectra disappear. It implies that their power spectra are not gravitationally produced because they (vector and tensor) are decoupled from the expanding de Sitter background, as a result of conformal invariance.

  6. Method and apparatus for measuring gravitational acceleration utilizing a high temperature superconducting bearing

    DOE Patents [OSTI]

    Hull, John R.

    2000-01-01

    Gravitational acceleration is measured in all spatial dimensions with improved sensitivity by utilizing a high temperature superconducting (HTS) gravimeter. The HTS gravimeter is comprised of a permanent magnet suspended in a spaced relationship from a high temperature superconductor, and a cantilever having a mass at its free end is connected to the permanent magnet at its fixed end. The permanent magnet and superconductor combine to form a bearing platform with extremely low frictional losses, and the rotational displacement of the mass is measured to determine gravitational acceleration. Employing a high temperature superconductor component has the significant advantage of having an operating temperature at or below 77K, whereby cooling may be accomplished with liquid nitrogen.

  7. Quantum states of neutrons in the gravitational and centrifugal potentials in a new GRANIT spectrometer

    ScienceCinema (OSTI)

    None

    2011-10-06

    We will discuss the scientific program to be studied in a new gravitational spectrometer GRANIT in a broad context of quantum states (quantum behaviour) of ultracold neutrons (UCN) in gravitational [1] and centrifugal [2] potentials, as well as applications of these phenomena/spectrometer to various domains of physics, ranging from studies of fundamental short-range interactions and symmetries to neutron quantum optics and reflectometry using UCN. All these topics, as well as related instrumental and methodical developments have been discussed during dedicated GRANIT-2010 Workshop [3]. The GRANIT spectrometer has been recently installed at the Institut Laue-Langevin, Grenoble, France [4] and could become operational in near future. 1. V.V. Nesvizhevsky et al (2002), Nature 415, 297. 2. V.V. Nesvizhevsky et al (2010), Nature Physics 6, 114. 3. GRANIT-2010, Les Houches, 14-19 february 2010. 4. M. Kreuz et al (2009), NIM 611, 326.

  8. Asymptotic behavior of dynamical variables and naked singularity formation in spherically symmetric gravitational collapse

    SciTech Connect (OSTI)

    Kawakami, Hayato; Mitsuda, Eiji; Nambu, Yasusada; Tomimatsu, Akira

    2009-07-15

    In considering the gravitational collapse of matter, it is an important problem to clarify what kind of conditions leads to the formation of naked singularity. For this purpose, we apply the 1+3 orthonormal frame formalism introduced by Uggla et al. to the spherically symmetric gravitational collapse of a perfect fluid. This formalism allows us to construct an autonomous system of evolution and constraint equations for scale-invariant dynamical variables normalized by the volume expansion rate of the timelike orthonormal frame vector. We investigate the asymptotic evolution of such dynamical variables towards the formation of a central singularity and present a conjecture that the steep spatial gradient for the normalized density function is a characteristic of the naked singularity formation.

  9. AN EXTREME GRAVITATIONALLY REDSHIFTED IRON LINE AT 4.8 KeV IN Mrk 876

    SciTech Connect (OSTI)

    Bottacini, Eugenio; Orlando, Elena; Moskalenko, Igor [W. W. Hansen Experimental Physics Laboratory and Kavli Institute for Particle Astrophysics and Cosmology, Stanford University (United States); Greiner, Jochen [Max-Planck-Institut fr extraterrestrische Physik, Giessenbachstrasse 1, D-85748 Garching (Germany); Ajello, Marco [Department of Physics and Astronomy, Clemson University, Clemson, SC 29634-0978 (United States); Persic, Massimo, E-mail: eugenio.bottacini@stanford.edu [INAF-Trieste, via G.B.Tiepolo 11, I-34143 Trieste (Italy)

    2015-01-01

    X-ray spectral lines at unforeseen energies are important because they can shed light on the extreme physical conditions of the environment around the supermassive black holes of active galactic nuclei (AGNs). Mrk 876 displays such a line at 4.80{sub ?0.04}{sup +0.05} rest-frame energy. A possible interpretation of its origin can be found in the hotspot scenario. In this scenario, the primary radiation from a flare in the hot corona of an AGN illuminates a limited portion of the accretion disk that emits by fluorescence. In this context, the line can represent an extreme gravitationally redshifted Fe line originating on the accretion disk below six gravitational radii from a rotating supermassive black hole. The correct estimate of the line significance requires a dedicated approach. Based on an existing rigorous approach, we have performed extensive Monte Carlo simulations. We determine that the line is a real feature at a ?99% confidence level.

  10. Problem of motion of the gravitationally interacting particles in Born-Infeld electrodynamics

    SciTech Connect (OSTI)

    Shkolnik, N.

    1984-01-01

    The motion of charged particles in the framework of the Einstein-Infeld-Hoffman method is examined. The Born-Infeld energy-momentum tensor is used in the right hand side of the gravitational field equations. It is shown that it results in a modified behavior of charged particles. In particular, it leads to a modification of Coulomb's law at small distances. It is also shown that a stable system of two charged particles is possible.

  11. Gravitational focusing and substructure effects on the rate modulation in direct dark matter searches

    SciTech Connect (OSTI)

    Nobile, Eugenio Del; Gelmini, Graciela B.; Witte, Samuel J.

    2015-08-21

    We study how gravitational focusing (GF) of dark matter by the Sun affects the annual and biannual modulation of the expected signal in non-directional direct dark matter searches, in the presence of dark matter substructure in the local dark halo. We consider the Sagittarius stream and a possible dark disk, and show that GF suppresses some, but not all, of the distinguishing features that would characterize substructure of the dark halo were GF neglected.

  12. Holographic dark energy with varying gravitational constant in Ho?ava-Lifshitz cosmology

    SciTech Connect (OSTI)

    Setare, M.R.; Jamil, Mubasher E-mail: mjamil@camp.nust.edu.pk

    2010-02-01

    We investigate the holographic dark energy scenario with a varying gravitational constant in a flat background in the context of Ho?ava-Lifshitz gravity. We extract the exact differential equation determining the evolution of the dark energy density parameter, which includes G variation term. Also we discuss a cosmological implication of our work by evaluating the dark energy equation of state for low redshifts containing varying G corrections.

  13. Therml & Gravitational Stress in Si Wafers; Lim. on Process Htg & Cool. Rates

    Energy Science and Technology Software Center (OSTI)

    1997-01-14

    The MacWafer code determines maximum allowable processing temperatures and maximum heating and cooling rates for thermal processing of silicon semiconductor wafers in single and multiple wafer furnaces. The program runs interactively on Macintosh, PC, and workstation computers. Execution time is typically 20 seconds on a Macintosh 68040 processor operating at 33 MHz. Gravitational stresses and displacements are first calculated based on the user''s input of a support system consisting of a ring beneath the wafermore » and/or arbitrarily placed point supports. The maximum operating temperature is then deduced by comparing the calculated gravitational stresses with the temperature-dependent wafer strength. At lower temperatures, the difference between wafer strength and gravitational stress is used to determine the allowable thermal stress, and hence the allowable radial temperature difference across the wafer. Finally, an analytical model of radial heat transfer in a batch furnace yields the maximum heating or cooling rate as a function of the allowable temperature difference based on the user''s inputs of wafer spacing and furnace power. Outputs to the screen include plots of stress components and vertical displacement, as well as tables of maximum stresses and maximum heating and cooling rates as a function of temperature. All inputs and outputs may be directed to user-named files for further processing or graphical display.« less

  14. Therml & Gravitational Stress in Si Wafers; Lim. on Process Htg & Cool. Rates

    Energy Science and Technology Software Center (OSTI)

    1997-01-14

    The MacWafer code determines maximum allowable processing temperatures and maximum heating and cooling rates for thermal processing of silicon semiconductor wafers in single and multiple wafer furnaces. The program runs interactively on Macintosh, PC, and workstation computers. Execution time is typically 20 seconds on a Macintosh 68040 processor operating at 33 MHz. Gravitational stresses and displacements are first calculated based on the user''s input of a support system consisting of a ring beneath the wafermoreand/or arbitrarily placed point supports. The maximum operating temperature is then deduced by comparing the calculated gravitational stresses with the temperature-dependent wafer strength. At lower temperatures, the difference between wafer strength and gravitational stress is used to determine the allowable thermal stress, and hence the allowable radial temperature difference across the wafer. Finally, an analytical model of radial heat transfer in a batch furnace yields the maximum heating or cooling rate as a function of the allowable temperature difference based on the user''s inputs of wafer spacing and furnace power. Outputs to the screen include plots of stress components and vertical displacement, as well as tables of maximum stresses and maximum heating and cooling rates as a function of temperature. All inputs and outputs may be directed to user-named files for further processing or graphical display.less

  15. Parameter-induced stochastic resonance based on spectral entropy and its application to weak signal detection

    SciTech Connect (OSTI)

    Zhang, Jinjing; Zhang, Tao

    2015-02-15

    The parameter-induced stochastic resonance based on spectral entropy (PSRSE) method is introduced for the detection of a very weak signal in the presence of strong noise. The effect of stochastic resonance on the detection is optimized using parameters obtained in spectral entropy analysis. Upon processing employing the PSRSE method, the amplitude of the weak signal is enhanced and the noise power is reduced, so that the frequency of the signal can be estimated with greater precision through spectral analysis. While the improvement in the signal-to-noise ratio is similar to that obtained using the Duffing oscillator algorithm, the computational cost reduces from O(N{sup 2}) to O(N). The PSRSE approach is applied to the frequency measurement of a weak signal made by a vortex flow meter. The results are compared with those obtained applying the Duffing oscillator algorithm.

  16. Review Article: The weak interactive characteristic of resonance cells and broadband effect of metamaterials

    SciTech Connect (OSTI)

    Zhao, Xiaopeng Song, Kun

    2014-10-15

    Metamaterials are artificial media designed to control electromagnetic wave propagation. Due to resonance, most present-day metamaterials inevitably suffer from narrow bandwidth, extremely limiting their practical applications. On the basis of tailored properties, a metamaterial within which each distinct unit cell resonates at its inherent frequency and has almost no coupling effect with the other ones, termed as weak interaction system, can be formulated. The total response of a weak interaction system can be treated as an overlap of the single resonance spectrum of each type of different unit cells. This intriguing feature therefore makes it possible to accomplish multiband or broadband metamaterials in a simple way. By introducing defects into metamaterials to form a weak interaction system, multiband and broadband electromagnetic metamaterials have first been experimentally demonstrated by our group. The similar concept can also be readily extended to acoustic and seismic metamaterials.

  17. High-energy jet quenching in weakly coupled quark-gluon plasmas

    SciTech Connect (OSTI)

    Arnold, Peter; Xiao Wei

    2008-12-15

    q is the average squared transverse momentum transfer per unit length to a high-energy particle traversing a QCD medium such as a quark-gluon plasma. We find the (UV-regulated) value of q to leading order in the weak coupling limit, {alpha}{sub s}(T)<<1. We then use this value to generalize previous analytic results on the gluon bremsstrahlung and pair production rates for massless high-energy particles in a weakly coupled quark-gluon plasma, at next-to-leading logarithmic order.

  18. Note: On-line weak signal detection via adaptive stochastic resonance

    SciTech Connect (OSTI)

    Lu, Siliang; He, Qingbo Kong, Fanrang

    2014-06-15

    We design an instrument with a novel embedded adaptive stochastic resonance (SR) algorithm that consists of a SR module and a digital zero crossing detection module for on-line weak signal detection in digital signal processing applications. The two modules are responsible for noise filtering and adaptive parameter configuration, respectively. The on-line weak signal detection can be stably achieved in seconds. The prototype instrument exhibits an advance of 20 dB averaged signal-to-noise ratio and 5 times averaged adjust R-square as compared to the input noisy signal, in considering different driving frequencies and noise levels.

  19. Carbon Lock-in Through Capital Stock Inertia Associated with Weak Near-term Climate Policies

    SciTech Connect (OSTI)

    Bertram, Christoph; Johnson, Nils; Luderer, Gunnar; Riahi, Keywan; Isaac, Morna; Eom, Jiyong

    2015-01-01

    Stringent long-term climate targets necessitate a strict limit on cumulative emissions in this century for which sufficient policy signals are so far lacking. Based on an ensemble of ten energy-economy models, we explore how long-term transformation pathways depend on policies pursued during the next two decades. We find that weak GHG emission targets for 2030 lead, in that year alone, to excess carbon dioxide emissions of nearly half of the annual emissions in 2010, mainly through coal electricity generation. Furthermore, by consuming more of the long-term cumulative emissions budget in the first two decades, weak policy increases the likelihood of overshooting the budget and the urgency of reducing GHG emissions. Therefore, to be successful under weak policies, models must prematurely retire much of the additional coal capacity post-2030 and remove large quantities of carbon dioxide from the atmosphere in the latter half of the century. While increased energy efficiency lowers mitigation costs considerably, even with weak near-term policies, it does not substantially reduce the short term reliance on coal electricity. However, increased energy efficiency does allow the energy system more flexibility in mitigating emissions and, thus, makes the post-2030 transition easier.

  20. Measuring the Weak Charge of the Proton via Elastic Electron-Proton Scattering

    SciTech Connect (OSTI)

    Jones, Donald C.

    2015-10-01

    The Qweak experiment which ran in Hall C at Jefferson Lab in Newport News, VA, and completed data taking in May 2012, measured the weak charge of the proton QpW via elastic electron-proton scattering. Longitudinally polarized electrons were scattered from an unpolarized liquid hydrogen target. The helicity of the electron beam was flipped at approximately 1 kHz between left and right spin states. The Standard Model predicts a small parity-violating asymmetry of scattering rates between right and left helicity states due to the weak interaction. An initial result using 4% of the data was published in October 2013 [1] with a measured parity-violating asymmetry of -279 ± 35(stat) ± 31 (syst) ppb. This asymmetry, along with other data from parity-violating electron scattering experiments, provided the world's first determination of the weak charge of the proton. The weak charge of the proton was found to be pW = 0.064 ± 0.012, in good agreement with the Standard Model prediction of pW(SM) = 0.0708 ± 0.0003[2].

  1. MEASUREMENTS OF CO REDSHIFTS WITH Z-SPEC FOR LENSED SUBMILLIMETER GALAXIES DISCOVERED IN THE H-ATLAS SURVEY

    SciTech Connect (OSTI)

    Lupu, R. E.; Scott, K. S.; Aguirre, J. E.; Aretxaga, I.; Auld, R.; Dariush, A.; Barton, E.; Cooke, J.; Cooray, A.; Beelen, A.; Bertoldi, F.; Bock, J. J.; Bradford, C. M.; Bonfield, D.; Buttiglione, S.; De Zotti, G.; Cava, A.; Dannerbauer, H.; and others

    2012-10-01

    We present new observations from Z-Spec, a broadband 185-305 GHz spectrometer, of five submillimeter bright lensed sources selected from the Herschel-Astrophysical Terahertz Large Area Survey science demonstration phase catalog. We construct a redshift-finding algorithm using combinations of the signal to noise of all the lines falling in the Z-Spec bandpass to determine redshifts with high confidence, even in cases where the signal to noise in individual lines is low. We measure the dust continuum in all sources and secure CO redshifts for four out of five (z {approx} 1.5-3). In one source, SDP.17, we tentatively identify two independent redshifts and a water line, confirmed at z = 2.308. Our sources have properties characteristic of dusty starburst galaxies, with magnification-corrected star formation rates of 10{sup 2-3} M{sub Sun} yr{sup -1}. Lower limits for the dust masses ({approx} a few 10{sup 8} M{sub Sun }) and spatial extents ({approx}1 kpc equivalent radius) are derived from the continuum spectral energy distributions, corresponding to dust temperatures between 54 and 69 K. In the local thermodynamic equilibrium (LTE) approximation, we derive relatively low CO excitation temperatures ({approx}< 100 K) and optical depths ({tau} {approx}< 1). Performing a non-LTE excitation analysis using RADEX, we find that the CO lines measured by Z-Spec (from J = 4 {yields} 3 to 10 {yields} 9, depending on the galaxy) localize the best solutions to either a high-temperature/low-density region or a low/temperature/high-density region near the LTE solution, with the optical depth varying accordingly. Observations of additional CO lines, CO(1-0) in particular, are needed to constrain the non-LTE models.

  2. Born energy, acid-base equilibrium, structure and interactions of end-grafted weak polyelectrolyte layers

    SciTech Connect (OSTI)

    Nap, R. J.; Tagliazucchi, M.; Szleifer, I.

    2014-01-14

    This work addresses the effect of the Born self-energy contribution in the modeling of the structural and thermodynamical properties of weak polyelectrolytes confined to planar and curved surfaces. The theoretical framework is based on a theory that explicitly includes the conformations, size, shape, and charge distribution of all molecular species and considers the acid-base equilibrium of the weak polyelectrolyte. Namely, the degree of charge in the polymers is not imposed but it is a local varying property that results from the minimization of the total free energy. Inclusion of the dielectric properties of the polyelectrolyte is important as the environment of a polymer layer is very different from that in the adjacent aqueous solution. The main effect of the Born energy contribution on the molecular organization of an end-grafted weak polyacid layer is uncharging the weak acid (or basic) groups and consequently decreasing the concentration of mobile ions within the layer. The magnitude of the effect increases with polymer density and, in the case of the average degree of charge, it is qualitatively equivalent to a small shift in the equilibrium constant for the acid-base equilibrium of the weak polyelectrolyte monomers. The degree of charge is established by the competition between electrostatic interactions, the polymer conformational entropy, the excluded volume interactions, the translational entropy of the counterions and the acid-base chemical equilibrium. Consideration of the Born energy introduces an additional energetic penalty to the presence of charged groups in the polyelectrolyte layer, whose effect is mitigated by down-regulating the amount of charge, i.e., by shifting the local-acid base equilibrium towards its uncharged state. Shifting of the local acid-base equilibrium and its effect on the properties of the polyelectrolyte layer, without considering the Born energy, have been theoretically predicted previously. Account of the Born energy leads to systematic, but in general small, corrections to earlier theoretical predictions describing the behavior of weak polyelectrolyte layers. However, polyelectrolyte uncharging results in a decrease in the concentration of counterions and inclusion of the Born Energy can result in a substantial decrease of the counterion concentration. The effect of considering the Born energy contribution is explored for end-grafted weak polyelectrolyte layers by calculating experimental observables which are known to depend on the presence of charges within the polyelectrolyte layer: inclusion of the Born energy contribution leads to a decrease in the capacitance of polyelectrolyte-modified electrodes, a decrease of conductivity of polyelectrolyte-modified nanopores and an increase in the repulsion exerted by a planar polyelectrolyte layer confined by an opposing wall.

  3. A proposed design and fabrication of lenses and mirrors from a set of spherical rings that produce desired energy distributions for solar energy applications

    SciTech Connect (OSTI)

    Gonzalez-Garcia, Jorge; Vazquez-Montiel, Sergio; Santiago-Alvarado, Agustin; Cordero-Davila, Alberto; Castro-Gonzalez, Graciela

    2009-12-15

    The amount of energy contained in the solar aureole affects the performance of solar systems. Solar optical systems are, therefore, dependent on the characteristics of the shape of the sun in a specific geographical location. For this reason, the present study proposes the design of solid lenses and mirrors modelled from a set of concentric spherical rings that give a desired distribution of energy in the focal plane. One hundred spherical rings, whose optimum curvature radius values were calculated by Genetic Algorithms, were employed in the modelling process. The study also proposes a design of a petal tool to polish lens and mirror surfaces. (author)

  4. N-BODY SIMULATION OF PLANETESIMAL FORMATION THROUGH GRAVITATIONAL INSTABILITY OF A DUST LAYER IN LAMINAR GAS DISK

    SciTech Connect (OSTI)

    Michikoshi, Shugo; Kokubo, Eiichiro [Center for Computational Astrophysics, National Astronomical Observatory of Japan, Osawa, Mitaka, Tokyo 181-8588 (Japan); Inutsuka, Shu-ichiro, E-mail: michikoshi@cfca.j, E-mail: kokubo@th.nao.ac.j, E-mail: inutsuka@nagoya-u.j [Department of Physics, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602 (Japan)

    2010-08-20

    We investigate the formation process of planetesimals from the dust layer by the gravitational instability in the gas disk using local N-body simulations. The gas is modeled as a background laminar flow. We study the formation process of planetesimals and its dependence on the strength of the gas drag. Our simulation results show that the formation process is divided into three stages qualitatively: the formation of wake-like density structures, the creation of planetesimal seeds, and their collisional growth. The linear analysis of the dissipative gravitational instability shows that the dust layer is secularly unstable although Toomre's Q value is larger than unity. However, in the initial stage, the growth time of the gravitational instability is longer than that of the dust sedimentation and the decrease in the velocity dispersion. Thus, the velocity dispersion decreases and the disk shrinks vertically. As the velocity dispersion becomes sufficiently small, the gravitational instability finally becomes dominant. Then wake-like density structures are formed by the gravitational instability. These structures fragment into planetesimal seeds. The seeds grow rapidly owing to mutual collisions.

  5. Measurement of the CP-violating weak phase ϕs and the decay width

    Office of Scientific and Technical Information (OSTI)

    difference ΔΓs using the Bs0→J/ψϕ(1020) decay channel in pp collisions at s=8 TeV (Journal Article) | SciTech Connect Measurement of the CP-violating weak phase ϕs and the decay width difference ΔΓs using the B s 0 → J / ψ ϕ ( 1020 ) decay channel in pp collisions at s = 8 TeV Citation Details In-Document Search Title: Measurement of the CP-violating weak phase ϕs and the decay width difference ΔΓs using the B s 0 → J / ψ ϕ ( 1020 ) decay channel in pp collisions at s = 8

  6. Forward Compton scattering with weak neutral current: Constraints from sum rules

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Gorchtein, Mikhail; Zhang, Xilin

    2015-06-09

    We generalize forward real Compton amplitude to the case of the interference of the electromagnetic and weak neutral current, formulate a low-energy theorem, relate the new amplitudes to the interference structure functions and obtain a new set of sum rules. Furthermore, we address a possible new sum rule that relates the product of the axial charge and magnetic moment of the nucleon to the 0th moment of the structure function g5(ν, 0). For the dispersive γ Z-box correction to the proton’s weak charge, the application of the GDH sum rule allows us to reduce the uncertainty due to resonance contributionsmore » by a factor of two. Finally, the finite energy sum rule helps addressing the uncertainty in that calculation due to possible duality violations.« less

  7. Symmetries of the triple degenerate DNLS equations for weakly nonlinear dispersive MHD waves

    SciTech Connect (OSTI)

    Webb, G. M.; Brio, M.; Zank, G. P.

    1996-07-20

    A formulation of Hamiltonian and Lagrangian variational principles, Lie point symmetries and conservation laws for the triple degenerate DNLS equations describing the propagation of weakly nonlinear dispersive MHD waves along the ambient magnetic field, in {beta}{approx}1 plasmas is given. The equations describe the interaction of the Alfven and magnetoacoustic modes near the triple umbilic point, where the fast magnetosonic, slow magnetosonic and Alfven speeds coincide and a{sub g}{sup 2}=V{sub A}{sup 2} where a{sub g} is the gas sound speed and V{sub A} is the Alfven speed. A discussion is given of the travelling wave similarity solutions of the equations, which include solitary wave and periodic traveling waves. Strongly compressible solutions indicate the necessity for the insertion of shocks in the flow, whereas weakly compressible, near Alfvenic solutions resemble similar, shock free travelling wave solutions of the DNLS equation.

  8. Determination of magneto-optical constant of Fe films with weak measurements

    SciTech Connect (OSTI)

    Qiu, Xiaodong; Hu, Dejiao; Du, Jinglei; Gao, Fuhua; Zhang, Zhiyou; Zhou, Xinxing; Luo, Hailu

    2014-09-29

    In this letter, a detecting method for the magneto-optical constant is presented by using weak measurements. The photonic spin Hall effect (PSHE), which manifests itself as spin-dependent splitting, is introduced to characterize the magneto-optical constant, and a propagation model to describe the quantitative relation between the magneto-optical constant and the PSHE is established. According to the amplified shift of the PSHE detected by weak measurements, we determinate the magneto-optical constant of the Fe film sample. The Kerr rotation is measured via the standard polarimetry method to verify the rationality and feasibility of our method. These findings may provide possible applications in magnetic physics research.

  9. Test of weak and strong factorization in nucleus-nucleuscollisions atseveral hundred MeV/nucleon

    SciTech Connect (OSTI)

    La Tessa, Chiara; Sihver, Lembit; Zeitlin, Cary; Miller, Jack; Guetersloh, Stephen; Heilbronn, Lawrence; Mancusi, Davide; Iwata,Yoshiuki; Murakami, Takeshi

    2006-06-21

    Total and partial charge-changing cross sections have been measured for argon projectiles at 400 MeV/nucleon in carbon, aluminum, copper, tin and lead targets; cross sections for hydrogen were also obtained, using a polyethylene target. The validity of weak and strong factorization properties has been investigated for partial charge-changing cross sections; preliminary cross section values obtained for carbon, neon and silicon at 290 and 400 MeV/nucleon and iron at 400 MeV/nucleon, in carbon, aluminum, copper, tin and lead targets have been also used for testing these properties. Two different analysis methods were applied and both indicated that these properties are valid, without any significant difference between weak and strong factorization. The factorization parameters have then been calculated and analyzed in order to find some systematic behavior useful for modeling purposes.

  10. Forward Compton scattering with weak neutral current: Constraints from sum rules

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Gorchtein, Mikhail; Zhang, Xilin

    2015-07-01

    We generalize forward real Compton amplitude to the case of the interference of the electromagnetic and weak neutral current, formulate a low-energy theorem, relate the new amplitudes to the interference structure functions and obtain a new set of sum rules. We address a possible new sum rule that relates the product of the axial charge and magnetic moment of the nucleon to the 0th moment of the structure function g?(?0). For the dispersive ? ?-box correction to the proton's weak charge, the application of the GDH sum rule allows us to reduce the uncertainty due to resonance contributions by amorefactor of two. The finite energy sum rule helps addressing the uncertainty in that calculation due to possible duality violations.less

  11. High-frequency electromagnetic surface waves in a semi-bounded weakly ionized plasma

    SciTech Connect (OSTI)

    Moaied, M.; Tyshetskiy, Yu.; Vladimirov, S. V.

    2013-02-15

    High-frequency electromagnetic surface waves (SWs) in a weakly ionized plasma half-space with Maxwellian electrons are studied taking into account elastic electron-neutral collisions. The SWs spectrum and damping rate are obtained numerically for a wide range of wavelengths, and the asymptotes of damping rate are analytically calculated in some limits. It is shown that the high-frequency SWs become strongly damped at wavelengths {lambda}<{lambda}{sub Min}, where {lambda}{sub Min} significantly depends on plasma parameters (e.g., electron temperature and electron and neutral atom density). The relative importance of collisional and Cherenkov (collisionless) damping of SWs is investigated and is graphically shown for a range of plasma parameters and SW wavelengths. The behavior of weakly ionized plasma with respect to the SW propagation has been recovered for the collisional parameter {eta}.

  12. Electronic structure and weak itinerant magnetism in metallic Y2Ni7

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Singh, David J.

    2015-11-03

    We describe a density functional study of the electronic structure and magnetism of Y₂Ni₇. The results show itinerant magnetism very similar to that in the weak itinerant ferromagnet Ni₃Al. The electropositive Y atoms in Y₂Ni₇ donate charge to the Ni host mostly in the form of s electrons. The non-spin-polarized state shows a high density of states at the Fermi level, N (EF), due to flat bands. This leads to a ferromagnetic instability. However, there are also several much more dispersive bands crossing E(F), which should promote the conductivity. Spin fluctuation effects appear to be comparable to or weaker thanmore » Ni₃Al, based on comparison with experimental data. Y₂Ni₇ provides a uniaxial analog to cubic Ni₃Al, for studying weak itinerant ferromagnetism, suggesting detailed measurements of its low temperature physical properties and spin fluctuations, as well as experiments under pressure.« less

  13. Discrete kinetic eigenmode spectra of electron plasma oscillations in weakly collisional plasma: A numerical study

    SciTech Connect (OSTI)

    Black, Carrie; Ng, C. S.

    2013-01-15

    It has been demonstrated that in the presence of weak collisions, described by the Lenard-Bernstein (LB) collision operator, the Landau-damped solutions become true eigenmodes of the system and constitute a complete set [C.-S. Ng et al., Phys. Rev. Lett. 83, 1974 (1999) and C. S. Ng et al., Phys. Rev. Lett. 96, 065002 (2004)]. We present numerical results from an Eulerian Vlasov code that incorporates the Lenard-Bernstein collision operator [A. Lenard and I. B. Bernstein, Phys. Rev. 112, 1456 (1958)]. The effect of collisions on the numerical recursion phenomenon seen in Vlasov codes is discussed. The code is benchmarked against exact linear eigenmode solutions in the presence of weak collisions, and a spectrum of Landau-damped solutions is determined within the limits of numerical resolution. Tests of the orthogonality and the completeness relation are presented.

  14. MAGNIFICATION BY GALAXY GROUP DARK MATTER HALOS

    SciTech Connect (OSTI)

    Ford, Jes; Hildebrandt, Hendrik; Van Waerbeke, Ludovic; Leauthaud, Alexie; Tanaka, Masayuki; Capak, Peter; Finoguenov, Alexis; George, Matthew R.; Rhodes, Jason

    2012-08-01

    We report on the detection of gravitational lensing magnification by a population of galaxy groups, at a significance level of 4.9{sigma}. Using X-ray-selected groups in the COSMOS 1.64 deg{sup 2} field, and high-redshift Lyman break galaxies as sources, we measure a lensing-induced angular cross-correlation between the samples. After satisfying consistency checks that demonstrate we have indeed detected a magnification signal, and are not suffering from contamination by physical overlap of samples, we proceed to implement an optimally weighted cross-correlation function to further boost the signal to noise of the measurement. Interpreting this optimally weighted measurement allows us to study properties of the lensing groups. We model the full distribution of group masses using a composite-halo approach, considering both the singular isothermal sphere and Navarro-Frenk-White profiles, and find our best-fit values to be consistent with those recovered using the weak-lensing shear technique. We argue that future weak-lensing studies will need to incorporate magnification along with shear, both to reduce residual systematics and to make full use of all available source information, in an effort to maximize scientific yield of the observations.

  15. Magnetic fields and fluctuations in weakly Mn doped ZnGeP{sub 2}

    SciTech Connect (OSTI)

    Mengyan, P. W.; Lichti, R. L.; Baker, B. B.; Celebi, Y. G.; Catak, E.; Carroll, B. R.; Zawilski, K. T.; Schunemann, P. G.

    2014-02-21

    We report on our measurements of local and bulk magnetic features in weakly Mn doped ZnGeP{sub 2}. Utilizing muon spin rotation and relaxation measurements, we identify local ferromagnetic order and fluctuations in the local fields as sampled by an implanted muon (?{sup +}). We also report on field induced ferromagnetism occurring above the claimed paramagnetic to ferromagnetic transition temperature (T{sub c} = 312 K)

  16. Qweak: First Direct Measurement of the Weak Charge of the Proton

    SciTech Connect (OSTI)

    Nuruzzaman, NFN

    2014-04-01

    The Qweak experiment at Hall C of Thomas Jefferson National Accelerator Facility has made the first direct measurement of the weak charge of the proton, QWp, through a precision measurement of the parity-violating asymmetry in elastic e-p scattering at low momentum transfer Q2= 0.025 (GeV/c)2 with incident electron beam energy of 1.155 GeV. The Qweak experiment, along with earlier results of parity violating elastic scattering experiments, is expected to determine the most precise value of QWp which is suppressed in the Standard Model. If this result is further combined with the 133Cs atomic parity violation (APV) measurement, significant constraints on the weak charge of the up quark, down quark, and neutron can be extracted. This data will also be used to determine the weak-mixing angle, sin2 ?W, with a relative uncertainty of < 0.5% that will provide a competitive measurement of the running of sin2 ?W to low Q2. An overview of the experiment and its results using the commissioning dataset, constituting approximately 4% of the data collected in the experiment, are reported here.

  17. CONDUCTION IN LOW MACH NUMBER FLOWS. I. LINEAR AND WEAKLY NONLINEAR REGIMES

    SciTech Connect (OSTI)

    Lecoanet, Daniel; Brown, Benjamin P.; Zweibel, Ellen G.; Burns, Keaton J.; Oishi, Jeffrey S.; Vasil, Geoffrey M.

    2014-12-20

    Thermal conduction is an important energy transfer and damping mechanism in astrophysical flows. Fourier's law, in which the heat flux is proportional to the negative temperature gradient, leading to temperature diffusion, is a well-known empirical model of thermal conduction. However, entropy diffusion has emerged as an alternative thermal conduction model, despite not ensuring the monotonicity of entropy. This paper investigates the differences between temperature and entropy diffusion for both linear internal gravity waves and weakly nonlinear convection. In addition to simulating the two thermal conduction models with the fully compressible Navier-Stokes equations, we also study their effects in the reduced ''soundproof'' anelastic and pseudoincompressible (PI) equations. We find that in the linear and weakly nonlinear regime, temperature and entropy diffusion give quantitatively similar results, although there are some larger errors in the PI equations with temperature diffusion due to inaccuracies in the equation of state. Extrapolating our weakly nonlinear results, we speculate that differences between temperature and entropy diffusion might become more important for strongly turbulent convection.

  18. Precise atmospheric parameters for the shortest-period binary white dwarfs: gravitational waves, metals, and pulsations

    SciTech Connect (OSTI)

    Gianninas, A.; Kilic, Mukremin; Dufour, P.; Bergeron, P.; Brown, Warren R.; Hermes, J. J.

    2014-10-10

    We present a detailed spectroscopic analysis of 61 low-mass white dwarfs and provide precise atmospheric parameters, masses, and updated binary system parameters based on our new model atmosphere grids and the most recent evolutionary model calculations. For the first time, we measure systematic abundances of He, Ca, and Mg for metal-rich, extremely low mass white dwarfs and examine the distribution of these abundances as a function of effective temperature and mass. Based on our preliminary results, we discuss the possibility that shell flashes may be responsible for the presence of the observed He and metals. We compare stellar radii derived from our spectroscopic analysis to model-independent measurements and find good agreement except for white dwarfs with T {sub eff} ≲ 10,000 K. We also calculate the expected gravitational wave strain for each system and discuss their significance to the eLISA space-borne gravitational wave observatory. Finally, we provide an update on the instability strip of extremely low mass white dwarf pulsators.

  19. Properties of gravitationally equilibrated Yukawa systemsA molecular dynamics study

    SciTech Connect (OSTI)

    Charan, Harish; Ganesh, Rajaraman Joy, Ashwin

    2014-04-15

    Using 2D Molecular Dynamics simulation, the equilibrium and dynamical properties of a gravitationally equilibrated Yukawa liquid are investigated. We observe that due to asymmetry introduced in one direction by gravity, several interesting features arise. For example, for a given value of coupling parameter ?, screening parameter ?, and according to a chosen value of gravitational force g (say in y-direction), the system is seen to exhibit super-, sub- or normal diffusion. Interestingly, x-averaged density profiles, unlike a barotropic fluid, acquires sharp, free surface with scale free linear y-dependence. As can be expected for a system with macroscopic gradients, self-diffusion calculated from Green-Kubos formalism does not agree with that obtained from Einstein-Smoluchowski diffusion. A 2D angular-radial pair correlation function g(r, ?) clearly indicates asymmetric features induced by gravity. We observe that due to compression in y-direction, though in liquid state for all values of gravity considered, the transverse mode is found to predominant as compared to the longitudinal mode, leading to a novel Anisotropic Solid-like Yukawa liquid.

  20. Gravitational wave signals from short-lived topological defects in the MSSM

    SciTech Connect (OSTI)

    Kamada, Ayuki; Yamada, Masaki

    2015-10-09

    Supersymmetric theories, including the minimal supersymmetric standard model, usually contain many scalar fields whose potentials are absent in the exact supersymmetric limit and within the renormalizable level. Since their potentials are vulnerable to the finite energy density of the Universe through supergravity effects, these flat directions have nontrivial dynamics in the early Universe. Recently, we have pointed out that a flat direction may have a positive Hubble induced mass term during inflation whereas a negative one after inflation. In this case, the flat direction stays at the origin of the potential during inflation and then obtain a large vacuum expectation value after inflation. After that, when the Hubble parameter decreases down to the mass of the flat direction, it starts to oscillate around the origin of the potential. In this paper, we investigate the dynamics of the flat direction with and without higher dimensional superpotentials and show that topological defects, such as cosmic strings and domain walls, form at the end of inflation and disappear at the beginning of oscillation of the flat direction. We numerically calculate their gravitational signals and find that the observation of gravitational signals would give us information of supersymmetric scale, the reheating temperature of the Universe, and higher dimensional operators.

  1. Formation of graded vanadium oxide (VO compound) under strong gravitational field

    SciTech Connect (OSTI)

    Khandaker, Jahirul Islam; Tokuda, Makoto; Ogata, Yudai; Januszko, Kamila; Mashimo, Tsutomu; Nishiyama, Tadao; Yoshiasa, Akira

    2015-05-14

    Sedimentation of atoms induced under strong gravitational field gives a tool for controlling elemental compositions in condensed matter. We performed a strong-gravity experiment (0.397??10{sup 6?}G at 400?C for 24 h) on a V{sub 2}O{sub 5} polycrystal using the high-temperature ultracentrifuge to examine the composition change and further the structure change. The graded composition structure of V and O was formed along gravity direction, where V increases and O decreases with gravity. It was found by the x-ray diffraction and Raman scattering method that VO{sub 2} and V{sub 2}O{sub 3} phases appeared and the amounts increased, while one of the V{sub 2}O{sub 5} phase decreased gradually along gravity direction. The X-ray absorption near edge structure spectra analysis identified the chemical valency decrease (+5 to +3). The UV-Vis absorption spectroscopy addressed the shifting in center of major absorption peak to longer wavelength (red shift) with the increase in gravitational field. The tail absorption peak (band gap 2.09?eV) at strong gravity region in the graded structure showed transparent conductive oxide.

  2. Reconstruction of source location in a network of gravitational wave interferometric detectors

    SciTech Connect (OSTI)

    Cavalier, Fabien; Barsuglia, Matteo; Bizouard, Marie-Anne; Brisson, Violette; Clapson, Andre-Claude; Davier, Michel; Hello, Patrice; Kreckelbergh, Stephane; Leroy, Nicolas; Varvella, Monica

    2006-10-15

    This paper deals with the reconstruction of the direction of a gravitational wave source using the detection made by a network of interferometric detectors, mainly the LIGO and Virgo detectors. We suppose that an event has been seen in coincidence using a filter applied on the three detector data streams. Using the arrival time (and its associated error) of the gravitational signal in each detector, the direction of the source in the sky is computed using a {chi}{sup 2} minimization technique. For reasonably large signals (SNR>4.5 in all detectors), the mean angular error between the real location and the reconstructed one is about 1 deg. . We also investigate the effect of the network geometry assuming the same angular response for all interferometric detectors. It appears that the reconstruction quality is not uniform over the sky and is degraded when the source approaches the plane defined by the three detectors. Adding at least one other detector to the LIGO-Virgo network reduces the blind regions and in the case of 6 detectors, a precision less than 1 deg. on the source direction can be reached for 99% of the sky.

  3. Is the effect of the Sun's gravitational potential on dark matter particles observable?

    SciTech Connect (OSTI)

    Bozorgnia, Nassim; Schwetz, Thomas E-mail: schwetz@fysik.su.se

    2014-08-01

    We consider the effect of the Sun's gravitational potential on the local phase space distribution of dark matter particles, focusing on its implication for the annual modulation signal in direct detection experiments. We perform a fit to the modulation signal observed in DAMA/LIBRA and show that the allowed region shrinks if Solar gravitational focusing (GF) is included compared to the one without GF. Furthermore, we consider a possible signal in a generic future direct detection experiment, irrespective of the DAMA/LIBRA signal. Even for scattering cross sections close to the current bound and a large exposure of a xenon target with 270 ton yr it will be hard to establish the presence of GF from data. In the region of dark matter masses below 40 GeV an annual modulation signal can be established for our assumed experimental setup, however GF is negligible for low masses. In the high mass region, where GF is more important, the significance of annual modulation itself is very low. We obtain similar results for lighter targets such as Ge and Ar. We comment also on inelastic scattering, noting that GF becomes somewhat more important for exothermic scattering compared to the elastic case.

  4. Interpretation of a short-term anomaly in the gravitational microlensing event MOA-2012-BLG-486

    SciTech Connect (OSTI)

    Hwang, K.-H.; Choi, J.-Y.; Han, C.; Bond, I. A.; Sumi, T.; Koshimoto, N.; Gaudi, B. S.; Gould, A.; Bozza, V.; Beaulieu, J.-P.; Tsapras, Y.; Abe, F.; Fukunaga, D.; Itow, Y.; Bennett, D. P.; Botzler, C. S.; Freeman, M.; Chote, P.; Harris, P.; Fukui, A.; Collaboration: MOA Collaboration; μFUN Collaboration; PLANET Collaboration; RoboNet Collaboration; and others

    2013-11-20

    A planetary microlensing signal is generally characterized by a short-term perturbation to the standard single lensing light curve. A subset of binary-source events can produce perturbations that mimic planetary signals, thereby introducing an ambiguity between the planetary and binary-source interpretations. In this paper, we present the analysis of the microlensing event MOA-2012-BLG-486, for which the light curve exhibits a short-lived perturbation. Routine modeling not considering data taken in different passbands yields a best-fit planetary model that is slightly preferred over the best-fit binary-source model. However, when allowed for a change in the color during the perturbation, we find that the binary-source model yields a significantly better fit and thus the degeneracy is clearly resolved. This event not only signifies the importance of considering various interpretations of short-term anomalies, but also demonstrates the importance of multi-band data for checking the possibility of false-positive planetary signals.

  5. Stopping distance for high energy jets in weakly coupled quark-gluon plasmas

    SciTech Connect (OSTI)

    Arnold, Peter; Cantrell, Sean; Xiao Wei

    2010-02-15

    We derive a simple formula for the stopping distance for a high-energy quark traveling through a weakly coupled quark-gluon plasma. The result is given to next-to-leading order in an expansion in inverse logarithms ln(E/T), where T is the temperature of the plasma. We also define a stopping distance for gluons and give a leading-log result. Discussion of stopping distance has a theoretical advantage over discussion of energy loss rates in that stopping distances can be generalized to the case of strong coupling, where one may not speak of individual partons.

  6. Field theory and weak Euler-Lagrange equation for classical particle-field systems

    SciTech Connect (OSTI)

    Qin, Hong; Burby, Joshua W; Davidson, Ronald C

    2014-10-01

    It is commonly believed that energy-momentum conservation is the result of space-time symmetry. However, for classical particle-field systems, e.g., Klimontovich-Maxwell and Klimontovich- Poisson systems, such a connection hasn't been formally established. The difficulty is due to the fact that particles and the electromagnetic fields reside on different manifolds. To establish the connection, the standard Euler-Lagrange equation needs to be generalized to a weak form. Using this technique, energy-momentum conservation laws that are difficult to find otherwise can be systematically derived.

  7. Perturbative analysis of sheared flow Kelvin-Helmholtz instability in a weakly relativistic magnetized electron fluid

    SciTech Connect (OSTI)

    Sundar, Sita; Das, Amita; Kaw, Predhiman [Institute for Plasma Research, Bhat, Gandhinagar-382428 (India)

    2012-05-15

    In the interaction of intense lasers with matter/plasma, energetic electrons having relativistic energies get created. These energetic electrons can often have sheared flow profiles as they propagate through the plasma medium. In an earlier study [Phys. Plasmas 17, 022101 (2010)], it was shown that a relativistic sheared electron flow modifies the growth rate and threshold condition of the conventional Kelvin-Helmholtz instability. A perturbative analytic treatment for the case of weakly relativistic regime has been provided here. It provides good agreement with the numerical results obtained earlier.

  8. SORPTION BEHAVIOR OF MONOSODIUM TITANATE AND AMORPHOUS PEROXOTITANATE MATERIALS UNDER WEAKLY ACIDIC CONDITIONS

    SciTech Connect (OSTI)

    Hobbs, D.; Elvington, M.; Click, D.

    2009-11-11

    Inorganic, titanate-based sorbents are tested with respect to adsorption of a variety of sorbates under weakly acidic conditions (pH 3). Specifically, monosodium titanate (MST) and amorphous peroxotitanate (APT) sorption characteristics are initially probed through a screening process consisting of a pair of mixed metal solutions containing a total of 29 sorbates including alkali metals, alkaline earth metals, transition metals, metalloids and nonmetals. MST and APT sorption characteristics are further analyzed individually with chromium(III) and cadmium(II) using a batch method at ambient laboratory temperature, varying concentrations of the sorbents and sorbates and contact times. Maximum sorbate loadings are obtained from the respective adsorption isotherms.

  9. Neutral weak-current two-body contributions in inclusive scattering from {sup 12}C

    SciTech Connect (OSTI)

    Lovato, Alessandro; Gandolfi, Stefano; Carlson, Joseph; Pieper, S. C.; Schiavilla, Rocco

    2014-05-01

    An {\\it ab initio} calculation of the sum rules of the neutral weak response functions in $^{12}$C is reported, based on a realistic Hamiltonian, including two- and three-nucleon potentials, and on realistic currents, consisting of one- and two-body terms. We find that the sum rules of the response functions associated with the longitudinal and transverse components of the (space-like) neutral current are largest and that a significant portion ($\\simeq 30$\\%) of the calculated strength is due to two-body terms. This fact may have implications for the MiniBooNE and other neutrino quasi-elastic scattering data on nuclei.

  10. Effects of a weakly 3-D equilibrium on ideal magnetohydrodynamic instabilities

    SciTech Connect (OSTI)

    Hegna, C. C.

    2014-07-15

    The effect of a small three-dimensional equilibrium distortion on an otherwise axisymmetric configuration is shown to be destabilizing to ideal magnetohydrodynamic modes. The calculations assume that the 3-D fields are weak and that shielding physics is present so that no islands appear in the resulting equilibrium. An eigenfunction that has coupled harmonics of different toroidal mode number is constructed using a perturbation approach. The theory is applied to the case of tokamak H-modes with shielded resonant magnetic perturbations (RMPs) present indicating RMPs can be destabilizing to intermediate-n peeling-ballooning modes.

  11. Gravitational waves versus X-ray and gamma-ray emission in a short gamma-ray burst

    SciTech Connect (OSTI)

    Oliveira, F. G.; Rueda, Jorge A.; Ruffini, R., E-mail: fe.fisica@gmail.com, E-mail: jorge.rueda@icra.it, E-mail: ruffini@icra.it [Dipartimento di Fisica and ICRA, Sapienza Universit di Roma, P.le Aldo Moro 5, I-00185 Rome (Italy)

    2014-06-01

    Recent progress in the understanding of the physical nature of neutron star equilibrium configurations and the first observational evidence of a genuinely short gamma-ray burst (GRB), GRB 090227B, allows us to give an estimate of the gravitational waves versus the X-ray and gamma-ray emission in a short GRB.

  12. The final stage of gravitational collapse for high density fluid medium

    SciTech Connect (OSTI)

    Souza, R. G.; De Campos, M.

    2013-03-25

    The High density high density fluids can be represented by a stiff matter state equation P={rho} and also by the Hagedorn state equation. The first is constructed using a lagrangian that allows bare nucleons to interact attractively via scalar meson exchange, and repulsively by a more massive vector meson exchange; the second consider that for large mass the spectrum of hadrons grows exponentially, namely {rho}(m) {approx}exp(m/T{sub H}), where T{sub H} is the Hagedorn temperature, resulting the state equation P = P{sub 0}+{rho}{sub 0}ln({rho}/{rho}{sub 0}). We study the gravitational collapse for a high density fluid, considering a Hagedorn state equation in a presence of a vacuum component.

  13. Most sub-arcsecond companions of Kepler exoplanet candidate host stars are gravitationally bound

    SciTech Connect (OSTI)

    Horch, Elliott P.; Howell, Steve B.; Everett, Mark E.; Ciardi, David R. E-mail: steve.b.howell@nasa.gov E-mail: ciardi@ipac.caltech.edu

    2014-11-01

    Using the known detection limits for high-resolution imaging observations and the statistical properties of true binary and line-of-sight companions, we estimate the binary fraction of Kepler exoplanet host stars. Our speckle imaging programs at the WIYN 3.5 m and Gemini North 8.1 m telescopes have observed over 600 Kepler objects of interest and detected 49 stellar companions within ?1 arcsec. Assuming binary stars follow a log-normal period distribution for an effective temperature range of 3000-10,000 K, then the model predicts that the vast majority of detected sub-arcsecond companions are long period (P > 50 yr), gravitationally bound companions. In comparing the model predictions to the number of real detections in both observational programs, we conclude that the overall binary fraction of host stars is similar to the 40%-50% rate observed for field stars.

  14. Stability analysis of self-similar behaviors in perfect fluid gravitational collapse

    SciTech Connect (OSTI)

    Mitsuda, Eiji; Tomimatsu, Akira

    2006-06-15

    Stability of self-similar solutions for gravitational collapse is an important problem to be investigated from the perspectives of their nature as an attractor, critical phenomena, and instability of a naked singularity. In this paper we study spherically symmetric non-self-similar perturbations of matter and metrics in spherically symmetric self-similar backgrounds. The collapsing matter is assumed to be a perfect fluid with the equation of state P={alpha}{rho}. We construct a single wave equation governing the perturbations, which makes their time evolution in arbitrary self-similar backgrounds analytically tractable. Further we propose an analytical application of this master wave equation to the stability problem by means of the normal mode analysis for the perturbations having the time dependence given by exp(i{omega}log vertical t vertical bar), and present some sufficient conditions for the absence of nonoscillatory unstable normal modes with purely imaginary {omega}.

  15. Conversion of relic gravitational waves into photons in cosmological magnetic fields

    SciTech Connect (OSTI)

    Dolgov, Alexander D.; Ejlli, Damian E-mail: ejlli@fe.infn.it

    2012-12-01

    Conversion of gravitational waves into electromagnetic radiation is discussed. The probability of transformations of gravitons into photons in presence of cosmological background magnetic field is calculated at the recombination epoch and during subsequent cosmological stages. The produced electromagnetic radiation is concentrated in the X-ray part of the spectrum. It is shown that if the early Universe was dominated by primordial black holes (PBHs) prior to Big Bang Nucleosynthesis (BBN), the relic gravitons emitted by PBHs would transform to an almost isotropic background of electromagnetic radiation due to conversion of gravitons into photons in cosmological magnetic fields. Such extragalactic radiation could be noticeable or even dominant component of Cosmic X-ray Background.

  16. THE GRAVITATIONAL POTENTIAL NEAR THE SUN FROM SEGUE K-DWARF KINEMATICS

    SciTech Connect (OSTI)

    Zhang Lan; Liu Chao; Zhao Gang; Rix, Hans-Walter; Van de Ven, Glenn; Bovy, Jo

    2013-08-01

    To constrain the Galactic gravitational potential near the Sun ({approx}1.5 kpc), we derive and model the spatial and velocity distributions for a sample of 9000 K-dwarfs with spectra from SDSS/SEGUE, which yield radial velocities and abundances ([Fe/H] and [{alpha}/Fe]). We first derive the spatial density distribution for three abundance-selected sub-populations of stars accounting for the survey's selection function. The vertical profiles of these sub-populations are simple exponentials and their vertical dispersion profile is nearly isothermal. To model these data, we apply the 'vertical' Jeans equation, which relates the observable tracer number density and vertical velocity dispersion to the gravitational potential or vertical force. We explore a number of functional forms for the vertical force law, fit the dispersion and density profiles of all abundance-selected sub-populations simultaneously in the same potential, and explore all parameter co-variances using a Markov Chain Monte Carlo technique. Our fits constrain a disk mass scale height {approx}< 300 pc and the total surface mass density to be 67 {+-} 6 M{sub Sun} pc{sup -2} at |z| = 1.0 kpc of which the contribution from all stars is 42 {+-} 5 M{sub Sun} pc{sup -2} (assuming a contribution from cold gas of 13 M{sub Sun} pc{sup -2}). We find significant constraints on the local dark matter density of 0.0065 {+-} 0.0023 M{sub Sun} pc{sup -3} (0.25 {+-} 0.09 GeV cm{sup -3}). Together with recent experiments this firms up the best estimate of 0.0075 {+-} 0.0021 M{sub Sun} pc{sup -3} (0.28 {+-} 0.08 GeV cm{sup -3}), consistent with global fits of approximately round dark matter halos to kinematic data in the outskirts of the Galaxy.

  17. THE BENEFITS OF VLBI ASTROMETRY TO PULSAR TIMING ARRAY SEARCHES FOR GRAVITATIONAL RADIATION

    SciTech Connect (OSTI)

    Madison, D. R.; Chatterjee, S.; Cordes, J. M.

    2013-11-10

    Precision astrometry is an integral component of successful pulsar timing campaigns. Astrometric parameters are commonly derived by fitting them as parameters of a timing model to a series of pulse times of arrival (TOAs). TOAs measured to microsecond precision over spans of several years can yield position measurements with sub-milliarcsecond precision. However, timing-based astrometry can become biased if a pulsar displays any red spin noise or a red signal produced by the stochastic gravitational wave background. We investigate how noise of different spectral types is absorbed by timing models, leading to significant estimation biases in the astrometric parameters. We find that commonly used techniques for fitting timing models in the presence of red noise (Cholesky whitening) prevent the absorption of noise into the timing model remarkably well if the time baseline of observations exceeds several years, but are inadequate for dealing with shorter pulsar data sets. Independent of timing, pulsar-optimized very long baseline interferometry (VLBI) is capable of providing position estimates precise to the sub-milliarcsecond levels needed for high-precision timing. In order to make VLBI astrometric parameters useful in pulsar timing models, the transformation between the International Celestial Reference Frame (ICRF) and the dynamical solar system ephemeris used for pulsar timing must be constrained to within a few microarcseconds. We compute a transformation between the ICRF and pulsar timing frames and quantitatively discuss how the transformation will improve in coming years. We find that incorporating VLBI astrometry into the timing models of pulsars for which only a couple of years of timing data exist will lead to more realistic assessments of red spin noise and could enhance the amplitude of gravitational wave signatures in post-fit timing residuals by factors of 20 or more.

  18. Images of gravitational and magnetic phenomena derived from two-dimensional back-projection Doppler tomography of interacting binary stars

    SciTech Connect (OSTI)

    Richards, Mercedes T.; Cocking, Alexander S.; Fisher, John G.; Conover, Marshall J. E-mail: asc5097@psu.edu

    2014-11-10

    We have used two-dimensional back-projection Doppler tomography as a tool to examine the influence of gravitational and magnetic phenomena in interacting binaries that undergo mass transfer from a magnetically active star onto a non-magnetic main-sequence star. This multitiered study of over 1300 time-resolved spectra of 13 Algol binaries involved calculations of the predicted dynamical behavior of the gravitational flow and the dynamics at the impact site, analysis of the velocity images constructed from tomography, and the influence on the tomograms of orbital inclination, systemic velocity, orbital coverage, and shadowing. The H? tomograms revealed eight sources: chromospheric emission, a gas stream along the gravitational trajectory, a star-stream impact region, a bulge of absorption or emission around the mass-gaining star, a Keplerian accretion disk, an absorption zone associated with hotter gas, a disk-stream impact region, and a hot spot where the stream strikes the edge of a disk. We described several methods used to extract the physical properties of the emission sources directly from the velocity images, including S-wave analysis, the creation of simulated velocity tomograms from hydrodynamic simulations, and the use of synthetic spectra with tomography to sequentially extract the separate sources of emission from the velocity image. In summary, the tomography images have revealed results that cannot be explained solely by gravitational effects: chromospheric emission moving with the mass-losing star, a gas stream deflected from the gravitational trajectory, and alternating behavior between stream state and disk state. Our results demonstrate that magnetic effects cannot be ignored in these interacting binaries.

  19. Positron impact excitations of hydrogen atom embedded in weakly coupled plasmas: Formation of Rydberg atoms

    SciTech Connect (OSTI)

    Rej, Pramit; Ghoshal, Arijit

    2014-09-15

    Formation of Rydberg atoms due to 1s?nlm excitations of hydrogen, for arbitrary n, l, m, by positron impact in weakly coupled plasma has been investigated using a distorted-wave theory in the momentum space. The interactions among the charged particles in the plasma have been represented by Debye-Huckel potentials. Making use of a simple variationally determined wave function for the hydrogen atom, it has been possible to obtain the distorted-wave scattering amplitude in a closed analytical form. A detailed study has been made on the effects of plasma screening on the differential and total cross sections in the energy range 20300?eV of incident positron. For the unscreened case, our results agree nicely with some of the most accurate results available in the literature. To the best of our knowledge, such a study on the differential and total cross sections for 1s?nlm inelastic positron-hydrogen collisions for arbitrary n, l, m in weakly coupled plasmas is the first reported in the literature.

  20. Resonance reactions and enhancement of weak interactions in collisions of cold molecules

    SciTech Connect (OSTI)

    Flambaum, V. V.; Ginges, J. S. M. [School of Physics, University of New South Wales, Sydney 2052 (Australia)

    2006-08-15

    With the creation of ultracold atoms and molecules, a new type of chemistry - 'resonance' chemistry - emerges: chemical reactions can occur when the energy of colliding atoms and molecules matches a bound state of the combined molecule (Feshbach resonance). This chemistry is rather similar to reactions that take place in nuclei at low energies. In this paper we suggest some problems for future experimental and theoretical work related to the resonance chemistry of ultracold molecules. Molecular Bose-Einstein condensates are particularly interesting because in this system collisions and chemical reactions are extremely sensitive to weak fields; also, a preferred reaction channel may be enhanced due to a finite number of final states. The sensitivity to weak fields arises due to the high density of narrow compound resonances and the macroscopic number of molecules with kinetic energy E=0 (in the ground state of a mean-field potential). The high sensitivity to the magnetic field may be used to measure the distribution of energy intervals, widths, and magnetic moments of compound resonances and study the onset of quantum chaos. A difference in the production rate of right-handed and left-handed chiral molecules may be produced by external electric E and magnetic B fields and the finite width {gamma} of the resonance (correlation {gamma}E{center_dot}B). The same effect may be produced by the parity-violating energy difference in chiral molecules.

  1. The Weak Charge of the Proton. A Search For Physics Beyond the Standard Model

    SciTech Connect (OSTI)

    MacEwan, Scott J.

    2015-05-01

    The Qweak experiment, which completed running in May of 2012 at Jefferson Laboratory, has measured the parity-violating asymmetry in elastic electron-proton scattering at four-momentum transfer Q2 =0.025 (GeV/c)2 in order to provide the first direct measurement of the proton's weak charge, Qpw. The Standard Model makes firm predictions for the weak charge; deviations from the predicted value would provide strong evidence of new physics beyond the Standard Model. Using an 89% polarized electron beam at 145 microA scattering from a 34.4 cm long liquid hydrogen target, scattered electrons were detected using an array of eight fused-silica detectors placed symmetric about the beam axis. The parity-violating asymmetry was then measured by reversing the helicity of the incoming electrons and measuring the normalized difference in rate seen in the detectors. The low Q2 enables a theoretically clean measurement; the higher order hadronic corrections are constrained using previous parity-violating electron scattering world data. The experimental method will be discussed, with recent results constituting 4% of our total data and projections of our proposed uncertainties on the full data set.

  2. Corrections to Morse and Ingard's variational-based treatment of weakly-nonlinear acoustics in lossless gases

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Christov, Ivan C.; Jordan, Pedro M.

    2015-07-17

    Errors in Morse and Ingard’s treatment of the topic of weakly-nonlinear acoustics in §6.2 of their book [Theoretical Acoustics (McGraw-Hill, New York, 1968)] are noted and corrected.

  3. HerMES: The rest-frame UV emission and a lensing model for the z = 6.34 luminous dusty starburst galaxy HFLS3

    SciTech Connect (OSTI)

    Cooray, Asantha; Calanog, Jae; Casey, C. M.; Ma, Brian; Osage, W. A.; Wardlow, Julie L.; Bock, J.; Bridge, C.; Burgarella, D.; Bussmann, R. S.; Clements, D.; Conley, A.; Farrah, D.; Fu, H.; Gavazzi, R.; Ivison, R. J.; La Porte, N.; Lo Faro, B.; Magdis, G.; Oliver, S. J.; and others

    2014-07-20

    We discuss the rest-frame ultraviolet emission from the starbursting galaxy HFLS3 at a redshift of 6.34. The galaxy was discovered in Herschel/SPIRE data due to its red color in the submillimeter wavelengths from 250 to 500 ?m. Keck/NIRC2 K{sub s}-band adaptive optics imaging data showed two potential near-IR counterparts near HFLS3. Previously, the northern galaxy was taken to be in the foreground at z = 2.1, while the southern galaxy was assumed to be HFLS3's near-IR counterpart. The recently acquired Hubble/WFC3 and Advanced Camera for Surveys (ACS) imaging data show conclusively that both optically bright galaxies are in the foreground at z < 6. A new lensing model based on the Hubble imaging data and the millimeter-wave continuum emission yields a magnification factor of 2.2 0.3, with a 95% confidence upper limit on the magnification of 3.5. When corrected for lensing, the instantaneous star formation rate is 1320 M{sub ?} yr{sup 1}, with the 95% confidence lower limit around 830 M{sub ?} yr{sup 1}. The dust and stellar masses of HFLS3 from the same spectral energy distribution (SED) models are at the level of 3 10{sup 8} M{sub ?} and ?5 10{sup 10} M{sub ?}, respectively, with large systematic uncertainties on assumptions related to the SED model. With Hubble/WFC3 images, we also find diffuse near-IR emission about 0.5 arcsec (?3 kpc) to the southwest of HFLS3 that remains undetected in the ACS imaging data. The emission has a photometric redshift consistent with either z ? 6 or a dusty galaxy template at z ? 2.

  4. NEW CONSTRAINTS ON THE EVOLUTION OF THE STELLAR-TO-DARK MATTER CONNECTION: A COMBINED ANALYSIS OF GALAXY-GALAXY LENSING, CLUSTERING, AND STELLAR MASS FUNCTIONS FROM z = 0.2 to z = 1

    SciTech Connect (OSTI)

    Leauthaud, Alexie; Tinker, Jeremy; Bundy, Kevin; George, Matthew R.; Behroozi, Peter S.; Wechsler, Risa H.; Busha, Michael T.; Schrabback, Tim; Massey, Richard; Rhodes, Jason; Benson, Andrew; Kneib, Jean-Paul; Ilbert, Olivier; Le Fevre, Oliver; Capak, Peter; Cortes, Marina; Koekemoer, Anton M.; Lilly, Simon; McCracken, Henry J.; Salvato, Mara; and others

    2012-01-10

    Using data from the COSMOS survey, we perform the first joint analysis of galaxy-galaxy weak lensing, galaxy spatial clustering, and galaxy number densities. Carefully accounting for sample variance and for scatter between stellar and halo mass, we model all three observables simultaneously using a novel and self-consistent theoretical framework. Our results provide strong constraints on the shape and redshift evolution of the stellar-to-halo mass relation (SHMR) from z = 0.2 to z = 1. At low stellar mass, we find that halo mass scales as M{sub h} {proportional_to}M{sup 0.46}{sub *} and that this scaling does not evolve significantly with redshift from z = 0.2 to z = 1. The slope of the SHMR rises sharply at M{sub *} > 5 Multiplication-Sign 10{sup 10} M{sub Sun} and as a consequence, the stellar mass of a central galaxy becomes a poor tracer of its parent halo mass. We show that the dark-to-stellar ratio, M{sub h} /M{sub *}, varies from low to high masses, reaching a minimum of M{sub h} /M{sub *} {approx} 27 at M{sub *} = 4.5 Multiplication-Sign 10{sup 10} M{sub Sun} and M{sub h} = 1.2 Multiplication-Sign 10{sup 12} M{sub Sun }. This minimum is important for models of galaxy formation because it marks the mass at which the accumulated stellar growth of the central galaxy has been the most efficient. We describe the SHMR at this minimum in terms of the 'pivot stellar mass', M{sup piv}{sub *}, the 'pivot halo mass', M{sup piv}{sub h}, and the 'pivot ratio', (M{sub h} /M{sub *}){sup piv}. Thanks to a homogeneous analysis of a single data set spanning a large redshift range, we report the first detection of mass downsizing trends for both M{sup piv}{sub h} and M{sup piv}{sub *}. The pivot stellar mass decreases from M{sup piv}{sub *} = 5.75 {+-} 0.13 Multiplication-Sign 10{sup 10} M{sub Sun} at z = 0.88 to M{sup piv}{sub *} = 3.55 {+-} 0.17 Multiplication-Sign 10{sup 10} M{sub Sun} at z = 0.37. Intriguingly, however, the corresponding evolution of M{sup piv}{sub h} leaves the pivot ratio constant with redshift at (M{sub h} /M{sub *}){sup piv} {approx} 27. We use simple arguments to show how this result raises the possibility that star formation quenching may ultimately depend on M{sub h} /M{sub *} and not simply on M{sub h} , as is commonly assumed. We show that simple models with such a dependence naturally lead to downsizing in the sites of star formation. Finally, we discuss the implications of our results in the context of popular quenching models, including disk instabilities and active galactic nucleus feedback.

  5. Analytical study of the propagation of acoustic waves in a 1D weakly disordered lattice

    SciTech Connect (OSTI)

    Richoux, O. Morand, E.; Simon, L.

    2009-09-15

    This paper presents an analytical approach of the propagation of an acoustic wave through a normally distributed disordered lattice made up of Helmholtz resonators connected to a cylindrical duct. This approach allows to determine analytically the exact transmission coefficient of a weakly disordered lattice. Analytical results are compared to a well-known numerical method based on a matrix product. Furthermore, this approach gives an analytical expression of the localization length apart from the Bragg stopband which depends only on the standard deviation of the normal distribution disorder. This expression permits to study on one hand the localization length as a function of both disorder strength and frequency, and on the other hand, the propagation characteristics on the edges of two sorts of stopbands (Bragg and Helmholtz stopbands). Lastly, the value of the localization length inside the Helmholtz stopband is compared to the localization length in the Bragg stopband.

  6. Electron-electron interaction, weak localization and spin valve effect in vertical-transport graphene devices

    SciTech Connect (OSTI)

    Long, Mingsheng; Gong, Youpin; Wei, Xiangfei; Zhu, Chao; Xu, Jianbao; Liu, Ping; Guo, Yufen; Li, Weiwei; Liu, Liwei; Liu, Guangtong

    2014-04-14

    We fabricated a vertical structure device, in which graphene is sandwiched between two asymmetric ferromagnetic electrodes. The measurements of electron and spin transport were performed across the combined channels containing the vertical and horizontal components. The presence of electron-electron interaction (EEI) was found not only at low temperatures but also at moderate temperatures up to ∼120 K, and EEI dominates over weak localization (WL) with and without applying magnetic fields perpendicular to the sample plane. Moreover, spin valve effect was observed when magnetic filed is swept at the direction parallel to the sample surface. We attribute the EEI and WL surviving at a relatively high temperature to the effective suppress of phonon scattering in the vertical device structure. The findings open a way for studying quantum correlation at relatively high temperature.

  7. Electron density and temperature measurement by continuum radiation emitted from weakly ionized atmospheric pressure plasmas

    SciTech Connect (OSTI)

    Park, Sanghoo; Choe, Wonho, E-mail: wchoe@kaist.ac.kr [Department of Physics, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Youn Moon, Se [High-enthalpy Plasma Research Center, Chonbuk National University, 567 Baekje-daero, Deokjin-gu, Jeonju 561-756 (Korea, Republic of); Park, Jaeyoung [5771 La Jolla Corona Drive, La Jolla, CA 92037 (United States)

    2014-02-24

    The electron-atom neutral bremsstrahlung continuum radiation emitted from weakly ionized plasmas is investigated for electron density and temperature diagnostics. The continuum spectrum in 4501000?nm emitted from the argon atmospheric pressure plasma is found to be in excellent agreement with the neutral bremsstrahlung formula with the electron-atom momentum transfer cross-section given by Popovi?. In 280450?nm, however, a large discrepancy between the measured and the neutral bremsstrahlung emissivities is observed. We find that without accounting for the radiative H{sub 2} dissociation continuum, the temperature, and density measurements would be largely wrong, so that it should be taken into account for accurate measurement.

  8. Neutron and weak-charge distributions of the 48Ca nucleus

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Hagen, Gaute; Forssen, Christian; Nazarewicz, Witold; Papenbrock, Thomas F.; Bacca, S.; Barnea, Nir; Carlsson, Boris; Drischler, Christian; Hebeler, Kai; Hjorth-Jensen, M.; et al

    2015-11-02

    What is the size of the atomic nucleus? This deceivably simple question is difficult to answer. Although the electric charge distributions in atomic nuclei were measured accurately already half a century ago, our knowledge of the distribution of neutrons is still deficient. In addition to constraining the size of atomic nuclei, the neutron distribution also impacts the number of nuclei that can exist and the size of neutron stars. We present an ab initio calculation of the neutron distribution of the neutron-rich nucleus 48Ca. We show that the neutron skin (difference between the radii of the neutron and proton distributions)more » is significantly smaller than previously thought. We also make predictions for the electric dipole polarizability and the weak form factor; both quantities that are at present targeted by precision measurements. Here, based on ab initio results for 48Ca, we provide a constraint on the size of a neutron star.« less

  9. Photo-induced strengthening of weak bonding in noble gas dimers

    SciTech Connect (OSTI)

    Miyamoto, Yoshiyuki; Miyazaki, Takehide; Rubio, Angel

    2014-05-19

    We demonstrate through extensive first-principles time-dependent density functional calculations that attractive van der Waals interaction between closed-shell atoms can be enhanced by light with constant spatial intensity. We illustrate this general phenomenon for a He dimer as a prototypical case of complex van der Waals interactions and show that when excited by light with a frequency close to the 1s → 2p He-atomic transition, an attractive force larger than 7 pN is produced. This force gain is manifested as a larger acceleration of He-He contraction under an optical field. The concerted dynamical motions of the He atoms together with polarity switching of the charge-induced dipole cause the contraction of the dimer. These findings are relevant for the photo-induced control of weakly bonded molecular species, either in gas phase or in solution.

  10. Source-plane reconstruction of the giant gravitational arc in A2667: A candidate Wolf-Rayet galaxy at z ? 1

    SciTech Connect (OSTI)

    Cao, Shuo; Zhu, Zong-Hong; Covone, Giovanni; Jullo, Eric; Richard, Johan; Izzo, Luca

    2015-01-01

    We present a new analysis of Hubble Space Telescope, Spitzer Space Telescope, and Very Large Telescope imaging and spectroscopic data of a bright lensed galaxy at z = 1.0334 in the lensing cluster A2667. Using this high-resolution imaging, we present an updated lens model that allows us to fully understand the lensing geometry and reconstruct the lensed galaxy in the source plane. This giant arc gives a unique opportunity to view the structure of a high-redshift disk galaxy. We find that the lensed galaxy of A2667 is a typical spiral galaxy with a morphology similar to the structure of its counterparts at higher redshift, z ? 2. The surface brightness of the reconstructed source galaxy in the z {sub 850} band reveals the central surface brightness I(0) = 20.28 0.22 mag arcsec{sup 2} and a characteristic radius r{sub s} = 2.01 0.16 kpc at redshift z ? 1. The morphological reconstruction in different bands shows obvious negative radial color gradients for this galaxy. Moreover, the redder central bulge tends to contain a metal-rich stellar population, rather than being heavily reddened by dust due to high and patchy obscuration. We analyze the VIMOS/integral field unit spectroscopic data and find that, in the given wavelength range (?1800-3200 ), the combined arc spectrum of the source galaxy is characterized by a strong continuum emission with strong UV absorption lines (Fe II and Mg II) and shows the features of a typical starburst Wolf-Rayet galaxy, NGC 5253. More specifically, we have measured the equivalent widths of Fe II and Mg II lines in the A2667 spectrum, and obtained similar values for the same wavelength interval of the NGC 5253 spectrum. Marginal evidence for [C III] 1909 emission at the edge of the grism range further confirms our expectation.

  11. Fermilab Today

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    South Pole Telescope: Gravitational lensing of the cosmic microwave background by galaxy clusters Photos of the Day: Bug sightings From Physics, May 20, 2015: Synopsis:...

  12. Fermilab Today | Results for the Frontiers | 2015

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    2015 South Pole Telescope: Gravitational lensing of the cosmic microwave background by galaxy clusters May 22, 2015 CMS: Two Z's or three? May 21, 2015 DZero: Measure thrice,...

  13. Determination of the weak charge of the proton through parity violating asymmetry measurements in the elastic e+p scattering

    SciTech Connect (OSTI)

    Subedi, Adesh

    2014-12-01

    The Qweak experiment has taken data to make a 2.5% measurement of parity violating elastic e+p asymmetry in the four momentum transfer region of 0.0250 (GeV/c)^2. This asymmetry is proportional to the weak charge of the proton, which is related to the weak mixing angle, sin^2(theta_W). The final Qweak measurement will provide the most precise measurement of the weak mixing angle below the Z^0 pole to test the Standard Model prediction. A description of the experimental apparatus is provided in this dissertation. The experiment was carried out using a longitudinally polarized electron beam of up to 180 microampere on a 34.5 cm long unpolarized liquid hydrogen target. The Qweak target is not only the world's highest cryogenic target ever built for a parity experiment but also is the least noisy target. This dissertation provides a detailed description of this target and presents a thorough analysis of the target performance. Statistical analysis of Run 1 data, collected between Feb - May 2011, is done to extract a blinded parity violating asymmetry of size -299.7 ± 13.4 (stat.) ± 17.2 (syst.) ± 68 (blinding) parts-per-billion. This resulted in a preliminary proton's weak charge of value 0.0865 ± 0.0085, a 9% measurement. Based on this blinded asymmetry, the weak mixing angle was determined to be sin^2(theta_W) = 0.23429 ± 0.00211.

  14. EARLY X-RAY AND OPTICAL AFTERGLOW OF GRAVITATIONAL WAVE BURSTS FROM MERGERS OF BINARY NEUTRON STARS

    SciTech Connect (OSTI)

    Zhang Bing [Kavli Institute of Astronomy and Astrophysics, Peking University, Beijing 100871 (China)

    2013-01-20

    Double neutron star mergers are strong sources of gravitational waves. The upcoming advanced gravitational wave detectors are expected to make the first detection of gravitational wave bursts (GWBs) associated with these sources. Proposed electromagnetic counterparts of a GWB include a short gamma-ray burst, an optical macronova, and a long-lasting radio afterglow. Here we suggest that at least some GWBs could be followed by an early afterglow lasting for thousands of seconds, if the post-merger product is a highly magnetized, rapidly rotating, massive neutron star rather than a black hole. This afterglow is powered by dissipation of a proto-magnetar wind. The X-ray flux is estimated to be as bright as (10{sup -8}-10{sup -7}) erg s{sup -1} cm{sup -2}. The optical flux is subject to large uncertainties but could be as bright as 17th magnitude in R band. We provide observational hints of such a scenario, and discuss the challenge and strategy to detect these signals.

  15. Sliding coherence window technique for hierarchical detection of continuous gravitational waves

    SciTech Connect (OSTI)

    Pletsch, Holger J.

    2011-06-15

    A novel hierarchical search technique is presented for all-sky surveys for continuous gravitational-wave sources, such as rapidly spinning nonaxisymmetric neutron stars. Analyzing yearlong detector data sets over realistic ranges of parameter space using fully coherent matched-filtering is computationally prohibitive. Thus more efficient, so-called hierarchical techniques are essential. Traditionally, the standard hierarchical approach consists of dividing the data into nonoverlapping segments of which each is coherently analyzed, and subsequently the matched-filter outputs from all segments are combined incoherently. The present work proposes to break the data into subsegments shorter than the desired maximum coherence time span (size of the coherence window). Then matched-filter outputs from the different subsegments are efficiently combined by sliding the coherence window in time: Subsegments whose timestamps are closer than coherence window size are combined coherently, otherwise incoherently. Compared to the standard scheme at the same coherence time baseline, data sets longer by about 50-100% would have to be analyzed to achieve the same search sensitivity as with the sliding coherence window approach. Numerical simulations attest to the analytically estimated improvement.

  16. Magnetic field mapping of the UCNTau magneto-gravitational trap: design study

    SciTech Connect (OSTI)

    Libersky, Matthew Murray

    2014-09-04

    The beta decay lifetime of the free neutron is an important input to the Standard Model of particle physics, but values measured using different methods have exhibited substantial disagreement. The UCN r experiment in development at Los Alamos National Laboratory (LANL) plans to explore better methods of measuring the neutron lifetime using ultracold neutrons (UCNs). In this experiment, UCNs are confined in a magneto-gravitational trap formed by a curved, asymmetric Halbach array placed inside a vacuum vessel and surrounded by holding field coils. If any defects present in the Halbach array are sufficient to reduce the local field near the surface below that needed to repel the desired energy level UCNs, loss by material interaction can occur at a rate similar to the loss by beta decay. A map of the magnetic field near the surface of the array is necessary to identify any such defects, but the array's curved geometry and placement in a vacuum vessel make conventional field mapping methods difficult. A system consisting of computer vision-based tracking and a rover holding a Hall probe has been designed to map the field near the surface of the array, and construction of an initial prototype has begun at LANL. The design of the system and initial results will be described here.

  17. Quantum superposition principle and gravitational collapse: Scattering times for spherical shells

    SciTech Connect (OSTI)

    Ambrus, M.; Hajicek, P.

    2005-09-15

    A quantum theory of spherically symmetric thin shells of null dust and their gravitational field is studied. In Nucl. Phys. B603, 555 (2001), it has been shown how superpositions of quantum states with different geometries can lead to a solution of the singularity problem and black hole information paradox: the shells bounce and re-expand and the evolution is unitary. The corresponding scattering times will be defined in the present paper. To this aim, a spherical mirror of radius R{sub m} is introduced. The classical formula for scattering times of the shell reflected from the mirror is extended to quantum theory. The scattering times and their spreads are calculated. They have a regular limit for R{sub m}{yields}0 and they reveal a resonance at E{sub m}=c{sup 4}R{sub m}/2G. Except for the resonance, they are roughly of the order of the time the light needs to cross the flat space distance between the observer and the mirror. Some ideas are discussed of how the construction of the quantum theory could be changed so that the scattering times become considerably longer.

  18. GRAVITATIONAL CONUNDRUM? DYNAMICAL MASS SEGREGATION VERSUS DISRUPTION OF BINARY STARS IN DENSE STELLAR SYSTEMS

    SciTech Connect (OSTI)

    De Grijs, Richard; Li, Chengyuan; Zheng, Yong; Kouwenhoven, M. B. N.; Deng, Licai; Hu, Yi; Wicker, James E.

    2013-03-01

    Upon their formation, dynamically cool (collapsing) star clusters will, within only a few million years, achieve stellar mass segregation for stars down to a few solar masses, simply because of gravitational two-body encounters. Since binary systems are, on average, more massive than single stars, one would expect them to also rapidly mass segregate dynamically. Contrary to these expectations and based on high-resolution Hubble Space Telescope observations, we show that the compact, 15-30 Myr old Large Magellanic Cloud cluster NGC 1818 exhibits tantalizing hints at the {approx}> 2{sigma} level of significance (>3{sigma} if we assume a power-law secondary-to-primary mass-ratio distribution) of an increasing fraction of F-star binary systems (with combined masses of 1.3-1.6 M {sub Sun }) with increasing distance from the cluster center, specifically between the inner 10''-20'' (approximately equivalent to the cluster's core and half-mass radii) and the outer 60''-80''. If confirmed, then this will offer support for the theoretically predicted but thus far unobserved dynamical disruption processes of the significant population of 'soft' binary systems-with relatively low binding energies compared to the kinetic energy of their stellar members-in star clusters, which we have access to here by virtue of the cluster's unique combination of youth and high stellar density.

  19. Gravitational collapse in asymptotically anti-de Sitter or de Sitter backgrounds

    SciTech Connect (OSTI)

    Madhav, T. Arun; Goswami, Rituparno; Joshi, Pankaj S.

    2005-10-15

    We study here the gravitational collapse of a matter cloud with a nonvanishing tangential pressure in the presence of a nonzero cosmological term {lambda}. It is investigated how {lambda} modifies the dynamics of the collapsing cloud and whether it affects the cosmic censorship. Conditions for bounce and singularity formation are derived. It is seen that when the tangential pressure vanishes, the bounce and singularity conditions reduce to the dust case studied earlier. The collapsing interior is matched to an exterior which is asymptotically de Sitter or anti-de Sitter, depending on the sign of the cosmological constant. The junction conditions for matching the cloud to the exterior are specified. The effect of {lambda} on apparent horizons is studied in some detail and the nature of central singularity is analyzed. The visibility of singularity and implications for the cosmic censorship conjecture are discussed. It is shown that for a nonvanishing cosmological constant, both black hole and naked singularities do form as collapse end states in spacetimes which are asymptotically de Sitter or anti-de Sitter.

  20. Storage of Ultracold Neutrons in the Magneto-Gravitational Trap of the UCN Experiment

    SciTech Connect (OSTI)

    Salvat, D. J. [Indiana University] [Indiana University; Adamek, E. R. [Indiana University] [Indiana University; Barlow, D. [Los Alamos National Laboratory (LANL)] [Los Alamos National Laboratory (LANL); Bowman, James D [ORNL] [ORNL; Broussard, L. J. [Los Alamos National Laboratory (LANL)] [Los Alamos National Laboratory (LANL); Callahan, N. B. [Indiana University] [Indiana University; Clayton, S. M. [Los Alamos National Laboratory (LANL)] [Los Alamos National Laboratory (LANL); Cude-Woods, C. [Indiana University] [Indiana University; Currie, S. [Los Alamos National Laboratory (LANL)] [Los Alamos National Laboratory (LANL); Dees, E. B. [North Carolina State University, Raleigh] [North Carolina State University, Raleigh; Fox, W. [Indiana University] [Indiana University; Geltenbort, P. [Inst Max Von Laue Paul Langevin, Grenoble, France] [Inst Max Von Laue Paul Langevin, Grenoble, France; Hickerson, K. P. [University of California, Los Angeles] [University of California, Los Angeles; Holley, A. T. [Indiana University] [Indiana University; Liu, C.-Y. [Indiana University] [Indiana University; Makela, M. [Los Alamos National Laboratory (LANL)] [Los Alamos National Laboratory (LANL); Medina, J. [Los Alamos National Laboratory (LANL)] [Los Alamos National Laboratory (LANL); Morley, D. J. [Los Alamos National Laboratory (LANL)] [Los Alamos National Laboratory (LANL); Morris, C. L. [Los Alamos National Laboratory (LANL)] [Los Alamos National Laboratory (LANL); Penttila, Seppo I [ORNL] [ORNL; Ramsey, J. [Los Alamos National Laboratory (LANL)] [Los Alamos National Laboratory (LANL); Saunders, A. [Los Alamos National Laboratory (LANL)] [Los Alamos National Laboratory (LANL); Seestrom, S. J. [Los Alamos National Laboratory (LANL)] [Los Alamos National Laboratory (LANL); Sharapov, E. I. [Joint Institute for Nuclear Research, Dubna, Russia] [Joint Institute for Nuclear Research, Dubna, Russia; Sjue, S. K. L. [Los Alamos National Laboratory (LANL)] [Los Alamos National Laboratory (LANL); Slaughter, B. A. [Indiana University] [Indiana University; Vanderwerp, J. [Indiana University] [Indiana University; VornDick, B. [North Carolina State University, Raleigh] [North Carolina State University, Raleigh; Walstrom, P. L. [Los Alamos National Laboratory (LANL)] [Los Alamos National Laboratory (LANL); Wang, Z. [Los Alamos National Laboratory (LANL)] [Los Alamos National Laboratory (LANL); Womack, T. L. [Los Alamos National Laboratory (LANL)] [Los Alamos National Laboratory (LANL); Young, A. R. [North Carolina State University, Raleigh] [North Carolina State University, Raleigh

    2014-01-01

    The UCN experiment is designed to measure the lifetime n of the free neutron by trapping ultracold neutrons (UCN) in a magneto-gravitational trap. An asymmetric bowl-shaped NdFeB magnet Halbach array confines low-field-seeking UCN within the apparatus, and a set of electromagnetic coils in a toroidal geometry provides a background holding field to eliminate depolarization-induced UCN loss caused by magnetic field nodes. We present a measurement of the storage time store of the trap by storing UCN for various times and counting the survivors. The data are consistent with a single exponential decay, and we find store = 860 19 s, within 1 of current global averages for n. The storage time with the holding field deactivated is found to be store = 470 160 s; this decreased storage time is due to the loss of UCN, which undergo Majorana spin flips while being stored. We discuss plans to increase the statistical sensitivity of the measurement and investigate potential systematic effects.

  1. BRIGHT BROADBAND AFTERGLOWS OF GRAVITATIONAL WAVE BURSTS FROM MERGERS OF BINARY NEUTRON STARS

    SciTech Connect (OSTI)

    Gao He; Ding Xuan; Wu Xuefeng; Zhang Bing; Dai Zigao E-mail: zhang@physics.unlv.edu

    2013-07-10

    If double neutron star mergers leave behind a massive magnetar rather than a black hole, then a bright early afterglow can follow the gravitational wave burst (GWB) even if there is no short gamma-ray burst (SGRB)-GWB association or if there is an association but the SGRB does not beam toward Earth. Besides directly dissipating the proto-magnetar wind, as suggested by Zhang, here we suggest that the magnetar wind could push the ejecta launched during the merger process and, under certain conditions, would reach a relativistic speed. Such a magnetar-powered ejecta, when interacting with the ambient medium, would develop a bright broadband afterglow due to synchrotron radiation. We study this physical scenario in detail and present the predicted X-ray, optical, and radio light curves for a range of magnetar and ejecta parameters. We show that the X-ray and optical light curves usually peak around the magnetar spin-down timescale ({approx}10{sup 3}-10{sup 5} s), reaching brightnesses readily detectable by wide-field X-ray and optical telescopes, and remain detectable for an extended period. The radio afterglow peaks later, but is much brighter than the case without a magnetar energy injection. Therefore, such bright broadband afterglows, if detected and combined with GWBs in the future, would be a probe of massive millisecond magnetars and stiff equations of state for nuclear matter.

  2. Cosmology without cosmic variance

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Bernstein, Gary M.; Cai, Yan -Chuan

    2011-10-01

    The growth of structures in the Universe is described by a function G that is predicted by the combination of the expansion history of the Universe and the laws of gravity within it. We examine the improvements in constraints on G that are available from the combination of a large-scale galaxy redshift survey with a weak gravitational lensing survey of background sources. We describe a new combination of such observations that in principle this yields a measure of the growth rate that is free of sample variance, i.e. the uncertainty in G can be reduced without bound by increasing themore » number of redshifts obtained within a finite survey volume. The addition of background weak lensing data to a redshift survey increases information on G by an amount equivalent to a 10-fold increase in the volume of a standard redshift-space distortion measurement - if the lensing signal can be measured to sub-per cent accuracy. This argues that a combined lensing and redshift survey over a common low-redshift volume of the Universe is a more powerful test of general relativity than an isolated redshift survey over larger volume at high redshift, especially as surveys begin to cover most of the available sky.« less

  3. Measurement of the Effective Weak Mixing Angle inpp¯→Z/γ*→e+e-Events

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Abazov, V.  M.; Abbott, B.; Acharya, B.  S.; Adams, M.; Adams, T.; Agnew, J.  P.; Alexeev, G.  D.; Alkhazov, G.; Alton, A.; Askew, A.; et al

    2015-07-22

    We present a measurement of the fundamental parameter of the standard model, the weak mixing angle sin2θℓeff which determines the relative strength of weak and electromagnetic interactions, in pp¯→Z/γ*→e+e- events at a center of mass energy of 1.96 TeV, using data corresponding to 9.7 fb-1 of integrated luminosity collected by the D0 detector at the Fermilab Tevatron. The effective weak mixing angle is extracted from the forward-backward charge asymmetry as a function of the invariant mass around the Z boson pole. The measured value of sin2θℓeff=0.23147±0.00047 is the most precise measurement from light quark interactions to date, with a precisionmore »close to the best LEP and SLD results.« less

  4. Measurement of the Effective Weak Mixing Angle inpp¯→Z/γ*→e+e-Events

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Abazov, V.  M.; Abbott, B.; Acharya, B.  S.; Adams, M.; Adams, T.; Agnew, J.  P.; Alexeev, G.  D.; Alkhazov, G.; Alton, A.; Askew, A.; et al

    2015-07-22

    We present a measurement of the fundamental parameter of the standard model, the weak mixing angle sin2θℓeff which determines the relative strength of weak and electromagnetic interactions, in pp¯→Z/γ*→e+e- events at a center of mass energy of 1.96 TeV, using data corresponding to 9.7 fb-1 of integrated luminosity collected by the D0 detector at the Fermilab Tevatron. The effective weak mixing angle is extracted from the forward-backward charge asymmetry as a function of the invariant mass around the Z boson pole. The measured value of sin2θℓeff=0.23147±0.00047 is the most precise measurement from light quark interactions to date, with a precisionmore » close to the best LEP and SLD results.« less

  5. Ultra-faint ultraviolet galaxies at z ∼ 2 behind the lensing cluster A1689: The luminosity function, dust extinction, and star formation rate density

    SciTech Connect (OSTI)

    Alavi, Anahita; Siana, Brian; Freeman, William R.; Dominguez, Alberto; Richard, Johan; Stark, Daniel P.; Robertson, Brant; Scarlata, Claudia; Teplitz, Harry I.; Rafelski, Marc; Kewley, Lisa

    2014-01-10

    We have obtained deep ultraviolet imaging of the lensing cluster A1689 with the WFC3/UVIS camera onboard the Hubble Space Telescope in the F275W (30 orbits) and F336W (4 orbits) filters. These images are used to identify z ∼ 2 star-forming galaxies via their Lyman break, in the same manner that galaxies are typically selected at z ≥ 3. Because of the unprecedented depth of the images and the large magnification provided by the lensing cluster, we detect galaxies 100× fainter than previous surveys at this redshift. After removing all multiple images, we have 58 galaxies in our sample in the range –19.5 < M {sub 1500} < –13 AB mag. Because the mass distribution of A1689 is well constrained, we are able to calculate the intrinsic sensitivity of the observations as a function of source plane position, allowing for accurate determinations of effective volume as a function of luminosity. We fit the faint-end slope of the luminosity function to be α = –1.74 ± 0.08, which is consistent with the values obtained for 2.5 < z < 6. Notably, there is no turnover in the luminosity function down to M {sub 1500} = –13 AB mag. We fit the UV spectral slopes with photometry from existing Hubble optical imaging. The observed trend of increasingly redder slopes with luminosity at higher redshifts is observed in our sample, but with redder slopes at all luminosities and average reddening of (E(B – V)) = 0.15 mag. We assume the stars in these galaxies are metal poor (0.2 Z {sub ☉}) compared to their brighter counterparts (Z {sub ☉}), resulting in bluer assumed intrinsic UV slopes and larger derived values for dust extinction. The total UV luminosity density at z ∼ 2 is 4.31{sub −0.60}{sup +0.68}×10{sup 26} erg s{sup –1} Hz{sup –1} Mpc{sup –3}, more than 70% of which is emitted by galaxies in the luminosity range of our sample. Finally, we determine the global star formation rate density from UV-selected galaxies at z ∼ 2 (assuming a constant dust extinction correction of 4.2 over all luminosities and a Kroupa initial mass function) of 0.148{sub −0.020}{sup +0.023} M {sub ☉} yr{sup –1} Mpc{sup –3}, significantly higher than previous determinations because of the additional population of fainter galaxies and the larger dust correction factors.

  6. Detection of Weakly Conserved Ancestral Mammalian RegulatorySequences by Primate Comparisons

    SciTech Connect (OSTI)

    Wang, Qian-fei; Prabhakar, Shyam; Chanan, Sumita; Cheng,Jan-Fang; Rubin, Edward M.; Boffelli, Dario

    2006-06-01

    Genomic comparisons between human and distant, non-primatemammals are commonly used to identify cis-regulatory elements based onconstrained sequence evolution. However, these methods fail to detectcryptic functional elements, which are too weakly conserved among mammalsto distinguish from nonfunctional DNA. To address this problem, weexplored the potential of deep intra-primate sequence comparisons. Wesequenced the orthologs of 558 kb of human genomic sequence, coveringmultiple loci involved in cholesterol homeostasis, in 6 nonhumanprimates. Our analysis identified 6 noncoding DNA elements displayingsignificant conservation among primates, but undetectable in more distantcomparisons. In vitro and in vivo tests revealed that at least three ofthese 6 elements have regulatory function. Notably, the mouse orthologsof these three functional human sequences had regulatory activity despitetheir lack of significant sequence conservation, indicating that they arecryptic ancestral cis-regulatory elements. These regulatory elementscould still be detected in a smaller set of three primate speciesincluding human, rhesus and marmoset. Since the human and rhesus genomesequences are already available, and the marmoset genome is activelybeing sequenced, the primate-specific conservation analysis describedhere can be applied in the near future on a whole-genome scale, tocomplement the annotation provided by more distant speciescomparisons.

  7. Weak interactions between water and clathrate-forming gases at low pressures

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Thürmer, Konrad; Yuan, Chunqing; Kimmel, Greg A.; Kay, Bruce D.; Smith, R. Scott

    2015-07-17

    Using scanning probe microscopy and temperature programed desorption we examined the interaction between water and two common clathrate-forming gases, methane and isobutane, at low temperature and low pressure. Water co-deposited with up to 10–1 mbar methane or 10–5 mbar isobutane at 140 K onto a Pt(111) substrate yielded pure crystalline ice, i.e., the exposure to up to ~ 107 gas molecules for each deposited water molecule did not have any detectable effect on the growing films. Exposing metastable, less than 2 molecular layers thick, water films to 10–5 mbar methane does not alter their morphology, suggesting that the presence ofmore » the Pt(111) surface is not a strong driver for hydrate formation. This weak water–gas interaction at low pressures is supported by our thermal desorption measurements from amorphous solid water and crystalline ice where 1 ML of methane desorbs near ~ 43 K and isobutane desorbs near ~ 100 K. As a result, similar desorption temperatures were observed for desorption from amorphous solid water.« less

  8. Extraction of weakly reductive and reductive coals with sub- and supercritical water

    SciTech Connect (OSTI)

    Bo Wu; Haoquan Hu; Shiping Huang; Yunming Fang; Xian Li; Meng Meng

    2008-11-15

    On a semi-continuous apparatus, a weakly reductive Shenfu-Dongsheng (SD) coal and a reductive Pingshuo (PS) coal were non-isothermally extracted with sub- and supercritical water to explore the differences between the two coals. The effect of the temperature on the extract formation rate, conversion, and product composition under different pressures was investigated. The extraction results of two coal samples indicate that the extract formation rate has a maximum in the studied temperature range between room temperature and 500{degree}C. The temperature corresponding to the maximum extract formation rate, changing with the pressure, is between 390 and 410{degree}C. The gas yield, extract yield, and conversion of two coals increase with the increasing pressure. In comparison to PS coal, SD coal has a low temperature corresponding to the maximum extract formation rate under the same pressure. Both coals have a main fraction of asphaltene, but SD coal has a higher fraction of oil than PS coal. The main gas components are CO{sub 2}, CH{sub 4}, and H{sub 2}. The gas from PS coal has a higher CH{sub 4} content and lower CO{sub 2} content than that from SD coal. The analysis results of the extraction residue indicated that SD coal has a low residue yield and the residue shows a large surface area and small average pore diameter compared to PS coal. 17 refs., 4 figs., 8 tabs.

  9. Validity of the Taylor hypothesis for linear kinetic waves in the weakly collisional solar wind

    SciTech Connect (OSTI)

    Howes, G. G.; Klein, K. G.; TenBarge, J. M.

    2014-07-10

    The interpretation of single-point spacecraft measurements of solar wind turbulence is complicated by the fact that the measurements are made in a frame of reference in relative motion with respect to the turbulent plasma. The Taylor hypothesisthat temporal fluctuations measured by a stationary probe in a rapidly flowing fluid are dominated by the advection of spatial structures in the fluid rest frameis often assumed to simplify the analysis. But measurements of turbulence in upcoming missions, such as Solar Probe Plus, threaten to violate the Taylor hypothesis, either due to slow flow of the plasma with respect to the spacecraft or to the dispersive nature of the plasma fluctuations at small scales. Assuming that the frequency of the turbulent fluctuations is characterized by the frequency of the linear waves supported by the plasma, we evaluate the validity of the Taylor hypothesis for the linear kinetic wave modes in the weakly collisional solar wind. The analysis predicts that a dissipation range of solar wind turbulence supported by whistler waves is likely to violate the Taylor hypothesis, while one supported by kinetic Alfvn waves is not.

  10. Weak-triplet, color-octet scalars and the CDF dijet excess

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Dobrescu, Bogdan A.; Krnjaic, Gordan Z.

    2012-04-24

    We extend the standard model to include a weak-triplet and color-octet scalar. This 'octo-triplet' field consists of three particles, two charged and one neutral, whose masses and renormalizable interactions depend only on two new parameters. The charged octo-triplet decay into a W boson and a gluon is suppressed by a loop factor and an accidental cancellation. Thus, the main decays of the charged octo-triplet may occur through higher-dimensional operators, mediated by a heavy vectorlike fermion, into quark pairs. For an octo-triplet mass below the tb¯ threshold, the decay into Wb b¯ through an off-shell top quark has a width comparablemore » to that into cs¯ or cb¯. Pair production with one octo-triplet decaying to two jets and the other decaying to a W and two soft b jets may explain the dijet-plus-W excess reported by the CDF Collaboration. The same higher-dimensional operators lead to CP violation in Bs-B¯s mixing.« less

  11. The effect of 12C + 12C rate uncertainties on the weak s-process component

    SciTech Connect (OSTI)

    Fryer, Christopher Lee; Hungerford, Aimee L; Hirschi, Raphael; Pignatari, Marco; Bennett, Michael E; Diehl, Steven; Herwig, Falk; Hillary, William; Richman, Debra; Rockefeller, Gabriel; Timmes, Frank X; Wiescher, Michael

    2010-09-10

    The contribution by massive stars (M > 15M{sub {circle_dot}}) to the weak s-process component of the solar system abundances is primarily due to the {sup 22}Ne neutron source, which is activated near the end of helium-core burning. The residual {sup 22}Ne left over from helium-core burning is then reignited during carbon burning, initiating further s-processing that modifies the isotopic distribution. This modification is sensitive to the stellar structure and the carbon burning reaction rate. Recent work on the {sup 12}C + {sup 12}C reaction suggests that resonances located within the Gamow peak may exist, causing a strong increase in the astrophysical S-factor and consequently the reaction rate. To investigate the effect of such a rate, 25M{sub {circle_dot}} stellar models with different carbon burning rates, at solar metallicity, were generated using the Geneva Stellar Evolution Code (GENEC) with nucleosynthesis post-processing calculated using the NuGrid Multi-zone Post-Processing Network code (MPPNP). A strongly enhanced rate can cause carbon burning to occur in a convective core rather than a radiative one and the convective core mixes the matter synthesized there up into the carbon shell, significantly altering the initial composition of the carbon-shell. In addition, an enhanced rate causes carbon-shell burning episodes to ignite earlier in the evolution of the star, igniting the {sup 22}Ne source at lower temperatures and reducing the neutron density.

  12. Weakly nonlinear Rayleigh-Taylor instability of a finite-thickness fluid layer

    SciTech Connect (OSTI)

    Wang, L. F. Ye, W. H. Liu, Jie; He, X. T.; Guo, H. Y.; Wu, J. F. Zhang, W. Y.

    2014-12-15

    A weakly nonlinear (WN) model has been developed for the Rayleigh-Taylor instability of a finite-thickness incompressible fluid layer (slab). We derive the coupling evolution equations for perturbations on the (upper) “linearly stable” and (lower) “linearly unstable” interfaces of the slab. Expressions of temporal evolutions of the amplitudes of the perturbation first three harmonics on the upper and lower interfaces are obtained. The classical feedthrough (interface coupling) solution obtained by Taylor [Proc. R. Soc. London A 201, 192 (1950)] is readily recovered by the first-order results. Our third-order model can depict the WN perturbation growth and the saturation of linear (exponential) growth of the perturbation fundamental mode on both interfaces. The dependence of the WN perturbation growth and the slab distortion on the normalized layer thickness (kd) is analytically investigated via the third-order solutions. Comparison is made with Jacobs-Catton's formula [J. W. Jacobs and I. Catton, J. Fluid Mech. 187, 329 (1988)] of the position of the “linearly unstable” interface. Using a reduced formula, the saturation amplitude of linear growth of the perturbation fundamental mode is studied. It is found that the finite-thickness effects play a dominant role in the WN evolution of the slab, especially when kd < 1. Thus, it should be included in applications where the interface coupling effects are important, such as inertial confinement fusion implosions and supernova explosions.

  13. Adsorption of small weak organic acids on goethite: Modeling of mechanisms

    SciTech Connect (OSTI)

    Filius, J.D.; Hiemstra, T.; Riemsdijk, W.H. Van

    1997-11-15

    The adsorption of lactate, oxalate, malonate, phthalate, and citrate has been determined experimentally as a function of concentration, pH, and ionic strength. The data have been described with the CD-MUSIC model of Hiemstra and Van Riemsdijk which allows a distribution of charge of the organic molecule over the surface and the Stern layer. Simultaneously, the concentration, pH, and salt dependency as well as the basic charging behavior of goethite could be described well. On the basis of model calculations, a distinction is made between inner and outer sphere complexation of weak organic acids by goethite. The results indicate that the affinity of the organic acids is dominated by the electrostatic attraction. The intrinsic affinity constants for the exchange reaction of surface water groups and organic acids, expressed per bond, increases with increasing number of reactive groups on the organic molecule. Ion pair formation between noncoordinated carboxylic groups of adsorbed organic acids and cations of the background electrolyte proved to be important for the salt dependency. The knowledge obtained may contribute to the interpretation of the binding of larger organic acids like fulvic and humic acids.

  14. Statistics for the Relative Detectability of Chemicals in Weak Gaseous Plumes in LWIR Hyperspectral Imagery

    SciTech Connect (OSTI)

    Metoyer, Candace N.; Walsh, Stephen J.; Tardiff, Mark F.; Chilton, Lawrence

    2008-10-30

    The detection and identification of weak gaseous plumes using thermal imaging data is complicated by many factors. These include variability due to atmosphere, ground and plume temperature, and background clutter. This paper presents an analysis of one formulation of the physics-based model that describes the at-sensor observed radiance. The motivating question for the analyses performed in this paper is as follows. Given a set of backgrounds, is there a way to predict the background over which the probability of detecting a given chemical will be the highest? Two statistics were developed to address this question. These statistics incorporate data from the long-wave infrared band to predict the background over which chemical detectability will be the highest. These statistics can be computed prior to data collection. As a preliminary exploration into the predictive ability of these statistics, analyses were performed on synthetic hyperspectral images. Each image contained one chemical (either carbon tetrachloride or ammonia) spread across six distinct background types. The statistics were used to generate predictions for the background ranks. Then, the predicted ranks were compared to the empirical ranks obtained from the analyses of the synthetic images. For the simplified images under consideration, the predicted and empirical ranks showed a promising amount of agreement. One statistic accurately predicted the best and worst background for detection in all of the images. Future work may include explorations of more complicated plume ingredients, background types, and noise structures.

  15. Weak interactions between water and clathrate-forming gases at low pressures

    SciTech Connect (OSTI)

    Thurmer, Konrad; Yuan, Chunqing; Kimmel, Gregory A.; Kay, Bruce D.; Smith, R. Scott

    2015-11-01

    Using scanning probe microscopy and temperature programed desorption we examined the interaction between water and two common clathrate-forming gases, methane and isobutane, at low temperature and low pressure. Water co-deposited with up to 10-1 mbar methane or 10-5 mbar isobutane at 140 K onto a Pt(111) substrate yielded pure crystalline ice, i.e., the exposure to up to ~107 gas molecules for each deposited water molecule did not have any detectable effect on the growing films. Exposing metastable, less than 2 molecular layers thick, water films to 10-5 mbar methane does not alter their morphology, suggesting that the presence of the Pt(111) surface is not a strong driver for hydrate formation. This weak water-gas interaction at low pressures is supported by our thermal desorption measurements from amorphous solid water and crystalline ice where 1 ML of methane desorbs near ~43 K and isobutane desorbs near ~100 K. Similar desorption temperatures were observed for desorption from amorphous solid water.

  16. Weak interactions between water and clathrate-forming gases at low pressures

    SciTech Connect (OSTI)

    Thürmer, Konrad; Yuan, Chunqing; Kimmel, Greg A.; Kay, Bruce D.; Smith, R. Scott

    2015-07-17

    Using scanning probe microscopy and temperature programed desorption we examined the interaction between water and two common clathrate-forming gases, methane and isobutane, at low temperature and low pressure. Water co-deposited with up to 10–1 mbar methane or 10–5 mbar isobutane at 140 K onto a Pt(111) substrate yielded pure crystalline ice, i.e., the exposure to up to ~ 107 gas molecules for each deposited water molecule did not have any detectable effect on the growing films. Exposing metastable, less than 2 molecular layers thick, water films to 10–5 mbar methane does not alter their morphology, suggesting that the presence of the Pt(111) surface is not a strong driver for hydrate formation. This weak water–gas interaction at low pressures is supported by our thermal desorption measurements from amorphous solid water and crystalline ice where 1 ML of methane desorbs near ~ 43 K and isobutane desorbs near ~ 100 K. As a result, similar desorption temperatures were observed for desorption from amorphous solid water.

  17. Hyperaccretion during tidal disruption events: Weakly bound debris envelopes and jets

    SciTech Connect (OSTI)

    Coughlin, Eric R.; Begelman, Mitchell C. E-mail: mitch@jila.colorado.edu

    2014-02-01

    After the destruction of the star during a tidal disruption event (TDE), the cataclysmic encounter between a star and the supermassive black hole (SMBH) of a galaxy, approximately half of the original stellar debris falls back onto the hole at a rate that can initially exceed the Eddington limit by orders of magnitude. We argue that the angular momentum of this matter is too low to allow it to attain a disk-like configuration with accretion proceeding at a mildly super-Eddington rate, the excess energy being carried away by a combination of radiative losses and radially distributed winds. Instead, we propose that the infalling gas traps accretion energy until it inflates into a weakly bound, quasi-spherical structure with gas extending nearly to the poles. We study the structure and evolution of such 'zero-Bernoulli accretion' flows as a model for the super-Eddington phase of TDEs. We argue that such flows cannot stop extremely super-Eddington accretion from occurring, and that once the envelope is maximally inflated, any excess accretion energy escapes through the poles in the form of powerful jets. We compare the predictions of our model to Swift J1644+57, the putative super-Eddington TDE, and show that it can qualitatively reproduce some of its observed features. Similar models, including self-gravity, could be applicable to gamma-ray bursts from collapsars and the growth of SMBH seeds inside quasi-stars.

  18. Dynamical theory of strongly coupled two-dimensional Coulomb fluids in the weakly degenerate quantum domain

    SciTech Connect (OSTI)

    Das, Mukunda P.; Golden, Kenneth I.; Green, Frederick

    2001-10-01

    We study the problem of dynamical response and plasma mode dispersion in strongly coupled two-dimensional Coulomb fluids (2DCFs) in the weakly degenerate quantum domain. Adapting the nonlinear response function approach of Golden and Kalman [Phys. Rev. A 19, 2112 (1979)] to the 2DCF, we construct a self-consistent approximation scheme for the calculation of the density response functions and plasma mode dispersion at long wavelengths. The basic ingredients in the construction are (i) the first kinetic equation in the Bogoliubov-Born-Green-Kirkwood-Yvon hierarchy, (ii) the velocity-average-approximation (VAA) hypothesis, (iii) the quadratic fluctuation-dissipation theorem, and (iv) the dynamical superposition approximation (DSA) closure hypothesis. The reliability of the VAA-DSA theory can be assessed by observing that the principal coupling correction to the 2D temperature-dependent Lindhard function is identified as being precisely the part of the third-frequency-moment sum-rule coefficient proportional to the potential energy.

  19. THE DETONATION MECHANISM OF THE PULSATIONALLY ASSISTED GRAVITATIONALLY CONFINED DETONATION MODEL OF Type Ia SUPERNOVAE

    SciTech Connect (OSTI)

    Jordan, G. C. IV; Graziani, C.; Weide, K.; Norris, J.; Hudson, R.; Lamb, D. Q.; Fisher, R. T.; Townsley, D. M.; Meakin, C.; Reid, L. B.

    2012-11-01

    We describe the detonation mechanism composing the 'pulsationally assisted' gravitationally confined detonation (GCD) model of Type Ia supernovae. This model is analogous to the previous GCD model reported in Jordan et al.; however, the chosen initial conditions produce a substantively different detonation mechanism, resulting from a larger energy release during the deflagration phase. The resulting final kinetic energy and {sup 56}Ni yields conform better to observational values than is the case for the 'classical' GCD models. In the present class of models, the ignition of a deflagration phase leads to a rising, burning plume of ash. The ash breaks out of the surface of the white dwarf, flows laterally around the star, and converges on the collision region at the antipodal point from where it broke out. The amount of energy released during the deflagration phase is enough to cause the star to rapidly expand, so that when the ash reaches the antipodal point, the surface density is too low to initiate a detonation. Instead, as the ash flows into the collision region (while mixing with surface fuel), the star reaches its maximally expanded state and then contracts. The stellar contraction acts to increase the density of the star, including the density in the collision region. This both raises the temperature and density of the fuel-ash mixture in the collision region and ultimately leads to thermodynamic conditions that are necessary for the Zel'dovich gradient mechanism to produce a detonation. We demonstrate feasibility of this scenario with three three-dimensional (3D), full star simulations of this model using the FLASH code. We characterized the simulations by the energy released during the deflagration phase, which ranged from 38% to 78% of the white dwarf's binding energy. We show that the necessary conditions for detonation are achieved in all three of the models.

  20. Inferring the gravitational potential of the Milky Way with a few precisely measured stars

    SciTech Connect (OSTI)

    Price-Whelan, Adrian M.; Johnston, Kathryn V.; Hendel, David; Hogg, David W.

    2014-10-10

    The dark matter halo of the Milky Way is expected to be triaxial and filled with substructure. It is hoped that streams or shells of stars produced by tidal disruption of stellar systems will provide precise measures of the gravitational potential to test these predictions. We develop a method for inferring the Galactic potential with tidal streams based on the idea that the stream stars were once close in phase space. Our method can flexibly adapt to any form for the Galactic potential: it works in phase-space rather than action-space and hence relies neither on our ability to derive actions nor on the integrability of the potential. Our model is probabilistic, with a likelihood function and priors on the parameters. The method can properly account for finite observational uncertainties and missing data dimensions. We test our method on synthetic data sets generated from N-body simulations of satellite disruption in a static, multi-component Milky Way, including a triaxial dark matter halo with observational uncertainties chosen to mimic current and near-future surveys of various stars. We find that with just eight well-measured stream stars, we can infer properties of a triaxial potential with precisions of the order of 5%-7%. Without proper motions, we obtain 10% constraints on most potential parameters and precisions around 5%-10% for recovering missing phase-space coordinates. These results are encouraging for the goal of using flexible, time-dependent potential models combined with larger data sets to unravel the detailed shape of the dark matter distribution around the Milky Way.

  1. Gravitational waves and stalled satellites from massive galaxy mergers at z ? 1

    SciTech Connect (OSTI)

    McWilliams, Sean T.; Pretorius, Frans; Ostriker, Jeremiah P.

    2014-07-10

    We present a model for merger-driven evolution of the mass function for massive galaxies and their central supermassive black holes at late times. We discuss the current observational evidence in favor of merger-driven massive galaxy evolution during this epoch, and demonstrate that the observed evolution of the mass function can be reproduced by evolving an initial mass function under the assumption of negligible star formation. We calculate the stochastic gravitational wave signal from the resulting black hole binary mergers in the low redshift universe (z ? 1) implied by this model, and find that this population has a signal-to-noise ratio 2 to 5 larger than previous estimates for pulsar timing arrays, with a (2?, 3?) lower limit within this model of h{sub c}(f = 1 yr{sup 1}) = (1.1 10{sup 15}, 6.8 10{sup 16}). The strength of this signal is sufficient to make it detectable with high probability under conservative assumptions within the next several years. A principle reason that this result is larger than previous estimates is our use of a recent recalibration of the black hole-stellar mass correlation for the brightest cluster galaxies, which increases our estimate by a factor of ?2 relative to past results. For cases where a galaxy merger fails to lead to a black hole merger, we estimate the probability for a given number of satellite black holes to remain within a massive host galaxy, and interpret the result in light of ULX observations. We find that in rare cases, wandering supermassive black holes may be bright enough to appear as ULXs.

  2. Phonons and magnetic excitation correlations in weak ferromagnetic YCrO{sub 3}

    SciTech Connect (OSTI)

    Sharma, Yogesh; Sahoo, Satyaprakash E-mail: guptaraj@iitk.ac.in Perez, William; Katiyar, Ram S. E-mail: guptaraj@iitk.ac.in; Mukherjee, Somdutta; Gupta, Rajeev E-mail: guptaraj@iitk.ac.in; Garg, Ashish; Chatterjee, Ratnamala

    2014-05-14

    Here, we report the temperature dependent Raman spectroscopic studies on orthorhombically distorted perovskite YCrO{sub 3} over a temperature range of 20–300 K. Temperature dependence of DC-magnetization measurements under field cooled and zero field cooled protocols confirmed a Néel transition at T{sub N} ∼ 142 K. Magnetization isotherms recorded at 125 K show a clear loop opening without any magnetization saturation up to 20 kOe, indicating a coexistence of antiferromagnetic (AFM) and weak ferromagnetic (WFM) phases. Estimation of exchange constants using mean-field approximation further confirm the presence of a complex magnetic phase below T{sub N}. Temperature evolution of Raman line-shape parameters of the selected modes (associated with the octahedral rotation and A(Y)-shift in the unit-cell) reveal an anomalous phonon shift near T{sub N}. An additional phonon anomaly was identified at T{sup *} ∼ 60 K, which could possibly be attributed to the change in the spin dynamics. Moreover, the positive and negative shifts in Raman frequencies between T{sub N} and T{sup *} suggest competing WFM and AFM interactions. A close match between the phonon frequency of B{sub 3g} (3)-octahedral rotation mode with the square of sublattice magnetization between T{sub N} and T{sup *} is indicative of the presence of spin-phonon coupling in multiferroic YCrO{sub 3}.

  3. Molecular Electronic Level Alignment at Weakly Coupled Organic Film/Metal Interfaces

    SciTech Connect (OSTI)

    Zhao, Jin; Feng, Min; Dougherty, Daniel B.; Sun, Hao; Petek, Hrvoje

    2014-10-28

    Electronic level alignment at interfaces of molecular materials with inorganic semiconductors and metals controls many interfacial phenomena. How the intrinsic properties of the interacting systems define the electronic structure of their interface remains one of the most important problems in molecular electronics and nanotechnology that can be solved through a combination of surface science experimental techniques and theoretical modeling. In this article, we address this fundamental problem through experimental and computational studies of molecular electronic level alignment of thin films of C6F6 on noble metal surfaces. The unoccupied electronic structure of C6F6 is characterized with single molecule resolution using low-temperature scanning tunneling microscopy-based constant-current distance-voltage spectroscopy. The experiments are performed on several noble metal surfaces with different work functions and distinct surface-normal projected band structures. In parallel, the electronic structures of the quantum wells (QWs) formed by the lowest unoccupied molecular orbital state of the C6F6 monolayer and multilayer films and their alignment with respect to the vacuum level of the metallic substrates are calculated by solving the Schrdinger equation for a semiempirical one-dimensional (1D) potential of the combined system using input from density functional theory. Our analysis shows that the level alignment for C6F6 molecules bound through weak van der Waals interactions to noble metal surfaces is primarily defined by the image potential of metal, the electron affinity of the molecule, and the molecule surface distance. We expect the same factors to determine the interfacial electronic structure for a broad range of molecule/metal interfaces.

  4. Van Allen Probes observation and modeling of chorus excitation and propagation during weak geomagnetic activities

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    He, Yihua; Xiao, Fuliang; Zhou, Qinghua; Yang, Chang; Liu, Si; Baker, D. N.; Kletzing, C. A.; Kurth, W. S.; Hospodarsky, G. B.; Spence, H. E.; et al

    2015-08-20

    We report correlated data on nightside chorus waves and energetic electrons during two small storm periods: 1 November 2012 (Dst ≈ –45) and 14 January 2013 (Dst ≈ –18). The Van Allen Probes simultaneously observed strong chorus waves at locations L = 5.8 – 6.3, with a lower frequency band 0.1–0.5fce and a peak spectral density ~10–4 nT2/Hz. In the same period, the fluxes and anisotropy of energetic (~10–300 keV) electrons were greatly enhanced in the interval of large negative interplanetary magnetic field Bz. Using a bi-Maxwellian distribution to model the observed electron distribution, we perform ray tracing simulations tomore » show that nightside chorus waves are indeed produced by the observed electron distribution with a peak growth for a field-aligned propagation approximately between 0.3fce and 0.4fce, at latitude <7°. Moreover, chorus waves launched with initial normal angles either θ < 90° or > 90° propagate along the field either northward or southward and then bounce back either away from Earth for a lower frequency or toward Earth for higher frequencies. The current results indicate that nightside chorus waves can be excited even during weak geomagnetic activities in cases of continuous injection associated with negative Bz. Furthermore, we examine a dayside event during a small storm C on 8 May 2014 (Dst ≈ –45) and find that the observed anisotropic energetic electron distributions potentially contribute to the generation of dayside chorus waves, but this requires more thorough studies in the future.« less

  5. Stabilization of weak ferromagnetism by strong magnetic response to epitaxial strain in multiferroic BiFeO3

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Cooper, Valentino R.; Lee, Jun Hee; Krogel, Jaron T.; Okamoto, Satoshi; Dixit, Hemant M.

    2015-08-06

    Multiferroic BiFeO3 exhibits excellent magnetoelectric coupling critical for magnetic information processing with minimal power consumption. Thus, the degenerate nature of the easy spin axis in the (111) plane presents roadblocks for real world applications. Here, we explore the stabilization and switchability of the weak ferromagnetic moments under applied epitaxial strain using a combination of first-principles calculations and group-theoretic analyses. We demonstrate that the antiferromagnetic moment vector can be stabilized along unique crystallographic directions ([110] and [-110]) under compressive and tensile strains. A direct coupling between the anisotropic antiferrodistortive rotations and Dzyaloshinskii-Moria interactions drives the stabilization of weak ferromagnetism. Furthermore, energeticallymore » competing C- and G-type magnetic orderings are observed at high compressive strains, suggesting that it may be possible to switch the weak ferromagnetism on and off under application of strain. These findings emphasize the importance of strain and antiferrodistortive rotations as routes to enhancing induced weak ferromagnetism in multiferroic oxides.« less

  6. Angular momentum exchange by gravitational torques and infall in the circumbinary disk of the protostellar system L1551 NE

    SciTech Connect (OSTI)

    Takakuwa, Shigehisa; Ho, Paul T. P. [Academia Sinica Institute of Astronomy and Astrophysics, P.O. Box 23-141, Taipei 10617, Taiwan (China); Saito, Masao [Joint ALMA Observatory, Ave. Alonso de Cordova 3107, Vitacura, Santiago (Chile); Saigo, Kazuya [ALMA Project Office, National Astronomical Observatory of Japan, Osawa 2-21-1, Mitaka, Tokyo 181-8588 (Japan); Matsumoto, Tomoaki [Faculty of Humanity and Environment, Hosei University, Chiyoda-ku, Tokyo 102-8160 (Japan); Lim, Jeremy [Department of Physics, University of Hong Kong, Pokfulam Road (Hong Kong); Hanawa, Tomoyuki, E-mail: takakuwa@asiaa.sinica.edu.tw [Center for Frontier Science, Chiba University, Inage-ku, Chiba 263-8522 (Japan)

    2014-11-20

    We report an ALMA observation of the Class I binary protostellar system L1551 NE in the 0.9 mm continuum, C{sup 18}O (3-2), and {sup 13}CO (3-2) lines at a ?1.6 times higher resolution and a ?6 times higher sensitivity than those of our previous SubMillimeter Array (SMA) observations, which revealed a r ? 300 AU scale circumbinary disk in Keplerian rotation. The 0.9 mm continuum shows two opposing U-shaped brightenings in the circumbinary disk and exhibits a depression between the circumbinary disk and the circumstellar disk of the primary protostar. The molecular lines trace non-axisymmetric deviations from Keplerian rotation in the circumbinary disk at higher velocities relative to the systemic velocity, where our previous SMA observations could not detect the lines. In addition, we detect inward motion along the minor axis of the circumbinary disk. To explain the newly observed features, we performed a numerical simulation of gas orbits in a Roche potential tailored to the inferred properties of L1551 NE. The observed U-shaped dust features coincide with locations where gravitational torques from the central binary system are predicted to impart angular momentum to the circumbinary disk, producing shocks and hence density enhancements seen as a pair of spiral arms. The observed inward gas motion coincides with locations where angular momentum is predicted to be lowered by the gravitational torques. The good agreement between our observation and model indicates that gravitational torques from the binary stars constitute the primary driver for exchanging angular momentum so as to permit infall through the circumbinary disk of L1551 NE.

  7. SEARCH FOR GRAVITATIONAL WAVES ASSOCIATED WITH GAMMA-RAY BURSTS DURING LIGO SCIENCE RUN 6 AND VIRGO SCIENCE RUNS 2 AND 3

    SciTech Connect (OSTI)

    Abadie, J.; Abbott, B. P.; Abbott, R.; Adhikari, R. X.; Ajith, P.; Anderson, S. B.; Arai, K.; Abbott, T. D.; Abernathy, M.; Accadia, T.; Adams, C.; Affeldt, C.; Allen, B.; Agathos, M.; Agatsuma, K.; Ceron, E. Amador; Anderson, W. G.; Amariutei, D.; Arain, M. A.; Collaboration: LIGO Scientific Collaboration; Virgo Collaboration; and others

    2012-11-20

    We present the results of a search for gravitational waves associated with 154 gamma-ray bursts (GRBs) that were detected by satellite-based gamma-ray experiments in 2009-2010, during the sixth LIGO science run and the second and third Virgo science runs. We perform two distinct searches: a modeled search for coalescences of either two neutron stars or a neutron star and black hole, and a search for generic, unmodeled gravitational-wave bursts. We find no evidence for gravitational-wave counterparts, either with any individual GRB in this sample or with the population as a whole. For all GRBs we place lower bounds on the distance to the progenitor, under the optimistic assumption of a gravitational-wave emission energy of 10{sup -2} M {sub Sun} c {sup 2} at 150 Hz, with a median limit of 17 Mpc. For short-hard GRBs we place exclusion distances on binary neutron star and neutron-star-black-hole progenitors, using astrophysically motivated priors on the source parameters, with median values of 16 Mpc and 28 Mpc, respectively. These distance limits, while significantly larger than for a search that is not aided by GRB satellite observations, are not large enough to expect a coincidence with a GRB. However, projecting these exclusions to the sensitivities of Advanced LIGO and Virgo, which should begin operation in 2015, we find that the detection of gravitational waves associated with GRBs will become quite possible.

  8. A study of cooling time reduction of interferometric cryogenic gravitational wave detectors using a high-emissivity coating

    SciTech Connect (OSTI)

    Sakakibara, Y.; Yamamoto, K.; Chen, D.; Tokoku, C.; Uchiyama, T.; Ohashi, M.; Kuroda, K.; Kimura, N.; Suzuki, T.; Koike, S.

    2014-01-29

    In interferometric cryogenic gravitational wave detectors, there are plans to cool mirrors and their suspension systems (payloads) in order to reduce thermal noise, that is, one of the fundamental noise sources. Because of the large payload masses (several hundred kg in total) and their thermal isolation, a cooling time of several months is required. Our calculation shows that a high-emissivity coating (e.g. a diamond-like carbon (DLC) coating) can reduce the cooling time effectively by enhancing radiation heat transfer. Here, we have experimentally verified the effect of the DLC coating on the reduction of the cooling time.

  9. Astrophysical Gyrokinetics: Kinetic and Fluid Turbulent Cascades In Magentized Weakly Collisional Plasmas

    SciTech Connect (OSTI)

    Schekochihin, A. A.; Cowley, S. C.; Dorland, W.; Hammett, G. W.; Howes, G. G.; Quataert, E.; Tatsuno, T.

    2009-04-23

    This paper presents a theoretical framework for understanding plasma turbulence in astrophysical plasmas. It is motivated by observations of electromagnetic and density fluctuations in the solar wind, interstellar medium and galaxy clusters, as well as by models of particle heating in accretion disks. All of these plasmas and many others have turbulentmotions at weakly collisional and collisionless scales. The paper focuses on turbulence in a strong mean magnetic field. The key assumptions are that the turbulent fluctuations are small compared to the mean field, spatially anisotropic with respect to it and that their frequency is low compared to the ion cyclotron frequency. The turbulence is assumed to be forced at some system-specific outer scale. The energy injected at this scale has to be dissipated into heat, which ultimately cannot be accomplished without collisions. A kinetic cascade develops that brings the energy to collisional scales both in space and velocity. The nature of the kinetic cascade in various scale ranges depends on the physics of plasma fluctuations that exist there. There are four special scales that separate physically distinct regimes: the electron and ion gyroscales, the mean free path and the electron diffusion scale. In each of the scale ranges separated by these scales, the fully kinetic problem is systematically reduced to a more physically transparent and computationally tractable system of equations, which are derived in a rigorous way. In the "inertial range" above the ion gyroscale, the kinetic cascade separates into two parts: a cascade of Alfvenic fluctuations and a passive cascade of density and magnetic-fieldstrength fluctuations. The former are governed by the Reduced Magnetohydrodynamic (RMHD) equations at both the collisional and collisionless scales; the latter obey a linear kinetic equation along the (moving) field lines associated with the Alfvenic component (in the collisional limit, these compressive fluctuations become the slow and entropy modes of the conventional MHD). In the "dissipation range" below ion gyroscale, there are again two cascades: the kinetic-Alfven-wave (KAW) cascade governed by two fluid-like Electron Reduced Magnetohydrodynamic (ERMHD) equations and a passive cascade of ion entropy fluctuations both in space and velocity. The latter cascade brings the energy of the inertial-range fluctuations that was Landau-damped at the ion gyroscale to collisional scales in the phase space and leads to ion heating. The KAWenergy is similarly damped at the electron gyroscale and converted into electron heat. Kolmogorov-style scaling relations are derived for all of these cascades. The relationship between the theoretical models proposed in this paper and astrophysical applications and observations is discussed in detail.

  10. GRAVITATIONAL WAVES FROM MASSIVE MAGNETARS FORMED IN BINARY NEUTRON STAR MERGERS

    SciTech Connect (OSTI)

    Dall'Osso, Simone [Theoretical Astrophysics, University of Tbingen, auf der Morgenstelle 10 D-72076 (Germany); Giacomazzo, Bruno [Physics Department, University of Trento, via Sommarive 14, I-38123 Trento (Italy); Perna, Rosalba [Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794 (United States); Stella, Luigi, E-mail: simone.dallosso@uni-tuebingen.de [INAF-Osservatorio Astronomico di Roma, via di Frascati 33, I-00040 Monteporzio Catone, Roma (Italy)

    2015-01-01

    Binary neutron star (NS) mergers are among the most promising sources of gravitational waves (GWs), as well as candidate progenitors for short gamma-ray bursts (SGRBs). Depending on the total initial mass of the system and the NS equation of state (EOS), the post-merger phase can be characterized by a prompt collapse to a black hole or by the formation of a supramassive NS, or even a stable NS. In the latter cases of post-merger NS (PMNS) formation, magnetic field amplification during the merger will produce a magnetar and induce a mass quadrupole moment in the newly formed NS. If the timescale for orthogonalization of the magnetic symmetry axis with the spin axis is smaller than the spindown time, the NS will radiate its spin down energy primarily via GWs. Here we study this scenario for the various outcomes of NS formation: we generalize the set of equilibrium states for a twisted torus magnetic configuration to include solutions that, for the same external dipolar field, carry a larger magnetic energy reservoir; we hence compute the magnetic ellipticity for such configurations, and the corresponding strength of the expected GW signal as a function of the relative magnitude of the dipolar and toroidal field components. The relative number of GW detections from PMNSs and from binary NSs is a very strong function of the NS EOS, being higher (?1%) for the stiffest EOSs and negligibly small for the softest ones. For intermediate-stiffness EOSs, such as the n = 4/7 polytrope recently used by Giacomazzo and Perna or the GM1 used by Lasky etal., the relative fraction is ?0.3%; correspondingly, we estimate a GW detection rate from stable PMNSs of ?0.1-1yr{sup 1} with advanced detectors, and of ?100-1000yr{sup 1} with detectors of third generation such as the Einstein Telescope. Measurement of such GW signals would provide constraints on the NS EOS and, in connection with an SGRB, on the nature of the binary progenitors giving rise to these events.

  11. SPECTROSCOPIC REDSHIFTS OF GALAXIES WITHIN THE FRONTIER FIELDS

    SciTech Connect (OSTI)

    Ebeling, Harald; Ma, Cheng-Jiun; Barrett, Elizabeth

    2014-04-01

    We present a catalog of 1921 spectroscopic redshifts measured in the fields of the massive galaxy clusters MACSJ0416.12403 (z = 0.397), MACSJ0717.5+3745 (z = 0.546), and MACSJ1149.5+2223 (z = 0.544), i.e., three of the four clusters selected by Space Telescope Science Institute as the targets of the Frontier Fields (FFs) initiative for studies of the distant Universe via gravitational lensing. Compiled in the course of the Massive Cluster Survey project (MACS) that detected the FF clusters, this catalog is provided to the community for three purposes: (1) to allow the identification of cluster members for studies of the galaxy population of these extreme systems, (2) to facilitate the removal of unlensed galaxies and thus reduce shear dilution in weak-lensing analyses, and (3) to improve the calibration of photometric redshifts based on both ground- and spacebased observations of the FF clusters.

  12. MSM Self-Energies at Finite Temperature in the Presence of Weak Magnetic Fields: Towards a Full Symmetry Restoration Study

    SciTech Connect (OSTI)

    Tejeda-Yeomans, Maria Elena; Navarro, Jorge; Sanchez, Angel; Piccinelli, Gabriella

    2008-07-02

    The study of the universe's primordial plasma at high temperature plays an important role when tackling different questions in cosmology, such as the origin of the matter-antimatter asymmetry. In the Minimal Standard Model (MSM) neither the amount of CP violation nor the strength of the phase transition are enough to produce and preserve baryon number during the Electroweak Phase Transition (EWPT), which are two of the three ingredients needed to develop baryon asymmetry. In this talk we present the first part of the analysis done within a scenario where it is viable to have improvements to the aforementioned situation: we work with the degrees of freedom in the broken symmetry phase of the MSM and analyze the development of the EWPT in the presence of a weak magnetic field. More specifically, we calculate the particle self-energies that include the effects of the weak magnetic field, needed for the MSM effective potential up to ring diagrams.

  13. Collisions induced by halo and weakly bound nuclei around the Coulomb barrier: Results at INFN-LNS Catania

    SciTech Connect (OSTI)

    Figuera, Pierpaolo

    2012-10-20

    The study of collisions around the Coulomb barrier induced by halo and/or weakly bound nuclei has been the object of many publications in the last years, since the peculiar structure of such nuclei can strongly affect the reaction dynamics. In this paper we will summarize some results on the above topic obtained by our group at INFN-LNS Catania. Results concerning the study of elastic scattering and different reaction mechanisms in collisions induced by the halo nuclei {sup 11}Be and {sup 6}He and by the weakly bound stable nuclei {sup 6,7}Li on a {sup 64}Zn target, at energies around the Coulomb barrier, will be presented. The conclusions of our studies will be compared with the ones of other authors, in order to show if clear systematic conclusions can be drawn from the different papers published in the literature so far.

  14. Energy dependence of the optical potential of weakly and tightly bound nuclei as projectiles on a medium-mass target

    SciTech Connect (OSTI)

    Figueira, J. M.; Arazi, A.; Carnelli, P.; Heimann, D. Martinez; Negri, A. E.; Pacheco, A. J.; Niello, J. O. Fernandez; Capurro, O. A.; Fimiani, L.; Marti, G. V.; Lubian, J.; Monteiro, D. S.; Gomes, P. R. S.

    2010-02-15

    Angular distributions for the elastic scattering of the weakly bound {sup 6,7}Li+{sup 144}Sm systems were measured with high accuracy at bombarding energies from 85% up to 170% of the Coulomb barrier. An optical model analysis was performed, and the relevant parameters of the real and imaginary parts of the optical potential were extracted. The results are compared with those previously published for the tightly bound {sup 12}C+{sup 144}Sm and {sup 16}O+{sup 144}Sm systems. The usual threshold anomaly observed in the behavior of the potential of tightly bound systems was not observed for either weakly bound system. This absence is attributed to the repulsion due to breakup coupling which cancels the attraction arising from couplings with bound channels.

  15. Application of asymptotic expansions for maximum likelihood estimators errors to gravitational waves from binary mergers: The single interferometer case

    SciTech Connect (OSTI)

    Zanolin, M.; Vitale, S.; Makris, N.

    2010-06-15

    In this paper we apply to gravitational waves (GW) from the inspiral phase of binary systems a recently derived frequentist methodology to calculate analytically the error for a maximum likelihood estimate of physical parameters. We use expansions of the covariance and the bias of a maximum likelihood estimate in terms of inverse powers of the signal-to-noise ration (SNR)s where the square root of the first order in the covariance expansion is the Cramer Rao lower bound (CRLB). We evaluate the expansions, for the first time, for GW signals in noises of GW interferometers. The examples are limited to a single, optimally oriented, interferometer. We also compare the error estimates using the first two orders of the expansions with existing numerical Monte Carlo simulations. The first two orders of the covariance allow us to get error predictions closer to what is observed in numerical simulations than the CRLB. The methodology also predicts a necessary SNR to approximate the error with the CRLB and provides new insight on the relationship between waveform properties, SNR, dimension of the parameter space and estimation errors. For example the timing match filtering can achieve the CRLB only if the SNR is larger than the Kurtosis of the gravitational wave spectrum and the necessary SNR is much larger if other physical parameters are also unknown.

  16. A coherent method for the detection and parameter estimation of continuous gravitational wave signals using a pulsar timing array

    SciTech Connect (OSTI)

    Wang, Yan; Mohanty, Soumya D.; Jenet, Fredrick A. [Department of Physics and Astronomy, University of Texas at Brownsville, 1 West University Boulevard, Brownsville, TX 78520 (United States)

    2014-11-01

    The use of a high precision pulsar timing array is a promising approach to detecting gravitational waves in the very low frequency regime (10{sup 6}-10{sup 9} Hz) that is complementary to ground-based efforts (e.g., LIGO, Virgo) at high frequencies (?10-10{sup 3} Hz) and space-based ones (e.g., LISA) at low frequencies (10{sup 4}-10{sup 1} Hz). One of the target sources for pulsar timing arrays is individual supermassive black hole binaries which are expected to form in galactic mergers. In this paper, a likelihood-based method for detection and parameter estimation is presented for a monochromatic continuous gravitational wave signal emitted by such a source. The so-called pulsar terms in the signal that arise due to the breakdown of the long-wavelength approximation are explicitly taken into account in this method. In addition, the method accounts for equality and inequality constraints involved in the semi-analytical maximization of the likelihood over a subset of the parameters. The remaining parameters are maximized over numerically using Particle Swarm Optimization. Thus, the method presented here solves the monochromatic continuous wave detection and parameter estimation problem without invoking some of the approximations that have been used in earlier studies.

  17. Weak links and critical current anisotropy in melt-textured HTSC ceramics studied by magneto-optical express control

    SciTech Connect (OSTI)

    Belyaeva, A.I.; Eremenko, V.V.; Nastenko, V.A.

    1997-06-01

    YBa{sub 2}Cu{sub 3}O{sub 7{minus}x} ceramics were prepared by the modified melt textured process on the polycrystalline substrate of the YBaCuO{sub 5} composition. Magneto-optical technique with the ferrogarnet films as sensor was used for visualization of magnetic flux distribution and their evaluation under remagnetization of specimens. The pictures of weak links visualized by the magneto-optical technique were correlated with the sample macro- and microstructure, studied by X-ray topography electron (SEM) and polarization fight microscopy. The role of different details of the structural peculiarities of the specimens in the weak links formation was analyzed and the problem of critical current anisotropy was reviewed. The weak links behavior under the magnetic field variation was studied in the details. The pinning centers, weak links, its dependence upon the (211) concentration, the particle size as well as its role in J{sub c} value formation were discussed. Experimental values of the critical current density varied from 2 10{sup 4} up to (5{divided_by}8) 10{sup 5} A cm{sup {minus}2} for the regions of specimen with the different structures. The authors report the first real time direct magneto-optic images of the isotropic magnetic flux distribution in the area of the sample which initially was substrate 211. The principal possibility of their modified method for obtaining highly textured isotropic Y-Ba-Cu-O ceramics capable of carrying current density up to 10{sup 6} A cm{sup {minus}2} was discussed.

  18. Applications of exact linearization techniques for steady-state stability enhancement in a weak ac/dc system

    SciTech Connect (OSTI)

    Kaprielian, S.; Clements, K. ); Turi, J. )

    1992-05-01

    A nonlinear control strategy to improve the steady-state stability of a weak AC/DC power system is presented. The approach described in this paper is based on the extension of feedback linearization techniques to nonlinear descriptor system models. This method produces a nonlinear control strategy which is capable of enhancing system performance for various system operating conditions. This claim is supported with simulation results.

  19. Magnification bias as a novel probe for primordial magnetic fields

    SciTech Connect (OSTI)

    Camera, S.; Fedeli, C.; Moscardini, L. E-mail: cosimo.fedeli@oabo.inaf.it

    2014-03-01

    In this paper we investigate magnetic fields generated in the early Universe. These fields are important candidates at explaining the origin of astrophysical magnetism observed in galaxies and galaxy clusters, whose genesis is still by and large unclear. Compared to the standard inflationary power spectrum, intermediate to small scales would experience further substantial matter clustering, were a cosmological magnetic field present prior to recombination. As a consequence, the bias and redshift distribution of galaxies would also be modified. Hitherto, primordial magnetic fields (PMFs) have been tested and constrained with a number of cosmological observables, e.g. the cosmic microwave background radiation, galaxy clustering and, more recently, weak gravitational lensing. Here, we explore the constraining potential of the density fluctuation bias induced by gravitational lensing magnification onto the galaxy-galaxy angular power spectrum. Such an effect is known as magnification bias. Compared to the usual galaxy clustering approach, magnification bias helps in lifting the pathological degeneracy present amongst power spectrum normalisation and galaxy bias. This is because magnification bias cross-correlates galaxy number density fluctuations of nearby objects with weak lensing distortions of high-redshift sources. Thus, it takes advantage of the gravitational deflection of light, which is insensitive to galaxy bias but powerful in constraining the density fluctuation amplitude. To scrutinise the potentiality of this method, we adopt a deep and wide-field spectroscopic galaxy survey. We show that magnification bias does contain important information on primordial magnetism, which will be useful in combination with galaxy clustering and shear. We find we shall be able to rule out at 95.4% CL amplitudes of PMFs larger than 5 × 10{sup −4} nG for values of the PMF power spectral index n{sub B} ∼ 0.

  20. Beam Normal Single Spin Asymmetry in Forward Angle Inelastic Electron-Proton Scattering using the Q-Weak Apparatus

    SciTech Connect (OSTI)

    Nuruzzaman, nfn

    2014-12-01

    The Q-weak experiment in Hall-C at the Thomas Jefferson National Accelerator Facility has made the first direct measurement of the weak charge of the proton through the precision measurement of the parity-violating asymmetry in elastic electron-proton scattering at low momentum transfer. There is also a parity conserving Beam Normal Single Spin Asymmetry or transverse asymmetry (B_n) on H_2 with a sin(phi)-like dependence due to two-photon exchange. If the size of elastic B_n is a few ppm, then a few percent residual transverse polarization in the beam, combined with small broken azimuthal symmetries in the detector, would require a few ppb correction to the Q-weak data. As part of a program of B_n background studies, we made the first measurement of B_n in the N-to-Delta(1232) transition using the Q-weak apparatus. The final transverse asymmetry, corrected for backgrounds and beam polarization, was found to be B_n = 42.82 ± 2.45 (stat) ± 16.07 (sys) ppm at beam energy E_beam = 1.155 GeV, scattering angle theta = 8.3 deg, and missing mass W = 1.2 GeV. B_n from electron-nucleon scattering is a unique tool to study the gamma^* Delta Delta form factors, and this measurement will help to improve the theoretical models on beam normal single spin asymmetry and thereby our understanding of the doubly virtual Compton scattering process. To help correct false asymmetries from beam noise, a beam modulation system was implemented to induce small position, angle, and energy changes at the target to characterize detector response to the beam jitter. Two air-core dipoles separated by ~10 m were pulsed at a time to produce position and angle changes at the target, for virtually any tune of the beamline. The beam energy was modulated using an SRF cavity. The hardware and associated control instrumentation will be described in this dissertation. Preliminary detector sensitivities were extracted which helped to reduce the width of the measured asymmetry. The beam modulation system has also proven valuable for tracking changes in the beamline optics, such as dispersion at the target.

  1. PROSPECTS FOR JOINT GRAVITATIONAL-WAVE AND ELECTROMAGNETIC OBSERVATIONS OF NEUTRON-STAR-BLACK-HOLE COALESCING BINARIES

    SciTech Connect (OSTI)

    Pannarale, Francesco; Ohme, Frank E-mail: frank.ohme@ligo.org

    2014-08-10

    Coalescing neutron-star-black-hole (NS-BH) binaries are a promising source of gravitational-wave (GW) signals detectable with large-scale laser interferometers such as the Advanced Laser Interferometer Gravitational-Wave Observatory and Virgo. They are also one of the main short gamma-ray burst (SGRB) progenitor candidates. If the black hole (BH) tidally disrupts its companion, an SGRB may be ignited when a sufficiently massive accretion disk forms around the remnant BH. Detecting an NS-BH coalescence both in the GW and electromagnetic (EM) spectrum offers a wealth of information about the nature of the source. How much can actually be inferred from a joint detection is unclear, however, as a mass/spin degeneracy may reduce the GW measurement accuracy. To shed light on this problem and on the potential of joint EM+GW observations, we here combine recent semi-analytical predictions for the remnant disk mass with estimates of the parameter-space portion that is selected by a GW detection. We identify cases in which an SGRB ignition is supported, others in which it can be excluded, and finally others in which the outcome depends on the chosen model for the currently unknown NS equation of state. We pinpoint a range of systems that would allow us to place lower bounds on the equation of state stiffness if both the GW emission and its EM counterpart are observed. The methods we develop can broaden the scope of existing GW detection and parameter-estimation algorithms and could allow us to disregard about half of the templates in an NS-BH search following an SGRB trigger, increasing its speed and sensitivity.

  2. Effect of the radio frequency discharge on the dust charging process in a weakly collisional and fully ionized plasma

    SciTech Connect (OSTI)

    Motie, Iman; Bokaeeyan, Mahyar

    2015-02-15

    A close analysis of dust charging process in the presence of radio frequency (RF) discharge on low pressure and fully ionized plasma for both weak and strong discharge's electric field is considered. When the electromagnetic waves pass throughout fully ionized plasma, the collision frequency of the plasma is derived. Moreover, the disturbed distribution function of plasma particles in the presence of the RF discharge is obtained. In this article, by using the Krook model, we separate the distribution function in two parts, the Maxwellian part and the perturbed part. The perturbed part of distribution can make an extra current, so-called the accretion rate of electron (or ion) current, towards a dust particle as a function of the average electron-ion collision frequency. It is proven that when the potential of dust grains increases, the accretion rate of electron current experiences an exponential reduction. Furthermore, the accretion rate of electron current for a strong electric field is relatively smaller than that for a weak electric field. The reasons are elaborated.

  3. Diamonds in the rough: a strong case for the inclusion of weak-intensity X-ray diffraction data

    SciTech Connect (OSTI)

    Wang, Jimin; Wing, Richard A.

    2014-05-01

    Here, new evidence is provided to show that the inclusion of weak-intensity, high-resolution X-ray diffraction data helps to improve the quality of experimental phases by imposing proper constraints on electron-density models during noncrystallographic symmetry averaging. Overwhelming evidence exists to show that the inclusion of weak-intensity, high-resolution X-ray diffraction data helps improve the refinement of atomic models by imposing strong constraints on individual and overall temperature B factors and thus the quality of crystal structures. Some researchers consider these data to be of little value and opt to discard them during data processing, particularly at medium and low resolution, at which individual B factors of atomic models cannot be refined. Here, new evidence is provided to show that the inclusion of these data helps to improve the quality of experimental phases by imposing proper constraints on electron-density models during noncrystallographic symmetry (NCS) averaging. Using electron-density correlation coefficients as criteria, the resolution of data has successfully been extended from 3.1 to 2.5 Å resolution with redundancy-independent merging R factors from below 100% to about 310%. It is further demonstrated that phase information can be fully extracted from observed amplitudes through de novo NCS averaging. Averaging starts with uniform density inside double-shelled spherical masks and NCS matrices that are derived from bound heavy-atom clusters at the vertices of cuboctahedrally symmetric protein particles.

  4. Characterization of a novel weak interaction between MUC1 and Src-SH3 using nuclear magnetic resonance spectroscopy

    SciTech Connect (OSTI)

    Gunasekara, Nirosha; Sykes, Brian; Hugh, Judith

    2012-05-18

    Highlights: Black-Right-Pointing-Pointer MUC1 binds the Src-SH3 domain potentially triggering Src dependent cell migration. Black-Right-Pointing-Pointer NMR Spectroscopy was used to monitor MUC1-CD and Src SH3 domain titrations. Black-Right-Pointing-Pointer MUC1-CD peptides bind with a low affinity (K{sub d} of 2-3 mM) to a non-canonical site. Black-Right-Pointing-Pointer Weak interactions may mediate dynamic processes like migration. Black-Right-Pointing-Pointer The MUC1-CD and Src-SH3 interaction may be a prime target to inhibit cell migration. -- Abstract: Breast cancer causes death through cancer cell migration and subsequent metastasis to distant organs. In vitro, the MUC1 mucin can mediate breast cancer cell migration by binding to intercellular adhesion molecule-1 (ICAM-1). This migration is dependent on MUC1 cytoplasmic domain (MUC1-CD) activation of the non-receptor tyrosine kinase, Src, possibly through competitive displacement of an inhibitory Src intramolecular SH3 binding. Therefore, we characterized the binding site and affinity of the MUC1-CD for Src-SH3 using multidimensional nuclear magnetic resonance (NMR) spectroscopy to monitor the titration of the {sup 15}N labeled Src-SH3 domain with synthetic native and mutant peptides of MUC1-CD. The results revealed that the dissociation constant (K{sub d}) for the interaction of the native MUC1-CD peptides and Src-SH3 domain was weak with a K{sub d} of 2-3 mM. Notably, the SH3 residues most perturbed upon peptide binding were located outside the usual hydrophobic binding cleft in a previously described alternate binding site on the Src-SH3, suggesting that MUC1-CD binds to a non-canonical site. The binding characteristics outlined here suggest that the interaction between Src-SH3 and MUC1-CD represents a novel weak electrostatic interaction of the type which is increasingly recognized as important in transient and dynamic protein complexes required for cell migration and signal transduction. As such, this study forms the foundation for the design of specific inhibitors of this interaction which may target breast cancer metastases with exquisite specificity.

  5. Probing neutrino physics with a self-consistent treatment of the weak decoupling, nucleosynthesis, and photon decoupling epochs

    SciTech Connect (OSTI)

    Grohs, E.; Fuller, George M.; Kishimoto, Chad T.; Paris, Mark W.

    2015-05-11

    In this study, we show that a self-consistent and coupled treatment of the weak decoupling, big bang nucleosynthesis, and photon decoupling epochs can be used to provide new insights and constraints on neutrino sector physics from high-precision measurements of light element abundances and Cosmic Microwave Background observables. Implications of beyond-standard-model physics in cosmology, especially within the neutrino sector, are assessed by comparing predictions against five observables: the baryon energy density, helium abundance, deuterium abundance, effective number of neutrinos, and sum of the light neutrino mass eigenstates. We give examples for constraints on dark radiation, neutrino rest mass, lepton numbers, and scenarios for light and heavy sterile neutrinos.

  6. The analog of Blanc`s law for drift velocities of electrons in gas mixtures in weakly ionized plasma

    SciTech Connect (OSTI)

    Chiflikian, R.V.

    1995-10-01

    The analog of Blanc`s law for drift velocities of electrons in multicomponent gas mixtures in weakly ionized spatially homogeneous low-temperature plasma is derived. The obtained approximate-analytical expressions are valid for average electron energy in the 1--5 eV range typical for plasma conditions of low-pressure direct current (DC) discharges. The accuracy of these formulas is {plus_minus}5%. The analytical criterion of the negative differential conductivity (NDC) of electrons in binary mixtures of gases is obtained. NDC of electrons is predicted in He:Kr and He:Xe rare gas mixtures. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

  7. Dynamical mean-field theory and weakly non-linear analysis for the phase separation of active Brownian particles

    SciTech Connect (OSTI)

    Speck, Thomas; Menzel, Andreas M.; Bialké, Julian; Löwen, Hartmut

    2015-06-14

    Recently, we have derived an effective Cahn-Hilliard equation for the phase separation dynamics of active Brownian particles by performing a weakly non-linear analysis of the effective hydrodynamic equations for density and polarization [Speck et al., Phys. Rev. Lett. 112, 218304 (2014)]. Here, we develop and explore this strategy in more detail and show explicitly how to get to such a large-scale, mean-field description starting from the microscopic dynamics. The effective free energy emerging from this approach has the form of a conventional Ginzburg-Landau function. On the coarsest scale, our results thus agree with the mapping of active phase separation onto that of passive fluids with attractive interactions through a global effective free energy (motility-induced phase transition). Particular attention is paid to the square-gradient term necessary for the phase separation kinetics. We finally discuss results from numerical simulations corroborating the analytical results.

  8. INFLUENCE OF MAGNETOROTATIONAL INSTABILITY ON NEUTRINO HEATING: A NEW MECHANISM FOR WEAKLY MAGNETIZED CORE-COLLAPSE SUPERNOVAE

    SciTech Connect (OSTI)

    Sawai, Hidetomo; Yamada, Shoichi

    2014-03-20

    We investigated the impact of magnetorotational instability (MRI) on the dynamics of weakly magnetized, rapidly rotating core-collapse supernovae by conducting high-resolution axisymmetric MHD simulations with simplified neutrino transfer. We found that an initially sub-magnetar-class magnetic field is drastically amplified by MRI and substantially affects the dynamics thereafter. Although the magnetic pressure is not strong enough to eject matter, the amplified magnetic field efficiently transfers angular momentum from small to large radii and from higher to lower latitudes, which causes the expansion of the heating region due to the extra centrifugal force. This then enhances the efficiency of neutrino heating and eventually leads to neutrino-driven explosion. This is a new scenario of core-collapse supernovae that has never been demonstrated by past numerical simulations.

  9. Probing neutrino physics with a self-consistent treatment of the weak decoupling, nucleosynthesis, and photon decoupling epochs

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Grohs, E.; Fuller, George M.; Kishimoto, Chad T.; Paris, Mark W.

    2015-05-11

    In this study, we show that a self-consistent and coupled treatment of the weak decoupling, big bang nucleosynthesis, and photon decoupling epochs can be used to provide new insights and constraints on neutrino sector physics from high-precision measurements of light element abundances and Cosmic Microwave Background observables. Implications of beyond-standard-model physics in cosmology, especially within the neutrino sector, are assessed by comparing predictions against five observables: the baryon energy density, helium abundance, deuterium abundance, effective number of neutrinos, and sum of the light neutrino mass eigenstates. We give examples for constraints on dark radiation, neutrino rest mass, lepton numbers, andmore » scenarios for light and heavy sterile neutrinos.« less

  10. Grain in weakly ionized plasma in the presence of an external magnetic field: Charging by plasma currents and effective potential

    SciTech Connect (OSTI)

    Momot, A. I.; M.M. Bogolubov Institute for Theoretical Physics, Nat. Acad. Sci. of Ukraine, 14b, Metrologichna Str., Kyiv, 03680

    2013-07-15

    The problem of grain screening is solved numerically for the case of weakly ionized plasma in the presence of an external magnetic field. The plasma dynamics is described within the drift-diffusion approximation under the assumption that the grain absorbs all encountered electrons and ions. We also assume that the plasma current through the grain surface is equal to zero in the stationary state. This condition is used to perform self-consistent calculations of the grain charge. The spatial distribution of the screened grain potential is studied and compared with the analytical estimates. It is shown that at the distances larger than the Debye length such potential has the Coulomb-like asymptotics with the effective charge dependent on the angle between the radius vector and the external magnetic field direction. The numerical solutions show that in the direction parallel to the external magnetic field the effective potential can have nonmonotonic behavior.

  11. Van der Waals Metal-Semiconductor Junction: Weak Fermi Level Pinning Enables Effective Tuning of Schottky Barrier

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Liu, Yuanyue; Stradins, Paul; Wei, Su-Huai

    2016-04-01

    Two-dimensional (2D) semiconductors have shown great potential for electronic and optoelectronic applications. However, their development is limited by a large Schottky barrier (SB) at the metal-semiconductor junction (MSJ), which is difficult to tune by using conventional metals because of the effect of strong Fermi level pinning (FLP). We show that this problem can be overcome by using 2D metals, which are bounded with 2D semiconductors through van der Waals (vdW) interactions. This success relies on a weak FLP at the vdW MSJ, which is attributed to the suppression of metal-induced gap states. Consequently, the SB becomes tunable and can vanishmore » with proper 2D metals (for example, H-NbS2). This work not only offers new insights into the fundamental properties of heterojunctions but also uncovers the great potential of 2D metals for device applications.« less

  12. Enhanced collective focusing of intense neutralized ion beam pulses in the presence of weak solenoidal magnetic fields

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Dorf, Mikhail A.; Davidson, Ronald C.; Kaganovich, Igor D.; Startsev, Edward A.

    2012-05-31

    In this study, the design of ion drivers for warm dense matter and high energy density physics applications and heavy ion fusion involves transverse focusing and longitudinal compression of intense ion beams to a small spot size on the target. To facilitate the process, the compression occurs in a long drift section filled with a dense background plasma, which neutralizes the intense beam self-fields. Typically, the ion bunch charge is better neutralized than its current, and as a result a net self-pinching (magnetic) force is produced. The self-pinching effect is of particular practical importance, and is used in various ionmore » driver designs in order to control the transverse beam envelope. In the present work we demonstrate that this radial self-focusing force can be significantly enhanced if a weak (B~100 G) solenoidal magnetic field is applied inside the neutralized drift section, thus allowing for substantially improved transport. It is shown that in contrast to magnetic self-pinching, the enhanced collective self-focusing has a radial electric field component and occurs as a result of the overcompensation of the beam charge by plasmaelectrons, whereas the beam current becomes well-neutralized. As the beam leaves the neutralizing drift section, additional transverse focusing can be applied. For instance, in the neutralized drift compression experiments (NDCX) a strong (several Tesla) final focus solenoid is used for this purpose. In the present analysis we propose that the tight final focus in the NDCX experiments may possibly be achieved by using a much weaker (few hundred Gauss) magnetic lens, provided the ion beam carries an equal amount of co-moving neutralizing electrons from the preceding drift section into the lens. In this case the enhanced focusing is provided by the collective electrondynamics strongly affected by a weak applied magnetic field.« less

  13. Enhanced collective focusing of intense neutralized ion beam pulses in the presence of weak solenoidal magnetic fields

    SciTech Connect (OSTI)

    Dorf, Mikhail A. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Davidson, Ronald C.; Kaganovich, Igor D.; Startsev, Edward A. [Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)

    2012-05-15

    The design of ion drivers for warm dense matter and high energy density physics applications and heavy ion fusion involves transverse focusing and longitudinal compression of intense ion beams to a small spot size on the target. To facilitate the process, the compression occurs in a long drift section filled with a dense background plasma, which neutralizes the intense beam self-fields. Typically, the ion bunch charge is better neutralized than its current, and as a result a net self-pinching (magnetic) force is produced. The self-pinching effect is of particular practical importance, and is used in various ion driver designs in order to control the transverse beam envelope. In the present work we demonstrate that this radial self-focusing force can be significantly enhanced if a weak (B {approx} 100 G) solenoidal magnetic field is applied inside the neutralized drift section, thus allowing for substantially improved transport. It is shown that in contrast to magnetic self-pinching, the enhanced collective self-focusing has a radial electric field component and occurs as a result of the overcompensation of the beam charge by plasma electrons, whereas the beam current becomes well-neutralized. As the beam leaves the neutralizing drift section, additional transverse focusing can be applied. For instance, in the neutralized drift compression experiments (NDCX) a strong (several Tesla) final focus solenoid is used for this purpose. In the present analysis we propose that the tight final focus in the NDCX experiments may possibly be achieved by using a much weaker (few hundred Gauss) magnetic lens, provided the ion beam carries an equal amount of co-moving neutralizing electrons from the preceding drift section into the lens. In this case the enhanced focusing is provided by the collective electron dynamics strongly affected by a weak applied magnetic field.

  14. CONNECTING STAR FORMATION QUENCHING WITH GALAXY STRUCTURE AND SUPERMASSIVE BLACK HOLES THROUGH GRAVITATIONAL HEATING OF COOLING FLOWS

    SciTech Connect (OSTI)

    Guo, Fulai

    2014-12-20

    Recent observations suggested that star formation quenching in galaxies is related to galaxy structure. Here we propose a new mechanism to explain the physical origin of this correlation. We assume that while quenching is maintained in quiescent galaxies by a feedback mechanism, cooling flows in the hot halo gas can still develop intermittently. We study cooling flows in a large suite of around 90 hydrodynamic simulations of an isolated galaxy group, and find that the flow development depends significantly on the gravitational potential well in the central galaxy. If the galaxy's gravity is not strong enough, cooling flows result in a central cooling catastrophe, supplying cold gas and feeding star formation to galactic bulges. When the bulge grows prominent enough, compressional heating starts to offset radiative cooling and maintains cooling flows in a long-term hot mode without producing a cooling catastrophe. Our model thus describes a self-limited growth channel for galaxy bulges and naturally explains the connection between quenching and bulge prominence. In particular, we explicitly demonstrate that M{sub ?}/R{sub eff}{sup 1.5} is a good structural predictor of quenching. We further find that the gravity from the central supermassive black hole also affects the bimodal fate of cooling flows, and we predict a more general quenching predictor to be M{sub bh}{sup 1.6}M{sub ?}/R{sub eff}{sup 1.5}, which may be tested in future observational studies.

  15. Weak-link capacitor

    DOE Patents [OSTI]

    Dirk, Shawn M.; Johnson, Ross S.; Wheeler, David R.; Bogart, Gregory R.

    2011-06-07

    A process for making a dielectric material where a precursor polymer selected from poly(phenylene vinylene) polyacetylene, poly(p-phenylene), poly(thienylene vinylene), poly(1,4-naphthylene vinylene), and poly(p-pyridine vinylene) is energized said by exposure by radiation or increase in temperature to a level sufficient to eliminate said leaving groups contained within the precursor polymer, thereby transforming the dielectric material into a conductive polymer. The leaving group in the precursor polymer can be a chloride, a bromide, an iodide, a fluoride, an ester, an xanthate, a nitrile, an amine, a nitro group, a carbonate, a dithiocarbamate, a sulfonium group, an oxonium group, an iodonium group, a pyridinium group, an ammonium group, a borate group, a borane group, a sulphinyl group, or a sulfonyl group.

  16. Weak-link capacitor

    DOE Patents [OSTI]

    Dirk, Shawn M.; Johnson, Ross S.; Wheeler, David R.; Bogart, Gregory R.

    2013-04-23

    A process for making a dielectric material where a precursor polymer selected from poly(phenylene vinylene)polyacetylene, poly(p-phenylene), poly(thienylene vinylene), poly(1,4-naphthylene vinylene), and poly(p-pyridine vinylene) is energized said by exposure by radiation or increase in temperature to a level sufficient to eliminate said leaving groups contained within the precursor polymer, thereby transforming the dielectric material into a conductive polymer. The leaving group in the precursor polymer can be a chloride, a bromide, an iodide, a fluoride, an ester, an xanthate, a nitrile, an amine, a nitro group, a carbonate, a dithiocarbamate, a sulfonium group, an oxonium group, an iodonium group, a pyridinium group, an ammonium group, a borate group, a borane group, a sulphinyl group, or a sulfonyl group.

  17. Extremely weak hydrogen flames

    SciTech Connect (OSTI)

    Lecoustre, V.R.; Sunderland, P.B. [Department of Fire Protection Engineering, University of Maryland, College Park, MD 20742 (United States); Chao, B.H. [Department of Mechanical Engineering, University of Hawaii, Honolulu, HI 96822 (United States); Axelbaum, R.L. [Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, MO 63130 (United States)

    2010-11-15

    Hydrogen jet diffusion flames were observed near their quenching limits. These involved downward laminar flow of hydrogen from a stainless steel hypodermic tube with an inside diameter of 0.15 mm. Near their quenching limits these flames had hydrogen flow rates of 3.9 and 2.1 {mu}g/s in air and oxygen, respectively. Assuming complete combustion, the associated heat release rates are 0.46 and 0.25 W. To the authors' knowledge, these are the weakest self-sustaining steady flames ever observed. (author)

  18. Coexistence of Weak Ferromagnetism and Polar Lattice Distortion in Epitaxial NiTiO3 thin films of the LiNbO3-Type Structure

    SciTech Connect (OSTI)

    Varga, Tamas; Droubay, Timothy C.; Bowden, Mark E.; Colby, Robert J.; Manandhar, Sandeep; Shutthanandan, V.; Hu, Dehong; Kabius, Bernd C.; Apra, Edoardo; Shelton, William A.; Chambers, Scott A.

    2013-04-15

    We report the magnetic and structural characteristics of epitaxial NiTiO3 films grown by pulsed laser deposition that are isostructural with acentric LiNbO3 (space group R3c). Optical second harmonic generation and magnetometry demonstrate lattice polarization at room temperature and weak ferromagnetism below 250 K, respectively. These results appear to be consistent with earlier predictions from first-principles calculations of the coexistence of ferroelectricity and weak ferromagnetism in a series of transition metal titanates crystallizing in the LiNbO3 structure. This acentric form of NiTiO3 is believed to be one of the rare examples of ferroelectrics exhibiting weak ferromagnetism generated by a Dzyaloshinskii-Moriya interaction.

  19. Measurement of the weak mixing angle with the Drell-Yan process in proton-proton collisions at the LHC

    SciTech Connect (OSTI)

    Chatrchyan, S.; et al.,

    2011-12-01

    A multivariate likelihood method to measure electroweak couplings with the Drell-Yan process at the LHC is presented. The process is described by the dilepton rapidity, invariant mass, and decay angle distributions. The decay angle ambiguity due to the unknown assignment of the scattered constituent quark and antiquark to the two protons in a collision is resolved statistically using correlations between the observables. The method is applied to a sample of dimuon events from proton-proton collisions at sqrt(s) = 7 TeV collected by the CMS experiment at the LHC, corresponding to an integrated luminosity of 1.1 inverse femtobarns. From the dominant u-ubar, d-dbar to gamma*/Z to opposite sign dimuons process, the effective weak mixing angle parameter is measured to be sin^2(theta[eff]) = 0.2287 +/- 0.0020 (stat.) +/- 0.0025 (syst.). This result is consistent with measurements from other processes, as expected within the standard model.

  20. Fabrication of superconducting metal-oxide textiles by heating impregnated polymeric material in a weakly oxidizing atmosphere

    SciTech Connect (OSTI)

    Van den Sype, J.S.

    1993-07-13

    A process is described for producing crystalline fibers, textiles or shapes comprised of YBa[sub 2]Cu[sub 3]O[sub 7[minus]x] where x varies from about 0 to about 0.4, said process comprising: (a) impregnating a preformed organic polymeric material with three metal compounds to provide metal elements in said material in substantially the atomic ratio occurring in said YBa[sub 2]Cu[sub 3]O[sub 7[minus]x]; (b) heating said impregnated material in a weakly oxidizing atmosphere containing from about 0.05% to about 2% oxygen by volume to a temperature sufficiently high to at least partially pyrolize and oxidize said organic material and at least partially oxidize said metal compounds substantially without ignition of said organic material and without formation of a molten phase or reaching a decomposition temperature of said YBa[sub 2]Cu[sub 3]O[sub 7[minus]x]; and (c) cooling the resulting material in at least a moderately oxidizing atmosphere to room temperature so as to obtain said fibers, textiles or shapes.

  1. Tunable inverse topological heterostructure utilizing (Bi1−xInx)2Se3 and multichannel weak-antilocalization effect

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Brahlek, Matthew J.; Koirala, Nikesh; Liu, Jianpeng; Yusufaly, Tahir I.; Salehi, Maryam; Han, Myung-Geun; Zhu, Yimei; Vanderbilt, David; Oh, Seongshik

    2016-03-10

    In typical topological insulator (TI) systems the TI is bordered by a non-TI insulator, and the surrounding conventional insulators, including vacuum, are not generally treated as part of the TI system. Here, we implement a material system where the roles are reversed, and the topological surface states form around the non-TI (instead of the TI) layers. This is realized by growing a layer of the tunable non-TI (Bi1-xInx)2Se3 in between two layers of the TI Bi2Se3 using the atomically precise molecular beam epitaxy technique. On this tunable inverse topological platform, we systematically vary the thickness and the composition of themore » (Bi1-xInx)2Se3 layer and show that this tunes the coupling between the TI layers from strongly coupled metallic to weakly coupled, and finally to a fully decoupled insulating regime. This system can be used to probe the fundamental nature of coupling in TI materials and provides a tunable insulating layer for TI devices.« less

  2. GRB 130427A AND SN 2013cq: A MULTI-WAVELENGTH ANALYSIS OF AN INDUCED GRAVITATIONAL COLLAPSE EVENT

    SciTech Connect (OSTI)

    Ruffini, R.; Wang, Y.; Enderli, M.; Muccino, M.; Kovacevic, M.; Bianco, C. L.; Pisani, G. B.; Rueda, J. A. [Dip. di Fisica and ICRA, Sapienza Universit di Roma, Piazzale Aldo Moro 5, I-00185 Rome (Italy); Penacchioni, A. V., E-mail: yu.wang@icranet.org [ICRANet-Rio, Centro Brasileiro de Pesquisas Fisicas, Rua Dr. Xavier Sigaud 150, Rio de Janeiro, RJ 22290-180 (Brazil)

    2015-01-01

    We performed a data analysis of the observations by the Swift, NuStar, and Fermi satellites in order to probe the induced gravitational collapse (IGC) paradigm for gamma-ray bursts (GRBs) associated with supernovae (SNe) in the terra incognita of GRB 130427A. We compare our data analysis with those in the literature. We have verified that GRB 130427A conforms to the IGC paradigm by examining the power law behavior of the luminosity in the early 10{sup 4} s of the XRT observations. This has led to the identification of the four different episodes of the binary driven hypernovae (BdHNe) and to the prediction, on 2013 May 2, of the occurrence of SN 2013cq, which was also observed in the optical band on 2013 May 13. The exceptional quality of the data has allowed the identification of novel features in Episode 3 including: (1) the confirmation and the extension of the existence of the recently discovered nested structure in the late X-ray luminosity in GRB 130427A, as well as the identification of a spiky structure at 10{sup 2} s in the cosmological rest-frame of the source; (2) a power law emission of the GeV luminosity light curve and its onset at the end of Episode 2; and (3) different Lorentz ? factors for the emitting regions of the X-ray and GeV emissions in this Episode 3. These results make it possible to test the details of the physical and astrophysical regimes at work in the BdHNe: (1) a newly born neutron star and the supernova ejecta, originating in Episode 1; (2) a newly formed black hole originating in Episode 2; and (3) the possible interaction among these components, observable in the standard features of Episode 3.

  3. A comparative study of lock-in-amplifiers and improved duffing chaotic oscillators for the detection and processing of weak signals

    SciTech Connect (OSTI)

    Tang, Yanmei; Li, Xinli; Bai, Yan

    2014-04-11

    The measurement of multiphase flow parameters is of great importance in a wide range of industries. In the measurement of multiphase, the signals from the sensors are extremely weak and often buried in strong background noise. It is thus desirable to develop effective signal processing techniques that can detect the weak signal from the sensor outputs. In this paper, two methods, i.e., lock-in-amplifier (LIA) and improved Duffing chaotic oscillator are compared to detect and process the weak signal. For sinusoidal signal buried in noise, the correlation detection with sinusoidal reference signal is simulated by using LIA. The improved Duffing chaotic oscillator method, which based on the Wigner transformation, can restore the signal waveform and detect the frequency. Two methods are combined to detect and extract the weak signal. Simulation results show the effectiveness and accuracy of the proposed improved method. The comparative analysis shows that the improved Duffing chaotic oscillator method can restrain noise strongly since it is sensitive to initial conditions.

  4. Search for: All records | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    distribution (2) optical properties (2) algorithms (1) astronomy and astrophysics dark energy, weak lensing, tomography, photometric redshift, clusters of galaxies (1)...

  5. The coyote universe extended: Precision emulation of the matter...

    Office of Scientific and Technical Information (OSTI)

    Modern sky surveys are returning precision measurements of cosmological statistics such as weak lensing shear correlations, the distribution of galaxies, and cluster abundance. To ...

  6. ON THE WEAK-WIND PROBLEM IN MASSIVE STARS: X-RAY SPECTRA REVEAL A MASSIVE HOT WIND IN {mu} COLUMBAE

    SciTech Connect (OSTI)

    Huenemoerder, David P.; Oskinova, Lidia M.; Todt, Helge; Ignace, Richard; Waldron, Wayne L.; Hamaguchi, Kenji

    2012-09-10

    {mu} Columbae is a prototypical weak-wind O star for which we have obtained a high-resolution X-ray spectrum with the Chandra LETG/ACIS instrument and a low-resolution spectrum with Suzaku. This allows us, for the first time, to investigate the role of X-rays on the wind structure in a bona fide weak-wind system and to determine whether there actually is a massive hot wind. The X-ray emission measure indicates that the outflow is an order of magnitude greater than that derived from UV lines and is commensurate with the nominal wind-luminosity relationship for O stars. Therefore, the {sup w}eak-wind problem{sup -}identified from cool wind UV/optical spectra-is largely resolved by accounting for the hot wind seen in X-rays. From X-ray line profiles, Doppler shifts, and relative strengths, we find that this weak-wind star is typical of other late O dwarfs. The X-ray spectra do not suggest a magnetically confined plasma-the spectrum is soft and lines are broadened; Suzaku spectra confirm the lack of emission above 2 keV. Nor do the relative line shifts and widths suggest any wind decoupling by ions. The He-like triplets indicate that the bulk of the X-ray emission is formed rather close to the star, within five stellar radii. Our results challenge the idea that some OB stars are 'weak-wind' stars that deviate from the standard wind-luminosity relationship. The wind is not weak, but it is hot and its bulk is only detectable in X-rays.

  7. MAPPING THE DARK MATTER WITH POLARIZED RADIO SURVEYS

    SciTech Connect (OSTI)

    Brown, Michael L.; Battye, Richard A.

    2011-07-01

    In a recent paper, we proposed the use of integrated polarization measurements of background galaxies in radio weak gravitational lensing surveys and investigated the potential impact on the statistical measurement of cosmic shear. Here we extend this idea to reconstruct maps of the projected dark matter distribution or lensing convergence field. The addition of polarization can, in principle, greatly reduce shape noise due to the intrinsic dispersion in galaxy ellipticities. We show that maps reconstructed using this technique in the radio band can be competitive with those derived using standard lensing techniques which make use of many more galaxies. In addition, since the reconstruction noise is uncorrelated between these standard techniques and the polarization technique, their comparison can serve as a powerful check for systematics and their combination can reduce noise further. We examine the convergence reconstruction which could be achieved with two forthcoming facilities: (1) a deep survey, covering 1.75 deg{sup 2} using the e-MERLIN instrument currently being commissioned in the UK and (2) the high-resolution, deep wide-field surveys which will eventually be conducted with the Square Kilometre Array.

  8. Areas of Weakly Anomalous to Anomalous Surface Temperature in Routt County, Colorado, as Identified from ASTER Thermal Data

    SciTech Connect (OSTI)

    Hussein, Khalid

    2012-02-01

    Citation Information: Originator: Earth Science &Observation Center (ESOC), CIRES, University of Colorado at Boulder Publication Date: 2012 Title: Warm Modeled Temperature Routt Edition: First Note: This Weakly Anomalous to Anomalous Surface Temperature dataset differs from the Anomalous Surface Temperature dataset for this county (another remotely sensed CIRES product) by showing areas of modeled temperatures between 1? and 2? above the mean, as opposed to the greater than 2? temperatures contained in the Anomalous Surface Temperature dataset. Publication Information: Publication Place: Earth Science & Observation Center, Cooperative Institute for Research in Environmental Science (CIRES), University of Colorado, Boulder Publisher: Earth Science &Observation Center (ESOC), CIRES, University of Colorado at Boulder Description: This layer contains areas of anomalous surface temperature in Routt County identified from ASTER thermal data and spatial based insolation model. The temperature is calculated using the Emissivity Normalization Algorithm that separate temperature from emissivity. The incoming solar radiation was calculated using spatial based insolation model developed by Fu and Rich (1999). Then the temperature due to solar radiation was calculated using emissivity derived from ASTER data. The residual temperature, i.e. temperature due to solar radiation subtracted from ASTER temperature was used to identify thermally anomalous areas. Areas that had temperature between 1? and 2? were considered ASTER modeled warm surface exposures (thermal anomalies) Spatial Domain: Extent: Top: 4501071.574000 m Left: 311351.975000 m Right: 359411.975000 m Bottom: 4447521.574000 m Contact Information: Contact Organization: Earth Science &Observation Center (ESOC), CIRES, University of Colorado at Boulder Contact Person: Khalid Hussein Address: CIRES, Ekeley Building Earth Science & Observation Center (ESOC) 216 UCB City: Boulder State: CO Postal Code: 80309-0216 Country: USA Contact Telephone: 303-492-6782 Spatial Reference Information: Coordinate System: Universal Transverse Mercator (UTM) WGS1984 Zone 13N False Easting: 500000.00000000 False Northing: 0.00000000 Central Meridian: -105.00000000 Scale Factor: 0.99960000 Latitude of Origin: 0.00000000 Linear Unit: Meter Datum: World Geodetic System 1984 (WGS 1984) Prime Meridian: Greenwich Angular Unit: Degree Digital Form: Format Name: Shape file

  9. Areas of Weakly Anomalous to Anomalous Surface Temperature in Chaffee County, Colorado, as Identified from ASTER Thermal Data

    SciTech Connect (OSTI)

    Hussein, Khalid

    2012-02-01

    Citation Information: Originator: Earth Science &Observation Center (ESOC), CIRES, University of Colorado at Boulder Publication Date: 2012 Title: Very Warm Modeled Temperature Chaffee Edition: First Note: This Weakly Anomalous to Anomalous Surface Temperature dataset differs from the Anomalous Surface Temperature dataset for this county (another remotely sensed CIRES product) by showing areas of modeled temperatures between 1? and 2? above the mean, as opposed to the greater than 2? temperatures contained in the Anomalous Surface Temperature dataset. Publication Information: Publication Place: Earth Science & Observation Center, Cooperative Institute for Research in Environmental Science (CIRES), University of Colorado, Boulder Publisher: Earth Science &Observation Center (ESOC), CIRES, University of Colorado at Boulder Description: This layer contains areas of anomalous surface temperature in Chaffee County identified from ASTER thermal data and spatial based insolation model. The temperature is calculated using the Emissivity Normalization Algorithm that separate temperature from emissivity. The incoming solar radiation was calculated using spatial based insolation model developed by Fu and Rich (1999). Then the temperature due to solar radiation was calculated using emissivity derived from ASTER data. The residual temperature, i.e. temperature due to solar radiation subtracted from ASTER temperature was used to identify thermally anomalous areas. Areas that had temperature greater than 2? were considered ASTER modeled very warm surface exposures (thermal anomalies) Spatial Domain: Extent: Top: 4333432.368072 m Left: 366907.700763 m Right: 452457.816015 m Bottom: 4208271.566715 m Contact Information: Contact Organization: Earth Science &Observation Center (ESOC), CIRES, University of Colorado at Boulder Contact Person: Khalid Hussein Address: CIRES, Ekeley Building Earth Science & Observation Center (ESOC) 216 UCB City: Boulder State: CO Postal Code: 80309-0216 Country: USA Contact Telephone: 303-492-6782 Spatial Reference Information: Coordinate System: Universal Transverse Mercator (UTM) WGS1984 Zone 13N False Easting: 500000.00000000 False Northing: 0.00000000 Central Meridian: -105.00000000 Scale Factor: 0.99960000 Latitude of Origin: 0.00000000 Linear Unit: Meter Datum: World Geodetic System 1984 (WGS 1984) Prime Meridian: Greenwich Angular Unit: Degree Digital Form: Format Name: Shape file

  10. Areas of Weakly Anomalous to Anomalous Surface Temperature in Archuleta County, Colorado, as Identified from ASTER Thermal Data

    SciTech Connect (OSTI)

    Hussein, Khalid

    2012-02-01

    Citation Information: Originator: Earth Science &Observation Center (ESOC), CIRES, University of Colorado at Boulder Publication Date: 2012 Title: Warm Modeled Temperature Archuleta Note: This Weakly Anomalous to Anomalous Surface Temperature dataset differs from the Anomalous Surface Temperature dataset for this county (another remotely sensed CIRES product) by showing areas of modeled temperatures between 1? and 2? above the mean, as opposed to the greater than 2? temperatures contained in the Anomalous Surface Temperature dataset. Edition: First Publication Information: Publication Place: Earth Science & Observation Center, Cooperative Institute for Research in Environmental Science (CIRES), University of Colorado, Boulder Publisher: Earth Science &Observation Center (ESOC), CIRES, University of Colorado at Boulder Description: This layer contains areas of anomalous surface temperature in Archuleta County identified from ASTER thermal data and spatial based insolation model. The temperature is calculated using the Emissivity Normalization Algorithm that separate temperature from emissivity. The incoming solar radiation was calculated using spatial based insolation model developed by Fu and Rich (1999). Then the temperature due to solar radiation was calculated using emissivity derived from ASTER data. The residual temperature, i.e. temperature due to solar radiation subtracted from ASTER temperature was used to identify thermally anomalous areas. Areas that had temperature between 1? and 2? were considered ASTER modeled warm surface exposures (thermal anomalies). Spatial Domain: Extent: Top: 4144825.235807 m Left: 285446.256851 m Right: 350577.338852 m Bottom: 4096962.250137 m Contact Information: Contact Organization: Earth Science &Observation Center (ESOC), CIRES, University of Colorado at Boulder Contact Person: Khalid Hussein Address: CIRES, Ekeley Building Earth Science & Observation Center (ESOC) 216 UCB City: Boulder State: CO Postal Code: 80309-0216 Country: USA Contact Telephone: 303-492-6782 Spatial Reference Information: Coordinate System: Universal Transverse Mercator (UTM) WGS1984 Zone 13N False Easting: 500000.00000000 False Northing: 0.00000000 Central Meridian: -105.00000000 Scale Factor: 0.99960000 Latitude of Origin: 0.00000000 Linear Unit: Meter Datum: World Geodetic System 1984 (WGS 1984) Prime Meridian: Greenwich Angular Unit: Degree Digital Form: Format Name: Shape file

  11. Areas of Weakly Anomalous to Anomalous Surface Temperature in Alamosa and Saguache Counties, Colorado, as Identified from ASTER Thermal Data

    SciTech Connect (OSTI)

    Hussein, Khalid

    2012-02-01

    Citation Information: Originator: Earth Science &Observation Center (ESOC), CIRES, University of Colorado at Boulder Publication Date: 2012 Title: Very Warm Modeled Temperature Alamosa Saguache Edition: First Note: This Weakly Anomalous to Anomalous Surface Temperature dataset differs from the Anomalous Surface Temperature dataset for this county (another remotely sensed CIRES product) by showing areas of modeled temperatures between 1? and 2? above the mean, as opposed to the greater than 2? temperatures contained in the Anomalous Surface Temperature dataset. Publication Information: Publication Place: Earth Science & Observation Center, Cooperative Institute for Research in Environmental Science (CIRES), University of Colorado, Boulder Publisher: Earth Science &Observation Center (ESOC), CIRES, University of Colorado at Boulder Description: This layer contains areas of anomalous surface temperature in Alamosa and Saguache Counties identified from ASTER thermal data and spatial based insolation model. The temperature is calculated using the Emissivity Normalization Algorithm that separate temperature from emissivity. The incoming solar radiation was calculated using spatial based insolation model developed by Fu and Rich (1999). Then the temperature due to solar radiation was calculated using emissivity derived from ASTER data. The residual temperature, i.e. temperature due to solar radiation subtracted from ASTER temperature was used to identify thermally anomalous areas. Areas that had temperature greater than 2? were considered ASTER modeled very warm surface exposures (thermal anomalies) Spatial Domain: Extent: Top: 4217727.601630 m Left: 394390.400264 m Right: 460179.841813 m Bottom: 4156258.036086 m Contact Information: Contact Organization: Earth Science &Observation Center (ESOC), CIRES, University of Colorado at Boulder Contact Person: Khalid Hussein Address: CIRES, Ekeley Building Earth Science & Observation Center (ESOC) 216 UCB City: Boulder State: CO Postal Code: 80309-0216 Country: USA Contact Telephone: 303-492-6782 Spatial Reference Information: Coordinate System: Universal Transverse Mercator (UTM) WGS1984 Zone 13N False Easting: 500000.00000000 False Northing: 0.00000000 Central Meridian: -105.00000000 Scale Factor: 0.99960000 Latitude of Origin: 0.00000000 Linear Unit: Meter Datum: World Geodetic System 1984 (WGS 1984) Prime Meridian: Greenwich Angular Unit: Degree Digital Form: Format Name: Shape file

  12. Areas of Weakly Anomalous to Anomalous Surface Temperature in Dolores County, Colorado, as Identified from ASTER Thermal Data

    SciTech Connect (OSTI)

    Hussein, Khalid

    2012-02-01

    Citation Information: Originator: Earth Science &Observation Center (ESOC), CIRES, University of Colorado at Boulder Publication Date: 2012 Title: Very Warm Modeled Temperature Dolores Edition: First Note: This Weakly Anomalous to Anomalous Surface Temperature dataset differs from the Anomalous Surface Temperature dataset for this county (another remotely sensed CIRES product) by showing areas of modeled temperatures between 1? and 2? above the mean, as opposed to the greater than 2? temperatures contained in the Anomalous Surface Temperature dataset. Publication Information: Publication Place: Earth Science & Observation Center, Cooperative Institute for Research in Environmental Science (CIRES), University of Colorado, Boulder Publisher: Earth Science &Observation Center (ESOC), CIRES, University of Colorado at Boulder Description: This layer contains areas of anomalous surface temperature in Dolores County identified from ASTER thermal data and spatial based insolation model. The temperature is calculated using the Emissivity Normalization Algorithm that separate temperature from emissivity. The incoming solar radiation was calculated using spatial based insolation model developed by Fu and Rich (1999). Then the temperature due to solar radiation was calculated using emissivity derived from ASTER data. The residual temperature, i.e. temperature due to solar radiation subtracted from ASTER temperature was used to identify thermally anomalous areas. Areas that had temperature greater than 2? were considered ASTER modeled very warm surface exposures (thermal anomalies) Spatial Domain: Extent: Top: 4186234.213315 m Left: 212558.673056 m Right: 232922.811862 m Bottom: 4176781.467043 m Contact Information: Contact Organization: Earth Science &Observation Center (ESOC), CIRES, University of Colorado at Boulder Contact Person: Khalid Hussein Address: CIRES, Ekeley Building Earth Science & Observation Center (ESOC) 216 UCB City: Boulder State: CO Postal Code: 80309-0216 Country: USA Contact Telephone: 303-492-6782 Spatial Reference Information: Coordinate System: Universal Transverse Mercator (UTM) WGS1984 Zone 13N False Easting: 500000.00000000 False Northing: 0.00000000 Central Meridian: -105.00000000 Scale Factor: 0.99960000 Latitude of Origin: 0.00000000 Linear Unit: Meter Datum: World Geodetic System 1984 (WGS 1984) Prime Meridian: Greenwich Angular Unit: Degree Digital Form: Format Name: Shape file

  13. Areas of Weakly Anomalous to Anomalous Surface Temperature in Garfield County, Colorado, as Identified from ASTER Thermal Data

    SciTech Connect (OSTI)

    Hussein, Khalid

    2012-02-01

    Citation Information: Originator: Earth Science &Observation Center (ESOC), CIRES, University of Colorado at Boulder Publication Date: 2012 Title: Warm Modeled Temperature Garfield Edition: First Note: This Weakly Anomalous to Anomalous Surface Temperature dataset differs from the Anomalous Surface Temperature dataset for this county (another remotely sensed CIRES product) by showing areas of modeled temperatures between 1? and 2? above the mean, as opposed to the greater than 2? temperatures contained in the Anomalous Surface Temperature dataset. Publication Information: Publication Place: Earth Science & Observation Center, Cooperative Institute for Research in Environmental Science (CIRES), University of Colorado, Boulder Publisher: Earth Science &Observation Center (ESOC), CIRES, University of Colorado at Boulder Description: This layer contains areas of anomalous surface temperature in Garfield County identified from ASTER thermal data and spatial based insolation model. The temperature is calculated using the Emissivity Normalization Algorithm that separate temperature from emissivity. The incoming solar radiation was calculated using spatial based insolation model developed by Fu and Rich (1999). Then the temperature due to solar radiation was calculated using emissivity derived from ASTER data. The residual temperature, i.e. temperature due to solar radiation subtracted from ASTER temperature was used to identify thermally anomalous areas. Areas that had temperature between 1? and 2? were considered ASTER modeled warm surface exposures (thermal anomalies) Spatial Domain: Extent: Top: 4442180.552290 m Left: 268655.053363 m Right: 359915.053363 m Bottom: 4312490.552290 m Contact Information: Contact Organization: Earth Science &Observation Center (ESOC), CIRES, University of Colorado at Boulder Contact Person: Khalid Hussein Address: CIRES, Ekeley Building Earth Science & Observation Center (ESOC) 216 UCB City: Boulder State: CO Postal Code: 80309-0216 Country: USA Contact Telephone: 303-492-6782 Spatial Reference Information: Coordinate System: Universal Transverse Mercator (UTM) WGS1984 Zone 13N False Easting: 500000.00000000 False Northing: 0.00000000 Central Meridian: -105.00000000 Scale Factor: 0.99960000 Latitude of Origin: 0.00000000 Linear Unit: Meter Datum: World Geodetic System 1984 (WGS 1984) Prime Meridian: Greenwich Angular Unit: Degree Digital Form: Format Name: Shape file

  14. Efficiencies and Optimization of Weak Base Anion Ion-Exchange Resin for Groundwater Hexavalent Chromium Removal at Hanford

    SciTech Connect (OSTI)

    Nesham, Dean O.; Ivarson, Kristine A.; Hanson, James P.; Miller, Charles W.; Meyers, P.; Jaschke, Naomi M.

    2014-02-03

    The U.S. Department of Energy’s (DOE’s) contractor, CH2M HILL Plateau Remediation Company, has successfully converted a series of groundwater treatment facilities to use a new treatment resin that is delivering more than $3 million in annual cost savings and efficiency in treating groundwater contamination at the DOE Hanford Site in southeastern Washington State. During the production era, the nuclear reactors at the Hanford Site required a continuous supply of high-quality cooling water during operations. Cooling water consumption ranged from about 151,417 to 378,541 L/min (40,000 to 100,000 gal/min) per reactor, depending on specific operating conditions. Water from the Columbia River was filtered and treated chemically prior to use as cooling water, including the addition of sodium dichromate as a corrosion inhibitor. Hexavalent chromium was the primary component of the sodium dichromate and was introduced into the groundwater at the Hanford Site as a result of planned and unplanned discharges from the reactors starting in 1944. Groundwater contamination by hexavalent chromium and other contaminants related to nuclear reactor operations resulted in the need for groundwater remedial actions within the Hanford Site reactor areas. Beginning in 1995, groundwater treatment methods were evaluated, leading to the use of pump-and-treat facilities with ion exchange using Dowex™ 21K, a regenerable, strong-base anion exchange resin. This required regeneration of the resin, which was performed offsite. In 2008, DOE recognized that regulatory agreements would require significant expansion for the groundwater chromium treatment capacity. As a result, CH2M HILL performed testing at the Hanford Site in 2009 and 2010 to demonstrate resin performance in the specific groundwater chemistry at different waste sites. The testing demonstrated that a weak-base anion, single-use resin, specifically ResinTech SIR-700 ®, was effective at removing chromium, had a significantly higher capacity, could be disposed of efficiently onsite, and would eliminate the complexities and programmatic risks from sampling, packaging, transportation, and return of resin for regeneration.

  15. Note on gravitational baryogenesis

    SciTech Connect (OSTI)

    Sadjadi, H. Mohseni

    2007-12-15

    The coupling between Ricci scalar curvature and the baryon number current dynamically breaks CPT in an expanding universe and leads to baryon asymmetry. We study the effect of time dependence of the equation of state parameter of the Friedmann-Robertson-Walker universe on this asymmetry.

  16. Data Plots of Run I - III Results from SLAC E-158: A precision Measurement of the Weak Mixing Angle in Moller Scattering

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Three physics runs were made in 2002 and 2003 by E-158. As a result, the E-158 Collaboration announced that it had made "the first observation of Parity Violation in electron-electron (Moller) scattering). This precise Parity Violation measurement gives the best determination of the electron's weak charge at low energy (low momentum transfer between interacting particles). E158's measurement tests the predicted running (or evolution) of this weak charge with energy, and searches for new phenomena at TeV energy scales (one thousand times the proton-mass energy scale).[Copied from the experiment's public home page at http://www-project slac.stanford.edu/3158/Default.htm] See also the E158 page for collaborators at http://www.slac.stanford.edu/exp/e158/. Both websites provide data and detailed information.

  17. A Measurement of the Weak Charge of the Proton through Parity Violating Electron Scattering using the Qweak Apparatus: A 21% Result

    SciTech Connect (OSTI)

    Beminiwattha, Rakitha

    2013-08-01

    After a decade of preparations, the Qweak experiment at Jefferson Lab is making the first direct measurement of the weak charge of the proton, Q^p_W. This quantity is suppressed in the Standard Model making a good candidate for search for new physics beyond the SM at the TeV scale. Operationally, we measure a small (about -0.200 ppm) parity-violating asymmetry in elastic electron-proton scattering in integrating mode while flipping the helicity of the electrons 1000 times per second. Commissioning took place Fall 2010, and we finished taking data in early summer 2012. This dissertation is based on the data taken on an initial two weeks period (Wien0). It will provide an overview of the Qweak apparatus, description of the data acquisition and analysis software systems, and final analysis and results from the Wien0 data set. The result is a 16% measurement of the parity violating electron-proton scattering asymmetry, A = -0.2788 +/- 0.0348 (stat.) +/- 0.0290 (syst.) ppm at Q^2 = 0.0250 +/- 0.0006 (GeV)^2. From this a 21% measurement of the weak charge of the proton, Q_w^p(msr)= +0.0952 +/- 0.0155 (stat.) +/- 0.0131 (syst.) +/- 0.0015 (theory) is extracted. From this a 2% measurement of the weak mixing angle, sin^2theta_W(msr)= +0.2328 +/- 0.0039 (stat.) +/- 0.0033 (syst.) +/- 0.0004 (theory) and improved constraints on isoscalar/isovector effective coupling constants of the weak neutral hadronic currents are extracted. These results deviate from the Standard Model by one standard deviation. The Wien0 results are a proof of principle of the Qweak data analysis and a highlight of the road ahead for obtaining full results.

  18. GREAT3 results - I. Systematic errors in shear estimation and the impact of real galaxy morphology

    SciTech Connect (OSTI)

    Mandelbaum, Rachel; Rowe, Barnaby; Armstrong, Robert; Bard, Deborah; Bertin, Emmanuel; Bosch, James; Boutigny, Dominique; Courbin, Frederic; Dawson, William A.; Donnarumma, Annamaria; Fenech Conti, Ian; Gavazzi, Raphael; Gentile, Marc; Gill, Mandeep S. S.; Hogg, David W.; Huff, Eric M.; Jee, M. James; Kacprzak, Tomasz; Kilbinger, Martin; Kuntzer, Thibault; Lang, Dustin; Luo, Wentao; March, Marisa C.; Marshall, Philip J.; Meyers, Joshua E.; Miller, Lance; Miyatake, Hironao; Nakajima, Reiko; Ngole Mboula, Fred Maurice; Nurbaeva, Guldariya; Okura, Yuki; Paulin-Henriksson, Stephane; Rhodes, Jason; Schneider, Michael D.; Shan, Huanyuan; Sheldon, Erin S.; Simet, Melanie; Starck, Jean -Luc; Sureau, Florent; Tewes, Malte; Zarb Adami, Kristian; Zhang, Jun; Zuntz, Joe

    2015-05-11

    The study present first results from the third GRavitational lEnsing Accuracy Testing (GREAT3) challenge, the third in a sequence of challenges for testing methods of inferring weak gravitational lensing shear distortions from simulated galaxy images. GREAT3 was divided into experiments to test three specific questions, and included simulated space- and ground-based data with constant or cosmologically varying shear fields. The simplest (control) experiment included parametric galaxies with a realistic distribution of signal-to-noise, size, and ellipticity, and a complex point spread function (PSF). The other experiments tested the additional impact of realistic galaxy morphology, multiple exposure imaging, and the uncertainty about a spatially varying PSF; the last two questions will be explored in Paper II. The 24 participating teams competed to estimate lensing shears to within systematic error tolerances for upcoming Stage-IV dark energy surveys, making 1525 submissions overall. GREAT3 saw considerable variety and innovation in the types of methods applied. Several teams now meet or exceed the targets in many of the tests conducted (to within the statistical errors). We conclude that the presence of realistic galaxy morphology in simulations changes shear calibration biases by ~1 per cent for a wide range of methods. Other effects such as truncation biases due to finite galaxy postage stamps, and the impact of galaxy type as measured by the Sérsic index, are quantified for the first time. Our results generalize previous studies regarding sensitivities to galaxy size and signal-to-noise, and to PSF properties such as seeing and defocus. Almost all methods’ results support the simple model in which additive shear biases depend linearly on PSF ellipticity.

  19. GREAT3 results - I. Systematic errors in shear estimation and the impact of real galaxy morphology

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Mandelbaum, Rachel; Rowe, Barnaby; Armstrong, Robert; Bard, Deborah; Bertin, Emmanuel; Bosch, James; Boutigny, Dominique; Courbin, Frederic; Dawson, William A.; Donnarumma, Annamaria; et al

    2015-05-11

    The study present first results from the third GRavitational lEnsing Accuracy Testing (GREAT3) challenge, the third in a sequence of challenges for testing methods of inferring weak gravitational lensing shear distortions from simulated galaxy images. GREAT3 was divided into experiments to test three specific questions, and included simulated space- and ground-based data with constant or cosmologically varying shear fields. The simplest (control) experiment included parametric galaxies with a realistic distribution of signal-to-noise, size, and ellipticity, and a complex point spread function (PSF). The other experiments tested the additional impact of realistic galaxy morphology, multiple exposure imaging, and the uncertainty aboutmore » a spatially varying PSF; the last two questions will be explored in Paper II. The 24 participating teams competed to estimate lensing shears to within systematic error tolerances for upcoming Stage-IV dark energy surveys, making 1525 submissions overall. GREAT3 saw considerable variety and innovation in the types of methods applied. Several teams now meet or exceed the targets in many of the tests conducted (to within the statistical errors). We conclude that the presence of realistic galaxy morphology in simulations changes shear calibration biases by ~1 per cent for a wide range of methods. Other effects such as truncation biases due to finite galaxy postage stamps, and the impact of galaxy type as measured by the Sérsic index, are quantified for the first time. Our results generalize previous studies regarding sensitivities to galaxy size and signal-to-noise, and to PSF properties such as seeing and defocus. Almost all methods’ results support the simple model in which additive shear biases depend linearly on PSF ellipticity.« less

  20. Development of finite local perturbations of electrical conductivity in the flow of a weakly-conducting gas when a magnetic field is present

    SciTech Connect (OSTI)

    Zaklyaz'minskiy, L.; Sokolov, V.; Degtyarev, L.; Kurdyusov, S.; Samarskiy, A.

    1988-08-08

    A study has been made of the possibility of development of a T-layer from local finite perturbation of electrical conductivity, introduced artificially into a steady-state flow of a weakly conducting gas. The analysis is made with the help of a numerical solution of equations of magnetic hydrodynamics, formulated in the assumption that the electron, ion and neutral components of the medium are found in thermodynamic equilibrium; the viscosity, Hall effect and transfer of energy by radiation are not taken into account.

  1. Introducing GAMER: A fast and accurate method for ray-tracing galaxies using procedural noise

    SciTech Connect (OSTI)

    Groeneboom, N. E.; Dahle, H.

    2014-03-10

    We developed a novel approach for fast and accurate ray-tracing of galaxies using procedural noise fields. Our method allows for efficient and realistic rendering of synthetic galaxy morphologies, where individual components such as the bulge, disk, stars, and dust can be synthesized in different wavelengths. These components follow empirically motivated overall intensity profiles but contain an additional procedural noise component that gives rise to complex natural patterns that mimic interstellar dust and star-forming regions. These patterns produce more realistic-looking galaxy images than using analytical expressions alone. The method is fully parallelized and creates accurate high- and low- resolution images that can be used, for example, in codes simulating strong and weak gravitational lensing. In addition to having a user-friendly graphical user interface, the C++ software package GAMER is easy to implement into an existing code.

  2. Measurements and modeling of the impact of weak magnetic fields on the plasma properties of a planar slot antenna driven plasma source

    SciTech Connect (OSTI)

    Yoshikawa, Jun Susa, Yoshio; Ventzek, Peter L. G.

    2015-05-15

    The radial line slot antenna plasma source is a type of surface wave plasma source driven by a planar slot antenna. Microwave power is transmitted through a slot antenna structure and dielectric window to a plasma characterized by a generation zone adjacent to the window and a diffusion zone that contacts a substrate. The diffusion zone is characterized by a very low electron temperature. This renders the source useful for soft etch applications and thin film deposition processes requiring low ion energy. Another property of the diffusion zone is that the plasma density tends to decrease from the axis to the walls under the action of ambipolar diffusion at distances far from where the plasma is generated. A previous simulation study [Yoshikawa and. Ventzek, J. Vac. Sci. Technol. A 31, 031306 (2013)] predicted that the anisotropy in transport parameters due to weak static magnetic fields less than 50 G could be leveraged to manipulate the plasma profile in the radial direction. These simulations motivated experimental tests in which weak magnetic fields were applied to a radial line slot antenna source. Plasma absorption probe measurements of electron density and etch rate showed that the magnetic fields remote from the wafer were able to manipulate both parameters. A summary of these results is presented in this paper. Argon plasma simulation trends are compared with experimental plasma and etch rate measurements. A test of the impact of magnetic fields on charge up damage showed no perceptible negative effect.

  3. Stellar yields of rotating first stars. I. Yields of weak supernovae and abundances of carbon-enhanced hyper-metal-poor stars

    SciTech Connect (OSTI)

    Takahashi, Koh; Umeda, Hideyuki [Department of Astronomy, The University of Tokyo, Bunkyo, Tokyo 113-0033 (Japan); Yoshida, Takashi, E-mail: ktakahashi@astron.s.u-tokyo.ac.jp [Yukawa Institute for Theoretical Physics, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-Ku, Kyoto 606-8502 (Japan)

    2014-10-10

    We perform a stellar evolution simulation of first stars and calculate stellar yields from the first supernovae. The initial masses are taken from 12 to 140 M {sub ?} to cover the whole range of core-collapse supernova progenitors, and stellar rotation is included, which results in efficient internal mixing. A weak explosion is assumed in supernova yield calculations, thus only outer distributed matter, which is not affected by the explosive nucleosynthesis, is ejected in the models. We show that the initial mass and the rotation affect the explosion yield. All the weak explosion models have abundances of [C/O] larger than unity. Stellar yields from massive progenitors of >40-60 M {sub ?} show enhancement of Mg and Si. Rotating models yield abundant Na and Al, and Ca is synthesized in nonrotating heavy massive models of >80 M {sub ?}. We fit the stellar yields to the three most iron-deficient stars and constrain the initial parameters of the mother progenitor stars. The abundance pattern in SMSS 03136708 is well explained by 50-80 M {sub ?} nonrotating models, rotating 30-40 M {sub ?} models well fit the abundance of HE 0107-5240, and both nonrotating and rotating 15-40 M {sub ?} models explain HE 1327-2326. The presented analysis will be applicable to other carbon-enhanced hyper-metal-poor stars observed in the future. The abundance analyses will give valuable information about the characteristics of the first stars.

  4. THE BURST CLUSTER: DARK MATTER IN A CLUSTER MERGER ASSOCIATED WITH THE SHORT GAMMA-RAY BURST, GRB 050509B

    SciTech Connect (OSTI)

    Dahle, H.; Sarazin, C. L.; Lopez, L. A.; Kouveliotou, C.; Rol, E.; Van der Horst, A. J.; Wijers, R. A. M. J.; Fynbo, J.; Michalowski, M. J.; Burrows, D. N.; Grupe, D.; Gehrels, N.

    2013-07-20

    We have identified a merging galaxy cluster with evidence of two distinct subclusters. The X-ray and optical data suggest that the subclusters are presently moving away from each other after closest approach. This cluster merger was discovered from observations of the first well-localized short-duration gamma-ray burst (GRB), GRB 050509B. The Swift/Burst Alert Telescope error position of the source is coincident with a cluster of galaxies ZwCl 1234.0+02916, while the subsequent Swift/X-Ray Telescope localization of the X-ray afterglow found the GRB coincident with 2MASX J12361286+2858580, a giant red elliptical galaxy in the cluster. Deep multi-epoch optical images were obtained in this field to constrain the evolution of the GRB afterglow, including a total of 27,480 s exposure in the F814W band with Hubble Space Telescope Advanced Camera for Surveys, among the deepest imaging ever obtained toward a known galaxy cluster in a single passband. We perform a weak gravitational lensing analysis based on these data, including mapping of the total mass distribution of the merger system with high spatial resolution. When combined with Chandra X-ray Observatory Advanced CCD Imaging Spectrometer and Swift/XRT observations, we are able to investigate the dynamical state of the merger to better understand the nature of the dark matter component. Our weak gravitational lensing measurements reveal a separation of the X-ray centroid of the western subcluster from the center of the mass and galaxy light distributions, which is somewhat similar to that of the famous 'Bullet cluster', and we conclude that this 'Burst cluster' adds another candidate to the previously known merger systems for determining the nature of dark matter, as well as for studying the environment of a short GRB. Finally, we discuss potential connections between the cluster dynamical state and/or matter composition, and compact object mergers, which is currently the leading model for the origin of short GRBs. We also present our results from a weak-lensing survey based on archival Very Large Telescope images in the areas of five other short GRBs, which do not provide any firm detections of mass concentrations representative of rich clusters.

  5. Equation of state of a weakly interacting two-dimensional Bose gas studied at zero temperature by means of quantum Monte Carlo methods

    SciTech Connect (OSTI)

    Astrakharchik, G. E.; Boronat, J.; Casulleras, J.; Kurbakov, I. L.; Lozovik, Yu. E.

    2009-05-15

    The equation of state of a weakly interacting two-dimensional Bose gas is studied at zero temperature by means of quantum Monte Carlo methods. Going down to as low densities as na{sup 2}{proportional_to}10{sup -100} permits us to obtain agreement on beyond mean-field level between predictions of perturbative methods and direct many-body numerical simulation, thus providing an answer to the fundamental question of the equation of state of a two-dimensional dilute Bose gas in the universal regime (i.e., entirely described by the gas parameter na{sup 2}). We also show that the measure of the frequency of a breathing collective oscillation in a trap at very low densities can be used to test the universal equation of state of a two-dimensional Bose gas.

  6. The nonlinear Schrödinger equation and the propagation of weakly nonlinear waves in optical fibers and on the water surface

    SciTech Connect (OSTI)

    Chabchoub, A.; Kibler, B.; Finot, C.; Millot, G.; Onorato, M.; Dudley, J.M.; Babanin, A.V.

    2015-10-15

    The dynamics of waves in weakly nonlinear dispersive media can be described by the nonlinear Schrödinger equation (NLSE). An important feature of the equation is that it can be derived in a number of different physical contexts; therefore, analogies between different fields, such as for example fiber optics, water waves, plasma waves and Bose–Einstein condensates, can be established. Here, we investigate the similarities between wave propagation in optical Kerr media and water waves. In particular, we discuss the modulation instability (MI) in both media. In analogy to the water wave problem, we derive for Kerr-media the Benjamin–Feir index, i.e. a nondimensional parameter related to the probability of formation of rogue waves in incoherent wave trains.

  7. Measurement of the second-order Zeeman effect on the sodium clock transition in the weak-magnetic-field region using the scalar Aharonov-Bohm phase

    SciTech Connect (OSTI)

    Numazaki, Kazuya; Imai, Hiromitsu; Morinaga, Atsuo [Department of Physics, Faculty of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda-shi, Chiba 278-8510 (Japan)

    2010-03-15

    The second-order Zeeman effect of the sodium clock transition in a weak magnetic field of less than 50 {mu}T was measured as the scalar Aharonov-Bohm phase by two-photon stimulated Raman atom interferometry. The ac Stark effect of the Raman pulse was canceled out by adopting an appropriate intensity ratio of two photons in the Raman pulse. The Ramsey fringes for the pulse separation of 7 ms were obtained with a phase uncertainty of {pi}/200 rad. The nondispersive feature of the scalar Aharonov-Bohm phase was clearly demonstrated through 18 fringes with constant amplitude. The Breit-Rabi formula of the sodium clock transition was verified to be {Delta}{nu}=(0.222{+-}0.003)x10{sup 12}xB{sup 1.998{+-}0.004} in a magnetic field of less than 50 {mu}T.

  8. High numerical aperture multilayer Laue lenses

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Morgan, Andrew J.; Prasciolu, Mauro; Andrejczuk, Andrzej; Krzywinski, Jacek; Meents, Alke; Pennicard, David; Graafsma, Heinz; Barty, Anton; Bean, Richard J.; Barthelmess, Miriam; et al

    2015-06-01

    The ever-increasing brightness of synchrotron radiation sources demands improved X-ray optics to utilise their capability for imaging and probing biological cells, nanodevices, and functional matter on the nanometer scale with chemical sensitivity. Here we demonstrate focusing a hard X-ray beam to an 8 nm focus using a volume zone plate (also referred to as a wedged multilayer Laue lens). This lens was constructed using a new deposition technique that enabled the independent control of the angle and thickness of diffracting layers to microradian and nanometer precision, respectively. This ensured that the Bragg condition is satisfied at each point along themore » lens, leading to a high numerical aperture that is limited only by its extent. We developed a phase-shifting interferometric method based on ptychography to characterise the lens focus. The precision of the fabrication and characterisation demonstrated here provides the path to efficient X-ray optics for imaging at 1 nm resolution.« less

  9. High numerical aperture multilayer Laue lenses

    SciTech Connect (OSTI)

    Morgan, Andrew J.; Prasciolu, Mauro; Andrejczuk, Andrzej; Krzywinski, Jacek; Meents, Alke; Pennicard, David; Graafsma, Heinz; Barty, Anton; Bean, Richard J.; Barthelmess, Miriam; Oberthuer, Dominik; Yefanov, Oleksandr; Aquila, Andrew; Chapman, Henry N.; Bajt, Saša

    2015-06-01

    The ever-increasing brightness of synchrotron radiation sources demands improved X-ray optics to utilise their capability for imaging and probing biological cells, nanodevices, and functional matter on the nanometer scale with chemical sensitivity. Here we demonstrate focusing a hard X-ray beam to an 8 nm focus using a volume zone plate (also referred to as a wedged multilayer Laue lens). This lens was constructed using a new deposition technique that enabled the independent control of the angle and thickness of diffracting layers to microradian and nanometer precision, respectively. This ensured that the Bragg condition is satisfied at each point along the lens, leading to a high numerical aperture that is limited only by its extent. We developed a phase-shifting interferometric method based on ptychography to characterise the lens focus. The precision of the fabrication and characterisation demonstrated here provides the path to efficient X-ray optics for imaging at 1 nm resolution.

  10. Population studies. XIII. A new analysis of the Bidelman-Macconnell 'weak-metal' stars - confirmation of metal-poor stars in the thick disk of the galaxy

    SciTech Connect (OSTI)

    Beers, Timothy C.; Norris, John E.; Placco, Vinicius M.; Lee, Young Sun; Rossi, Silvia; Carollo, Daniela; Masseron, Thomas E-mail: jen@mso.anu.edu.au E-mail: youngsun@cnu.ac.kr E-mail: daniela.carollo@mq.edu.au

    2014-10-10

    A new set of very high signal-to-noise (S/N > 100/1), medium-resolution (R ∼ 3000) optical spectra have been obtained for 302 of the candidate 'weak-metal' stars selected by Bidelman and MacConnell. We use these data to calibrate the recently developed generalization of the Sloan Extension for Galactic Exploration and Understanding and Exploration (SEGUE) Stellar Parameter Pipeline, and obtain estimates of the atmospheric parameters (T {sub eff}, log g, and [Fe/H]) for these non-Sloan Digital Sky Survey/SEGUE data; we also obtain estimates of [C/Fe]. The new abundance measurements are shown to be consistent with available high-resolution spectroscopic determinations, and represent a substantial improvement over the accuracies obtained from the previous photometric estimates reported in Paper I of this series. The apparent offset in the photometric abundances of the giants in this sample noted by several authors is confirmed by our new spectroscopy; no such effect is found for the dwarfs. The presence of a metal-weak thick-disk (MWTD) population is clearly supported by these new abundance data. Some 25% of the stars with metallicities –1.8 < [Fe/H] ≤–0.8 exhibit orbital eccentricities e < 0.4, yet are clearly separated from members of the inner-halo population with similar metallicities by their location in a Lindblad energy versus angular momentum diagram. A comparison is made with recent results for a similar-size sample of Radial Velocity Experiment stars from Ruchti et al. We conclude, based on both of these samples, that the MWTD is real, and must be accounted for in discussions of the formation and evolution of the disk system of the Milky Way.

  11. A low-noise transimpedance amplifier for the detection of Violin-Mode resonances in advanced Laser Interferometer Gravitational wave Observatory suspensions

    SciTech Connect (OSTI)

    Lockerbie, N. A.; Tokmakov, K. V.

    2014-11-15

    This paper describes the design and performance of an extremely low-noise differential transimpedance amplifier, which takes its two inputs from separate photodiodes. The amplifier was planned to serve as the front-end electronics for a highly sensitive shadow-displacement sensing system, aimed at detecting very low-level Violin-Mode (VM) oscillations in 0.4 mm diameter by 600 mm long fused-silica suspension fibres. Four such highly tensioned fibres support the 40 kg test-masses/mirrors of the Advanced Laser Interferometer Gravitational wave Observatory interferometers. This novel design of amplifier incorporates features which prevent noise-gain peaking arising from large area photodiode (and cable) capacitances, and which also usefully separate the DC and AC photocurrents coming from the photodiodes. In consequence, the differential amplifier was able to generate straightforwardly two DC outputs, one per photodiode, as well as a single high-gain output for monitoring the VM oscillationsthis output being derived from the difference of the photodiodes two, naturally anti-phase, AC photocurrents. Following a displacement calibration, the amplifier's final VM signal output was found to have an AC displacement responsivity at 500 Hz of (9.43 1.20) MV(rms) m{sup ?1}(rms), and, therefore, a shot-noise limited sensitivity to such AC shadow- (i.e., fibre-) displacements of (69 13) picometres/?Hz at this frequency, over a measuring span of 0.1 mm.

  12. FIRST INVESTIGATION OF THE COMBINED IMPACT OF IONIZING RADIATION AND MOMENTUM WINDS FROM A MASSIVE STAR ON A SELF-GRAVITATING CORE

    SciTech Connect (OSTI)

    Ngoumou, Judith; Hubber, David; Dale, James E.; Burkert, Andreas

    2015-01-01

    Massive stars shape the surrounding interstellar matter (ISM) by emitting ionizing photons and ejecting material through stellar winds. To study the impact of the momentum from the wind of a massive star on the surrounding neutral or ionized material, we implemented a new HEALPix-based momentum-conserving wind scheme in the smoothed particle hydrodynamics (SPH) code SEREN. A qualitative study of the impact of the feedback from an O7.5-like star on a self-gravitating sphere shows that on its own, the transfer of momentum from a wind onto cold surrounding gas has both a compressing and dispersing effect. It mostly affects gas at low and intermediate densities. When combined with a stellar source's ionizing ultraviolet (UV) radiation, we find the momentum-driven wind to have little direct effect on the gas. We conclude that during a massive star's main sequence, the UV ionizing radiation is the main feedback mechanism shaping and compressing the cold gas. Overall, the wind's effects on the dense gas dynamics and on the triggering of star formation are very modest. The structures formed in the ionization-only simulation and in the combined feedback simulation are remarkably similar. However, in the combined feedback case, different SPH particles end up being compressed. This indicates that the microphysics of gas mixing differ between the two feedback simulations and that the winds can contribute to the localized redistribution and reshuffling of gas.

  13. Conservation Laws in Weak Interactions

    DOE R&D Accomplishments [OSTI]

    Lee, T. D.

    1957-03-01

    Notes are presented on four lectures given at Harvard University in March 1957 on elementary particle physics, the theta-tau problem, validity of parity conservation, tests for invariance under P, C, and T, and the two-component theory of the neutrino. (W.D.M.)

  14. The growth of structure in interacting dark energy models

    SciTech Connect (OSTI)

    Caldera-Cabral, Gabriela; Maartens, Roy; Schaefer, Bjoern Malte E-mail: roy.maartens@port.ac.uk

    2009-07-01

    If dark energy interacts with dark matter, there is a change in the background evolution of the universe, since the dark matter density no longer evolves as a{sup ?3}. In addition, the non-gravitational interaction affects the growth of structure. In principle, these changes allow us to detect and constrain an interaction in the dark sector. Here we investigate the growth factor and the weak lensing signal for a new class of interacting dark energy models. In these models, the interaction generalises the simple cases where one dark fluid decays into the other. In order to calculate the effect on structure formation, we perform a careful analysis of the perturbed interaction and its effect on peculiar velocities. Assuming a normalization to today's values of dark matter density and overdensity, the signal of the interaction is an enhancement (suppression) of both the growth factor and the lensing power, when the energy transfer in the background is from dark matter to dark energy (dark energy to dark matter)

  15. DESI and other Dark Energy experiments in the era of neutrino mass measurements

    SciTech Connect (OSTI)

    Font-Ribera, Andreu; McDonald, Patrick; Mostek, Nick; Reid, Beth A.; Seo, Hee-Jong; Slosar, Ane E-mail: PVMcDonald@lbl.gov E-mail: BAReid@lbl.gov E-mail: anze@bnl.gov

    2014-05-01

    We present Fisher matrix projections for future cosmological parameter measurements, including neutrino masses, Dark Energy, curvature, modified gravity, the inflationary perturbation spectrum, non-Gaussianity, and dark radiation. We focus on DESI and generally redshift surveys (BOSS, HETDEX, eBOSS, Euclid, and WFIRST), but also include CMB (Planck) and weak gravitational lensing (DES and LSST) constraints. The goal is to present a consistent set of projections, for concrete experiments, which are otherwise scattered throughout many papers and proposals. We include neutrino mass as a free parameter in most projections, as it will inevitably be relevant DESI and other experiments can measure the sum of neutrino masses to ? 0.02 eV or better, while the minimum possible sum is ? 0.06 eV. We note that constraints on Dark Energy are significantly degraded by the presence of neutrino mass uncertainty, especially when using galaxy clustering only as a probe of the BAO distance scale (because this introduces additional uncertainty in the background evolution after the CMB epoch). Using broadband galaxy power becomes relatively more powerful, and bigger gains are achieved by combining lensing survey constraints with redshift survey constraints. We do not try to be especially innovative, e.g., with complex treatments of potential systematic errors these projections are intended as a straightforward baseline for comparison to more detailed analyses.

  16. Evidence for a particle produced in association with weak bosons and decaying to a bottom-antibottom quark pair in Higgs boson searches at the Tevatron

    SciTech Connect (OSTI)

    Aaltonen, T.; Abazov, V.M.; Abbott, B.; Acharya, B.S.; Adams, M.; Adams, T.; Alexeev, G.D.; Alkhazov, G.; Alton, A.; Alvarez Gonzalez, B.; Alverson, G.; /Northeastern U. /INFN, Padua

    2012-07-01

    We combine searches by the CDF and D0 Collaborations for the associated production of a Higgs boson with a W or Z boson and subsequent decay of the Higgs boson to a bottom-antibottom quark pair. The data, originating from Fermilab Tevatron p{bar p} collisions at {radical}s=1.96 TeV, correspond to integrated luminosities of up to 9.7 fb{sup -1}. The searches are conducted for a Higgs boson with mass in the range 100-150 GeV/c{sup 2}. We observe an excess of events in the data compared with the background predictions, which is most significant in the mass range between 120 and 135 GeV/c{sup 2}. The largest local significance is 3.3 standard deviations, corresponding to a global significance of 3.1 standard deviations. We interpret this as evidence for the presence of a new particle consistent with the standard model Higgs boson, which is produced in association with a weak vector boson and decays to a bottom-antibottom quark pair.

  17. Study of dust particle charging in weakly ionized inert gases taking into account the nonlocality of the electron energy distribution function

    SciTech Connect (OSTI)

    Filippov, A. V. Dyatko, N. A.; Kostenko, A. S.

    2014-11-15

    The charging of dust particles in weakly ionized inert gases at atmospheric pressure has been investigated. The conditions under which the gas is ionized by an external source, a beam of fast electrons, are considered. The electron energy distribution function in argon, krypton, and xenon has been calculated for three rates of gas ionization by fast electrons: 10{sup 13}, 10{sup 14}, and 10{sup 15} cm{sup ?1}. A model of dust particle charging with allowance for the nonlocal formation of the electron energy distribution function in the region of strong plasma quasi-neutrality violation around the dust particle is described. The nonlocality is taken into account in an approximation where the distribution function is a function of only the total electron energy. Comparative calculations of the dust particle charge with and without allowance for the nonlocality of the electron energy distribution function have been performed. Allowance for the nonlocality is shown to lead to a noticeable increase in the dust particle charge due to the influence of the group of hot electrons from the tail of the distribution function. It has been established that the screening constant virtually coincides with the smallest screening constant determined according to the asymptotic theory of screening with the electron transport and recombination coefficients in an unperturbed plasma.

  18. Suppression of unimolecular decay of laser desorbed peptide and protein ions by entrainment in rarefied supersonic gas jets under weak electric fields

    SciTech Connect (OSTI)

    Hieke, Andreas

    2014-01-21

    Unimolecular decay of sample ions imposes a limit on the usable laser fluence in matrix-assisted laser desorption/ionization (MALDI) ion sources. Traditionally, some modest degree of collisional sample ion cooling has been achieved by connecting MALDI ion sources directly to gas-filled radio frequency (RF) multipoles. It was also discovered in the early 1990s that gas-filled RF multipoles exhibit increased ion transmission efficiency due to collisional ion focusing effects. This unexpected experimental finding was later supported by elementary Monte Carlo simulations. Both experiments and simulations assumed a resting background gas with typical pressures of the order of 1 Pa. However, considerable additional improvements can be achieved if laser desorbed sample ions are introduced immediately after desorption, still within the ion source, in an axisymmetric rarefied supersonic gas jet with peak pressure of the order of 100 Pa and flow velocities >300 m/s, and under weak electric fields. We describe here the design principle and report performance data of an ion source coined “MALDI-2,” which incorporates elements of both rarefied aerodynamics and particle optics. Such a design allows superb suppression of metastable fragmentation due to rapid collisional cooling in <10 μs and nearly perfect injection efficiency into the attached RF ion guide, as numerous experiments have confirmed.

  19. AN INDIRECT SEARCH FOR WEAKLY INTERACTING MASSIVE PARTICLES IN THE SUN USING 3109.6 DAYS OF UPWARD-GOING MUONS IN SUPER-KAMIOKANDE

    SciTech Connect (OSTI)

    Tanaka, T.; Abe, K.; Hayato, Y.; Iida, T.; Kameda, J.; Koshio, Y.; Kouzuma, Y.; Miura, M.; Moriyama, S.; Nakahata, M.; Nakayama, S.; Obayashi, Y.; Sekiya, H.; Shiozawa, M.; Suzuki, Y.; Takeda, A.; Takenaga, Y.; Ueno, K.; Ueshima, K.; Yamada, S.; Collaboration: Super-Kamiokande Collaboration; and others

    2011-12-01

    We present the result of an indirect search for high energy neutrinos from Weakly Interacting Massive Particle (WIMP) annihilation in the Sun using upward-going muon (upmu) events at Super-Kamiokande. Data sets from SKI-SKIII (3109.6 days) were used for the analysis. We looked for an excess of neutrino signal from the Sun as compared with the expected atmospheric neutrino background in three upmu categories: stopping, non-showering, and showering. No significant excess was observed. The 90% C.L. upper limits of upmu flux induced by WIMPs of 100 GeV c{sup -2} were 6.4 Multiplication-Sign 10{sup -15} cm{sup -2} s{sup -1} and 4.0 Multiplication-Sign 10{sup -15} cm{sup -2} s{sup -1} for the soft and hard annihilation channels, respectively. These limits correspond to upper limits of 4.5 Multiplication-Sign 10{sup -39} cm{sup -2} and 2.7 Multiplication-Sign 10{sup -40} cm{sup -2} for spin-dependent WIMP-nucleon scattering cross sections in the soft and hard annihilation channels, respectively.

  20. Water on BN doped benzene: A hard test for exchange-correlation functionals and the impact of exact exchange on weak binding

    SciTech Connect (OSTI)

    Al-Hamdani, Yasmine S.; Alf, Dario; von Lilienfeld, O. Anatole; Michaelides, Angelos

    2014-10-22

    Density functional theory (DFT) studies of weakly interacting complexes have recently focused on the importance of van der Waals dispersion forces, whereas the role of exchange has received far less attention. Here, by exploiting the subtle binding between water and a boron and nitrogen doped benzene derivative (1,2-azaborine) we show how exact exchange can alter the binding conformation within a complex. Benchmark values have been calculated for three orientations of the water monomer on 1,2-azaborine from explicitly correlated quantum chemical methods, and we have also used diffusion quantum Monte Carlo. For a host of popular DFT exchange-correlation functionals we show that the lack of exact exchange leads to the wrong lowest energy orientation of water on 1,2-azaborine. As such, we suggest that a high proportion of exact exchange and the associated improvement in the electronic structure could be needed for the accurate prediction of physisorption sites on doped surfaces and in complex organic molecules. Meanwhile to predict correct absolute interaction energies an accurate description of exchange needs to be augmented by dispersion inclusive functionals, and certain non-local van der Waals functionals (optB88- and optB86b-vdW) perform very well for absolute interaction energies. Through a comparison with water on benzene and borazine (B?N?H?) we show that these results could have implications for the interaction of water with doped graphene surfaces, and suggest a possible way of tuning the interaction energy.