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Sample records for vleet hol ly

  1. LY

    Office of Legacy Management (LM)

    bee:- L. Brazley, ECT R. Ramsey, ECT W. Brown, GC W. Mott, ECT E. Hardison, OR A. Whitman, ECT Division C. Kouts, EV-11 S. Miller, GC EV-10 EV-131 RWRamseyzs 62779 6P7 79 ----...

  2. Constraining the Ly? escape fraction with far-infrared observations of Ly? emitters

    SciTech Connect (OSTI)

    Wardlow, Julie L.; Calanog, J.; Cooray, A.; Malhotra, S.; Zheng, Z.; Rhoads, J.; Finkelstein, S.; Bock, J.; Bridge, C.; Ciardullo, R.; Gronwall, C.; Conley, A.; Farrah, D.; Gawiser, E.; Heinis, S.; Ibar, E.; Ivison, R. J.; Marsden, G.; Oliver, S. J.; Riechers, D.; and others

    2014-05-20

    We study the far-infrared properties of 498 Ly? emitters (LAEs) at z = 2.8, 3.1, and 4.5 in the Extended Chandra Deep Field-South, using 250, 350, and 500 ?m data from the Herschel Multi-tiered Extragalactic Survey and 870 ?m data from the LABOCA ECDFS Submillimeter Survey. None of the 126, 280, or 92 LAEs at z = 2.8, 3.1, and 4.5, respectively, are individually detected in the far-infrared data. We use stacking to probe the average emission to deeper flux limits, reaching 1? depths of ?0.1 to 0.4 mJy. The LAEs are also undetected at ?3? in the stacks, although a 2.5? signal is observed at 870 ?m for the z = 2.8 sources. We consider a wide range of far-infrared spectral energy distributions (SEDs), including an M82 and an Sd galaxy template, to determine upper limits on the far-infrared luminosities and far-infrared-derived star formation rates of the LAEs. These star formation rates are then combined with those inferred from the Ly? and UV emission to determine lower limits on the LAEs' Ly? escape fraction (f {sub esc}(Ly?)). For the Sd SED template, the inferred LAEs f {sub esc}(Ly?) are ? 30% (1?) at z = 2.8, 3.1, and 4.5, which are all significantly higher than the global f {sub esc}(Ly?) at these redshifts. Thus, if the LAEs f {sub esc}(Ly?) follows the global evolution, then they have warmer far-infrared SEDs than the Sd galaxy template. The average and M82 SEDs produce lower limits on the LAE f {sub esc}(Ly?) of ?10%-20% (1?), all of which are slightly higher than the global evolution of f {sub esc}(Ly?), but consistent with it at the 2?-3? level.

  3. LyMAS: Predicting large-scale Ly? forest statistics from the dark matter density field

    SciTech Connect (OSTI)

    Peirani, Sbastien; Colombi, Stphane; Dubois, Yohan; Pichon, Christophe; Weinberg, David H.; Blaizot, Jrmy

    2014-03-20

    We describe Ly? Mass Association Scheme (LyMAS), a method of predicting clustering statistics in the Ly? forest on large scales from moderate-resolution simulations of the dark matter (DM) distribution, with calibration from high-resolution hydrodynamic simulations of smaller volumes. We use the 'Horizon-MareNostrum' simulation, a 50 h {sup 1} Mpc comoving volume evolved with the adaptive mesh hydrodynamic code RAMSES, to compute the conditional probability distribution P(F{sub s} |? {sub s}) of the transmitted flux F{sub s} , smoothed (one-dimensionally, 1D) over the spectral resolution scale, on the DM density contrast ? {sub s}, smoothed (three-dimensionally, 3D) over a similar scale. In this study we adopt the spectral resolution of the SDSS-III Baryon Oscillation Spectroscopic Survey (BOSS) at z = 2.5, and we find optimal results for a DM smoothing length ? = 0.3 h {sup 1} Mpc (comoving). In its simplest form, LyMAS draws randomly from the hydro-calibrated P(F{sub s} |? {sub s}) to convert DM skewers into Ly? forest pseudo-spectra, which are then used to compute cross-sightline flux statistics. In extended form, LyMAS exactly reproduces both the 1D power spectrum and one-point flux distribution of the hydro simulation spectra. Applied to the MareNostrum DM field, LyMAS accurately predicts the two-point conditional flux distribution and flux correlation function of the full hydro simulation for transverse sightline separations as small as 1 h {sup 1} Mpc, including redshift-space distortion effects. It is substantially more accurate than a deterministic density-flux mapping ({sup F}luctuating Gunn-Peterson Approximation{sup )}, often used for large-volume simulations of the forest. With the MareNostrum calibration, we apply LyMAS to 1024{sup 3} N-body simulations of a 300 h {sup 1} Mpc and 1.0 h {sup 1} Gpc cube to produce large, publicly available catalogs of mock BOSS spectra that probe a large comoving volume. LyMAS will be a powerful tool for interpreting 3D Ly? forest data, thereby transforming measurements from BOSS and other massive quasar absorption surveys into constraints on dark energy, DM, space geometry, and intergalactic medium physics.

  4. LINKING Lyα AND LOW-IONIZATION TRANSITIONS AT LOW OPTICAL DEPTH

    SciTech Connect (OSTI)

    Jaskot, A. E.; Oey, M. S.

    2014-08-20

    We suggest that low optical depth in the Lyman continuum (LyC) may relate the Lyα emission, C II and Si II absorption, and C II* and Si II* emission seen in high-redshift galaxies. We base this analysis on Hubble Space Telescope Cosmic Origins Spectrograph spectra of four Green Pea (GP) galaxies, which may be analogs of z > 2 Lyα emitters (LAEs). In the two GPs with the strongest Lyα emission, the Lyα line profiles show reduced signs of resonant scattering. Instead, the Lyα profiles resemble the Hα line profiles of evolved star ejecta, suggesting that the Lyα emission originates from a low column density and similar outflow geometry. The weak C II absorption and presence of non-resonant C II* emission in these GPs support this interpretation and imply a low LyC optical depth along the line of sight. In two additional GPs, weak Lyα emission and strong C II absorption suggest a higher optical depth. These two GPs differ in their Lyα profile shapes and C II* emission strengths, however, indicating different inclinations of the outflows to our line of sight. With these four GPs as examples, we explain the observed trends linking Lyα, C II, and C II* in stacked LAE spectra, in the context of optical depth and geometric effects. Specifically, in some galaxies with strong Lyα emission, a low LyC optical depth may allow Lyα to escape with reduced scattering. Furthermore, C II absorption, C II* emission, and Lyα profile shape can reveal the optical depth, constrain the orientation of neutral outflows in LAEs, and identify candidate LyC emitters.

  5. ionic liquids biological-ly derived from lignin and hemicellulose

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

    biological-ly derived from lignin and hemicellulose - 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 Battery Testing Nuclear Fuel Cycle Defense Waste

  6. z ? 1 Ly? emitters. I. The luminosity function , , ,

    SciTech Connect (OSTI)

    Wold, Isak G. B.; Barger, Amy J.; Cowie, Lennox L. E-mail: barger@astro.wisc.edu

    2014-03-10

    We construct a flux-limited sample of 135 candidate z ? 1 Ly? emitters (LAEs) from Galaxy Evolution Explorer (GALEX) grism data using a new data cube search method. These LAEs have luminosities comparable to those at high redshifts and lie within a 7 Gyr gap present in existing LAE samples. We use archival and newly obtained optical spectra to verify the UV redshifts of these LAEs. We use the combination of the GALEX UV spectra, optical spectra, and X-ray imaging data to estimate the active galactic nucleus (AGN) fraction and its dependence on Ly? luminosity. We remove the AGNs and compute the luminosity function (LF) from 60 z ? 1 LAE galaxies. We find that the best-fit LF implies a luminosity density increase by a factor of ?1.5 from z ? 0.3 to z ? 1 and ?20 from z ? 1 to z ? 2. We find a z ? 1 volumetric Ly? escape fraction of 0.7% 0.4%.

  7. Accelerated evolution of the Ly? luminosity function at z ? 7 revealed by the Subaru ultra-deep survey for Ly? emitters at z = 7.3

    SciTech Connect (OSTI)

    Konno, Akira; Ouchi, Masami; Ono, Yoshiaki; Shibuya, Takatoshi; Naito, Yoshiaki; Momose, Rieko; Yuma, Suraphong; Shimasaku, Kazuhiro; Nakajima, Kimihiko; Furusawa, Hisanori; Iye, Masanori

    2014-12-10

    We present the ultra-deep Subaru narrowband imaging survey for Ly? emitters (LAEs) at z = 7.3 in the Subaru/XMM-Newton Deep Survey (SXDS) and Cosmic Evolution Survey (COSMOS) fields (?0.5 deg{sup 2}) with a total integration time of 106 hr. Exploiting our new sharp bandwidth filter, NB101, installed on the Suprime-Cam, we have reached L(Ly?) = 2.4 10{sup 42} erg s{sup 1} (5?) for z = 7.3 LAEs, about four times deeper than previous Subaru z ? 7 studies, which allows us to reliably investigate the evolution of the Ly? luminosity function (LF) for the first time down to the luminosity limit same as those of Subaru z = 3.1-6.6 LAE samples. Surprisingly, we only find three and four LAEs in the SXDS and COSMOS fields, respectively, while one expects a total of ?65 LAEs by our survey in the case of no Ly? LF evolution from z = 6.6 to 7.3. We identify a decrease of the Ly? LF from z = 6.6 to 7.3 at the >90% confidence level from our z = 7.3 Ly? LF with the best-fit Schechter parameters of L{sub Ly?}{sup ?}=2.7{sub ?1.2}{sup +8.0}10{sup 42} erg s{sup ?1} and ?{sup ?}=3.7{sub ?3.3}{sup +17.6}10{sup ?4} Mpc{sup ?3} for a fixed ? = 1.5. Moreover, the evolution of the Ly? LF is clearly accelerated at z > 6.6 beyond the measurement uncertainties including cosmic variance. Because no such accelerated evolution of the UV-continuum LF or the cosmic star formation rate (SFR) is found at z ? 7, but suggested only at z > 8, this accelerated Ly? LF evolution is explained by physical mechanisms different from a pure SFR decrease but related to the Ly? production and escape in the process of cosmic reionization. Because a simple accelerating increase of intergalactic medium neutral hydrogen absorbing Ly? cannot be reconciled with Thomson scattering of optical depth measurements from WMAP and Planck, our findings may support new physical pictures suggested by recent theoretical studies, such as the existence of HI clumpy clouds within cosmic ionized bubbles that are selectively absorbing Ly? and the large ionizing photon escape fraction of galaxies causing weak Ly? emission.

  8. COMPUTING INTRINSIC LY{alpha} FLUXES OF F5 V TO M5 V STARS

    SciTech Connect (OSTI)

    Linsky, Jeffrey L.; France, Kevin; Ayres, Tom

    2013-04-01

    The Ly{alpha} emission line dominates the far-ultraviolet spectra of late-type stars and is a major source for photodissociation of important molecules including H{sub 2}O, CH{sub 4}, and CO{sub 2} in exoplanet atmospheres. The incident flux in this line illuminating an exoplanet's atmosphere cannot be measured directly as neutral hydrogen in the interstellar medium (ISM) attenuates most of the flux reaching the Earth. Reconstruction of the intrinsic Ly{alpha} line has been accomplished for a limited number of nearby stars, but is not feasible for distant or faint host stars. We identify correlations connecting the intrinsic Ly{alpha} flux with the flux in other emission lines formed in the stellar chromosphere, and find that these correlations depend only gradually on the flux in the other lines. These correlations, which are based on Hubble Space Telescope spectra, reconstructed Ly{alpha} line fluxes, and irradiance spectra of the quiet and active Sun, are required for photochemical models of exoplanet atmospheres when intrinsic Ly{alpha} fluxes are not available. We find a tight correlation of the intrinsic Ly{alpha} flux with stellar X-ray flux for F5 V to K5 V stars, but much larger dispersion for M stars. We also show that knowledge of the stellar effective temperature and rotation rate can provide reasonably accurate estimates of the Ly{alpha} flux for G and K stars, and less accurate estimates for cooler stars.

  9. A z ? 5.7 Ly? emission line with an ultrabroad red wing

    SciTech Connect (OSTI)

    Yang, Huan; Wang, JunXian; Zheng, Zhen-Ya; Malhotra, Sangeeta; Rhoads, James E.; Infante, Leopoldo E-mail: jxw@mail.ustc.edu.cn E-mail: smalhotr@asu.edu E-mail: linfante@astro.puc.cl

    2014-03-20

    Using the Ly? emission line as a tracer of high-redshift, star-forming galaxies, hundreds of Ly? emission line galaxies (LAEs) at z > 5 have been detected. These LAEs are considered to be low-mass young galaxies, critical to the re-ionization of the universe and the metal enrichment of the circumgalactic medium (CGM) and the intergalactic medium (IGM). It is assumed that outflows in LAEs can help both ionizing photons and Ly? photons escape from galaxies. However, we still know little about the outflows in high-redshift LAEs due to observational difficulties, especially at redshift >5. Models of Ly? radiative transfer predict asymmetric Ly? line profiles with broad red wings in LAEs with outflows. Here, we report a z ? 5.7 Ly? emission line with a broad red wing extending to >1000 km s{sup 1} relative to the peak of Ly? line, which has been detected in only a couple of z > 5 LAEs until now. If the broad red wing is ascribed to gas outflow instead of active galactic nucleus activity, the outflow velocity could be larger than the escape velocity (?500 km s{sup 1}) of a typical halo mass of z ? 5.7 LAEs, which is consistent with the idea that outflows in LAEs disperse metals to CGM and IGM.

  10. Ly{alpha} EMITTERS AT z = 7 IN THE SUBARU/XMM-NEWTON DEEP SURVEY FIELD:

    Office of Scientific and Technical Information (OSTI)

    PHOTOMETRIC CANDIDATES AND LUMINOSITY FUNCTION (Journal Article) | SciTech Connect Ly{alpha} EMITTERS AT z = 7 IN THE SUBARU/XMM-NEWTON DEEP SURVEY FIELD: PHOTOMETRIC CANDIDATES AND LUMINOSITY FUNCTION Citation Details In-Document Search Title: Ly{alpha} EMITTERS AT z = 7 IN THE SUBARU/XMM-NEWTON DEEP SURVEY FIELD: PHOTOMETRIC CANDIDATES AND LUMINOSITY FUNCTION We conducted a deep narrowband NB973 (FWHM = 200 A centered at 9755 A) survey of z = 7 Ly{alpha} emitters (LAEs) in the

  11. X-RAY CONSTRAINTS ON THE Ly{alpha} ESCAPE FRACTION

    SciTech Connect (OSTI)

    Zheng Zhenya; Wang Junxian; Malhotra, Sangeeta; Rhoads, James E.; Finkelstein, Steven L.; Gawiser, Eric; Gronwall, Caryl; Ciardullo, Robin; Guaita, Lucia; Nilsson, Kim K.

    2012-02-10

    We have co-added the X-ray flux of all known Ly{alpha} emitters (LAEs) in the 4 Ms Chandra Deep Field South (CDF-S) region, achieving the tightest upper limits yet on the X-ray to Ly{alpha} ratio. We use the X-ray data to place sensitive upper limits on the average unobscured star formation rate (SFR{sub X}) in these galaxies. A very small fraction of Ly{alpha} galaxies in the field are individually detected in the X-rays, implying a low fraction of active galactic nucleus activity. After excluding the few X-ray-detected LAEs, we stack the undetected LAEs located in the 4 Ms CDF-S data and 250 ks Extended CDF-S (ECDF-S) data, and compute a 1{sigma} upper limit on SFR{sub X} < 1.6, 14, 28, 28, 140, 440, 880 M{sub Sun} yr{sup -1} for LAEs located at z {approx} 0.3 and z = 2.1, 3.1, 3.2, 4.5, 5.7, and 6.5, respectively. The upper limit of SFR{sub X} in LAEs can be then compared to SFR{sub Ly{alpha}} derived from Ly{alpha} line and thus can constrain on the Ly{alpha} escape fraction (f{sup Esc}{sub Ly{alpha}}). The f{sup Esc}{sub Ly{alpha}} from X-ray at z {approx} 0.3 is substantially larger than that from UV or H{alpha}. Three X-ray-detected LAE galaxies at z {approx} 0.3 show f{sup Esc}{sub Ly{alpha}} {approx} 3%-22%, and the average Ly{alpha} escape fraction from stacking the X-ray-undetected LAEs show f{sup Esc}{sub Ly{alpha}} > 28% at 3{sigma} significance level at the same redshift. We derive a lower limit on f{sup Esc}{sub Ly{alpha}} > 14% (84% confidence level, 1{sigma} lower limit) for LAEs at redshift z {approx} 2.1 and z {approx} 3.1-3.2. At z > 4, the current LAE samples are not of sufficient size to constrain SFR{sub X} well. By averaging all the LAEs at z > 2, the X-ray non-detection constrains f{sup Esc}{sub Ly{alpha}} > 17% (84% confidence level, 1{sigma} lower limit), and rejects f{sup Esc}{sub Ly{alpha}} < 5.7% at the 99.87% confidence level from 2.1 < z < 6.5.

  12. A submillimeter galaxy illuminating its circumgalactic medium: Ly? scattering in a cold, clumpy outflow

    SciTech Connect (OSTI)

    Geach, J. E.; Coppin, K. E. K.; Smith, D. J. B.; Bower, R. G.; Alexander, D. M.; Swinbank, A. M.; Blain, A. W.; Bremer, M. N.; Chapin, E. L.; Chapman, S. C.; Clements, D. L.; Dunlop, J. S.; Koprowski, M. P.; Micha?owski, M. J.; Farrah, D.; Jenness, T.; Robson, E. I.; Scott, D.; Spaans, M.; Van der Werf, P.

    2014-09-20

    We report the detection at 850 ?m of the central source in SSA22-LAB1, the archetypal 'Lyman-? Blob' (LAB), a 100 kpc scale radio-quiet emission-line nebula at z = 3.1. The flux density of the source, S {sub 850} = 4.6 1.1 mJy, implies the presence of a galaxy or group of galaxies with a total luminosity of L {sub IR} ? 10{sup 12} L {sub ?}. The position of an active source at the center of a ?50 kpc radius ring of linearly polarized Ly? emission detected by Hayes et al. suggests that the central source is leaking Ly? photons preferentially in the plane of the sky, which undergo scattering in H I clouds at a large galactocentric radius. The Ly? morphology around the submillimeter detection is reminiscent of a biconical outflow, and the average Ly? line profiles of the two 'lobes' are dominated by a red peak, which is expected for a resonant line emerging from a medium with a bulk velocity gradient that is outflowing relative to the line center. Taken together, these observations provide compelling evidence that the central active galaxy (or galaxies) is responsible for a large fraction of the extended Ly? emission and morphology. Less clear is the history of the cold gas in the circumgalactic medium being traced by Ly?: is it mainly pristine material accreting into the halo that has not yet been processed through an interstellar medium (ISM), now being blown back as it encounters an outflow, or does it mainly comprise gas that has been swept-up within the ISM and expelled from the galaxy?.

  13. Foreground contamination in Ly? intensity mapping during the epoch of reionization

    SciTech Connect (OSTI)

    Gong, Yan; Cooray, Asantha; Silva, Marta; Santos, Mario G.

    2014-04-10

    The intensity mapping of Ly? emission during the epoch of reionization will be contaminated by foreground emission lines from lower redshifts. We calculate the mean intensity and the power spectrum of Ly? emission at z ? 7 and estimate the uncertainties according to the relevant astrophysical processes. We find that the low-redshift emission lines from 6563 H?, 5007 [O III], and 3727 [O II] will be strong contaminants on the observed Ly? power spectrum. We make use of both the star formation rate and luminosity functions to estimate the mean intensity and power spectra of the three foreground lines at z ? 0.5 for H?, z ? 0.9 for [O III], and z ? 1.6 for [O II], as they will contaminate the Ly? emission at z ? 7. The [O II] line is found to be the strongest. We analyze the masking of the bright survey pixels with a foreground line above some line intensity threshold as a way to reduce the contamination in an intensity mapping survey. We find that the foreground contamination can be neglected if we remove pixels with fluxes above 1.4 10{sup 20} W m{sup 2}.

  14. Ly{alpha} ESCAPE FROM z {approx} 0.03 STAR-FORMING GALAXIES: THE DOMINANT ROLE OF OUTFLOWS

    SciTech Connect (OSTI)

    Wofford, Aida; Leitherer, Claus [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Salzer, John, E-mail: wofford@stsci.edu [Astronomy Department, Indiana University, Swain West 408, 727 East Third Street, Bloomington, IN 47405 (United States)

    2013-03-10

    The usefulness of H I Ly{alpha} photons for characterizing star formation in the distant universe is limited by our understanding of the astrophysical processes that regulate their escape from galaxies. These processes can only be observed in detail out to a few Multiplication-Sign 100 Mpc. Past nearby (z < 0.3) spectroscopic studies are based on small samples and/or kinematically unresolved data. Taking advantage of the high sensitivity of Hubble Space Telescope's Cosmic Origins Spectrograph (COS), we observed the Ly{alpha} lines of 20 H{alpha}-selected galaxies located at =0.03. The galaxies cover a broad range of luminosity, oxygen abundance, and reddening. In this paper, we characterize the observed Ly{alpha} lines and establish correlations with fundamental galaxy properties. We find seven emitters. These host young ({<=}10 Myr) stellar populations have rest-frame equivalent widths in the range 1-12 A, and have Ly{alpha} escape fractions within the COS aperture in the range 1%-12%. One emitter has a double-peaked Ly{alpha} with peaks 370 km s{sup -1} apart and a stronger blue peak. Excluding this object, the emitters have Ly{alpha} and O I {lambda}1302 offsets from H{alpha} in agreement with expanding-shell models and Lyman break galaxies observations. The absorbers have offsets that are almost consistent with a static medium. We find no one-to-one correspondence between Ly{alpha} emission and age, metallicity, or reddening. Thus, we confirm that Ly{alpha} is enhanced by outflows and is regulated by the dust and H I column density surrounding the hot stars.

  15. PREDICTING Lyα AND Mg II FLUXES FROM K AND M DWARFS USING GALAXY EVOLUTION EXPLORER ULTRAVIOLET PHOTOMETRY

    SciTech Connect (OSTI)

    Shkolnik, Evgenya L.; Rolph, Kristina A.; Peacock, Sarah; Barman, Travis S. E-mail: kristina.rolph@fandm.edu E-mail: barman@lpl.arizona.edu

    2014-11-20

    A star's ultraviolet (UV) emission can greatly affect the atmospheric chemistry and physical properties of closely orbiting planets with the potential for severe mass loss. In particular, the Lyα emission line at 1216 Å, which dominates the far-ultraviolet (FUV) spectrum, is a major source of photodissociation of important atmospheric molecules such as water and methane. The intrinsic flux of Lyα, however, cannot be directly measured due to the absorption of neutral hydrogen in the interstellar medium and contamination by geocoronal emission. To date, reconstruction of the intrinsic Lyα line based on Hubble Space Telescope spectra has been accomplished for 46 FGKM nearby stars, 28 of which have also been observed by the Galaxy Evolution Explorer (GALEX). Our investigation provides a correlation between published intrinsic Lyα and GALEX far- and near-ultraviolet (NUV) chromospheric fluxes for K and M stars. The negative correlations between the ratio of the Lyα to the GALEX fluxes reveal how the relative strength of Lyα compared to the broadband fluxes weakens as the FUV and NUV excess flux increase. We also correlate GALEX fluxes with the strong NUV Mg II h+k spectral emission lines formed at lower chromospheric temperatures than Lyα. The reported correlations provide estimates of intrinsic Lyα and Mg II fluxes for the thousands of K and M stars in the archived GALEX all-sky surveys. These will constrain new stellar upper atmosphere models for cool stars and provide realistic inputs to models describing exoplanetary photochemistry and atmospheric evolution in the absence of UV spectroscopy.

  16. He II Ly{beta} GUNN-PETERSON ABSORPTION: NEW HST OBSERVATIONS AND THEORETICAL EXPECTATIONS

    SciTech Connect (OSTI)

    Syphers, David; Pieri, Matthew; Shull, J. Michael; Anderson, Scott F.; Zheng, Wei; Kriss, Gerard A.; Smith, Britton; Meiksin, Avery; Schneider, Donald P.; York, Donald G.

    2011-12-01

    Observations of He II Ly{alpha} Gunn-Peterson troughs have proved to be a valuable probe of the epoch of helium reionization at z {approx} 3. Since this optical depth can become unmeasurably large even for modest He II fractions, various alternate techniques have been proposed to push to higher redshift, and among the more promising is looking at higher-order Lyman-series troughs. We here report four new observations of the He II Ly{beta} trough, including new data on the only sightline with a prior Ly{beta} observation. However, the effective optical depth ratio {tau}{sub eff,{beta}}/{tau}{sub eff,{alpha}} is not simply predicted by f{sub {beta}}{lambda}{sub {beta}}/f{sub {alpha}}{lambda}{sub {alpha}} = 0.16, and we analyze cosmological simulations to find that the correct ratio for helium at z {approx} 3 is {approx_equal}0.35. In one case we infer {tau}{sub eff,{alpha}} > 8.8, strong evidence that helium was not fully reionized at z = 3.2-3.5, in agreement with previous measurements suggesting a later completion of reionization.

  17. BROAD Ly{alpha} EMISSION FROM THREE NEARBY BL LACERTAE OBJECTS

    SciTech Connect (OSTI)

    Stocke, John T.; Danforth, Charles W. [CASA, Department of Astrophysical and Planetary Sciences, University of Colorado, 389-UCB, Boulder, CO 80309 (United States); Perlman, Eric S., E-mail: danforth@casa.colorado.edu, E-mail: stocke@casa.colorado.edu, E-mail: eperlman@fit.edu [Florida Institute of Technology, Physics and Space Sciences Department, 150 West University Boulevard, Melbourne, FL 32901 (United States)

    2011-05-10

    We present far-UV HST/COS spectra of four nearby BL Lac objects. BL Lac spectra are dominated by a smooth, power-law continuum which arises in a relativistic jet. However, the spectra are not necessarily featureless; weak, broad- and/or narrow-line emission is sometimes seen in high-quality optical spectra. We present detections of Ly{alpha} emission in HST/COS spectra of Mrk 421 (z = 0.030) and PKS 2005-489 (z = 0.071) as well as an archival HST/GHRS observation of Mrk 501 (z = 0.0337). Archival HST/STIS observations of PKS 2155-304 (z = 0.116) show no Ly{alpha} emission to a very low upper limit. Using the assumption that the broad-line region (BLR) clouds are symmetrically placed around the active galactic nucleus (AGN), we use these measured Ly{alpha} emission features to constrain either the relativistic {Gamma} values for the ionizing continuum produced by the jet (in the ionization-bounded case) or the mass of warm gas (in the density-bounded case). While realistic {Gamma} values can be obtained for all four cases, the values for Mrk 421 and PKS 2155-304 are high enough to suggest that covering factors of BLR clouds of {approx}1%-2% might be required to provide consistency with earlier values of Doppler boosting and viewing angles suggested for this class of BL Lacs. This discrepancy also exists in the case of M 87, where the amount of Doppler boosting in our direction is expected to be minimal, again suggestive of a small covering factor of BLR clouds. If, as these small covering factors might suggest, the assumptions of a density-bounded model could be more correct, then the observed Ly{alpha} luminosities require that BL Lac/FR 1 nuclei possess very little warm gas (10{sup -4} to 10{sup -5} M{sub sun}) as suggested by Guilbert et al. If these clouds are in pressure balance with a hotter ({approx}10{sup 6} K) gas, the BLR contains too little mass to power the AGN by accretion alone.

  18. SITES ELIHlNAlED FRCil FUW' ~1WWk'l ffi LY

    Office of Legacy Management (LM)

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  19. HUBBLE/COS OBSERVATIONS OF THE Ly{alpha} FOREST TOWARD THE BL Lac OBJECT 1ES 1553+113

    SciTech Connect (OSTI)

    Danforth, Charles W.; Keeney, Brian A.; Stocke, John T.; Shull, J. Michael; Yao Yangsen, E-mail: danforth@casa.colorado.ed [CASA, Department of Astrophysical and Planetary Sciences, University of Colorado, 389-UCB, Boulder, CO 80309 (United States)

    2010-09-01

    We present new moderate-resolution, far-ultraviolet spectra from the Hubble Space Telescope/Cosmic Origins Spectrograph (HST/COS) of the BL Lac object 1ES 1553+113 covering the wavelength range 1135 A < {lambda} < 1795 A. The data show a smooth continuum with a wealth of narrow (b < 100 km s{sup -1}) absorption features arising in the interstellar medium and intergalactic medium. These features include 41 Ly{alpha} absorbers at 0 < z{sub abs} < 0.43, 14 of which are detected in multiple Lyman lines and 6 of which show absorption in one or more metal lines. We analyze a metal-rich triplet ({Delta}cz {approx} 1000 km s{sup -1}) of Ly{alpha} absorbers at z{sub abs} {approx} 0.188 in which O VI, N V, and C III absorption is detected. Silicon ions (Si III, Si IV) are not detected to fairly strong upper limits and we use the measured Si III/C III upper limit to derive an abundance limit (C/Si) {>=} 4(C/Si){sub sun} for the strongest component of the absorber complex. Galaxy redshift surveys show a number of massive galaxies at approximately the same redshift as this absorption complex, suggesting that it arises in a large-scale galaxy filament. As one of the brightest extragalactic X-ray and {gamma}-ray sources, 1ES 1553+113 is of great interest to the high-energy astrophysics community. With no intrinsic emission or absorption features, 1ES 1553+113 has no direct redshift determination. We use intervening Ly{alpha} absorbers to place a direct limit on the redshift: z{sub em}>0.395 based on a confirmed Ly{alpha}+O VI absorber and z{sub em}>0.433 based on a single-line detection of Ly{alpha}. The current COS data are only sensitive to Ly{alpha} absorbers at z < 0.47, but we present statistical arguments that z{sub em} {approx}< 0.58 (at a 1{sigma} confidence limit) based on the non-detection of any Ly{beta} absorbers at z>0.4.

  20. The impact of gas bulk rotation on the Lyα line

    SciTech Connect (OSTI)

    Garavito-Camargo, Juan N.; Forero-Romero, Jaime E.; Dijkstra, Mark E-mail: je.forero@uniandes.edu.co

    2014-11-10

    We present results of radiative transfer calculations to measure the impact of gas bulk rotation on the morphology of the Lyα emission line in distant galaxies. We model a galaxy as a sphere with an homogeneous mixture of dust and hydrogen at a constant temperature. These spheres undergo solid-body rotation with maximum velocities in the range 0-300 km s{sup –1} and neutral hydrogen optical depths in the range τ{sub H} = 10{sup 5}-10{sup 7}. We consider two types of source distributions in the sphere: central and homogeneous. Our main result is that rotation introduces a dependence of the line morphology with viewing angle and rotational velocity. Observations with a line of sight parallel to the rotation axis yield line morphologies similar to the static case. For lines of sight perpendicular to the rotation axis, both the intensity at the line center and the line width increase with rotational velocity. Along the same line of sight, the line becomes single peaked at rotational velocities close to half the line width in the static case. Notably, we find that rotation does not induce any spatial anisotropy in the integrated line flux, the escape fraction or the average number of scatterings. This is because Lyman scattering through a rotating solid-body proceeds identically to the static case. The only difference is the Doppler shift from the different regions in the sphere that move with respect to the observer. This allows us to derive an analytic approximation for the viewing-angle dependence of the emerging spectrum, as a function of rotational velocity.

  1. LY? FOREST TOMOGRAPHY FROM BACKGROUND GALAXIES: THE FIRST MEGAPARSEC-RESOLUTION LARGE-SCALE STRUCTURE MAP AT z > 2

    SciTech Connect (OSTI)

    Lee, Khee-Gan; Hennawi, Joseph F.; Eilers, Anna-Christina [Max Planck Institute for Astronomy, Knigstuhl 17, D-69117 Heidelberg (Germany); Stark, Casey; White, Martin [Department of Astronomy, University of California at Berkeley, B-20 Hearst Field Annex 3411, Berkeley, CA 94720 (United States); Prochaska, J. Xavier [Department of Astronomy and Astrophysics, University of California, 1156 High Street, Santa Cruz, CA 95064 (United States); Schlegel, David J. [University of California Observatories, Lick Observatory, 1156 High Street, Santa Cruz, CA 95064 (United States); Arinyo-i-Prats, Andreu [Institut de Cincies del Cosmos, Universitat de Barcelona (IEEC-UB), Mart Franqus 1, E-08028 Barcelona (Spain); Suzuki, Nao [Kavli Institute for the Physics and Mathematics of the Universe (IPMU), The University of Tokyo, Kashiwano-ha 5-1-5, Kashiwa-shi, Chiba (Japan); Croft, Rupert A. C. [Department of Physics, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA 15213 (United States); Caputi, Karina I. [Kapteyn Astronomical Institute, University of Groningen, P.O. Box 800, 9700-AV Groningen (Netherlands); Cassata, Paolo [Instituto de Fisica y Astronomia, Facultad de Ciencias, Universidad de Valparaiso, Av. Gran Bretana 1111, Casilla 5030, Valparaiso (Chile); Ilbert, Olivier; Le Brun, Vincent; Le Fvre, Olivier [Aix Marseille Universit, CNRS, LAM (Laboratoire d'Astrophysique de Marseille) UMR 7326, F-13388 Marseille (France); Garilli, Bianca [INAF-IASF, Via Bassini 15, I-20133, Milano (Italy); Koekemoer, Anton M. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Maccagni, Dario [INAF-Osservatorio Astronomico di Bologna, Via Ranzani,1, I-40127 Bologna (Italy); Nugent, Peter, E-mail: lee@mpia.de [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); and others

    2014-11-01

    We present the first observations of foreground Ly? forest absorption from high-redshift galaxies, targeting 24 star-forming galaxies (SFGs) with z ? 2.3-2.8 within a 5' 14' region of the COSMOS field. The transverse sightline separation is ?2 h {sup 1} Mpc comoving, allowing us to create a tomographic reconstruction of the three-dimensional (3D) Ly? forest absorption field over the redshift range 2.20 ? z ? 2.45. The resulting map covers 6 h {sup 1} Mpc 14 h {sup 1} Mpc in the transverse plane and 230 h {sup 1} Mpc along the line of sight with a spatial resolution of ?3.5 h {sup 1} Mpc, and is the first high-fidelity map of a large-scale structure on ?Mpc scales at z > 2. Our map reveals significant structures with ? 10 h {sup 1} Mpc extent, including several spanning the entire transverse breadth, providing qualitative evidence for the filamentary structures predicted to exist in the high-redshift cosmic web. Simulated reconstructions with the same sightline sampling, spectral resolution, and signal-to-noise ratio recover the salient structures present in the underlying 3D absorption fields. Using data from other surveys, we identified 18 galaxies with known redshifts coeval with our map volume, enabling a direct comparison with our tomographic map. This shows that galaxies preferentially occupy high-density regions, in qualitative agreement with the same comparison applied to simulations. Our results establish the feasibility of the CLAMATO survey, which aims to obtain Ly? forest spectra for ?1000 SFGs over ?1 deg{sup 2} of the COSMOS field, in order to map out the intergalactic medium large-scale structure at (z) ? 2.3 over a large volume (100 h {sup 1} Mpc){sup 3}.

  2. HST/COS detection of deuterated molecular hydrogen in a damped Ly? system at z = 0.18

    SciTech Connect (OSTI)

    Oliveira, Cristina M.; Sembach, Kenneth R.; Tumlinson, Jason; Thom, Christopher [Space Telescope Science Institute, Baltimore, MD 21218 (United States); O'Meara, John, E-mail: oliveira@stsci.edu [Saint Michael's College, Colchester, VT 05439 (United States)

    2014-03-01

    We report on the detection of deuterated molecular hydrogen, HD, at z = 0.18. HD and H{sub 2} are detected in HST/COS data of a low-metallicity (Z ? 0.07 Z {sub ?}) damped Ly? (DLA) system at z = 0.18562 toward QSO B012028, with log N(H I) = 20.50 0.10. Four absorption components are clearly resolved in H{sub 2}, while two components are resolved in HD; the bulk of the molecular hydrogen is associated with the components traced by HD. We find total column densities log N(HD) = 14.82 0.15 and log N(H{sub 2}) = 20.00 0.10. This system has a high molecular fraction, f(H{sub 2}) = 0.39 0.10, and a low HD-to-H{sub 2} ratio, log (HD/2H{sub 2}) = 5.5 0.2 dex. The excitation temperature, T {sub 01} = 65 2 K, in the component containing the bulk of the molecular gas is lower than in other DLAs. These properties are unlike those in other higher redshift DLA systems known to contain HD, but are consistent with what is observed in dense clouds in the Milky Way.

  3. X-RAY PROPERTIES OF THE z {approx} 4.5 Ly{alpha} EMITTERS IN THE CHANDRA DEEP FIELD SOUTH REGION

    SciTech Connect (OSTI)

    Zheng, Z. Y.; Wang, J. X.; Finkelstein, S. L.; Finkelstein, K. D.; Malhotra, S.; Rhoads, J. E. E-mail: jxw@ustc.edu.c

    2010-07-20

    We report the first X-ray detection of Ly{alpha} emitters (LAEs) at redshift z {approx} 4.5. One source (J033127.2-274247) is detected in the Extended Chandra Deep Field-South (ECDF-S) X-ray data and has been spectroscopically confirmed as a z = 4.48 quasar with L{sub X} = 4.2 x 10{sup 44} erg s{sup -1}. The single detection gives an Ly{alpha} quasar density of {approx} 2.7{sup +6.2} {sub -2.2} x 10{sup -6} Mpc{sup -3}, consistent with the X-ray luminosity function of quasars. Another 22 LAEs in the central Chandra Deep Field-South region are not detected individually, but their co-added counts yield an S/N = 2.4 (p = 99.83%) detection at soft band, with an effective exposure time of {approx}36 Ms. Further analysis of the equivalent width (EW) distribution shows that all the signals come from 12 LAE candidates with EW{sub rest}< 400 A and 2 of them contribute about half of the signal. From follow-up spectroscopic observations, we find that one of the two is a low-redshift emission-line galaxy, and the other is a Lyman break galaxy at z = 4.4 with little or no Ly{alpha} emission. Excluding these two and combined with ECDF-S data, we derive a 3{sigma} upper limit on the average X-ray flux of F {sub 0.5-2.0keV} < 1.6 x 10{sup -18} erg cm{sup -2} s{sup -1}, which corresponds to an average luminosity of (L {sub 0.5-2keV}) <2.4 x 10{sup 42} erg s{sup -1} for z {approx} 4.5 LAEs. If the average X-ray emission is due to star formation, it corresponds to a star formation rate (SFR) of <180-530 M {sub sun} yr{sup -1}. We use this SFR {sub X} as an upper limit of the unobscured SFR to constrain the escape fraction of Ly{alpha} photons and find a lower limit of f{sub esc,Ly{alpha}} > 3%-10%. However, our upper limit on the SFR {sub X} is {approx}7 times larger than the upper limit on SFR {sub X} on z {approx} 3.1 LAEs in the same field and at least 30 times higher than the SFR estimated from Ly{alpha} emission. From the average X-ray-to-Ly{alpha} line ratio, we estimate that fewer than 3.2% (6.3%) of our LAEs could be high-redshift type 1 (type 2) active galactic nuclei (AGNs) and those hidden AGNs likely show low rest-frame EWs.

  4. DETECTIONS OF FAINT Ly{alpha} EMITTERS AT z = 5.7: GALAXY BUILDING BLOCKS AND ENGINES OF REIONIZATION

    SciTech Connect (OSTI)

    Dressler, Alan; McCarthy, Patrick; Martin, Crystal L.; Henry, Alaina; Sawicki, Marcin E-mail: sawicki@ap.smu.ca

    2011-10-20

    We report results of an unprecedentedly deep, blind search for Ly{alpha} emitters (LAEs) at z = 5.7 using the Inamori-Magellan Areal Camera and Spectrograph (IMACS), with the goal of identifying missing sources of reionization that could also be basic building blocks for today's L* galaxies. We describe how improvements in wide field imaging with the Baade telescope, upgrades to IMACS, and the accumulation of {approx}20 hr of integration per field in excellent seeing led to the detection of single-emission-line sources as faint as F {approx} 2 x 10{sup -18} erg s{sup -1} cm{sup -2}, a sensitivity five times deeper than our first search. A reasonable correction for foreground interlopers implies a steep rise of approximately an order of magnitude in source density for a factor of four drop in flux, from F = 10{sup -17.0} erg s{sup -1} cm{sup -2} to F = 10{sup -17.6} (2.5 x 10{sup -18}) erg s{sup -1} cm{sup -2}. At this flux the putative LAEs have reached a surface density of {approx}1 arcmin{sup -2}-a comoving volume density of 4 x 10{sup -3} Mpc{sup -3}, several times the density of L* galaxies today. Such a population of faint LAEs would account for a significant fraction of the critical flux density required to complete reionization at this epoch, and would be good candidates for building blocks of stellar mass {approx}10{sup 8}-10{sup 9} M{sub sun} for the young galaxies of this epoch.

  5. A glimpse at quasar host galaxy far-UV emission using damped Lyα's as natural coronagraphs

    SciTech Connect (OSTI)

    Cai, Zheng; Fan, Xiaohui; Wang, Ran; McGreer, Ian; Noterdaeme, Pasquier; Finley, Hayley; Petitjean, Patrick; Carithers, Bill; Bian, Fuyan; Miralda-Escudé, Jordi; Pâris, Isabelle; Schneider, Donald P.; Zakamska, Nadia L.; Ge, Jian; Slosar, Anze

    2014-10-01

    In merger-driven models of massive galaxy evolution, the luminous quasar phase is expected to be accompanied by vigorous star formation in quasar host galaxies. In this paper, we use high column density damped Lyα (DLA) systems along quasar sight lines as natural coronagraphs to directly study the far-UV (FUV) radiation from the host galaxies of luminous background quasars. We have stacked the spectra of ∼2000 DLA systems (N {sub H} {sub I} > 10{sup 20.6} cm{sup –2}) with a median absorption redshift (z) = 2.6 selected from quasars observed in the SDSS-III Baryon Oscillation Spectroscopic Survey. We detect residual flux in the dark troughs of the composite DLA spectra. The level of this residual flux significantly exceeds systematic errors in the Sloan Digital Sky Survey fiber sky subtraction; furthermore, the residual flux is strongly correlated with the continuum luminosity of the background quasar, while uncorrelated with DLA column density or metallicity. We conclude that the flux could be associated with the average FUV radiation from the background quasar host galaxies (with medium redshift (z) = 3.1) that is not blocked by the intervening DLA. Assuming that all of the detected flux originates from quasar hosts, for the highest quasar luminosity bin ((L) = 2.5 × 10{sup 13} L {sub ☉}), the host galaxy has an FUV intensity of 1.5 ± 0.2 × 10{sup 40} erg s{sup –1} Å{sup –1}; this corresponds to an unobscured UV star formation rate of 9 M {sub ☉} yr{sup –1}.

  6. PHYSICAL PROPERTIES OF SPECTROSCOPICALLY CONFIRMED GALAXIES AT z {>=} 6. II. MORPHOLOGY OF THE REST-FRAME UV CONTINUUM AND Ly{alpha} EMISSION

    SciTech Connect (OSTI)

    Jiang Linhua; Windhorst, Rogier A.; Cohen, Seth H.; Mechtley, Matthew; Egami, Eiichi; Fan Xiaohui; Dave, Romeel; Finlator, Kristian; Kashikawa, Nobunari; Ouchi, Masami; Shimasaku, Kazuhiro

    2013-08-20

    We present a detailed structural and morphological study of a large sample of spectroscopically confirmed galaxies at z {>=} 6 using deep Hubble Space Telescope (HST) near-IR broad-band images and Subaru Telescope optical narrow-band images. The galaxy sample consists of 51 Ly{alpha} emitters (LAEs) at z {approx_equal} 5.7, 6.5, and 7.0, and 16 Lyman break galaxies (LBGs) at 5.9 {<=} z {<=} 6.5. These galaxies exhibit a wide range of rest-frame UV continuum morphology in the HST images, from compact features to multiple component systems. The fraction of merging/interacting galaxies reaches 40%-50% at the brightest end of M{sub 1500} {<=} -20.5 mag. The intrinsic half-light radii r{sub hl,in}, after correcting for point-spread function (PSF) broadening, are roughly between r{sub hl,in} {approx_equal} 0.''05 (0.3 kpc) and 0.''3 (1.7 kpc) at M{sub 1500} {<=} -19.5 mag. The median r{sub hl,in} value is 0.''16 ({approx}0.9 kpc). This is consistent with the sizes of bright LAEs and LBGs at z {>=} 6 found in previous studies. In addition, more luminous galaxies tend to be larger and exhibit a weak size-luminosity relation, r{sub hl,in}{proportional_to}L {sup 0.14} at M{sub 1500} {<=} -19.5 mag. The slope of 0.14 is significantly flatter than those in fainter LBG samples. We discuss the morphology of z {>=} 6 galaxies with nonparametric methods, including the concentration, asymmetry, and smoothness system and the Gini and M{sub 20} parameters, and demonstrate their validity through simulations. We search for extended Ly{alpha} emission halos around LAEs at z {approx_equal} 5.7 and 6.5 by stacking a number of narrow-band images. We do not find evidence of extended Ly{alpha} halos predicted by cosmological simulations. Such halos, if they exist, could be weaker than predicted. Finally, we investigate positional misalignment between the UV continuum and Ly{alpha} emissions in LAEs. While the two positions are generally consistent, several merging galaxies show significant positional differences. This is likely caused by a disturbed interstellar medium distribution due to merging activity.

  7. PHYSICAL PROPERTIES OF SPECTROSCOPICALLY CONFIRMED GALAXIES AT z {>=} 6. I. BASIC CHARACTERISTICS OF THE REST-FRAME UV CONTINUUM AND Ly{alpha} EMISSION

    SciTech Connect (OSTI)

    Jiang Linhua; Mechtley, Matthew; Cohen, Seth H.; Windhorst, Rogier A.; Egami, Eiichi; Fan Xiaohui; Dave, Romeel; Finlator, Kristian; Kashikawa, Nobunari; Ouchi, Masami; Shimasaku, Kazuhiro

    2013-08-01

    We present deep Hubble Space Telescope near-IR and Spitzer mid-IR observations of a large sample of spectroscopically confirmed galaxies at z {>=} 6. The sample consists of 51 Ly{alpha} emitters (LAEs) at z {approx_equal} 5.7, 6.5, and 7.0, and 16 Lyman break galaxies (LBGs) at 5.9 {<=} z {<=} 6.5. The near-IR images were mostly obtained with WFC3 in the F125W and F160W bands, and the mid-IR images were obtained with IRAC in the 3.6 {mu}m and 4.5 {mu}m bands. Our galaxies also have deep optical imaging data from Subaru Suprime-Cam. We utilize the multi-band data and secure redshifts to derive their rest-frame UV properties. These galaxies have steep UV-continuum slopes roughly between {beta} {approx_equal} -1.5 and -3.5, with an average value of {beta} {approx_equal} -2.3, slightly steeper than the slopes of LBGs in previous studies. The slope shows little dependence on UV-continuum luminosity except for a few of the brightest galaxies. We find a statistically significant excess of galaxies with slopes around {beta} {approx_equal} -3, suggesting the existence of very young stellar populations with extremely low metallicity and dust content. Our galaxies have moderately strong rest-frame Ly{alpha} equivalent width (EW) in a range of {approx}10 to {approx}200 A. The star formation rates are also moderate, from a few to a few tens of solar masses per year. The LAEs and LBGs in this sample share many common properties, implying that LAEs represent a subset of LBGs with strong Ly{alpha} emission. Finally, the comparison of the UV luminosity functions between LAEs and LBGs suggests that there exists a substantial population of faint galaxies with weak Ly{alpha} emission (EW < 20 A) that could be the dominant contribution to the total ionizing flux at z {>=} 6.

  8. filekLyDib

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

  9. Living SafeLy

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

    as safe as the electrical wiring in our homes - or just as danger- ous. The key is learning to act safely around them. This booklet is a basic safety guide for those who live...

  10. Intergalactic medium emission observations with the cosmic web imager. II. Discovery of extended, kinematically linked emission around SSA22 Ly? BLOB 2

    SciTech Connect (OSTI)

    Christopher Martin, D.; Chang, Daphne; Matuszewski, Matt; Morrissey, Patrick; Rahman, Shahin; Moore, Anna; Steidel, Charles C.; Matsuda, Yuichi

    2014-05-10

    The intergalactic medium (IGM) is the dominant reservoir of baryons, delineates the large-scale structure of the universe at low to moderate overdensities, and provides gas from which galaxies form and evolve. Simulations of a cold-dark-matter- (CDM-) dominated universe predict that the IGM is distributed in a cosmic web of filaments and that galaxies should form along and at the intersections of these filaments. While observations of QSO absorption lines and the large-scale distribution of galaxies have confirmed the CDM paradigm, the cosmic web of IGM has never been confirmed by direct imaging. Here we report our observation of the Ly? blob 2 (LAB2) in SSA22 with the Cosmic Web Imager (CWI). This is an integral field spectrograph optimized for low surface brightness, extended emission. With 22 hr of total on- and off-source exposure, CWI has revealed that LAB2 has extended Ly? emission that is organized into azimuthal zones consistent with filaments. We perform numerous tests with simulations and the data to secure the robustness of this result, which relies on data with modest signal-to-noise ratios. We have developed a smoothing algorithm that permits visualization of data cube slices along image or spectral image planes. With both raw and smoothed data cubes we demonstrate that the filaments are kinematically associated with LAB2 and display double-peaked profiles characteristic of optically thick Ly? emission. The flux is 10-20 times brighter than expected for the average emission from the IGM but is consistent with boosted fluorescence from a buried QSO or gravitation cooling radiation. Using simple emission models, we infer a baryon mass in the filaments of at least 1-4 10{sup 11} M {sub ?}, and the dark halo mass is at least 2 10{sup 12} M {sub ?}. The spatial-kinematic morphology is more consistent with inflow from the cosmic web than outflow from LAB2, although an outflow feature maybe present at one azimuth. LAB2 and the surrounding gas have significant and coaligned angular momentum, strengthening the case for their association.

  11. An HST/COS observation of broad Ly? emission and associated absorption lines of the BL Lacertae object H 2356-309

    SciTech Connect (OSTI)

    Fang, Taotao [Department of Astronomy and Institute of Theoretical Physics and Astrophysics, Xiamen University, Xiamen, Fujian 361005 (China); Danforth, Charles W.; Stocke, John T.; Shull, J. Michael [CASA, Department of Astrophysical and Planetary Sciences, University of Colorado, 389-UCB, Boulder, CO 80309 (United States); Buote, David A. [Department of Physics and Astronomy, 4129 Frederick Reines Hall, University of California, Irvine, CA 92697 (United States); Canizares, Claude R. [Department of Physics and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Gastaldello, Fabio, E-mail: fangt@xmu.edu.cn [IASF-Milano, INAF, via Bassini 15, Milan I-20133 (Italy)

    2014-11-01

    Weak spectral features in BL Lacertae objects (BL Lacs) often provide a unique opportunity to probe the inner region of this rare type of active galactic nucleus. We present a Hubble Space Telescope/Cosmic Origins Spectrograph observation of the BL Lac H 2356-309. A weak Ly? emission line was detected. This is the fourth detection of a weak Ly? emission feature in the ultraviolet (UV) band in the so-called high-energy peaked BL Lacs, after Stocke et al. Assuming the line-emitting gas is located in the broad line region (BLR) and the ionizing source is the off-axis jet emission, we constrain the Lorentz factor (?) of the relativistic jet to be ?8.1 with a maximum viewing angle of 3.6. The derived ? is somewhat larger than previous measurements of ? ? 3-5, implying a covering factor of ?3% of the line-emitting gas. Alternatively, the BLR clouds could be optically thin, in which case we constrain the BLR warm gas to be ?10{sup 5} M {sub ?}. We also detected two H I and one O VI absorption lines that are within |?v| < 150 km s{sup 1} of the BL Lac object. The O VI and one of the H I absorbers likely coexist due to their nearly identical velocities. We discuss several ionization models and find a photoionization model where the ionizing photon source is the BL Lac object that can fit the observed ion column densities with reasonable physical parameters. This absorber can either be located in the interstellar medium of the host galaxy or in the BLR.

  12. Radiation damage and associated phase change effect on photodesorption rates from icesLy? studies of the surface behavior of CO{sub 2}(ice)

    SciTech Connect (OSTI)

    Yuan, Chunqing; Yates, John T. Jr.

    2014-01-01

    Photodesorption from a crystalline film of CO{sub 2}(ice) at 75 K has been studied using Ly? (10.2 eV) radiation. We combine quantitative mass spectrometric studies of gases evolved and transmission IR studies of species trapped in the ice. Direct CO desorption is observed from the primary CO{sub 2} photodissociation process, which occurs promptly for CO{sub 2} molecules located on the outermost surface of the ice (Process I). As the fluence of Ly? radiation increases to ?5.5 10{sup 17} photons cm{sup 2}, extensive damage to the crystalline ice occurs and photo-produced CO molecules from deeper regions (Process II) are found to desorb at a rapidly increasing rate, which becomes two orders of magnitude greater than Process I. It is postulated that deep radiation damage to produce an extensive amorphous phase of CO{sub 2} occurs in the 50 nm ice film and that CO (and CO{sub 2}) diffusive transport is strongly enhanced in the amorphous phase. Photodesorption in Process II is a combination of electronic and thermally activated processes. Radiation damage in crystalline CO{sub 2} ice has been monitored by its effects on the vibrational line shapes of CO{sub 2}(ice). Here the crystalline-to-amorphous phase transition has been correlated with the occurrence of efficient molecular transport over long distances through the amorphous phase of CO{sub 2}(ice). Future studies of the composition of the interstellar region, generated by photodesorption from ice layers on grains, will have to consider the significant effects of radiation damage on photodesorption rates.

  13. STELLAR POPULATIONS OF Ly{alpha} EMITTERS AT z {approx} 6-7: CONSTRAINTS ON THE ESCAPE FRACTION OF IONIZING PHOTONS FROM GALAXY BUILDING BLOCKS

    SciTech Connect (OSTI)

    Ono, Yoshiaki; Shimasaku, Kazuhiro; Okamura, Sadanori; Masami Ouchi; Dunlop, James; Farrah, Duncan; McLure, Ross

    2010-12-01

    We investigate the stellar populations of Ly{alpha} emitters (LAEs) at z = 5.7 and 6.6 in a 0.65 deg{sup 2} sky of the Subaru/XMM-Newton Deep Survey (SXDS) Field, using deep images taken with the Subaru/Suprime-Cam, United Kingdom Infrared Telescope/Wide Field Infrared Camera, and Spitzer/Infrared Array Camera (IRAC). We produce stacked multiband images at each redshift from 165 (z = 5.7) and 91 (z = 6.6) IRAC-undetected objects to derive typical spectral energy distributions (SEDs) of z {approx} 6-7 LAEs for the first time. The stacked LAEs have as blue UV continua as the Hubble Space Telescope (HST)/Wide Field Camera 3 (WFC3) z-dropout galaxies of similar M{sub UV}, with a spectral slope {beta} {approx} -3, but at the same time they have red UV-to-optical colors with detection in the 3.6 {mu}m band. Using SED fitting we find that the stacked LAEs have low stellar masses of {approx}(3-10) x 10{sup 7} M{sub sun}, very young ages of {approx}1-3 Myr, negligible dust extinction, and strong nebular emission from the ionized interstellar medium, although the z = 6.6 object is fitted similarly well with high-mass models without nebular emission; inclusion of nebular emission reproduces the red UV-to-optical colors while keeping the UV colors sufficiently blue. We infer that typical LAEs at z {approx} 6-7 are building blocks of galaxies seen at lower redshifts. We find a tentative decrease in the Ly{alpha} escape fraction from z = 5.7 to 6.6, which may imply an increase in the intergalactic medium neutral fraction. From the minimum contribution of nebular emission required to fit the observed SEDs, we place an upper limit on the escape fraction of ionizing photons of f {sup ion}{sub esc} {approx} 0.6 at z = 5.7 and {approx}0.9 at z = 6.6. We also compare the stellar populations of our LAEs with those of stacked HST/WFC3 z-dropout galaxies.

  14. THE FIRST OBSERVATIONS OF LOW-REDSHIFT DAMPED Ly{alpha} SYSTEMS WITH THE COSMIC ORIGINS SPECTROGRAPH: CHEMICAL ABUNDANCES AND AFFILIATED GALAXIES

    SciTech Connect (OSTI)

    Battisti, A. J.; Meiring, J. D.; Tripp, T. M. [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States); Prochaska, J. X.; Werk, J. K. [Department of Astronomy and Astrophysics, University of California Observatories-Lick Observatory, UC Santa Cruz, CA 95064 (United States); Jenkins, E. B. [Department of Astrophysical Sciences, Princeton University Observatory, Princeton, NJ 08544 (United States); Lehner, N. [Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Tumlinson, J.; Thom, C. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)

    2012-01-10

    We present Cosmic Origins Spectrograph (COS) measurements of metal abundances in eight 0.083 < z{sub abs} < 0.321 damped Ly{alpha} (DLA) and sub-DLA absorption systems serendipitously discovered in the COS-Halos survey. We find that these systems show a large range in metallicities, with -1.10 < [Z/H] < 0.31, similar to the spread found at higher redshifts. These low-redshift systems on average have subsolar metallicities, but do show a rise in metallicity over cosmic time when compared to higher-redshift systems. We find that the average sub-DLA metallicity is higher than the average DLA metallicity at all redshifts. Nitrogen is underabundant with respect to {alpha}-group elements in all but perhaps one of the absorbers. In some cases, [N/{alpha}] is significantly below the lowest nitrogen measurements in nearby galaxies. Systems for which depletion patterns can be studied show little, if any, depletion, which is characteristic of Milky Way halo-type gas. We also identify affiliated galaxies for three of the sub-DLAs using spectra obtained from a Keck/Low Resolution Imaging Spectrometer (LRIS). None of these sub-DLAs arise in the stellar disks of luminous galaxies; instead, these absorbers may exist in galaxy halos at impact parameters ranging from 38 to 92 kpc. Multiple galaxies are present near two of the sub-DLAs, and galaxy interactions may play a role in the dispersal of the gas. Many of these low-redshift absorbers exhibit simple kinematics, but one sub-DLA has a complicated mix of at least 13 components spread over 150 km s{sup -1}. We find three galaxies near this sub-DLA, which also suggests that galaxy interactions roil the gas. This study reinforces the view that DLAs have a variety of origins, and low-redshift studies are crucial for understanding absorber-galaxy connections.

  15. METALLICITIES, DUST, AND MOLECULAR CONTENT OF A QSO-DAMPED Ly{alpha} SYSTEM REACHING log N(H I) = 22: AN ANALOG TO GRB-DLAs

    SciTech Connect (OSTI)

    Guimaraes, R.; Noterdaeme, P.; Petitjean, P.; Ledoux, C.; Srianand, R.; Rahmani, H.; Lopez, S.

    2012-06-15

    We present the elemental abundance and H{sub 2} content measurements of a damped Ly{alpha} (DLA) system with an extremely large H I column density, log N(H I) (cm{sup -2}) = 22.0 {+-} 0.10, at z{sub abs} = 3.287 toward the QSO SDSS J081634+144612. We measure column densities of H{sub 2}, C I, C I*, Zn II, Fe II, Cr II, Ni II, and Si II from a high signal-to-noise and high spectral resolution VLT-UVES spectrum. The overall metallicity of the system is [Zn/H] = -1.10 {+-} 0.10 relative to solar. Two molecular hydrogen absorption components are seen at z = 3.28667 and 3.28742 (a velocity separation of Almost-Equal-To 52 km s{sup -1}) in rotational levels up to J = 3. We derive a total H{sub 2} column density of log N(H{sub 2}) (cm{sup -2}) = 18.66 and a mean molecular fraction of f = 2N(H{sub 2})/[2N(H{sub 2}) + N(H I)] = 10{sup -3.04{+-}0.37}, typical of known H{sub 2}-bearing DLA systems. From the observed abundance ratios we conclude that dust is present in the interstellar medium of this galaxy, with an enhanced abundance in the H{sub 2}-bearing clouds. However, the total amount of dust along the line of sight is not large and does not produce any significant reddening of the background QSO. The physical conditions in the H{sub 2}-bearing clouds are constrained directly from the column densities of H{sub 2} in different rotational levels, C I and C I*. The kinetic temperature is found to be T Almost-Equal-To 75 K and the particle density lies in the range n{sub H} = 50-80 cm{sup -3}. The neutral hydrogen column density of this DLA is similar to the mean H I column density of DLAs observed at the redshift of {gamma}-ray bursts (GRBs). We explore the relationship between GRB-DLAs and the high column density end of QSO-DLAs finding that the properties (metallicity and depletion) of DLAs with log N(H I) > 21.5 in the two populations do not appear to be significantly different.

  16. Tru-ly Clean - What Does It Mean?

    SciTech Connect (OSTI)

    Hopkins, A.

    2008-07-01

    The evolution and genesis of the definition of transuranic waste (known as TRU) and its application to the cleanup criteria applied to soils contaminated with transuranics, specifically plutonium, has been a matter of discussion at contaminated sites in the United States and elsewhere. Cleanup decisions and the processes that led up to those decisions have varied at several plutonium contaminated sites within the United States and without the pacific region. The sites with radionuclide soil action levels include Bikini and Enewetak Atolls, Republic of the Marshall Islands; Johnston Atoll, Hawaii; the Hanford Site in Washington State; the Nevada Test Site; the Rocky Flats Environmental Technology Site in Colorado; the Chariot Site in north Alaska; and the Maralinga Site in Australia. The soil-action level developed for Rocky Flats by the U.S. Department of Energy, U.S. Environmental Protection Agency, and the Colorado Department of Public Health and Environment for plutonium is one of the higher soil-action levels approved by regulatory agencies that is considered protective for future use of land at a cleanup site. The Republic of the Marshall Islands has adopted a relatively conservative cleanup standard to accommodate the subsistence lifestyle of the islanders, while the Rocky Flats Environmental Technology Site has been transferred to the U.S. Department of the Interior to be used as a fish and wildlife refuge, a land use that resulted in a less conservative plutonium soil cleanup level. (authors)

  17. IGM CONSTRAINTS FROM THE SDSS-III/BOSS DR9 Lyα FOREST TRANSMISSION...

    Office of Scientific and Technical Information (OSTI)

    Authors: Lee, Khee-Gan ; Hennawi, Joseph F. 1 ; Spergel, David N. 2 ; Weinberg, David H. 3 ; Hogg, David W. 4 ; Viel, Matteo 5 ; Bolton, James S. 6 ; Bailey, Stephen ; ...

  18. SEARCHING FOR z {approx} 7.7 Ly{alpha} EMITTERS IN THE COSMOS...

    Office of Scientific and Technical Information (OSTI)

    universe is a useful probe of the epoch of reionization, as the Lyalpha line should be attenuated by the intergalactic medium (IGM) at low to moderate neutral hydrogen fractions. ...

  19. Ly{alpha} EMITTERS AT z = 7 IN THE SUBARU/XMM-NEWTON DEEP SURVEY...

    Office of Scientific and Technical Information (OSTI)

    This could be due to evolution of the LAE population at these epochs as a recent galaxy evolution model predicts that the LAE modestly evolves from z 5.7 to 7. However, even ...

  20. Sandia Energy Biomass

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

    Lignin-Feasting Microbe Holds Promise for Biofuels http:energy.sandia.govlignin-feasting-microbe-holds-promise-for-biofuels http:energy.sandia.govlignin-feasting-microbe-hol...

  1. THE END OF HELIUM REIONIZATION AT z {approx_equal} 2.7 INFERRED FROM COSMIC VARIANCE IN HST/COS He II Ly{alpha} ABSORPTION SPECTRA

    SciTech Connect (OSTI)

    Worseck, Gabor; Xavier Prochaska, J. [Department of Astronomy and Astrophysics, UCO/Lick Observatory, University of California, 1156 High Street, Santa Cruz, CA 95064 (United States); McQuinn, Matthew [Department of Astronomy, University of California, 601 Campbell Hall, Berkeley, CA 94720 (United States); Dall'Aglio, Aldo; Wisotzki, Lutz [Astrophysikalisches Institut Potsdam, An der Sternwarte 16, 14482 Potsdam (Germany); Fechner, Cora; Richter, Philipp [Institut fuer Physik und Astronomie, Universitaet Potsdam, Karl-Liebknecht-Str. 24/25, 14476 Potsdam (Germany); Hennawi, Joseph F. [Max-Planck-Institut fuer Astronomie, Koenigstuhl 17, 69117 Heidelberg (Germany); Reimers, Dieter, E-mail: gworseck@ucolick.org [Hamburger Sternwarte, Universitaet Hamburg, Gojenbergsweg 112, 21029 Hamburg (Germany)

    2011-06-01

    We report on the detection of strongly varying intergalactic He II absorption in HST/COS spectra of two z{sub em} {approx_equal} 3 quasars. From our homogeneous analysis of the He II absorption in these and three archival sightlines, we find a marked increase in the mean He II effective optical depth from <{tau}{sub eff},He{sub ii}>{approx_equal}1 at z {approx_equal} 2.3 to <{tau}{sub eff},He{sub ii}>{approx}>5 at z {approx_equal} 3.2, but with a large scatter of 2{approx}<{tau}{sub eff},He{sub ii}{approx}<5 at 2.7 < z < 3 on scales of {approx}10 proper Mpc. This scatter is primarily due to fluctuations in the He II fraction and the He II-ionizing background, rather than density variations that are probed by the coeval H I forest. Semianalytic models of He II absorption require a strong decrease in the He II-ionizing background to explain the strong increase of the absorption at z {approx}> 2.7, probably indicating He II reionization was incomplete at z{sub reion} {approx}> 2.7. Likewise, recent three-dimensional numerical simulations of He II reionization qualitatively agree with the observed trend only if He II reionization completes at z{sub reion} {approx_equal} 2.7 or even below, as suggested by a large {tau}{sub eff},He{sub ii}{approx}>3 in two of our five sightlines at z < 2.8. By doubling the sample size at 2.7 {approx}< z {approx}< 3, our newly discovered He II sightlines for the first time probe the diversity of the second epoch of reionization when helium became fully ionized.

  2. S A N D I A T E C H N O L O G Y A Q UA RT E R LY R E S E A R

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    ... Nenoff adds that because of the novel tech- niques being ... By Hanchen Huang Department of Mechanical, Aerospace, and ... to consoli- date the pretreatment steps and get us one ...

  3. S A N D I A T E C H N O L O G Y A Q UA RT E R LY R E S E A R

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    ... foam developed to dash away bio warfare agents is being sold in stores to combat ... But information gathered by examining a large population of cells may mask underlying ...

  4. S A N D I A T E C H N O L O G Y A Q UA RT E R LY R E S E A R

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    ... The 18-month effort, backed by a 6.7 million DARPA project award, aims to develop, demonstrate, and commercialize a process by October to produce the JP-8 fuel used by U.S. and ...

  5. East Coast Utilities prepare for Hurricane Sandy | OpenEI Community

    Open Energy Info (EERE)

    Please report your outage to 1-800-833-7476, http:bit.lywbqiUb or through our mobile app at http:bit.lyL3Bvs4 . Please check our outage map for updates: http:bit.ly...

  6. Spring 2015 Henderson Hall Education and Career Fair

    Office of Energy Efficiency and Renewable Energy (EERE)

    Location: Smith Gym, Henderson Hall, Arlington, VAPOC: DOECorporateRecruitment@hq.doe.govWebsite: http://bit.ly/1FRIJOF

  7. 2009 Publications | Stanford Synchrotron Radiation Lightsource

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

    09 Publications Journal Papers J. Abendroth, A. C. Kreger and W. G. J. Hol, "The Dimer Formed by the Periplasmic Domain of EpsL from the Type 2 Secretion System of Vibrio parahaemolyticus", J. Struct. Biol. 168, 313 (2009) doi: 10.1016/j.jsb.2009.07.022 J. Abendroth, D. D. Mitchell, K. V. Korotkov, T. L. Johnson, A. Kreger, M. Sandkvist and W. G. J. Hol, "The Three-dimensional Structure of the Cytoplasmic Domains of EpsF from the Type 2 Secretion System of Vibrio cholerae",

  8. The Lyman alpha reference sample. II. Hubble space telescope imaging results, integrated properties, and trends

    SciTech Connect (OSTI)

    Hayes, Matthew; stlin, Gran; Duval, Florent; Sandberg, Andreas; Guaita, Lucia; Melinder, Jens; Rivera-Thorsen, Thger; Adamo, Angela; Schaerer, Daniel; Verhamme, Anne; Orlitov, Ivana; Mas-Hesse, J. Miguel; Ot-Floranes, Hctor; Cannon, John M.; Pardy, Stephen; Atek, Hakim; Kunth, Daniel; Laursen, Peter; Herenz, E. Christian

    2014-02-10

    We report new results regarding the Ly? output of galaxies, derived from the Lyman Alpha Reference Sample, and focused on Hubble Space Telescope imaging. For 14 galaxies we present intensity images in Ly?, H?, and UV, and maps of H?/H?, Ly? equivalent width (EW), and Ly?/H?. We present Ly? and UV radial light profiles and show they are well-fitted by Srsic profiles, but Ly? profiles show indices systematically lower than those of the UV (n ? 1-2 instead of ? 4). This reveals a general lack of the central concentration in Ly? that is ubiquitous in the UV. Photometric growth curves increase more slowly for Ly? than the far ultraviolet, showing that small apertures may underestimate the EW. For most galaxies, however, flux and EW curves flatten by radii ?10 kpc, suggesting that if placed at high-z only a few of our galaxies would suffer from large flux losses. We compute global properties of the sample in large apertures, and show total Ly? luminosities to be independent of all other quantities. Normalized Ly? throughput, however, shows significant correlations: escape is found to be higher in galaxies of lower star formation rate, dust content, mass, and nebular quantities that suggest harder ionizing continuum and lower metallicity. Six galaxies would be selected as high-z Ly? emitters, based upon their luminosity and EW. We discuss the results in the context of high-z Ly? and UV samples. A few galaxies have EWs above 50 , and one shows f{sub esc}{sup Ly?} of 80%; such objects have not previously been reported at low-z.

  9. Narrowband Lyman-continuum imaging of galaxies at z ? 2.85

    SciTech Connect (OSTI)

    Mostardi, R. E.; Shapley, A. E.; Nestor, D. B.; Steidel, C. C.; Trainor, R. F.; Reddy, N. A.

    2013-12-10

    We present results from a survey for z ? 2.85 Lyman-continuum (LyC) emission in the HS1549+1933 field and place constraints on the amount of ionizing radiation escaping from star-forming galaxies. Using a custom narrowband filter (NB3420) tuned to wavelengths just below the Lyman limit at z ? 2.82, we probe the LyC spectral region of 49 Lyman break galaxies (LBGs) and 91 Ly? emitters (LAEs) spectroscopically confirmed at z ? 2.82. Four LBGs and seven LAEs are detected in NB3420. Using V-band data probing the rest-frame nonionizing UV, we observe that many NB3420-detected galaxies exhibit spatial offsets between their LyC and nonionizing UV emission and are characterized by extremely blue NB3420V colors, corresponding to low ratios of nonionizing to ionizing radiation (F {sub UV}/F {sub LyC}) that are in tension with current stellar population synthesis models. We measure average values of (F {sub UV}/F {sub LyC}) for our LBG and LAE samples, correcting for foreground galaxy contamination and H I absorption in the intergalactic medium. We find (F{sub UV}/F{sub LyC}){sub corr}{sup LBG}=8245 and (F{sub UV}/F{sub LyC}){sub corr}{sup LAE}=7.43.6. These flux density ratios correspond, respectively, to relative LyC escape fractions of f{sub esc,} {sub rel}{sup LBG}=5%--8% and f{sub esc,} {sub rel}{sup LAE}=18%--49%, absolute LyC escape fractions of f{sub esc}{sup LBG}=1%--2% and f{sub esc}{sup LAE}=5%--15%, and a comoving LyC emissivity from star-forming galaxies of 8.8-15.0 10{sup 24} erg s{sup 1} Hz{sup 1} Mpc{sup 3}. In order to study the differential properties of galaxies with and without LyC detections, we analyze narrowband Ly? imaging and rest-frame near-infrared imaging, finding that while LAEs with LyC detections have lower Ly? equivalent widths on average, there is no substantial difference in the rest-frame near-infrared colors of LBGs or LAEs with and without LyC detections. These preliminary results are consistent with an orientation-dependent model where LyC emission escapes through cleared paths in a patchy interstellar medium.

  10. VTKADIOSSCHEMAREADER

    Energy Science and Technology Software Center (OSTI)

    003354WKSTN00 ADIOS Schema reader for VTK https://www.dropbox.com/s/ly94k82xdd41hyi/AdiosSchemaReader-master.zip

  11. InMon,

    Gasoline and Diesel Fuel Update (EIA)

    gas (common- tenance infrastructure. (Denver, also a Clean City, has also ly known as propane); coal-derived liquid fuels; fuels other than alcohol that are derived from...

  12. Careers & the disABLED Career Expo

    Broader source: Energy.gov [DOE]

    Location: Ronald Reagan Bldg, Washington, DCAttendees:  Terri Sosa (Science)POC:  Donna FriendWebsite: http://bit.ly/1tlHhNr

  13. Pittsburgh Forum on Veteran Employment/Career Fair

    Broader source: Energy.gov [DOE]

    Location: Heinz Field, 100 Art Rooney Avenue, Pittsburgh, PAPOC:  Donna FriendWebsite: http://bit.ly/1q90WNk

  14. SunShot Initiative 2014 Peer Review Report

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

    ... Thermochemical Storage with Anhydrous Ammonia: ... that are identified by theory and transmission electron microscopy ... concise- ly describes a line of actions that allows ...

  15. Anisotropic Lyman-alpha emission

    SciTech Connect (OSTI)

    Zheng, Zheng; Wallace, Joshua

    2014-10-20

    As a result of resonant scatterings off hydrogen atoms, Lyα emission from star-forming galaxies provides a probe of the (hardly isotropic) neutral gas environment around them. We study the effect of the environmental anisotropy on the observed Lyα emission by performing radiative transfer calculations for models of neutral hydrogen clouds with prescriptions of spatial and kinematic anisotropies. The environmental anisotropy leads to corresponding anisotropy in the Lyα flux and spectral properties and induces correlations among them. The Lyα flux (or observed luminosity) depends on the viewing angle and shows an approximate correlation with the initial Lyα optical depth in the viewing direction relative to those in all other directions. The distribution of Lyα flux from a set of randomly oriented clouds is skewed to high values, providing a natural contribution to the Lyα equivalent width (EW) distribution seen in observation. A narrower EW distribution is found at a larger peak offset of the Lyα line, similar to the trend suggested in observation. The peak offset appears to correlate with the line shape (full width at half-maximum and asymmetry), pointing to a possibility of using Lyα line features alone to determine the systemic redshifts of galaxies. The study suggests that anisotropies in the spatial and kinematic distributions of neutral hydrogen can be an important ingredient in shaping the observed properties of Lyα emission from star-forming galaxies. We discuss the implications of using Lyα emission to probe the circumgalactic and intergalactic environments of galaxies.

  16. ON THE DETECTION OF IONIZING RADIATION ARISING FROM STAR-FORMING GALAXIES AT REDSHIFT z {approx} 3-4: LOOKING FOR ANALOGS OF 'STELLAR RE-IONIZERS'

    SciTech Connect (OSTI)

    Vanzella, Eros; Cristiani, Stefano; Nonino, Mario; Guo Yicheng; Giavalisco, Mauro; Grazian, Andrea; Castellano, Marco; Fontana, Adriano; Giallongo, Emanuele; Pentericci, Laura; Galametz, Audrey; Dickinson, Mark; Faber, S. M.; Newman, Jeffrey; Siana, Brian D.

    2012-05-20

    We use the spatially resolved, multi-band photometry in the GOODS South field acquired by the CANDELS project to constrain the nature of candidate Lyman continuum (LyC) emitters at redshift z {approx} 3.7 identified using ultradeep imaging below the Lyman limit (1{sigma} limit of Almost-Equal-To 30 AB in a 2'' diameter aperture). In 19 candidates out of a sample of 20 with flux detected at >3{sigma} level, the light centroid of the candidate LyC emission is offset from that of the Lyman break galaxy (LBG) by up to 1.''5. We fit the spectral energy distribution of the LyC candidates to spectral population synthesis models to measure photometric redshifts and the stellar population parameters. We also discuss the differences in the UV colors between the LBG and the LyC candidates, and how to estimate the escape fraction of ionizing radiation (f{sub esc}) in cases, like in most of our galaxies, where the LyC emission is spatially offset from the host galaxy. In all but one case we conclude that the candidate LyC emission is most likely due to lower redshift interlopers. Based on these findings, we argue that the majority of similar measurements reported in the literature need further investigation before it can be firmly concluded that LyC emission is detected. Our only surviving LyC candidate is an LBG at z = 3.795, which shows the bluest (B - V) color among LBGs at similar redshift, a stellar mass of M {approx} 2 Multiplication-Sign 10{sup 9} M{sub Sun }, weak interstellar absorption lines, and a flat UV spectral slope with no Ly{alpha} in emission. We estimate its f{sub esc} to be in the range 25%-100%, depending on the dust and intergalactic attenuation.

  17. Central Washington University: 2014 Engineering Technologies, Safety & Construction Fair

    Broader source: Energy.gov [DOE]

    Location: 400 E. University Way Ellensburg, WA 98926, SURC BallroomPOC: Heather BainWebsite: http://bit.ly/1pgOpN7

  18. Search for: All records | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    ... The inhibition of PI3K-Akt activation by LY294002 significantly reduced the viral yield, including a reduction in budded viruses and occlusion bodies. The virus production was ...

  19. INTERNATIONAL AGREEMENTS

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

    ... DATE: August 14, 2001 DATE: LY 3 3OOJ PLACE: Washingon, D.C. PLACE: Lima, Peru Witnessed by John R. Hamilton Ambassador of the United States of America -6- ANNEX INTELLECTUAL ...

  20. Veterans Employment Forum

    Broader source: Energy.gov [DOE]

    Location: 614 SW 11th Avenue, Portland, OR 97205, 2nd Floor Library RoomPOC: Heather BainWebsite: http://bit.ly/1t6XjaO

  1. The Honorable Richard M. Daley,. Jr. 121 N.. LaSalle Street

    Office of Legacy Management (LM)

    W. Alexander.Williams (301-427-1719) of my staff. Enclosures Sine ly, 67 J- d&- r A*;" JamesW. Wagoner II ,Director Off-SiteSavannah River Division. Office of Eastern Area ...

  2. The Honorable Gary Loster 1315 S. Washington Avenue

    Office of Legacy Management (LM)

    W. Alerander Williams (301-427-1719) of my staff. Sincer ly, 4 z&a Oames W. Wagoner II" Director Off-SiteSavannah River Division Office of Eastern Area Programs Office of ...

  3. Social Media | Argonne National Laboratory

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

    Timeline Photos from Facebook More Twitter @argonne 4 hours ago Missed "What is the Brain Initiative?" Fear not, science-y goodness awaits you here @C2ST - http:bit.ly...

  4. IES TM-30-15: Learn the Basics, See the Results

    Energy Savers [EERE]

    IES Method for Evaluating Light Source Color Rendition http:bit.ly1IWZxVu Optics Express journal article that provides overview of the IES method: Development of the...

  5. HBCU College Festival sponsored by Alfred Street Baptist Church

    Broader source: Energy.gov [DOE]

    Location: T.C. Williams High School, 3330 King St, Alexandria, VA 22302Attendees: Rauland Sharp (HC) and Dameone Ferguson (NNSA)POC: Chester Scott Website: http://bit.ly/1BARRqp

  6. 2013 Progress Report -- DOE Joint Genome Institute None 59 BASIC...

    Office of Scientific and Technical Information (OSTI)

    bit.lyJGI-Vision for the Institute. A central focus of this Strategic Vision is to bridge the gap between sequenced genomes and an understanding of biological functions at the...

  7. TITLE AUTHORS SUBJECT SUBJECT RELATED DESCRIPTION PUBLISHER AVAILABILI...

    Office of Scientific and Technical Information (OSTI)

    bit ly JGI Vision for the Institute A central focus of this Strategic Vision is to bridge the gap between sequenced genomes and an understanding of biological functions at the...

  8. "Title","Creator/Author","Publication Date","OSTI Identifier...

    Office of Scientific and Technical Information (OSTI)

    bit.lyJGI-Vision for the Institute. A central focus of this Strategic Vision is to bridge the gap between sequenced genomes and an understanding of biological functions at the...

  9. INTERIOR

    Office of Legacy Management (LM)

    September lyGg by R. M. Hamilton, B. E. Smith and J. H. Healy Own-File R e w r t 1970 ... R. M. Hamilton, B. E : Smith, and J. 11. Healy . . . . . ' 16 February 1970 . . . . . . S ...

  10. 03-10-05.cdr

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

    drums 27,031 cubic meters Operations: First on, last out A "TRU-ly" unique waste story ... ... Working Smart: Submissions wanted Join the search for an official WIPP logo and motto ... ...

  11. Naval Support Activity (NSA) in Bethesda Employment Education Fair

    Broader source: Energy.gov [DOE]

    Location: NSA Bethesda Fitness Center (Gymnasium, Bldg 17), 8901 Wisconsin Ave., Bethesda, MD 20889Attendees: Donna Friend (HC) and Rauland Sharp (HC)POC: Donna FriendWebsite: http://bit.ly/1yTjTNu

  12. Gallaudet University Spring 2015 Career Fair

    Broader source: Energy.gov [DOE]

    Gallaudet University, Field House Gymnasium, 800 Florida Avenue NE, Washington, DC 20002 Contact: DOECorporateRecruitment@hq.doe.govhttp://bit.ly/1vjfWjFThis event was rescheduled due to inclement...

  13. Black Engineering of the Year Awards and STEM Conference Career Fair

    Broader source: Energy.gov [DOE]

    Location:  Washington Marriott Wardman Park, 2660 Woodley Road, NW, Washington, DC 20008Website Link:  http://bit.ly/1CbVvraPOC:  Dameone Ferguson (NNSA)

  14. NARROWBAND IMAGING OF ESCAPING LYMAN-CONTINUUM EMISSION IN THE SSA22 FIELD

    SciTech Connect (OSTI)

    Nestor, Daniel B.; Shapley, Alice E.; Steidel, Charles C.; Siana, Brian

    2011-07-20

    We present the results of an ultradeep, narrowband imaging survey for Lyman-continuum (LyC) emission at z {approx} 3 in the SSA22a field. We employ a custom narrowband filter centered at {lambda} = 3640 A (NB3640), which probes the LyC region for galaxies at z {>=} 3.06. We also analyze new and archival NB4980 imaging tuned to the wavelength of the Ly{alpha} emission line at z = 3.09, and archival broadband B, V, and R images of the non-ionizing UV continuum. Our NB3640 images contain 26 z {>=} 3.06 Lyman break galaxies (LBGs) as well as a set of 130 Ly{alpha} emitters (LAEs), identified by their excess NB4980 flux relative to the BV continuum. Six LBGs and 28 LAEs are detected in the NB3640 image. LBGs appear to span a range of NB3640-R colors, while LAEs appear bimodal in their NB3640-R properties. We estimate average UV-to-LyC flux density ratios, corrected for foreground contamination and intergalactic medium absorption, finding (F{sub UV}/F{sub LyC}){sup LBG}{sub corr} = 11.3{sup +10.3}{sub -5.4}, which implies an LBG LyC escape fraction f{sup LyC}{sub esc} {approx} 0.1, and (F{sub UV}/F{sub LyC}){sup LAE}{sub corr} = 2.2{sup +0.9}{sub -0.6}. The strikingly blue LAE flux density ratios defy interpretation in terms of standard stellar population models. Assuming (F{sub UV}/F{sub LyC}){sup LBG}{sub corr} applies down to L = 0.1L*, we estimate a galaxy contribution to the intergalactic hydrogen ionization rate that is consistent with independent estimates based on the Ly{alpha} forest opacity at z {approx_equal} 3. If we assume that (F{sub UV}/F{sub LyC}){sup LAE}{sub corr} holds at the faintest luminosities, the galaxy contribution significantly exceeds that inferred from the Ly{alpha} forest. We interpret our results in terms of a model where LyC photons escape over only {approx}10%-20% of solid angle. When advantageously oriented, a galaxy will exhibit a low UV-to-LyC ratio, an effect enhanced for more compact galaxies. This model, however, does not adequately explain the extremely blue NB3640-R colors measured for some LAEs in our sample. Further follow-up study of these faint LAEs is crucial, given the potentially important contribution similar objects make to the process of reionization.

  15. LANL: AOT & LANSCE The Pulse May 2012

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

    2 Los Alamos National Laboratory * Est. 1943 The Pulse-Newsletter of the Los Alamos Neutron Science Center and Accelerator Operations and Technology Division I N S I D E 2 From Steve'S DeSk 3 experimentS hint that the atomic nucleuS Still holDS Some SurpriSeS 4 Spin anD orbital orDering in Y 1-x la x vo 3 5 probing manganite FilmS chemical uniFor- mitY with polarizeD neutronS 6 heaDS up! By Diana Del Mauro ADEPS Communications As joint Accelerator Operations and Technology (AOT) deputy division

  16. A REFINED ESTIMATE OF THE IONIZING EMISSIVITY FROM GALAXIES AT z {approx_equal} 3: SPECTROSCOPIC FOLLOW-UP IN THE SSA22a FIELD

    SciTech Connect (OSTI)

    Nestor, Daniel B.; Shapley, Alice E.; Kornei, Katherine A.; Steidel, Charles C.; Siana, Brian

    2013-03-01

    We investigate the contribution of star-forming galaxies to the ionizing background at z {approx} 3, building on previous work based on narrowband (NB3640) imaging in the SSA22a field. We use new Keck/LRIS spectra of Lyman break galaxies (LBGs) and narrowband-selected Ly{alpha} emitters (LAEs) to measure redshifts for 16 LBGs and 87 LAEs at z > 3.055, such that our NB3640 imaging probes the Lyman-continuum (LyC) region. When we include the existing set of spectroscopically confirmed LBGs, our total sample with z > 3.055 consists of 41 LBGs and 91 LAEs, of which 9 LBGs and 20 LAEs are detected in our NB3640 image. With our combined imaging and spectroscopic data sets, we critically investigate the origin of NB3640 emission for detected LBGs and LAEs. We remove from our samples three LBGs and three LAEs with spectroscopic evidence of contamination of their NB3640 flux by foreground galaxies and statistically model the effects of additional, unidentified foreground contaminants. The resulting contamination and LyC-detection rates, respectively, are 62% {+-} 13% and 8% {+-} 3% for our LBG sample, and 47% {+-} 10% and 12% {+-} 2% for our LAE sample. The corresponding ratios of non-ionizing UV to LyC flux density, corrected for intergalactic medium (IGM) attenuation, are 18.0{sup +34.8} {sub -7.4} for LBGs and 3.7{sup +2.5} {sub -1.1} for LAEs. We use these ratios to estimate the total contribution of star-forming galaxies to the ionizing background and the hydrogen photoionization rate in the IGM, finding values larger than, but consistent with, those measured in the Ly{alpha} forest. Finally, the measured UV to LyC flux-density ratios imply model-dependent LyC escape fractions of f {sup LyC} {sub esc} {approx} 5%-7% for our LBG sample and f {sup LyC} {sub esc} {approx} 10%-30% for our fainter LAE sample.

  17. The mystery of spectral breaks: Lyman continuum absorption by photon-photon pair production in the Fermi GeV spectra of bright blazars

    SciTech Connect (OSTI)

    Stern, Boris E. [Institute for Nuclear Research, Russian Academy of Sciences, Prospekt 60-letiya Oktyabrya 7a, Moscow 117312 (Russian Federation); Poutanen, Juri, E-mail: stern.boris@gmail.com, E-mail: juri.poutanen@utu.fi [Tuorla Observatory, University of Turku, Vislntie 20, FI-21500 Piikki (Finland)

    2014-10-10

    We re-analyze Fermi/LAT ?-ray spectra of bright blazars using the new Pass 7 version of the detector response files and detect breaks at ?5 GeV in the rest-frame spectra of 3C 454.3 and possibly also 4C +21.35, associated with the photon-photon pair production absorption by the He II Lyman continuum (LyC). We also detect significant breaks at ?20 GeV associated with hydrogen LyC in both the individual spectra and the stacked redshift-corrected spectrum of several bright blazars. The detected breaks in the stacked spectra univocally prove that they are associated with atomic ultraviolet emission features of the quasar broad-line region (BLR). The dominance of the absorption by the hydrogen Ly complex over He II, a small detected optical depth, and break energy consistent with head-on collisions with LyC photons imply that the ?-ray emission site is located within the BLR, but most of the BLR emission comes from a flat disk-like structure producing little opacity. Alternatively, the LyC emission region size might be larger than the BLR size measured from reverberation mapping, and/or the ?-ray emitting region is extended. These solutions would resolve the long-standing issue of how the multi-hundred GeV photons can escape from the emission zone without being absorbed by softer photons.

  18. Influence of Lymphatic Invasion on Locoregional Recurrence Following Mastectomy: Indication for Postmastectomy Radiotherapy for Breast Cancer Patients With One to Three Positive Nodes

    SciTech Connect (OSTI)

    Matsunuma, Ryoichi; Oguchi, Masahiko; Fujikane, Tomoko; Matsuura, Masaaki; Sakai, Takehiko; Kimura, Kiyomi; Morizono, Hidetomo; Iijima, Kotaro; Izumori, Ayumi; Miyagi, Yumi; Nishimura, Seiichiro; Makita, Masujiro; Gomi, Naoya; Horii, Rie; Akiyama, Futoshi; Iwase, Takuji

    2012-07-01

    Purpose: The indication for postmastectomy radiotherapy (PMRT) in breast cancer patients with one to three positive lymph nodes has been in discussion. The purpose of this study was to identify patient groups for whom PMRT may be indicated, focusing on varied locoregional recurrence rates depending on lymphatic invasion (ly) status. Methods and Materials: Retrospective analysis of 1,994 node-positive patients who had undergone mastectomy without postoperative radiotherapy between January 1990 and December 2000 at our hospital was performed. Patient groups for whom PMRT should be indicated were assessed using statistical tests based on the relationship between locoregional recurrence rate and ly status. Results: Multivariate analysis showed that the ly status affected the locoregional recurrence rate to as great a degree as the number of positive lymph nodes (p < 0.001). Especially for patients with one to three positive nodes, extensive ly was a more significant factor than stage T3 in the TNM staging system for locoregional recurrence (p < 0.001 vs. p = 0.295). Conclusion: Among postmastectomy patients with one to three positive lymph nodes, patients with extensive ly seem to require local therapy regimens similar to those used for patients with four or more positive nodes and also seem to require consideration of the use of PMRT.

  19. Sandia R E S E A R H J

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

    a n a u r y 2 0 1 5 * Vo l 2 , Is s u e 3 When you A B S O LU T E LY P O S I T I V E LY have to get it right 2 w w w. s a n d i a . g o v Sandia Research is a quarterly magazine published by Sandia National Laboratories. Sandia is a multiprogram engi- neering and science laboratory operated by Sandia Corporation, a Lockheed Martin company, for the U.S. Department of Energy. With main facilities in Albuquerque, New Mexico, and Livermore, California, Sandia has research and development

  20. THE PHOTON UNDERPRODUCTION CRISIS

    SciTech Connect (OSTI)

    Kollmeier, Juna A. [Observatories of the Carnegie Institution of Washington, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Weinberg, David H.; McEwen, Joseph [Astronomy Department and CCAPP, Ohio State University, Columbus, OH 43210 (United States); Oppenheimer, Benjamin D.; Danforth, Charles [Astronomy Department, University of Colorado, Boulder, CO 80309 (United States); Haardt, Francesco [Dipartimento di Scienza e Alta Tecnologia, Universit dell'Insubria, Via Valleggio 11, I-22100 Como (Italy); Katz, Neal; Fardal, Mark [Astronomy Department, University of Massachusetts, Amherst, MA 01003 (United States); Dav, Romeel [University of the Western Cape, Bellville, Cape Town 7535 (South Africa); Madau, Piero [Department of Astronomy and Astrophysics, University of California, 1156 High Street, Santa Cruz, CA 95064 (United States); Ford, Amanda B. [Astronomy Department, University of Arizona, Tucson, AZ 85721 (United States); Peeples, Molly S., E-mail: jak@obs.carnegiescience.edu [Space Telescope Science Institute, Baltimore, MD 21218 (United States)

    2014-07-10

    We examine the statistics of the low-redshift Ly? forest from smoothed particle hydrodynamic simulations in light of recent improvements in the estimated evolution of the cosmic ultraviolet background (UVB) and recent observations from the Cosmic Origins Spectrograph (COS). We find that the value of the metagalactic photoionization rate (?{sub HI}) required by our simulations to match the observed properties of the low-redshift Ly? forest is a factor of five larger than the value predicted by state-of-the art models for the evolution of this quantity. This mismatch in ?{sub HI} results in the mean flux decrement of the Ly? forest being overpredicted by at least a factor of two (a 10? discrepancy with observations) and a column density distribution of Ly? forest absorbers systematically and significantly elevated compared to observations over nearly two decades in column density. We examine potential resolutions to this mismatch and find that either conventional sources of ionizing photons (galaxies and quasars) must contribute considerably more than current observational estimates or our theoretical understanding of the low-redshift universe is in need of substantial revision.

  1. "Ask Argonne" - Charlie Catlett, Computer Scientist, Part 2

    ScienceCinema (OSTI)

    Catlett, Charlie

    2014-07-15

    A few weeks back, computer scientist Charlie Catlett talked a bit about the work he does and invited questions from the public during Part 1 of his "Ask Argonne" video set (http://bit.ly/1joBtzk). In Part 2, he answers some of the questions that were submitted. Enjoy!

  2. "Ask Argonne" - Robert Jacob, Climate Scientist, Part 2

    ScienceCinema (OSTI)

    Jacob, Robert

    2014-11-24

    Previously, climate scientist Robert Jacob talked a bit about the work he does and invited questions from the public during Part 1 of his "Ask Argonne" video set (http://bit.ly/1aK6WDv). In Part 2, he answers some of the questions that were submitted.

  3. "Ask Argonne" - Robert Jacob, Climate Scientist, Part 2

    SciTech Connect (OSTI)

    Jacob, Robert

    2014-01-08

    Previously, climate scientist Robert Jacob talked a bit about the work he does and invited questions from the public during Part 1 of his "Ask Argonne" video set (http://bit.ly/1aK6WDv). In Part 2, he answers some of the questions that were submitted.

  4. "Ask Argonne" - Charlie Catlett, Computer Scientist, Part 2

    SciTech Connect (OSTI)

    Catlett, Charlie

    2014-06-17

    A few weeks back, computer scientist Charlie Catlett talked a bit about the work he does and invited questions from the public during Part 1 of his "Ask Argonne" video set (http://bit.ly/1joBtzk). In Part 2, he answers some of the questions that were submitted. Enjoy!

  5. A SPECTROSCOPIC SEARCH FOR LEAKING LYMAN CONTINUUM AT z {approx} 0.7

    SciTech Connect (OSTI)

    Bridge, Carrie R.; Siana, Brian; Salvato, Mara; Rudie, Gwen C.; Teplitz, Harry I.; Scarlata, Claudia; Colbert, James; Armus, Lee; Conselice, Christopher J.; Ferguson, Henry C.; Brown, Thomas M.; Giavalisco, Mauro; De Mello, Duilia F.; Gardner, Jonathan P.

    2010-09-01

    We present the results of rest-frame, UV slitless spectroscopic observations of a sample of 32 z {approx} 0.7 Lyman break galaxy (LBG) analogs in the COSMOS field. The spectroscopic search was performed with the Solar Blind Channel on the Hubble Space Telescope. We report the detection of leaking Lyman continuum (LyC) radiation from an active galactic nucleus-starburst composite. While we find no direct detections of LyC emission in the remainder of our sample, we achieve individual lower limits (3{sigma}) of the observed non-ionizing UV-to-LyC flux density ratios, f{sub {nu}} (1500 A)/f{sub {nu}}(830 A) of 20 to 204 (median of 73.5) and 378.7 for the stack. Assuming an intrinsic Lyman break of 3.4 and an intergalactic medium transmission of LyC photons along the line of sight to the galaxy of 85%, we report an upper limit for the relative escape fraction in individual galaxies of 0.02-0.19 and a stacked 3{sigma} upper limit of 0.01. We find no indication of a relative escape fraction near unity as seen in some LBGs at z {approx} 3. Our UV spectra achieve the deepest limits to date at any redshift for the escape fraction in individual sources. The contrast between these z {approx} 0.7 low escape fraction LBG analogs with z {approx} 3 LBGs suggests that either the processes conducive to high f{sub esc} are not being selected for in the z {approx}< 1 samples or the average escape fraction is decreasing from z {approx} 3 to z {approx} 1. We discuss possible mechanisms that could affect the escape of LyC photons.

  6. Excitation wavelength dependence of water-window line emissions from boron-nitride laser-produced plasmas

    SciTech Connect (OSTI)

    Crank, M.; Harilal, S. S.; Hassan, S. M.; Hassanein, A.

    2012-02-01

    We investigated the effects of laser excitation wavelength on water-window emission lines of laser-produced boron-nitride plasmas. Plasmas are produced by focusing 1064 nm and harmonically generated 532 and 266 nm radiation from a Nd:YAG laser on BN target in vacuum. Soft x-ray emission lines in the water-window region are recorded using a grazing-incidence spectrograph. Filtered photodiodes are used to obtain complementary data for water-window emission intensity and angular dependence. Spectral emission intensity changes in nitrogen Ly-{alpha} and He-{alpha} are used to show how laser wavelength affects emission. Our results show that the relative intensity of spectral lines is laser wavelength dependent, with the ratio of Ly-{alpha} to He-{alpha} emission intensity decreasing as laser wavelength is shortened. Filtered photodiode measurements of angular dependence showed that 266 and 532 nm laser wavelengths produce uniform emission.

  7. Theoretical model for plasma expansion generated by hypervelocity impact

    SciTech Connect (OSTI)

    Ju, Yuanyuan; Zhang, Qingming Zhang, Dongjiang; Long, Renrong; Chen, Li; Huang, Fenglei; Gong, Zizheng

    2014-09-15

    The hypervelocity impact experiments of spherical LY12 aluminum projectile diameter of 6.4?mm on LY12 aluminum target thickness of 23?mm have been conducted using a two-stage light gas gun. The impact velocity of the projectile is 5.2, 5.7, and 6.3?km/s, respectively. The experimental results show that the plasma phase transition appears under the current experiment conditions, and the plasma expansion consists of accumulation, equilibrium, and attenuation. The plasma characteristic parameters decrease as the plasma expands outward and are proportional with the third power of the impact velocity, i.e., (T{sub e}, n{sub e})???v{sub p}{sup 3}. Based on the experimental results, a theoretical model on the plasma expansion is developed and the theoretical results are consistent with the experimental data.

  8. 2013 Progress Report -- DOE Joint Genome Institute (Program Document) |

    Office of Scientific and Technical Information (OSTI)

    SciTech Connect Program Document: 2013 Progress Report -- DOE Joint Genome Institute Citation Details In-Document Search Title: 2013 Progress Report -- DOE Joint Genome Institute In October 2012, we introduced a 10-Year Strategic Vision [http://bit.ly/JGI-Vision] for the Institute. A central focus of this Strategic Vision is to bridge the gap between sequenced genomes and an understanding of biological functions at the organism and ecosystem level. This involves the continued massive-scale

  9. Layout 1

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

    32 0163-6804/11/$25.00 © 2011 IEEE INTRODUCTION A grid network is a collection of geographical- ly distributed resources, such as storage clus- ters, supercomputers, and scientific equipment, that are accessible to users over a network. Examples of e-Science grids include the Large Hadron Collider Computing Grid Project, the Biomedical Informatics Research Network, and the George E. Brown Network for Earthquake Engineering and Simulation. These networks typically deal with the trans- fer of

  10. 2013 Science Bowl | Princeton Plasma Physics Lab

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

    SciTech Connect Program Document: 2013 Progress Report -- DOE Joint Genome Institute Citation Details In-Document Search Title: 2013 Progress Report -- DOE Joint Genome Institute In October 2012, we introduced a 10-Year Strategic Vision [http://bit.ly/JGI-Vision] for the Institute. A central focus of this Strategic Vision is to bridge the gap between sequenced genomes and an understanding of biological functions at the organism and ecosystem level. This involves the continued massive-scale

  11. UNITED STATES A T O M I C ENERGY C O M M I S S I O N

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

    AECU - 785 THE EFFECT OF ELECTRONIC PARAMAGNETISM ON NUCLEAR MAGNETIC RESONANCE FREQUENCIES IN METALS By C. H. Townes Conyers Herring W. D. Knig^it Columbia University Bell Telephone Laboratories Trinity College Tochnicai Information Division, ORE, Oak Ridgo, Tonnossoo J^ This document is FUBLK:LY RELEASABLF //> [\AAUMJ DISCLAIMER This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency Thereof,

  12. BPAonFabric_jk

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

    J U LY 2 9 - AU G U S T 2 , 2 0 1 3 Bloodstain Pattern Analysis on Fabrics This advanced level course is designed for practitioners who routinely examine bloodstained fabrics and other textiles and are required to assess, interpret and report on bloodstain patterns as part of those examinations. The course builds upon fundamental knowledge of the forensic discipline of BPA and is designed to facilitate an improved level of examination, interpretation and reporting with respect to those

  13. A LYMAN BREAK GALAXY IN THE EPOCH OF REIONIZATION FROM HUBBLE SPACE TELESCOPE GRISM SPECTROSCOPY

    SciTech Connect (OSTI)

    Rhoads, James E.; Malhotra, Sangeeta; Cohen, Seth; Zheng Zhenya; Stern, Daniel; Dickinson, Mark; Pirzkal, Norbert; Grogin, Norman; Koekemoer, Anton; Peth, Michael A.; Spinrad, Hyron; Reddy, Naveen; Hathi, Nimish; Budavari, Tamas; Ferreras, Ignacio; Gardner, Jonathan P.; Gronwall, Caryl; Haiman, Zoltan; Kuemmel, Martin; Meurer, Gerhardt; and others

    2013-08-10

    We present observations of a luminous galaxy at z = 6.573-the end of the reionization epoch-which has been spectroscopically confirmed twice. The first spectroscopic confirmation comes from slitless Hubble Space Telescope Advanced Camera for Surveys grism spectra from the PEARS survey (Probing Evolution And Reionization Spectroscopically), which show a dramatic continuum break in the spectrum at rest frame 1216 A. The second confirmation is done with Keck + DEIMOS. The continuum is not clearly detected with ground-based spectra, but high wavelength resolution enables the Ly{alpha} emission line profile to be determined. We compare the line profile to composite line profiles at z = 4.5. The Ly{alpha} line profile shows no signature of a damping wing attenuation, confirming that the intergalactic gas is ionized at z = 6.57. Spectra of Lyman breaks at yet higher redshifts will be possible using comparably deep observations with IR-sensitive grisms, even at redshifts where Ly{alpha} is too attenuated by the neutral intergalactic medium to be detectable using traditional spectroscopy from the ground.

  14. Mechanism and computational model for Lyman-{alpha}-radiation generation by high-intensity-laser four-wave mixing in Kr-Ar gas

    SciTech Connect (OSTI)

    Louchev, Oleg A.; Saito, Norihito; Wada, Satoshi; Bakule, Pavel; Yokoyama, Koji; Ishida, Katsuhiko; Iwasaki, Masahiko

    2011-09-15

    We present a theoretical model combined with a computational study of a laser four-wave mixing process under optical discharge in which the non-steady-state four-wave amplitude equations are integrated with the kinetic equations of initial optical discharge and electron avalanche ionization in Kr-Ar gas. The model is validated by earlier experimental data showing strong inhibition of the generation of pulsed, tunable Lyman-{alpha} (Ly-{alpha}) radiation when using sum-difference frequency mixing of 212.6 nm and tunable infrared radiation (820-850 nm). The rigorous computational approach to the problem reveals the possibility and mechanism of strong auto-oscillations in sum-difference resonant Ly-{alpha} generation due to the combined effect of (i) 212.6-nm (2+1)-photon ionization producing initial electrons, followed by (ii) the electron avalanche dominated by 843-nm radiation, and (iii) the final breakdown of the phase matching condition. The model shows that the final efficiency of Ly-{alpha} radiation generation can achieve a value of {approx}5x10{sup -4} which is restricted by the total combined absorption of the fundamental and generated radiation.

  15. A DEEP HUBBLE SPACE TELESCOPE SEARCH FOR ESCAPING LYMAN CONTINUUM FLUX AT z {approx} 1.3: EVIDENCE FOR AN EVOLVING IONIZING EMISSIVITY

    SciTech Connect (OSTI)

    Siana, Brian; Bridge, Carrie R.; Teplitz, Harry I.; Chary, Ranga-Ram; Colbert, James W.; Scarlata, Claudia; Ferguson, Henry C.; Brown, Thomas M.; Giavalisco, Mauro; Dickinson, Mark; De Mello, Duilia F.; Conselice, Christopher J.; Gardner, Jonathan P.

    2010-11-01

    We have obtained deep Hubble Space Telescope far-UV images of 15 starburst galaxies at z {approx} 1.3 in the GOODS fields to search for escaping Lyman continuum (LyC) photons. These are the deepest far-UV images (m{sub AB} = 28.7, 3{sigma}, 1'' diameter) over this large an area (4.83 arcmin{sup 2}) and provide some of the best escape fraction constraints for any galaxies at any redshift. We do not detect any individual galaxies, with 3{sigma} limits to the LyC ({approx}700 A) flux 50-149 times fainter (in f{sub {nu}}) than the rest-frame UV (1500 A) continuum fluxes. Correcting for the mean intergalactic medium (IGM) attenuation (factor {approx}2), as well as an intrinsic stellar Lyman break (factor {approx}3), these limits translate to relative escape fraction limits of f{sub esc,rel} < [0.03, 0.21]. The stacked limit is f{sub esc,rel}(3{sigma}) < 0.02. We use a Monte Carlo simulation to properly account for the expected distribution of line-of-sight IGM opacities. When including constraints from previous surveys at z {approx} 1.3 we find that, at the 95% confidence level, no more than 8% of star-forming galaxies at z {approx} 1.3 can have relative escape fractions greater than 0.50. Alternatively, if the majority of galaxies have low, but non-zero, escaping LyC, the escape fraction cannot be more than 0.04. In light of some evidence for strong LyC emission from UV-faint regions of Lyman break galaxies (LBGs) at z {approx} 3, we also stack sub-regions of our galaxies with different surface brightnesses and detect no significant LyC flux at the f{sub esc,rel} < 0.03 level. Both the stacked limits and the limits from the Monte Carlo simulation suggest that the average ionizing emissivity (relative to non-ionizing UV emissivity) at z {approx} 1.3 is significantly lower than has been observed in LBGs at z {approx} 3. If the ionizing emissivity of star-forming galaxies is in fact increasing with redshift, it would help to explain the high photoionization rates seen in the IGM at z>4 and reionization of the IGM at z>6.

  16. Intergalactic medium emission observations with the cosmic web imager. I. The circum-QSO medium of QSO 1549+19, and evidence for a filamentary gas inflow

    SciTech Connect (OSTI)

    Martin, D. Christopher; Chang, Daphne; Matuszewski, Matt; Morrissey, Patrick; Rahman, Shahin; Moore, Anna; Steidel, Charles C.

    2014-05-10

    The Palomar Cosmic Web Imager (PCWI), an integral field spectrograph designed to detect and map low surface brightness emission, has obtained imaging spectroscopic maps of Ly? from the circum-QSO medium (CQM) of QSO HS1549+19 at redshift z = 2.843. Extensive extended emission is detected from the CQM, consistent with fluorescent and pumped Ly? produced by the ionizing and Ly? continuum of the QSO. Many features present in PCWI spectral images match those detected in narrow-band images. Filamentary structures with narrow line profiles are detected in several cases as long as 250-400 kpc. One of these is centered at a velocity redshifted with respect to the systemic velocity, and displays a spatially collimated and kinematically cold line profile increasing in velocity width approaching the QSO. This suggests that the filament gas is infalling onto the QSO, perhaps in a cold accretion flow. Because of the strong ionizing flux, the neutral column density is low, typically N(H I)?10{sup 12}--10{sup 15} cm{sup ?2}, and the line center optical depth is also low (typically ?{sub 0} < 10), insufficient to display well separated double peak emission characteristic of higher line optical depths. With a simple ionization and cloud model we can very roughly estimate the total gas mass (log M {sub gas} = 12.5 0.5) and the total (log M {sub tot} = 13.3 0.5). We can also calculate a kinematic mass from the total line profile (2 10{sup 13} M {sub ?}), which agrees with the mass estimated from the gas emission. The intensity-binned spectrum of the CQM shows a progression in kinematic properties consistent with heirarchical structure formation.

  17. PROBING THE SOLAR WIND ACCELERATION REGION WITH THE SUN-GRAZING COMET C/2002 S2

    SciTech Connect (OSTI)

    Giordano, S.; Raymond, J. C.; Lamy, P.; Uzzo, M.; Dobrzycka, D.

    2015-01-01

    Comet C/2002 S2, a member of the Kreutz family of sungrazing comets, was discovered in white-light images of the Large Angle and Spectromeric Coronagraph Experiment coronagraph on the Solar and Heliospheric Observatory (SOHO) on 2002 September 18 and observed in H I Ly? emission by the SOHO Ultraviolet Coronagraph Spectrometer (UVCS) instrument at four different heights as it approached the Sun. The H I Ly? line profiles detected by UVCS are analyzed to determine the spectral parameters: line intensity, width, and Doppler shift with respect to the coronal background. Two-dimensional comet images of these parameters are reconstructed at the different heights. A novel aspect of the observations of this sungrazing comet data is that, whereas the emission from most of the tail is blueshifted, that along one edge of the tail is redshifted. We attribute these shifts to a combination of solar wind speed and interaction with the magnetic field. In order to use the comet to probe the density, temperature, and speed of the corona and solar wind through which it passes, as well as to determine the outgassing rate of the comet, we develop a Monte Carlo simulation of the H I Ly? emission of a comet moving through a coronal plasma. From the outgassing rate, we estimate a nucleus diameter of about 9 m. This rate steadily increases as the comet approaches the Sun, while the optical brightness decreases by more than a factor of 10 and suddenly recovers. This indicates that the optical brightness is determined by the lifetimes of the grains, sodium atoms, and molecules produced by the comet.

  18. NREL Analysis Insights: Renewable Energy On The Grid, Redefining What's Possible (Brochure), NREL (National Renewable Energy Laboratory)

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

    3367 A P R I L 2 0 1 5 A N A LY S I S I N S I G H T S RENEWABLE ENERGY ON THE GRID Redefining What's Possible 2 RENEWABLE ENERGY ON THE GRID Environmental regulations, state-level portfolio standards, new methods for accessing natural gas reserves and aging power plants are opening opportunities for new electricity generation from renewable resources and natural gas. Advances in efficiency and smart grid technologies also have the potential to change historical demand curves. New renewable

  19. 14C

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

    Thermal Neutron Capture Evaluated Data Measurements 1975SM02: 13C(n, γ); measured atomic mass. 1981MUZU: 13C(n, γ), E = thermal; measured σ(capture), ratio. 14C level deduced spectroscopic factor. 1982MU14: 13C(n, γ), E = thermal; measured σ(Eγ), Iγ; deduced capture mechanism. 1987LY01, 1987LYZY: 13C(n, γ), E = thermal; calculated capture σ. 1990RA03: 13C(n, γ), E = resonance; measured Eγ, Iγ. 14C levels deduced partial, total Γγ. Valence capture mechanism. 1992JUZZ: 13C(n, γ);

  20. One West Third Street Tulsa Oklahoma

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

    LaKesha Robertson Administrative Technician WNT Contractor Jonesboro Special thanks to: Pat Boone Ruben Garcia Larry Harp Darlene Low Jerry Martin Beth Nielsen Jim Sherwood Rutha Williams Jon Worthington U P D AT E S O U T H W E S T E R N P O W E R A D M I N I S T R A T I O N J U LY - S E P T E M B E R 2 0 0 4 Southwestern Honored for Outstanding E-Government In a ceremony held August 4, 2004 at Department of Energy (DOE) Headquarters in Washington, D.C., Secretary of Energy Spencer Abraham

  1. One West Third Street Tulsa Oklahoma

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

    Conley Jennings Lineman Springfield, MO Special thanks to: Marshall Boyken Mike Deihl Ruben Garcia Bethel Herrold William Hiller Beth Nielsen George Robbins Gary Swartzlander Cris Van Horn Rutha Williams Jan Woolverton U P D AT E S O U T H W E S T E R N P O W E R A D M I N I S T R A T I O N J U LY - S E P T E M B E R 2 0 0 5 Strategic Workshop Unites Hydropower Community At the invitation of the U.S. Army Corps of Engineers (Corps), Federal power customers joined representatives of the Corps,

  2. DOE Loan Programs Office Update

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

    N S O L I C I TAT I O N S | A P P LY N O W IN THIS UPDATE: FEBRUARY 2015 SUPPORTING THE AMERICAN AUTO INDUSTRY UPDATED ATVM LOAN PROGRAM GUIDANCE NEW GREENHOUSE GAS EMISSIONS WORKSHEET CURRENT OPEN SOLICITATIONS SUPPORTING THE FUTURE OF THE AMERICAN AUTO INDUSTRY Last month, President Obama underscored the importance of innovation in the American auto industry during his visit to one of the many factories upgraded with a $5.9 billion loan to the Ford Motor Company through the Advanced Technology

  3. U.S. NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT

    Office of Legacy Management (LM)

    -., * : . ; * c i. :i; $i 4 5 ' I jr 1 ly i *- 1 U.S. NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT Region I Report No. 078-154-A - Part1 of 2 Subject: Radioactive Material in Norton, Massachusetts Uncontrolled ' :-- . . . _ > Location, Investigation at: Norton and Attleboro, Massachusetts Investigation conducted: November 14, 28-30; December 1, 7, 8, 21, 1978; January 9-12, 1978 Investigators: ?-9,7G Phys'ical Security-Inspector I dati sibntd rl,puet ryyl Ilty Inspector

  4. Inverse Design of Mn-based ternary p-type wide-gap oxides

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

    ZnO is an important prototypical wide-gap oxide semiconductor. The discrepancy between band- structure theory and ARPES is removed by a correction for the Zn-d band energy in GW calculations. Significance and Impact The present approach improves the capability for property prediction and design of energy materials. Benchmarking Band-Structure Calculations Against Angular-Resolved Photoemission Spectroscopy (ARPES) for ZnO L.Y. Lim, S. Lany, Y.J. Chang, E. Rotenberg, A. Zunger, M.F. Toney,

  5. Analysis Insights: Energy Storage - Possibilities for Expanding Electric Grid Flexibility (Brochure), NREL (National Renewable Energy Laboratory)

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

    764 F E B R U A R Y 2 0 1 6 A N A LY S I S I N S I G H T S ENERGY STORAGE Possibilities for Expanding Electric Grid Flexibility POTENTIAL GRID APPLICATIONS STORAGE TECHNOLOGY CHARACTERISTICS 0.1 1 10 100 1000 Seconds Minutes Hours Days Generation Transmission & Distribution End Use E ciency 85-100% 70-85% 45-70% 30-45% Energy Management Operating & Ramping Reserves Frequency Response & Regulation Provide uninterruptable power supply-provide back-up power Optimize time of use retail

  6. I~

    Office of Legacy Management (LM)

    __, I,- __.j .^,, ~~.,l~, _I.x__ . ,,,,, ,_^_ ,,_xx,. ,~.__~_x -,-.. _1 ,.,., - I~ .c \ -- - g-' . @ ~--~Z~, Ls-u &. 0 -*,- hiK ,,-& b TO FILE ' = .-. r. AUG 2 9 1945 A~TPPHC~~~ METALS COPUDOP~TIO~ '* ~,ci~ly~1~~ 41 BROAD STREET (In duplicate) November 6, 1942 The District Engineer, u. s . Zngineer Office, Zanhattarn District, P. 0. 30x 4.2, Station P., i?C:: York, X.Y. Attention: Idajo- Thomas T. Crenshav:. Gentlemen: Classification Cancc!!A ZG? ;~yp~~ Follo~5.nS our conversation of

  7. Microsoft Word - DR_benefits_Congress_v9_2 03 06 12pm.doc

    Energy Savers [EERE]

    pp u ly Demand Price of Electricity Supply Quantity of Electricity P P DR Q DR Q Demand DR BENEFITS OF DEMAND RESPONSE IN ELECTRICITY MARKETS AND RECOMMENDATIONS FOR ACHIEVING THEM A REPORT TO THE UNITED STATES CONGRESS PURSUANT TO SECTION 1252 OF THE ENERGY POLICY ACT OF 2005 U.S. Department of Energy February 2006 U.S. Department of Energy Benefits of Demand Response and Recommendations ii U.S. Department of Energy Benefits of Demand Response and Recommendations iii The Secretary [of Energy]

  8. 2page.indd

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

    P D AT E S O U T H W E S T E R N P O W E R A D M I N I S T R A T I O N S U P P L E M E N T A L E D I T I O N J U LY 1 3 , 2 0 0 6 PMA Partnership Implements New SCADA System at Springfield Operations Center Southwestern successfully installed its new Supervisory Control and Data Acquisition (SCADA) system at its Operations Center in Springfield, MO, on June 20, 2006. This new software, developed in cooperation with Western Area Power Administration (Western), essentially replaces the old

  9. AdvancedBPA_jk

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

    A DVA N C E D B L O O D S TA I N P A T T E R N A NA LY S I S WORKSHOP S E P T E M B E R 2 3 - 2 7 , 2 0 1 3 Advanced Bloodstain Pattern Analysis Workshop This advanced level course is designed for practitioners who have successfully completed basic instruction in Bloodstain Pattern Analysis and desire to build on that fundamental knowledge while working toward expertise in the discipline. This workshop will begin with a brief review of the basic concepts and will continue with the student

  10. Assessing

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

    dental disease in minutes Understanding climate change Keeping watch on the world SPRING 2007 S A N D I A T E C H N O L O G Y A Q UA RT E R LY R E S E A R C H & D E V E LO P M E N T MAG A Z I N E - VO LUM E 9 , N O. 1 Sandia Technology (ISSN: 1547-5190) is a quarterly maga- zine published by Sandia National Laboratories. Sandia is a multiprogram engineering and science laboratory operated by Sandia Corporation, a Lockheed Martin company, for the Department of Energy. With main facilities in

  11. BNL-24136

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

    24136 GAUSSIAN 76 - An ab initio molecular orbital program. J. S. Binkley, R. Whiteside, P. c. Hariharan, R. Seeger, W. J. Hehre, w. A. Lathan, M. D. Newton, R. Ditchfield and J. A. Pople Abstract GAUSSIAN 76 is a general-purpose computer program for ab initio Hartree-Fock molecular orbital _calculations. It can handle basis sets involving s, p and d-type gaussian functions. Certain standard sets * (ST0-3G, 4-31G, 6-31G etc.) are stored internal ly for easy use. Closed shell (RHF) or

  12. Discovery of eight z ? 6 quasars from Pan-STARRS1

    SciTech Connect (OSTI)

    Baados, E.; Venemans, B. P.; Morganson, E.; Decarli, R.; Walter, F.; Rix, H.-W.; Farina, E. P.; Chambers, K. C.; Morgan, J. S.; Burgett, W. S.; Kaiser, N.; Kudritzki, R.-P.; Fan, X.; McGreer, I.; Jiang, L.; De Rosa, G.; Simcoe, R.; Wei, A.; Price, P. A.; Greiner, J.; and others

    2014-07-01

    High-redshift quasars are currently the only probes of the growth of supermassive black holes and potential tracers of structure evolution at early cosmic time. Here we present our candidate selection criteria from the Panoramic Survey Telescope and Rapid Response System 1 and follow-up strategy to discover quasars in the redshift range 5.7 ? z ? 6.2. With this strategy we discovered eight new 5.7 ? z ? 6.0 quasars, increasing the number of known quasars at z > 5.7 by more than 10%. We additionally recovered 18 previously known quasars. The eight quasars presented here span a large range of luminosities (27.3 ? M {sub 1450} ? 25.4; 19.6 ? z {sub P1} ? 21.2) and are remarkably heterogeneous in their spectral features: half of them show bright emission lines whereas the other half show a weak or no Ly? emission line (25% with rest-frame equivalent width of the Ly? +N V line lower than 15 ). We find a larger fraction of weak-line emission quasars than in lower redshift studies. This may imply that the weak-line quasar population at the highest redshifts could be more abundant than previously thought. However, larger samples of quasars are needed to increase the statistical significance of this finding.

  13. GADRAS isotope ID users manual for analysis of gamma-ray measurements and API for Linux and Android .

    SciTech Connect (OSTI)

    Mitchell, Dean J; Harding, Lee T.

    2014-05-01

    Isotope identification algorithms that are contained in the Gamma Detector Response and Analysis Software (GADRAS) can be used for real-time stationary measurement and search applications on platforms operating under Linux or Android operating sys-tems. Since the background radiation can vary considerably due to variations in natu-rally-occurring radioactive materials (NORM), spectral algorithms can be substantial-ly more sensitive to threat materials than search algorithms based strictly on count rate. Specific isotopes or interest can be designated for the search algorithm, which permits suppression of alarms for non-threatening sources, such as such as medical radionuclides. The same isotope identification algorithms that are used for search ap-plications can also be used to process static measurements. The isotope identification algorithms follow the same protocols as those used by the Windows version of GADRAS, so files that are created under the Windows interface can be copied direct-ly to processors on fielded sensors. The analysis algorithms contain provisions for gain adjustment and energy lineariza-tion, which enables direct processing of spectra as they are recorded by multichannel analyzers. Gain compensation is performed by utilizing photopeaks in background spectra. Incorporation of this energy calibration tasks into the analysis algorithm also eliminates one of the more difficult challenges associated with development of radia-tion detection equipment.

  14. VUV emission spectroscopy diagnostics of a 14 GHz ECR negative hydrogen ion source

    SciTech Connect (OSTI)

    Tamura, R. Ichikawa, T.; Kasuya, T.; Wada, M.; Nishiura, M.; Shimozuma, T.

    2015-04-08

    Vacuum Ultra Violet(VUV) emission from a 4 cm diameter 2 cm long compact ion source excited by 14 GHz microwave has been investigated. Intensity ratio of band spectrum emission near Ly-α to Ly-α line spectrum is determined from the measured spectrum. which shows preferential excitation of molecules near the entrance of microwave input power. The ratio does not depend strongly upon pressure nor the input microwave power when the intensity is integrated over the volume of the plasma. The spatial distribution of the spectrum intensity ratio exhibits concentrations near microwave inlet and the opposite side where the microwave matching structure is located. The ratio at these peripheral regions is about two times as high as that of the central region. The ratio increased in proportion to the ion source pressure up to about 3.0 Pa, indicating efficient production of high energy electrons by ECR up to this pressure.

  15. COSMIC ORIGINS SPECTROGRAPH OBSERVATIONS OF WARM INTERVENING GAS AT z {approx} 0.325 TOWARD 3C 263

    SciTech Connect (OSTI)

    Narayanan, Anand [Indian Institute of Space Science and Technology, Thiruvananthapuram 695547, Kerala (India); Savage, Blair D.; Wakker, Bart P., E-mail: anand@iist.ac.in, E-mail: savage@astro.wisc.edu, E-mail: wakker@astro.wisc.edu [Department of Astronomy, University of Wisconsin-Madison, 5534 Sterling Hall, 475 N. Charter Street, Madison, WI 53706-1582 (United States)

    2012-06-10

    We present HST/COS high-S/N observations of the z = 0.32566 multiphase absorber toward 3C 263. The Cosmic Origins Spectrograph (COS) data show absorption from H I (Ly{alpha} to Ly{theta}), O VI, C III, N III, Si III, and C II. The Ne VIII in this absorber is detected in the FUSE spectrum along with O III, O IV, and N IV. The low and intermediate ions are kinematically aligned with each other and H I and display narrow line widths of b {approx} 6-8 km s{sup -1}. The O VI {lambda}{lambda}1031, 1037 lines are kinematically offset by {Delta}v {approx} 12 km s{sup -1} from the low ions and are a factor of {approx}4 broader. All metal ions except O VI and Ne VIII are consistent with an origin in gas photoionized by the extragalactic background radiation. The bulk of the observed H I is also traced by this photoionized medium. The metallicity in this gas phase is Z {approx}> 0.15 Z{sub Sun} with carbon having near-solar abundances. The O VI and Ne VIII favor an origin in collisionally ionized gas at T = 5.2 Multiplication-Sign 10{sup 5} K. The H I absorption associated with this warm absorber is a broad-Ly{alpha} absorber (BLA) marginally detected in the COS spectrum. This warm gas phase has a metallicity of [X/H] {approx}-0.12 dex, and a total hydrogen column density of N( H) {approx} 3 Multiplication-Sign 10{sup 19} cm{sup -2}, which is {approx}2 dex higher than what is traced by the photoionized gas. Simultaneous detection of O VI, Ne VIII, and BLAs in an absorber can be a strong diagnostic of gas with T {approx} 10{sup 5}-10{sup 6} K corresponding to the warm phase of the warm-hot intergalactic medium or shock-heated gas in the extended halos of galaxies.

  16. CRITICAL STAR FORMATION RATES FOR REIONIZATION: FULL REIONIZATION OCCURS AT REDSHIFT z Almost-Equal-To 7

    SciTech Connect (OSTI)

    Michael Shull, J.; Harness, Anthony; Trenti, Michele; Smith, Britton D. E-mail: trenti@colorado.edu E-mail: smit1685@msu.edu

    2012-03-10

    We assess the probable redshift (z{sub rei} Almost-Equal-To 7) for full reionization of the intergalactic medium (IGM) using a prescription for the comoving star formation rate (SFR) density ({rho}-dot{sub SFR}) required to maintain photoionization against recombination. Our newly developed online reionization simulator allows users to assess the required SFR and ionization histories, using a variety of assumptions for galactic and stellar populations, IGM clumping factor and temperature, and Lyman continuum (LyC) escape fraction. The decline in high-redshift galaxy candidates and Ly{alpha} emitters at z = 6-8 suggests a rising neutral fraction, with reionization at z {approx}> 7 increasingly difficult owing to increased recombination rates and constraints from the ionizing background and LyC mean free path. The required rate is {rho}-dot{sub SFR}{approx}(.018 M{sub sun}yr{sup -1}Mpc{sup -3})[(1+z)/8]{sup 3}(C{sub H}/3)(0.2/f{sub esc})T{sub 4}{sup -0.845} scaled to fiducial values of clumping factor C{sub H} = 3, escape fraction f{sub esc} = 0.2, electron temperature T{sub e} = 10{sup 4} K, and low-metallicity initial mass functions (IMFs) and stellar atmospheres. Our hydrodynamical + N-body simulations find a mean clumping factor C{sub H} Almost-Equal-To (2.9)[(1 + z)/6]{sup -1.1} in the photoionized, photoheated filaments at z = 5-9. The critical SFR could be reduced by increasing the minimum stellar mass, invoking a top-heavy IMF, or systematically increasing f{sub esc} at high z. The cosmic microwave background optical depth, {tau}{sub e} = 0.088 {+-} 0.015, could be explained by full reionization, producing {tau}{sub e} = 0.050 back to z{sub rei} Almost-Equal-To 7, augmented by {Delta}{tau}{sub e} Almost-Equal-To 0.01-0.04 in a partially ionized IGM at z > 7. In this scenario, the strongest 21 cm signal should occur at redshifted frequencies 124-167 MHz owing to IGM heating over an interval {Delta}z Almost-Equal-To 3 in the range z Almost-Equal-To 7.5-10.5.

  17. THE FAR-ULTRAVIOLET 'CONTINUUM' IN PROTOPLANETARY DISK SYSTEMS. II. CARBON MONOXIDE FOURTH POSITIVE EMISSION AND ABSORPTION

    SciTech Connect (OSTI)

    France, Kevin; Schindhelm, Eric; Burgh, Eric B.; Brown, Alexander; Green, James C.; Herczeg, Gregory J.; Brown, Joanna M.; Harper, Graham M.; Linsky, Jeffrey L.; Yang Hao; Abgrall, Herve; Ardila, David R.; Bergin, Edwin; Bethell, Thomas; Calvet, Nuria; Ingleby, Laura; Espaillat, Catherine; Gregory, Scott G.; Hillenbrand, Lynne A.; Hussain, Gaitee

    2011-06-10

    We exploit the high sensitivity and moderate spectral resolution of the Hubble Space Telescope Cosmic Origins Spectrograph to detect far-ultraviolet (UV) spectral features of carbon monoxide (CO) present in the inner regions of protoplanetary disks for the first time. We present spectra of the classical T Tauri stars HN Tau, RECX-11, and V4046 Sgr, representative of a range of CO radiative processes. HN Tau shows CO bands in absorption against the accretion continuum. The CO absorption most likely arises in warm inner disk gas. We measure a CO column density and rotational excitation temperature of N(CO) = (2 {+-} 1) x 10{sup 17} cm{sup -2} and T{sub rot}(CO) 500 {+-} 200 K for the absorbing gas. We also detect CO A-X band emission in RECX-11 and V4046 Sgr, excited by UV line photons, predominantly H I Ly{alpha}. All three objects show emission from CO bands at {lambda} > 1560 A, which may be excited by a combination of UV photons and collisions with non-thermal electrons. In previous observations these emission processes were not accounted for due to blending with emission from the accretion shock, collisionally excited H{sub 2}, and photo-excited H{sub 2}, all of which appeared as a 'continuum' whose components could not be separated. The CO emission spectrum is strongly dependent upon the shape of the incident stellar Ly{alpha} emission profile. We find CO parameters in the range: N(CO) {approx} 10{sup 18}-10{sup 19} cm{sup -2}, T{sub rot}(CO) {approx}> 300 K for the Ly{alpha}-pumped emission. We combine these results with recent work on photo-excited and collisionally excited H{sub 2} emission, concluding that the observations of UV-emitting CO and H{sub 2} are consistent with a common spatial origin. We suggest that the CO/H{sub 2} ratio ({identical_to} N(CO)/N(H{sub 2})) in the inner disk is {approx}1, a transition between the much lower interstellar value and the higher value observed in solar system comets today, a result that will require future observational and theoretical study to confirm.

  18. Improved DC Gun Insulator Assembly

    SciTech Connect (OSTI)

    Sah, R.; Dudas, A.; Neubauer, M. L.; Poelker, M.; Surles-Law, K. E.L.

    2010-05-23

    Many user facilities such as synchrotron radiation light sources and free electron lasers require accelerating structures that support electric fields of 10-100 MV/m, especially at the start of the accelerator chain where ceramic insulators are used for very high gradient DC guns. These insulators are difficult to manufacture, require long commissioning times, and often exhibit poor reliability. Two technical approaches to solving this problem will be investigated. Firstly, inverted ceramics offer solutions for reduced gradients between the electrodes and ground. An inverted design will be presented for 350 kV, with maximum gradients in the range of 5-10 MV/m. Secondly, novel ceramic manufacturing processes will be studied, in order to protect triple junction locations from emission, by applying a coating with a bulk resistivity. The processes for creating this coating will be optimized to provide protection as well as be used to coat a ceramic with an appropriate gradient in bulk resistivity from the vacuum side to the air side of an HV standoff ceramic cylinder. Example insulator designs are being computer modelled, and insulator samples are being manufactured and tested

  19. 1663_Issue19indd.indd

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

    J U LY 2 0 1 3 Early Warning for Biothreats Clean Fuel from Wind and Solar Modeling the Living Ocean Infrastructure Self-Check 1 663 LO S A L A M O S S C I E N C E A N D T E C H N O LO G Y M AG A Z I N E Los Alamos Firsts About Our Name: During World War II, all that the outside world knew of Los Alamos and its top-secret laboratory was the mailing address-P . O. Box 1663, Santa Fe, New Mexico. That box number, still part of our address, symbolizes our historic role in the nation's service.

  20. Research News July 2015, Issue 10

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

    Alloy Raises the Bar for High-Temperature Performance page 3 the ENERGY lab NATIONAL ENERGY TECHNOLOGY LABORATORY From NETL's Office of Research & Development Researchnews July 2015, Issue 10 FE AT U RE ST O RY : A ll o y R a is e s th e B a r fo r H ig h -T e m p e ra F ro m N E T L' s O ff ic e o f R e s e a rc h & D e v e lo p m e n t R e s e a r c h n e w s Ju ly 20 15 , Is su e 10 Contents July 2015, Issue 10 2 Editorial: NETL's Educational Programs 3 Feature Story: Alloy Raises the

  1. EVIDENCE FOR A WEAK WIND FROM THE YOUNG SUN

    SciTech Connect (OSTI)

    Wood, Brian E.; Mller, Hans-Reinhard; Redfield, Seth; Edelman, Eric

    2014-02-01

    The early history of the solar wind has remained largely a mystery due to the difficulty of detecting winds around young stars that can serve as analogs for the young Sun. Here we report on the detection of a wind from the 500Myr old solar analog ?{sup 1} UMa (G1.5V), using spectroscopic observations from the Hubble Space Telescope. We detect H I Ly? absorption from the interaction region between the stellar wind and interstellar medium, i.e., the stellar astrosphere. With the assistance of hydrodynamic models of the ?{sup 1} UMa astrosphere, we infer a wind only half as strong as the solar wind for this star. This suggests that the Sun and solar-like stars do not have particularly strong coronal winds in their youth.

  2. A=11C (1985AJ01)

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

    5AJ01) (See Energy Level Diagrams for 11C) GENERAL: See also (1980AJ01) and Table 11.17 [Table of Energy Levels] (in PDF or PS). Model calculations:(1981RA06, 1983SH38). Special states:(1981RA06). Complex reactions involving 11C:(1979BO22, 1980GR10, 1980WI1K, 1980WI1L, 1981MO20, 1982GE05, 1982LY1A, 1982RA31, 1983FR1A, 1983OL1A, 1983WI1A, 1984GR08, 1984HI1A). Electromagnetic transitions:(1978KR19). Applied work:(1979DE1H, 1982BO1N, 1982HI1H, 1982KA1R, 1982ME1C, 1982NE1D, 1982PI1H, 1982YA1C,

  3. I I LI I L I

    Office of Legacy Management (LM)

    LI - I L I 1 II C c - ORNL/RASA-9618 OAK RlDGE NATlONAl. LA8ORATORY Results of the Independent Radiological Verification Survey at B&T Metals, 425 West Town Street, Columbus, Ohio (cooolv) M . E. Murray V. P. Patania C. A. Johnson M N M E D *wD OPEbM~ B V WUCNEEDllW?ME IWiARCH CoRpoRAng FoRTHEwITf@%tATeB ltEpAAMwTmBMeR(Ly ORNL-27 (34el ~~- L._~ This report has been reproduced directly from the best available copy. Avaiiable to DOE and DOE contractors from the Office of Scientific and

  4. I

    Office of Legacy Management (LM)

    --&) /+' ) 3 -i/ ii!' M/k "3 . . * . ~T~&,TTSTT:~ .: -~53~~i!&i-:r~ 1: c r I * .I " / : , ; . . . 3. .i - w ~trial IIyi-;iene Orand Re&lh and safety Laboratmy Im,mdc Octokr 21, u% 2' ' - ' 1' !!T?H _ - .a r. ,...~.b,)i~XTia~ !I4%L, XYm 2. ..T* 2zdJ-- l ,,C 1 .rJh, !' 11., ;dv 2: ;" 11 I:r,t, :433kr 3- :r. L. r> .-. ? Ly-m-i, ! pm* j!., >- I I;- ,:r* : "y l hl~wt, li:.!l, iah pm ~iL.A.4 ;'A0 U.S. .' .LJf& Er++r;;;- LI3zL?.i !!w ' Lsriz Qcr&N.~~3

  5. Neutral particle beam sensing and steering

    DOE Patents [OSTI]

    Maier, II, William B. (Los Alamos, NM); Cobb, Donald D. (Los Alamos, NM); Robiscoe, Richard T. (Los Alamos, NM)

    1991-01-01

    The direction of a neutral particle beam (NPB) is determined by detecting Ly.alpha. radiation emitted during motional quenching of excited H(2S) atoms in the beam during movement of the atoms through a magnetic field. At least one detector is placed adjacent the beam exit to define an optical axis that intercepts the beam at a viewing angle to include a volume generating a selected number of photons for detection. The detection system includes a lens having an area that is small relative to the NPB area and a pixel array located in the focal plane of the lens. The lens viewing angle and area pixel array are selected to optimize the beam tilt sensitivity. In one embodiment, two detectors are placed coplanar with the beam axis to generate a difference signal that is insensitive to beam variations other than beam tilt.

  6. Inelastic X-ray Scattering from Shocked Liquid Deuterium

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

    Regan, S. P.; Falk, K.; Gregori, G.; Radha, P. B.; Hu, S. X.; Boehly, T. R.; Crowley, B.; Glenzer, S. H.; Landen, O.; Gericke, D. O.; et al

    2012-12-28

    The Fermi-degenerate plasma conditions created in liquid deuterium by a laser-ablation—driven shock wave were probed with noncollective, spectrally resolved, inelastic x-ray Thomson scattering employing Cl Lyα line emission at 2.96 keV. Thus, these first x-ray Thomson scattering measurements of the microscopic properties of shocked deuterium show an inferred spatially averaged electron temperature of 8±5 eV, an electron density of 2.2(±0.5)×1023 cm-3, and an ionization of 0.8 (-0.25, +0.15). Our two-dimensional hydrodynamic simulations using equation-of-state models suited for the extreme parameters occurring in inertial confinement fusion research and planetary interiors are consistent with the experimental results.

  7. THE CIRCUMGALACTIC MEDIUM OF MASSIVE GALAXIES AT z {approx} 3: A TEST FOR STELLAR FEEDBACK, GALACTIC OUTFLOWS, AND COLD STREAMS

    SciTech Connect (OSTI)

    Shen Sijing; Madau, Piero; Prochaska, J. Xavier [Department of Astronomy and Astrophysics, University of California, 1156 High Street, Santa Cruz, CA 95064 (United States); Guedes, Javiera [Institute for Astronomy, ETH Zurich, Wolgang-Pauli-Strasse 27, CH-8093 Zurich (Switzerland); Mayer, Lucio [Institute of Theoretical Physics, University of Zurich, Winterthurerstrasse 190, CH-9057 Zurich (Switzerland); Wadsley, James [Department of Physics and Astronomy, McMaster University, Hamilton, ON L8S 4M1 (Canada)

    2013-03-10

    We present new results on the kinematics, thermal and ionization state, and spatial distribution of metal-enriched gas in the circumgalactic medium (CGM) of massive galaxies at redshift {approx}3, using the Eris suite of cosmological hydrodynamic ''zoom-in'' simulations. The reference run adopts a blastwave scheme for supernova feedback that produces large-scale galactic outflows, a star formation recipe based on a high gas density threshold, metal-dependent radiative cooling, and a model for the diffusion of metals and thermal energy. The effect of the local UV radiation field is added in post-processing. The CGM (defined as all gas at R > 0.2 R{sub vir} = 10 kpc, where R{sub vir} is the virial radius) contains multiple phases having a wide range of physical conditions, with more than half of its heavy elements locked in a warm-hot component at T > 10{sup 5} K. Synthetic spectra, generated by drawing sightlines through the CGM, produce interstellar absorption-line strengths of Ly{alpha}, C II, C IV, Si II, and Si IV as a function of the galactocentric impact parameter (scaled to the virial radius) that are in broad agreement with those observed at high redshift by Steidel et al. The covering factor of absorbing material declines less rapidly with impact parameter for Ly{alpha} and C IV compared to C II, Si IV, and Si II, with Ly{alpha} remaining strong (W{sub Ly{alpha}} > 300 mA) to {approx}> 5 R{sub vir} = 250 kpc. Only about one third of all the gas within R{sub vir} is outflowing. The fraction of sightlines within one virial radius that intercept optically thick, N{sub H{sub I}}>10{sup 17.2} cm{sup -2} material is 27%, in agreement with recent observations by Rudie et al. Such optically thick absorption is shown to trace inflowing ''cold'' streams that penetrate deep inside the virial radius. The streams, enriched to metallicities above 0.01 solar by previous episodes of star formation in the main host and in nearby dwarfs, are the origin of strong (N{sub C{sub II}}>10{sup 13} cm{sup -2}) C II absorption with a covering factor of 22% within R{sub vir} and 10% within 2 R{sub vir}. Galactic outflows do not cause any substantial suppression of the cold accretion mode. The central galaxy is surrounded by a large O VI halo, with a typical column density N{sub O{sub VI}} {approx}> 10{sup 14} cm{sup -2} and a near unity covering factor maintained all the way out to 150 kpc. This matches the trends recently observed in star-forming galaxies at low redshift by Tumlinson et al. Our zoom-in simulations of this single system appear then to reproduce quantitatively the complex baryonic processes that determine the exchange of matter, energy, and metals between galaxies and their surroundings.

  8. Laser heating of solid matter by light pressure-driven shocks

    SciTech Connect (OSTI)

    Akli, K; Hansen, S B; Kemp, A J; Freeman, R R; Beg, F N; Clark, D; Chen, S; Hey, D; Highbarger, K; Giraldez, E; Green, J; Gregori, G; Lancaster, K; Ma, T; MacKinnon, A J; Norreys, P A; Patel, N; Patel, P; Shearer, C; Stephens, R B; Stoeckl, C; Storm, M; Theobald, W; Van Woerkom, L; Weber, R; Key, M H

    2007-05-04

    Heating by irradiation of a solid surface in vacuum with 5 x 10{sup 20} W cm{sup -2}, 0.8 ps, 1.05 {micro}m wavelength laser light is studied by x-ray spectroscopy of the K-shell emission from thin layers of Ni, Mo and V. A surface layer is heated to {approx} 5 keV with an axial temperature gradient of 0.6 {micro}m scale length. Images of Ni Ly{sub {alpha}} show the hot region has a {approx} 25 {micro}m diameter, much smaller than {approx} 70 {micro}m region of K{sub {alpha}} emission. 2D particle-in-cell (PIC) simulations suggest that the surface heating is due to a light pressure driven shock.

  9. HST/COS SPECTRA OF THREE QSOs THAT PROBE THE CIRCUMGALACTIC MEDIUM OF A SINGLE SPIRAL GALAXY: EVIDENCE FOR GAS RECYCLING AND OUTFLOW

    SciTech Connect (OSTI)

    Keeney, Brian A.; Stocke, John T.; Danforth, Charles W.; Shull, J. Michael; Green, James C. [Center for Astrophysics and Space Astronomy, Department of Astrophysical and Planetary Sciences, University of Colorado, 389 UCB, Boulder, CO 80309 (United States)] [Center for Astrophysics and Space Astronomy, Department of Astrophysical and Planetary Sciences, University of Colorado, 389 UCB, Boulder, CO 80309 (United States); Rosenberg, Jessica L. [Department of Physics and Astronomy, George Mason University, Fairfax, VA 22030 (United States)] [Department of Physics and Astronomy, George Mason University, Fairfax, VA 22030 (United States); Ryan-Weber, Emma V. [Centre for Astrophysics and Supercomputing, Swinburne University of Technology, Mail H30, P.O. Box 218, Hawthorn, 3122 VIC (Australia)] [Centre for Astrophysics and Supercomputing, Swinburne University of Technology, Mail H30, P.O. Box 218, Hawthorn, 3122 VIC (Australia); Savage, Blair D., E-mail: brian.keeney@colorado.edu [Department of Astronomy, University of Wisconsin-Madison, 5534 Sterling Hall, 475 North Charter Street, Madison, WI 53706 (United States)

    2013-03-01

    We have used the Cosmic Origins Spectrograph (COS) to obtain far-UV spectra of three closely spaced QSO sight lines that probe the circumgalactic medium (CGM) of an edge-on spiral galaxy, ESO 157-49, at impact parameters of 74 and 93 h {sup -1} {sub 70} kpc near its major axis and 172 h {sup -1} {sub 70} kpc along its minor axis. H I Ly{alpha} absorption is detected at the galaxy redshift in the spectra of all three QSOs, and metal lines of Si III, Si IV, and C IV are detected along the two major-axis sight lines. Photoionization models of these clouds suggest metallicities close to the galaxy metallicity, cloud sizes of {approx}1 kpc, and gas masses of {approx}10{sup 4} M {sub Sun }. Given the high covering factor of these clouds, ESO 157-49 could harbor {approx}2 Multiplication-Sign 10{sup 9} M {sub Sun} of warm CGM gas. We detect no metals in the sight line that probes the galaxy along its minor axis, but gas at the galaxy metallicity would not have detectable metal absorption with ionization conditions similar to the major-axis clouds. The kinematics of the major-axis clouds favor these being portions of a 'galactic fountain' of recycled gas, while two of the three minor-axis clouds are constrained geometrically to be outflowing gas. In addition, one of our QSO sight lines probes a second more distant spiral, ESO 157-50, along its major axis at an impact parameter of 88 h {sup -1} {sub 70} kpc. Strong H I Ly{alpha} and C IV absorption only are detected in the QSO spectrum at the redshift of ESO 157-50.

  10. THE He II POST-REIONIZATION EPOCH: HST/COS OBSERVATIONS OF THE QUASAR HS1700+6416

    SciTech Connect (OSTI)

    Syphers, David; Shull, J. Michael, E-mail: david.syphers@colorado.edu, E-mail: michael.shull@colorado.edu [CASA, Department of Astrophysical and Planetary Sciences, University of Colorado, Boulder, CO 80309 (United States)

    2013-03-10

    The reionization epoch of singly ionized helium (He II) is believed to start at redshifts z {approx} 3.5-4 and be nearly complete by z {approx_equal} 2.7. We explore the post-reionization epoch with far-ultraviolet spectra of the bright, high-redshift quasar HS1700+6416 taken by the Cosmic Origins Spectrograph (COS) on the Hubble Space Telescope, which show strong He II ({lambda}303.78) absorption shortward of the QSO redshift, z{sub QSO} = 2.75. We discuss these data as they probe the post-reionization history of He II and the local ionization environment around the quasar and transverse to the line of sight, finding that quasars are likely responsible for much of the ionization. We compare previous spectra taken by the Far-Ultraviolet Spectroscopic Explorer to the current COS data, which have a substantially higher signal-to-noise ratio. The Gunn-Peterson trough recovers at lower redshifts, with the effective optical depth falling from {tau}{sub eff} {approx_equal} 1.8 at z {approx} 2.7 to {tau}{sub eff} {approx_equal} 0.7 at z {approx} 2.3, higher than has been reported in earlier work. We see an interesting excess of flux near the He II Ly{alpha} break, which could be quasar line emission, although likely not He II Ly{alpha}. We present spectra of four possible transverse-proximity quasars, although the UV hardness data are not of sufficient quality to say if their effects are seen along the HS1700 sightline.

  11. Reconstitution of the cellular response to DNA damage in vitro using damage-activated extracts from mammalian cells

    SciTech Connect (OSTI)

    Roper, Katherine; Coverley, Dawn

    2012-03-10

    In proliferating mammalian cells, DNA damage is detected by sensors that elicit a cellular response which arrests the cell cycle and repairs the damage. As part of the DNA damage response, DNA replication is inhibited and, within seconds, histone H2AX is phosphorylated. Here we describe a cell-free system that reconstitutes the cellular response to DNA double strand breaks using damage-activated cell extracts and naieve nuclei. Using this system the effect of damage signalling on nuclei that do not contain DNA lesions can be studied, thereby uncoupling signalling and repair. Soluble extracts from G1/S phase cells that were treated with etoposide before isolation, or pre-incubated with nuclei from etoposide-treated cells during an in vitro activation reaction, restrain both initiation and elongation of DNA replication in naieve nuclei. At the same time, H2AX is phosphorylated in naieve nuclei in a manner that is dependent upon the phosphatidylinositol 3-kinase-like protein kinases. Notably, phosphorylated H2AX is not focal in naieve nuclei, but is evident throughout the nucleus suggesting that in the absence of DNA lesions the signal is not amplified such that discrete foci can be detected. This system offers a novel screening approach for inhibitors of DNA damage response kinases, which we demonstrate using the inhibitors wortmannin and LY294002. -- Highlights: Black-Right-Pointing-Pointer A cell free system that reconstitutes the response to DNA damage in the absence of DNA lesions. Black-Right-Pointing-Pointer Damage-activated extracts impose the cellular response to DNA damage on naieve nuclei. Black-Right-Pointing-Pointer PIKK-dependent response impacts positively and negatively on two separate fluorescent outputs. Black-Right-Pointing-Pointer Can be used to screen for inhibitors that impact on the response to damage but not on DNA repair. Black-Right-Pointing-Pointer LY294002 and wortmannin demonstrate the system's potential as a pathway focused screening approach.

  12. Water vapor distribution in protoplanetary disks

    SciTech Connect (OSTI)

    Du, Fujun; Bergin, Edwin A.

    2014-09-01

    Water vapor has been detected in protoplanetary disks. In this work, we model the distribution of water vapor in protoplanetary disks with a thermo-chemical code. For a set of parameterized disk models, we calculate the distribution of dust temperature and radiation field of the disk with a Monte Carlo method, and then solve the gas temperature distribution and chemical composition. The radiative transfer includes detailed treatment of scattering by atomic hydrogen and absorption by water of Lyα photons, since the Lyα line dominates the UV spectrum of accreting young stars. In a fiducial model, we find that warm water vapor with temperature around 300 K is mainly distributed in a small and well-confined region in the inner disk. The inner boundary of the warm water region is where the shielding of UV field due to dust and water itself become significant. The outer boundary is where the dust temperature drops below the water condensation temperature. A more luminous central star leads to a more extended distribution of warm water vapor, while dust growth and settling tends to reduce the amount of warm water vapor. Based on typical assumptions regarding the elemental oxygen abundance and the water chemistry, the column density of warm water vapor can be as high as 10{sup 22} cm{sup –2}. A small amount of hot water vapor with temperature higher than ∼300 K exists in a more extended region in the upper atmosphere of the disk. Cold water vapor with temperature lower than 100 K is distributed over the entire disk, produced by photodesorption of the water ice.

  13. A HUBBLE SPACE TELESCOPE/COSMIC ORIGINS SPECTROGRAPH SEARCH FOR WARM-HOT BARYONS IN THE Mrk 421 SIGHT LINE

    SciTech Connect (OSTI)

    Danforth, Charles W.; Stocke, John T.; Keeney, Brian A.; Penton, Steven V.; Shull, J. Michael; Yao Yangsen; Green, James C., E-mail: danforth@colorado.edu [CASA, Department of Astrophysical and Planetary Sciences, University of Colorado, 389-UCB, Boulder, CO 80309 (United States)

    2011-12-10

    Thermally broadened Ly{alpha} absorbers (BLAs) offer an alternate method to using highly ionized metal absorbers (O VI, O VII, etc.) to probe the warm-hot intergalactic medium (WHIM, T = 10{sup 5}-10{sup 7} K). Until now, WHIM surveys via BLAs have been no less ambiguous than those via far-UV and X-ray metal-ion probes. Detecting these weak, broad features requires background sources with a well-characterized far-UV continuum and data of very high quality. However, a recent Hubble Space Telescope/Cosmic Origins Spectrograph (COS) observation of the z = 0.03 blazar Mrk 421 allows us to perform a metal-independent search for WHIM gas with unprecedented precision. The data have high signal-to-noise ratio (S/N Almost-Equal-To 50 per {approx}20 km s{sup -1} resolution element) and the smooth, power-law blazar spectrum allows a fully parametric continuum model. We analyze the Mrk 421 sight line for BLA absorbers, particularly for counterparts to the proposed O VII WHIM systems reported by Nicastro et al. based on Chandra/Low Energy Transmission Grating observations. We derive the Ly{alpha} profiles predicted by the X-ray observations. The S/N of the COS data is high (S/N Almost-Equal-To 25 pixel{sup -1}), but much higher S/N can be obtained by binning the data to widths characteristic of the expected BLA profiles. With this technique, we are sensitive to WHIM gas over a large (N{sub H}, T) parameter range in the Mrk 421 sight line. We rule out the claimed Nicastro et al. O VII detections at their nominal temperatures (T {approx} 1-2 Multiplication-Sign 10{sup 6} K) and metallicities (Z = 0.1 Z{sub Sun }) at {approx}> 2{sigma} level. However, WHIM gas at higher temperatures and/or higher metallicities is consistent with our COS non-detections.

  14. An HST COS 'SNAPSHOT' spectrum of the K supergiant ? Vel (K4Ib-II)

    SciTech Connect (OSTI)

    Carpenter, Kenneth G. [NASA/GSFC Code 667, Greenbelt, MD 20771 (United States); Ayres, Thomas R. [University of Colorado, CASA, 389-UCB, Boulder, CO 80309 (United States); Harper, Graham M. [School of Physics, Trinity College, Dublin 2 (Ireland); Kober, Gladys; Nielsen, Krister E.; Wahlgren, Glenn M., E-mail: Kenneth.G.Carpenter@nasa.gov [Deptartment of Physics, Catholic University of America, Washington, DC 20064 (United States)

    2014-10-10

    We present a far-ultraviolet spectrum of the K4 Ib-II supergiant ? Vel obtained with the Hubble Space Telescope's Cosmic Origins Spectrograph (COS) as a part of the SNAPshot program 'SNAPing coronal iron' (GO 11687). The observation covers a wavelength region (1326-1467 ) not previously recorded for ? Vel at a spectral resolving power of R ? 20,000 and displays strong emission and absorption features, superposed on a bright chromospheric continuum. Fluorescent excitation is responsible for much of the observed emission, mainly powered by strong H I Ly? and the O I (UV 2) triplet emission near ?1304. The molecular CO and H{sub 2} fluorescences are weaker than in the early-K giant ? Boo while the Fe II and Cr II lines, also pumped by H I Ly?, are stronger in ? Vel. This pattern of relative line strengths between the two stars is explained by the lower iron-group element abundance in ? Boo, which weakens that star's Fe II and Cr II emission without reducing the molecular fluorescences. The ? Vel spectrum shows fluorescent Fe II, Cr II, and H{sub 2} emission similar to that observed in the M supergiant ? Ori, but more numerous well-defined narrow emissions from CO. The additional CO emissions are visible in the spectrum of ? Vel since that star does not have the cool, opaque circumstellar shells that surround ? Ori and produce broad circumstellar CO (A-X) band absorptions that hide those emissions in the cooler star. The presence of Si IV emission in ? Vel indicates a ?8 10{sup 4} K plasma that is mixed into the cooler chromosphere. Evidence of the stellar wind is seen in the C II ??1334,1335 lines and in the blueshifted Fe II and Ni II wind absorption lines. Line modeling using Sobolev with Exact Integration for the C II lines indicates a larger terminal velocity (?45 versus ?30 km s{sup 1}) and turbulence (?27 versus <21 km s{sup 1}) with a more quickly accelerating wind (? = 0.35 versus 0.7) at the time of this COS observation in 2010 than derived from Goddard High Resolution Spectrograph data obtained in 1994. The Fe II and Ni II absorptions are blueshifted by 7.6 km s{sup 1} relative to the chromospheric emission, suggesting formation in lower levels of the accelerating wind and their widths indicate a higher turbulence in the ? Vel wind compared to ? Ori.

  15. High Power Coax Window

    SciTech Connect (OSTI)

    Neubauer, M. L.; Dudas, A.; Sah, R.; Elliott, T. S.; Rimmer, R. A.; Stirbet, M. S.

    2010-05-23

    A su­per­con­duct­ing RF (SRF) power cou­pler ca­pa­ble of han­dling 500 kW CW RF power is re­quired for pre­sent and fu­ture stor­age rings and linacs. There are over 35 cou­pler de­signs for SRF cav­i­ties rang­ing in fre­quen­cy from 325 to 1500 MHz. Cou­pler win­dows vary from cylin­ders to cones to disks, and RF power cou­plers are lim­it­ed by the abil­i­ty of ce­ram­ic win­dows to with­stand the stress­es due to heat­ing and me­chan­i­cal flex­ure. We pro­pose a novel ro­bust co-ax­i­al SRF cou­pler de­sign which uses com­pressed win­dow tech­nol­o­gy. This tech­nol­o­gy will allow the use of high­ly ther­mal­ly con­duc­tive ma­te­ri­als for cryo­genic win­dows. Using com­pressed win­dow tech­niques on disk co-ax­i­al win­dows will make sig­nif­i­cant im­prove­ments in the power han­dling of SRF cou­plers. We pre­sent the bench test re­sults of two win­dow as­sem­blies back to back, as well as in­di­vid­u­al win­dow VSWR in EIA3.125 coax. A vac­u­um test as­sem­bly was made and the win­dows baked out at 155C. The pro­cess­es used to build win­dows is scal­able to larg­er di­am­e­ter coax and to high­er power lev­els.

  16. The BigBoss Experiment

    SciTech Connect (OSTI)

    Schelgel, D.; Abdalla, F.; Abraham, T.; Ahn, C.; Allende Prieto, C.; Annis, J.; Aubourg, E.; Azzaro, M.; Bailey, S.; Baltay, C.; Baugh, C.; Bebek, C.; Becerril, S.; Blanton, M.; Bolton, A.; Bromley, B.; Cahn, R.; Carton, P.-H.; Cervanted-Cota, J.L.; Chu, Y.; Cortes, M.; /APC, Paris /Brookhaven /IRFU, Saclay /Marseille, CPPM /Marseille, CPT /Durham U. / /IEU, Seoul /Fermilab /IAA, Granada /IAC, La Laguna / /IAC, Mexico / / /Madrid, IFT /Marseille, Lab. Astrophys. / / /New York U. /Valencia U.

    2012-06-07

    BigBOSS is a Stage IV ground-based dark energy experiment to study baryon acoustic oscillations (BAO) and the growth of structure with a wide-area galaxy and quasar redshift survey over 14,000 square degrees. It has been conditionally accepted by NOAO in response to a call for major new instrumentation and a high-impact science program for the 4-m Mayall telescope at Kitt Peak. The BigBOSS instrument is a robotically-actuated, fiber-fed spectrograph capable of taking 5000 simultaneous spectra over a wavelength range from 340 nm to 1060 nm, with a resolution R = {lambda}/{Delta}{lambda} = 3000-4800. Using data from imaging surveys that are already underway, spectroscopic targets are selected that trace the underlying dark matter distribution. In particular, targets include luminous red galaxies (LRGs) up to z = 1.0, extending the BOSS LRG survey in both redshift and survey area. To probe the universe out to even higher redshift, BigBOSS will target bright [OII] emission line galaxies (ELGs) up to z = 1.7. In total, 20 million galaxy redshifts are obtained to measure the BAO feature, trace the matter power spectrum at smaller scales, and detect redshift space distortions. BigBOSS will provide additional constraints on early dark energy and on the curvature of the universe by measuring the Ly-alpha forest in the spectra of over 600,000 2.2 < z < 3.5 quasars. BigBOSS galaxy BAO measurements combined with an analysis of the broadband power, including the Ly-alpha forest in BigBOSS quasar spectra, achieves a FOM of 395 with Planck plus Stage III priors. This FOM is based on conservative assumptions for the analysis of broad band power (k{sub max} = 0.15), and could grow to over 600 if current work allows us to push the analysis to higher wave numbers (k{sub max} = 0.3). BigBOSS will also place constraints on theories of modified gravity and inflation, and will measure the sum of neutrino masses to 0.024 eV accuracy.

  17. THE GREAT OBSERVATORIES ORIGINS DEEP SURVEY: CONSTRAINTS ON THE LYMAN CONTINUUM ESCAPE FRACTION DISTRIBUTION OF LYMAN-BREAK GALAXIES AT 3.4 < z < 4.5

    SciTech Connect (OSTI)

    Vanzella, E.; Nonino, M.; Fontanot, F.; Cristiani, S.; Tozzi, P.; Giavalisco, M.; Inoue, A. K.; Grazian, A.; Giallongo, E.; Boutsia, K.; Fontana, A.; Pentericci, L.; Dickinson, M.; Stern, D.; Ferguson, H.; Spinrad, H.; Rosati, P.

    2010-12-10

    We use ultra-deep ultraviolet VLT/VIMOS intermediate-band and VLT/FORS1 narrowband imaging in the GOODS Southern field to derive limits on the distribution of the escape fraction (f{sub esc}) of ionizing radiation for L {>=} L*{sub z=3} Lyman-break galaxies (LBGs) at redshift 3.4-4.5. Only one LBG, at redshift z = 3.795, is detected in its Lyman continuum (LyC; S/N {approx_equal} 5.5), the highest redshift galaxy currently known with a direct detection. Its ultraviolet morphology is quite compact (R{sub eff} = 0.8 kpc physical). Three out of seven active galactic nuclei are also detected in their LyC, including one at redshift z = 3.951 and z{sub 850} = 26.1. From stacked data (LBGs), we set an upper limit to the average f{sub esc} in the range 5%-20%, depending on how the data are selected (e.g., by magnitude and/or redshift). We undertake extensive Monte Carlo simulations that take into account intergalactic attenuation, stellar population synthesis models, dust extinction, and photometric noise in order to explore the moments of the distribution of the escaping radiation. Various distributions (exponential, log-normal, and Gaussian) are explored. We find that the median f{sub esc} is lower than {approx_equal}6% with an 84% percentile limit not larger than 20%. If this result remains valid for fainter LBGs down to current observational limits, then the LBG population might be not sufficient to account for the entire photoionization budget at the redshifts considered here, with the exact details dependent upon the assumed ionizing background and QSO contribution thereto. It is possible that f{sub esc} depends on the UV luminosity of the galaxies, with fainter galaxies having higher f{sub esc}, and estimates of f{sub esc} from a sample of faint LBGs from HUDF (i{sub 775} {<=}28.5) are in broad quantitative agreement with such a scenario.

  18. Halo mass dependence of H I and O VI absorption: evidence for differential kinematics

    SciTech Connect (OSTI)

    Mathes, Nigel L.; Churchill, Christopher W.; Nielsen, Nikole M.; Trujillo-Gomez, Sebastian; Kacprzak, Glenn G.; Charlton, Jane; Muzahid, Sowgat

    2014-09-10

    We studied a sample of 14 galaxies (0.1 < z < 0.7) using HST/WFPC2 imaging and high-resolution HST/COS or HST/STIS quasar spectroscopy of Lyα, Lyβ, and O VI λλ1031, 1037 absorption. The galaxies, having 10.8 ≤ log (M {sub h}/M {sub ☉}) ≤ 12.2, lie within D = 300 kpc of quasar sightlines, probing out to D/R {sub vir} = 3. When the full range of M {sub h} and D/R {sub vir} of the sample are examined, ∼40% of the H I absorbing clouds can be inferred to be escaping their host halo. The fraction of bound clouds decreases as D/R {sub vir} increases such that the escaping fraction is ∼15% for D/R {sub vir} < 1, ∼45% for 1 ≤ D/R {sub vir} < 2, and ∼90% for 2 ≤ D/R {sub vir} < 3. Adopting the median mass log M {sub h}/M {sub ☉} = 11.5 to divide the sample into 'higher' and 'lower' mass galaxies, we find a mass dependency for the hot circumgalactic medium kinematics. To our survey limits, O VI absorption is found in only ∼40% of the H I clouds in and around lower mass halos as compared to ∼85% around higher mass halos. For D/R {sub vir} < 1, lower mass halos have an escape fraction of ∼65%, whereas higher mass halos have an escape fraction of ∼5%. For 1 ≤ D/R {sub vir} < 2, the escape fractions are ∼55% and ∼35% for lower mass and higher mass halos, respectively. For 2 ≤ D/R {sub vir} < 3, the escape fraction for lower mass halos is ∼90%. We show that it is highly likely that the absorbing clouds reside within 4R {sub vir} of their host galaxies and that the kinematics are dominated by outflows. Our finding of 'differential kinematics' is consistent with the scenario of 'differential wind recycling' proposed by Oppenheimer et al. We discuss the implications for galaxy evolution, the stellar to halo mass function, and the mass-metallicity relationship of galaxies.

  19. THE COLUMN DENSITY DISTRIBUTION AND CONTINUUM OPACITY OF THE INTERGALACTIC AND CIRCUMGALACTIC MEDIUM AT REDSHIFT (z) = 2.4

    SciTech Connect (OSTI)

    Rudie, Gwen C.; Steidel, Charles C. [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, MS 249-17, Pasadena, CA 91125 (United States); Shapley, Alice E. [Department of Astronomy, University of California, Los Angeles, 430 Portola Plaza, Los Angeles, CA 90024 (United States); Pettini, Max, E-mail: gwen@astro.caltech.edu [Institute of Astronomy, Madingley Road, Cambridge CB3 0HA (United Kingdom)

    2013-06-01

    We present new high-precision measurements of the opacity of the intergalactic and circumgalactic medium (IGM; CGM) at (z) = 2.4. Using Voigt profile fits to the full Ly{alpha} and Ly{beta} forests in 15 high-resolution high-S/N spectra of hyperluminous QSOs, we make the first statistically robust measurement of the frequency of absorbers with H I column densities 14{approx}< log (N{sub H{sub I}}/cm{sup -2}){approx}<17.2. We also present the first measurements of the frequency distribution of H I absorbers in the volume surrounding high-z galaxies (the CGM, 300 pkpc), finding that the incidence of absorbers in the CGM is much higher than in the IGM. In agreement with Rudie et al., we find that there are fractionally more high-N{sub H{sub I}} absorbers than low-N{sub H{sub I}} absorbers in the CGM compared to the IGM, leading to a shallower power law fit to the CGM frequency distribution. We use these new measurements to calculate the total opacity of the IGM and CGM to hydrogen-ionizing photons, finding significantly higher opacity than most previous studies, especially from absorbers with log (N{sub H{sub I}}/cm{sup -2}) < 17.2. Reproducing the opacity measured in our data as well as the incidence of absorbers with log (N{sub H{sub I}}/cm{sup -2})>17.2 requires a broken power law parameterization of the frequency distribution with a break near N{sub H{sub I}} Almost-Equal-To 10{sup 15} cm{sup -2}. We compute new estimates of the mean free path ({lambda}{sub mfp}) to hydrogen-ionizing photons at z{sub em} = 2.4, finding {lambda}{sub mfp} = 147 {+-} 15 Mpc when considering only IGM opacity. If instead, we consider photons emanating from a high-z star-forming galaxy and account for the local excess opacity due to the surrounding CGM of the galaxy itself, the mean free path is reduced to {lambda}{sub mfp} = 121 {+-} 15 Mpc. These {lambda}{sub mfp} measurements are smaller than recent estimates and should inform future studies of the metagalactic UV background and of ionizing sources at z Almost-Equal-To 2-3.

  20. THE LOW-REDSHIFT INTERGALACTIC MEDIUM AS SEEN IN ARCHIVAL LEGACY HST/STIS AND FUSE DATA

    SciTech Connect (OSTI)

    Tilton, Evan M.; Danforth, Charles W.; Michael Shull, J. [CASA, Department of Astrophysical and Planetary Sciences, University of Colorado, 389-UCB, Boulder, CO 80309 (United States); Ross, Teresa L., E-mail: evan.tilton@colorado.edu, E-mail: charles.danforth@colorado.edu, E-mail: michael.shull@colorado.edu, E-mail: rosst@nmsu.edu [Department of Astronomy, New Mexico State University, Las Cruces, NM 88003 (United States)

    2012-11-10

    We present a comprehensive catalog of ultraviolet (HST/STIS and FUSE) absorbers in the low-redshift intergalactic medium (IGM) at z < 0.4. The catalog draws from much of the extensive literature on IGM absorption and reconciles discrepancies among several previous catalogs through a critical evaluation of all reported absorption features in light of new HST/COS data. We report on 746 H I absorbers down to a rest-frame equivalent width of 12 mA over a maximum redshift path length {Delta}z = 5.38. We also confirm 111 O VI absorbers, 29 C IV absorbers, and numerous absorption lines due to other metal ions. We characterize the bivariate distribution of absorbers in redshift and column density as a power law, {partial_derivative}{sup 2}N/{partial_derivative}z{partial_derivative}N) {proportional_to} N{sup -{beta}}, where {beta} = 2.08 {+-} 0.12 for O VI and {beta} = 1.68 {+-} 0.03 for H I. Utilizing a more sophisticated accounting technique than past work, our catalog accounts for {approx}43% of the baryons: 24% {+-} 2% in the photoionized Ly{alpha} forest and 19% {+-} 2% in the warm-hot IGM as traced by O VI. We discuss the large systematic effects of various assumed metallicities and ionization states on these calculations, and we implement recent simulation results in our estimates.

  1. METHOD AND APPARATUS FOR THE DETECTION OF LEAKS IN PIPE LINES

    DOE Patents [OSTI]

    Jefferson, S.; Cameron, J.F.

    1961-11-28

    A method is described for detecting leaks in pipe lines carrying fluid. The steps include the following: injecting a radioactive solution into a fluid flowing in the line; flushing the line clear of the radioactive solution; introducing a detector-recorder unit, comprising a radioactivity radiation detector and a recorder which records the detector signal over a time period at a substantially constant speed, into the line in association with a go-devil capable of propelling the detector-recorder unit through the line in the direction of the fluid flow at a substantia1ly constant velocity; placing a series of sources of radioactivity at predetermined distances along the downstream part of the line to make a characteristic signal on the recorder record at intervals corresponding to the location of said sources; recovering the detector-recorder unit at a downstream point along the line; transcribing the recorder record of any radioactivity detected during the travel of the detector- recorder unit in terms of distance along the line. (AEC)

  2. Evolution of Elastic X-ray Scattering in Laser-Shocked Warm Dense Li

    SciTech Connect (OSTI)

    Kugland, N L; Gregori, G; Bandyopadhyay, S; Brenner, C; Brown, C; Constantin, C; Glenzer, S H; Khattak, F; Kritcher, A L; Niemann, C; Otten, A; Pasley, J; Pelka, A; Roth, M; Spindloe, C; Riley, D

    2009-06-02

    We have studied the dynamics of warm dense Li with near-elastic x-ray scattering. Li foils were heated and compressed using shock waves driven by 4 ns long laser pulses. Separate 1 ns long laser pulses were used to generate a bright source of 2.96 keV Cl Ly-{alpha} photons for x-ray scattering, and the spectrum of scattered photons was recorded at a scattering angle of 120{sup o} using a HOPG crystal operated in the von Hamos geometry. A variable delay between the heater and backlighter laser beams measured the scattering time evolution. Comparison with radiation hydrodynamics simulations shows that the plasma is highly coupled during the first several nanoseconds, then relaxes to a moderate coupling state at later times. Near-elastic scattering amplitudes have been successfully simulated using the screened one-component plasma model. Our main finding is that the near-elastic scattering amplitudes are quite sensitive to the mean ionization state {bar Z}, and by extension to the choice of ionization model in the radiation-hydrodynamics simulations used to predict plasma properties within the shocked Li.

  3. THE EXTRAGALACTIC BACKGROUND LIGHT FROM THE MEASUREMENTS OF THE ATTENUATION OF HIGH-ENERGY GAMMA-RAY SPECTRUM

    SciTech Connect (OSTI)

    Gong Yan; Cooray, Asantha [Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States)

    2013-07-20

    The attenuation of high-energy gamma-ray spectrum due to the electron-positron pair production against the extragalactic background light (EBL) provides an indirect method to measure the EBL of the universe. We use the measurements of the absorption features of the gamma-rays from blazars as seen by the Fermi Gamma-ray Space Telescope to explore the EBL flux density and constrain the EBL spectrum, star formation rate density (SFRD), and photon escape fraction from galaxies out to z = 6. Our results are basically consistent with the existing determinations of the quantities. We find a larger photon escape fraction at high redshifts, especially at z = 3, compared to the result from recent Ly{alpha} measurements. Our SFRD result is consistent with the data from both gamma-ray burst and ultraviolet (UV) observations in the 1{sigma} level. However, the average SFRD we obtain at z {approx}> 3 matches the gamma-ray data better than the UV data. Thus our SFRD result at z {approx}> 6 favors the fact that star formation alone is sufficiently high enough to reionize the universe.

  4. PULSE AMPLITUDE DISTRIBUTION RECORDER

    DOE Patents [OSTI]

    Cowper, G.

    1958-08-12

    A device is described for automatica1ly recording pulse annplitude distribution received from a counter. The novelty of the device consists of the over-all arrangement of conventional circuit elements to provide an easy to read permanent record of the pulse amplitude distribution during a certain time period. In the device a pulse analyzer separates the pulses according to annplitude into several channels. A scaler in each channel counts the pulses and operates a pen marker positioned over a drivable recorder sheet. Since the scalers in each channel have the sanne capacity, the control circuitry permits counting of the incoming pulses until one scaler reaches capacity, whereupon the input is removed and an internal oscillator supplies the necessary pulses to fill up the other scalers. Movement of the chart sheet is initiated wben the first scaler reaches capacity to thereby give a series of marks at spacings proportional to the time required to fill the remaining scalers, and accessory equipment marks calibration points on the recorder sheet to facilitate direct reading of the number of external pulses supplied to each scaler.

  5. The Eighth Data Release of the Sloan Digital Sky Survey: First Data from SDSS-III

    SciTech Connect (OSTI)

    Aihara, Hiroaki; Prieto, Carlos Allende; An, Deokkeun; Anderson, Scott F.; Aubourg, Eric; Balbinot, Eduardo; Beers, Timothy C.; Berlind, Andreas A.; Bickerton, Steven J.; Bizyaev, Dmitry; Blanton, Michael R.; /New York U., CCPP /Penn State U.

    2011-01-01

    The Sloan Digital Sky Survey (SDSS) started a new phase in August 2008, with new instrumentation and new surveys focused on Galactic structure and chemical evolution, measurements of the baryon oscillation feature in the clustering of galaxies and the quasar Ly{alpha} forest, and a radial velocity search for planets around {approx}8000 stars. This paper describes the first data release of SDSS-III (and the eighth counting from the beginning of the SDSS). The release includes 5-band imaging of roughly 5200 deg{sup 2} in the Southern Galactic Cap, bringing the total footprint of the SDSS imaging to 14,555 deg{sup 2}, or over a third of the Celestial Sphere. All the imaging data have been reprocessed with an improved sky-subtraction algorithm and a final, self-consistent recalibration and flat-field determination. This release also includes all data from the second phase of the Sloan Extension for Galactic Understanding and Evolution (SEGUE-2), consisting of spectroscopy of approximately 118,000 stars at both high and low Galactic latitudes. All the more than half a million stellar spectra obtained with the SDSS spectrograph have been reprocessed through an improved stellar parameters pipeline, which has better determination of metallicity for high metallicity stars.

  6. HST/COS OBSERVATIONS OF THIRTEEN NEW He II QUASARS

    SciTech Connect (OSTI)

    Syphers, David; Anderson, Scott F.; Zheng Wei; Meiksin, Avery; Schneider, Donald P.; York, Donald G.

    2012-04-15

    The full reionization of intergalactic helium was a major event in the history of the intergalactic medium (IGM), and UV observations of the He II Gunn-Peterson trough allow us to characterize the end of this process at z {approx} 3. Due to intervening hydrogen absorption, quasars allowing such study are rare, with only 33 known in the literature, and most of those are very recent discoveries. We expand on our previous discovery work, and present 13 new He II quasars with redshifts 2.82 < z < 3.77, here selected with {approx}80% efficiency, and including several that are much brighter than the vast majority of those previously known. This is the largest sample of uniformly observed He II quasars covering such a broad redshift range, and they show evidence of IGM opacity increasing with redshift, as expected for the helium reionization epoch. No evidence of He II Ly{alpha} quasar emission is seen in individual or averaged spectra, posing a problem for standard models of the broad-line region. The current rapid advance in the study of He II quasars has been greatly facilitated by the Cosmic Origins Spectrograph on the Hubble Space Telescope, and we discuss the instrumental and other subtleties that must be taken into account in IGM He II observations.

  7. THE GEOMETRY EFFECTS OF AN EXPANDING UNIVERSE ON THE DETECTION OF COOL NEUTRAL GAS AT HIGH REDSHIFT

    SciTech Connect (OSTI)

    Curran, S. J.

    2012-03-20

    Recent high-redshift surveys for 21 cm absorption in damped Ly{alpha} absorption systems (DLAs) take the number of published searches at z{sub abs} > 2 to 25, the same number as at z{sub abs} < 2, although the detection rate at high redshift remains significantly lower (20% compared to 60%). Using the known properties of the DLAs to estimate the unknown profile widths of the 21 cm non-detections and including the limits via a survival analysis, we show that the mean spin temperature/covering factor degeneracy at high redshift is, on average, double that of the low-redshift sample. This value is significantly lower than the previous factor of eight for the spin temperatures and is about the same factor as in the angular diameter distance ratios between the low- and high-redshift samples. That is, without the need for the several pivotal assumptions, which lead to an evolution in the spin temperature, we show that the observed distribution of 21 cm detections in DLAs can be accounted for by the geometry effects of an expanding universe. That is, as yet there is no evidence of the spin temperature of gas-rich galaxies evolving with redshift.

  8. A FOURTH H I 21 cm ABSORPTION SYSTEM IN THE SIGHT LINE OF MG J0414+0534: A RECORD FOR INTERVENING ABSORBERS

    SciTech Connect (OSTI)

    Tanna, A.; Webb, J. K.; Curran, S. J.; Whiting, M. T.; Bignell, C.

    2013-08-01

    We report the detection of a strong H I 21 cm absorption system at z = 0.5344, as well as a candidate system at z = 0.3389, in the sight line toward the z = 2.64 quasar MG J0414+0534. This, in addition to the absorption at the host redshift and the other two intervening absorbers, takes the total to four (possibly five). The previous maximum number of 21 cm absorbers detected along a single sight line is two and so we suspect that this number of gas-rich absorbers is in some way related to the very red color of the background source. Despite this, no molecular gas (through OH absorption) has yet been detected at any of the 21 cm redshifts, although, from the population of 21 cm absorbers as a whole, there is evidence for a weak correlation between the atomic line strength and the optical-near-infrared color. In either case, the fact that so many gas-rich galaxies (likely to be damped Ly{alpha} absorption systems) have been found along a single sight line toward a highly obscured source may have far-reaching implications for the population of faint galaxies not detected in optical surveys, a possibility which could be addressed through future wide-field absorption line surveys with the Square Kilometer Array.

  9. Quasar-Lyman ? forest cross-correlation from BOSS DR11: Baryon Acoustic Oscillations

    SciTech Connect (OSTI)

    Font-Ribera, Andreu; Kirkby, David; Blomqvist, Michael; Busca, Nicolas; Aubourg, ric; Bautista, Julian; Ross, Nicholas P.; Bailey, Stephen; Beutler, Florian; Carithers, Bill; Slosar, Ane; Rich, James; Delubac, Timothe; Bhardwaj, Vaishali; Bizyaev, Dmitry; Brewington, Howard; Brinkmann, Jon; Brownstein, Joel R.; Dawson, Kyle S.; and others

    2014-05-01

    We measure the large-scale cross-correlation of quasars with the Ly? forest absorption, using over 164,000 quasars from Data Release 11 of the SDSS-III Baryon Oscillation Spectroscopic Survey. We extend the previous study of roughly 60,000 quasars from Data Release 9 to larger separations, allowing a measurement of the Baryonic Acoustic Oscillation (BAO) scale along the line of sight c/(H(z = 2.36)r{sub s}) = 9.00.3 and across the line of sight D{sub A}(z = 2.36)/r{sub s} = 10.80.4, consistent with CMB and other BAO data. Using the best fit value of the sound horizon from Planck data (r{sub s} = 147.49Mpc), we can translate these results to a measurement of the Hubble parameter of H(z = 2.36) = 2268kms{sup ?1}Mpc{sup ?1} and of the angular diameter distance of D{sub A}(z = 2.36) = 159060Mpc. The measured cross-correlation function and an update of the code to fit the BAO scale (baofit) are made publicly available.

  10. A dual-channel, curved-crystal spectrograph for petawatt laser, x-ray backlighter source studies

    SciTech Connect (OSTI)

    Theobald, W.; Stoeckl, C.; Jaanimagi, P. A.; Nilson, P. M.; Storm, M.; Meyerhofer, D. D.; Sangster, T. C.; Hey, D.; MacKinnon, A. J.; Park, H.-S.; Patel, P. K.; Shepherd, R.; Snavely, R. A.; Key, M. H.; King, J. A.; Zhang, B.; Stephens, R. B.; Akli, K. U.; Highbarger, K.; Daskalova, R. L.; and others

    2009-08-15

    A dual-channel, curved-crystal spectrograph was designed to measure time-integrated x-ray spectra in the {approx}1.5 to 2 keV range (6.2-8.2 A wavelength) from small-mass, thin-foil targets irradiated by the VULCAN petawatt laser focused up to 4x10{sup 20} W/cm{sup 2}. The spectrograph consists of two cylindrically curved potassium-acid-phthalate crystals bent in the meridional plane to increase the spectral range by a factor of {approx}10 compared to a flat crystal. The device acquires single-shot x-ray spectra with good signal-to-background ratios in the hard x-ray background environment of petawatt laser-plasma interactions. The peak spectral energies of the aluminum He{sub {alpha}} and Ly{sub {alpha}} resonance lines were {approx}1.8 and {approx}1.0 mJ/eV sr ({approx}0.4 and 0.25 J/A sr), respectively, for 220 J, 10 ps laser irradiation.

  11. A=17O (71AJ02)

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

    71AJ02) (See Energy Level Diagrams for 17O) GENERAL: See also (59AJ76) and Table 17.5 [Table of Energy Levels] (in PDF or PS). Shell model: (WI57H, BR59M, FE59E, KH59, SA59C, AK60, TA60L, BA61N, NE61C, BH62, TA62, TA62F, CO63B, HA63A, KU63I, PA63C, BR64Z, RI64B, GI65D, LE65G, MA65J, ZA65B, AR66H, BO66J, BR66C, BR66S, BR66CC, DE66M, LA66L, MA66BB, QU66, RI66G, SO66A, ZA66A, BO67B, EL67C, EN67, FE67A, GO67B, LY67, NI67, PA67K, PF67, BI68A, DE68K, EL68, EL68E, HE68J, HO68, KA68, MA68DD, NI68,

  12. Elastic Neutron Scattering at 96 MeV

    SciTech Connect (OSTI)

    Hildebrand, A.; Blomgren, J.; Atac, A.; Bergenwall, B.; Johansson, C.; Klug, J.; Mermod, P.; Nilsson, L.; Pomp, S.; Esterlund, M.; Dangtip, S.; Tippawan, U.; Phansuke, P.; Jonsson, O.; Renberg, P.-U.; Prokofiev, A.; Nadel-Turonski, P.; Elmgren, K.; Olsson, N.; Blideanu, V.

    2005-05-24

    A facility for detection of scattered neutrons in the energy interval 50-130 MeV, SCANDAL (SCAttered Nucleon Detection AssembLy), has recently been installed at the 20 - 180-MeV neutron beam line of The Svedberg Laboratory, Uppsala. Elastic neutron scattering from 12C, 16O, 56Fe, 89Y, and 208Pb has been studied at 96 MeV in the 10-70 deg. interval. The results from 12C and 208Pb have recently been published,6 while the data from 16O, 56Fe, and 89Y are under analysis. The achieved energy resolution, 3.7 MeV, is about an order of magnitude better than for any previous experiment above 65 MeV incident energy. The present experiment represents the highest neutron energy where the ground state has been resolved from the first excited state in neutron scattering. A novel method for normalization of the absolute scale of the cross section has been used. The estimated normalization uncertainty, 3%, is unprecedented for a neutron-induced differential cross section measurement on a nuclear target. The results are compared with modern optical model predictions, based on phenomenology or microscopic theory. Applications for these measurements are nuclear-waste incineration, single-event upsets in electronics, and fast-neutron therapy.

  13. Measurements of Martin-Puplett Interferometer Limitations using Blackbody Source

    SciTech Connect (OSTI)

    Evtushenko, Pavel E.; Klopf, John M.

    2013-06-01

    Frequency domain measurements with Martin-Puplett interferometer is one of a few techniques capable of bunch length measurements at the level of ~ 100 fs. As the bunch length becomes shorter, it is important to know and be able to measure the limitations of the instrument in terms of shortest measurable bunch length. In this paper we describe an experiment using a blackbody source with the modified Martin-Puplett interferometer that is routine- ly used for bunch length measurements at the JLab FEL, as a way to estimate the shortest, measurable bunch length. The limitation comes from high frequency cut-off of the wire-grid polarizer currently used and is estimated to be 50 fs RMS. The measurements are made with the same Golay cell detector that is used for beam measure- ments. We demonstrate that, even though the blackbody source is many orders of magnitude less bright than the coherent transition or synchrotron radiation, it can be used for the measurements and gives a very good signal to noise ratio in combination with lock-in detection. We also compare the measurements made in air and in vacuum to characterize the very strong effect of the atmospheric absorption.

  14. PIK3CA is implicated as an oncogene in ovarian cancer

    SciTech Connect (OSTI)

    Shayesteh, Laleh; Lu, Yiling; Kuo, Wen-Lin; Baldocchi, Russell; Godfrey, Tony; Collins, Colin; Pinkel, Daniel; Powell, Bethan; Mills,Gordon B.; Gray, Joe W.

    1998-03-25

    Ovarian cancer is the leading cause of death from gynecological malignancy and the fourth leading cause of cancer death among American women, yet little is known about its molecular aetiology. Studies using comparative genomic hybridization (CGH) have revealed several regions of recurrent, abnormal, DNA sequence copy number that may encode genes involved in the genesis or progression of the disease. One region at 3q26 found to be increased in copy number in approximately 40 percent of ovarian and other cancers contains PIK3CA, which encodes the p110 a catalytic subunit of phosphatidylinositol 3-kinase(PI3-kinase). The association between PIK3CA copy number and PI3-kinase activity makes PIK3CA a candidate oncogene because a broad range of cancer-related functions have been associated with PI3-kinase mediated signaling. These include proliferation, glucose transport and catabolism, cell adhesion, apoptosis, RAS signaling and oncogenic transformation. In addition, downstream effectors of PI3-kinase,AKT1 and AKT2, have been found to be amplified or activated in human tumors, including ovarian cancer. We show here that PIK3CA is frequently increased in copy number in ovarian cancers, that the increased copy number is associated with increased PIK3CA transcription, p110 a protein expression and PI3-kinase activity and that treatment with the PI3-kinase inhibitor LY294002 decreases proliferation and increases apoptosis. Our observations suggest PIK3CA is an oncogene that has an important role in ovarian cancer.

  15. A star-forming shock front in radio galaxy 4C+41.17 resolved with laser-assisted adaptive optics spectroscopy

    SciTech Connect (OSTI)

    Steinbring, Eric

    2014-07-01

    Near-infrared integral-field spectroscopy of redshifted [O III], H?, and optical continuum emission from the z = 3.8 radio galaxy 4C+41.17 is presented, obtained with the laser-guide-star adaptive optics facility on the Gemini North telescope. Employing a specialized dithering technique, a spatial resolution of 0.''10, or 0.7 kpc, is achieved in each spectral element, with a velocity resolution of ?70 km s{sup 1}. Spectra similar to local starbursts are found for bright knots coincident in archival Hubble Space Telescope ( HST) rest-frame ultraviolet images, which also allows a key line diagnostic to be mapped together with new kinematic information. There emerges a clearer picture of the nebular emission associated with the jet in 8.3 GHz and 15 GHz Very Large Array maps, closely tied to a Ly?-bright shell-shaped structure seen with HST. This supports a previous interpretation of that arc tracing a bow shock, inducing ?10{sup 1011} M {sub ?} star formation regions that comprise the clumpy broadband optical/ultraviolet morphology near the core.

  16. LOW-RESOLUTION SPECTROSCOPY OF GAMMA-RAY BURST OPTICAL AFTERGLOWS: BIASES IN THE SWIFT SAMPLE AND CHARACTERIZATION OF THE ABSORBERS

    SciTech Connect (OSTI)

    Fynbo, J. P. U.; Malesani, D.; Vreeswijk, P. M.; Hjorth, J.; Sollerman, J.; Thoene, C. C.; Jakobsson, P.; Bjoernsson, G.; De Cia, A.; Prochaska, J. X.; Nardini, M.; Chen, H.-W.; Bloom, J. S.; Castro-Tirado, A. J.; Gorosabel, J.; Christensen, L.; Fruchter, A. S.

    2009-12-01

    We present a sample of 77 optical afterglows (OAs) of Swift detected gamma-ray bursts (GRBs) for which spectroscopic follow-up observations have been secured. Our first objective is to measure the redshifts of the bursts. For the majority (90%) of the afterglows, the redshifts have been determined from the spectra. We provide line lists and equivalent widths (EWs) for all detected lines redward of Ly{alpha} covered by the spectra. In addition to the GRB absorption systems, these lists include line strengths for a total of 33 intervening absorption systems. We discuss to what extent the current sample of Swift bursts with OA spectroscopy is a biased subsample of all Swift detected GRBs. For that purpose we define an X-ray-selected statistical sample of Swift bursts with optimal conditions for ground-based follow-up from the period 2005 March to 2008 September; 146 bursts fulfill our sample criteria. We derive the redshift distribution for the statistical (X-ray selected) sample and conclude that less than 18% of Swift bursts can be at z > 7. We compare the high-energy properties (e.g., {gamma}-ray (15-350 keV) fluence and duration, X-ray flux, and excess absorption) for three subsamples of bursts in the statistical sample: (1) bursts with redshifts measured from OA spectroscopy; (2) bursts with detected optical and/or near-IR afterglow, but no afterglow-based redshift; and (3) bursts with no detection of the OA. The bursts in group (1) have slightly higher {gamma}-ray fluences and higher X-ray fluxes and significantly less excess X-ray absorption than bursts in the other two groups. In addition, the fractions of dark bursts, defined as bursts with an optical to X-ray slope {beta}{sub OX} < 0.5, is 14% in group (1), 38% in group (2), and >39% in group (3). For the full sample, the dark burst fraction is constrained to be in the range 25%-42%. From this we conclude that the sample of GRBs with OA spectroscopy is not representative for all Swift bursts, most likely due to a bias against the most dusty sight lines. This should be taken into account when determining, e.g., the redshift or metallicity distribution of GRBs and when using GRBs as a probe of star formation. Finally, we characterize GRB absorption systems as a class and compare them to QSO absorption systems, in particular the damped Ly{alpha} absorbers (DLAs). On average GRB absorbers are characterized by significantly stronger EWs for H I as well as for both low and high ionization metal lines than what is seen in intervening QSO absorbers. However, the distribution of line strengths is very broad and several GRB absorbers have lines with EWs well within the range spanned by QSO-DLAs. Based on the 33 z > 2 bursts in the sample, we place a 95% confidence upper limit of 7.5% on the mean escape fraction of ionizing photons from star-forming galaxies.

  17. ENO1 promotes tumor proliferation and cell adhesion mediated drug resistance (CAM-DR) in Non-Hodgkin's Lymphomas

    SciTech Connect (OSTI)

    Zhu, Xinghua; Miao, Xiaobing; Wu, Yaxun; Li, Chunsun; Guo, Yan; Liu, Yushan; Chen, Yali; Lu, Xiaoyun; Wang, Yuchan; He, Song

    2015-07-15

    Enolases are glycolytic enzymes responsible for the ATP-generated conversion of 2-phosphoglycerate to phosphoenolpyruvate. In addition to the glycolytic function, Enolase 1 (ENO1) has been reported up-regulation in several tumor tissues. In this study, we investigated the expression and biologic function of ENO1 in Non-Hodgkin's Lymphomas (NHLs). Clinically, by western blot analysis we observed that ENO1 expression was apparently higher in diffuse large B-cell lymphoma than in the reactive lymphoid tissues. Subsequently, immunohistochemical staining of 144 NHLs suggested that the expression of ENO1 was significantly lower in the indolent lymphomas compared with the progressive lymphomas. Further, we identified ENO1 as an independent prognostic factor, and it was significantly correlated with overall survival of NHL patients. In addition, we found that ENO1 could promote cell proliferation, regulate cell cycle associated gene and PI3K/AKT signaling pathway in NHLs. Finally, we verified that ENO1 participated in the process of lymphoma cell adhesion mediated drug resistance (CAM-DR). Adhesion to FN or HS5 cells significantly protected OCI-Ly8 and Daudi cells from cytotoxicity compared with those cultured in suspension, and these effects were attenuated when transfected with ENO1-siRNA. Based on the study, we propose that inhibition of ENO1 expression may be a novel strategy for therapy for NHLs patients, and it may be a target for drug resistance. - Highlights: • ENO1 expression is reversely correlated with clinical outcomes of patients with NHLs. • ENO1 promotes the proliferation of NHL cells. • ENO1 regulates cell adhesion mediated drug resistance.

  18. COS OBSERVATIONS OF METAL LINE AND BROAD LYMAN-{alpha} ABSORPTION IN THE MULTI-PHASE O VI AND Ne VIII SYSTEM AT z = 0.20701 TOWARD HE 0226-4110

    SciTech Connect (OSTI)

    Savage, B. D. [Department of Astronomy, University of Wisconsin-Madison, 475 North Charter Street, Madison, WI 53706 (United States); Lehner, N. [Department of Physics, University of Notre Dame, 225 Nieuwland Science Hall, Notre Dame, IN 46556 (United States); Narayanan, A. [Indian Institute of Space Science and Technology, Thiruvananthapuram 695547, Kerala (India)

    2011-12-20

    Observations of the QSO HE 0226-4110 (z{sub em} = 0.495) with the Cosmic Origins Spectrograph (COS) from 1134 to 1796 A with a resolution of {approx}17 km s{sup -1} and signal-to-noise ratio (S/N) per resolution element of 20-40 are used to study the multi-phase absorption system at z = 0.20701 containing O VI and Ne VIII. The system was previously studied with lower S/N observations with Far-Ultraviolet Spectroscopic Explorer (FUSE) and Space Telescope Imaging Spectrograph (STIS). The COS observations provide more reliable measures of the H I and metal lines present in the system and reveal the clear presence of broad Ly{alpha} (BLA) absorption with b = 72(+13, -6) km s{sup -1} and log N(H I) = 13.87 {+-} 0.08. Detecting BLAs associated with warm gas absorbers is crucial for determining the temperature, metallicity, and total baryonic content of the absorbers. The BLA is probably recording the trace amount of thermally broadened H I in the collisionally ionized plasma with log T {approx} 5.7 that also produces the O VI and Ne VIII absorption. The total hydrogen column in the collisionally ionized gas, log N(H) {approx} 20.1, exceeds that in the cooler photoionized gas in the system by a factor of {approx}22. The oxygen abundance in the collisionally ionized gas is [O/H] = -0.89 {+-} 0.08 {+-} 0.07. The absorber probably occurs in the circumgalactic environment (halo) of a foreground L = 0.25L{sub *} disk galaxy with an impact parameter of 109 h{sub 70}{sup -1} kpc identified by Mulchaey and Chen.

  19. THE COSMIC ORIGINS SPECTROGRAPH

    SciTech Connect (OSTI)

    Green, James C.; Michael Shull, J.; Snow, Theodore P.; Stocke, John [Department of Astrophysical and Planetary Sciences, University of Colorado, 391-UCB, Boulder, CO 80309 (United States); Froning, Cynthia S.; Osterman, Steve; Beland, Stephane; Burgh, Eric B.; Danforth, Charles; France, Kevin [Center for Astrophysics and Space Astronomy, University of Colorado, 389-UCB, Boulder, CO 80309 (United States); Ebbets, Dennis [Ball Aerospace and Technologies Corp., 1600 Commerce Street, Boulder, CO 80301 (United States); Heap, Sara H. [NASA Goddard Space Flight Center, Code 681, Greenbelt, MD 20771 (United States); Leitherer, Claus; Sembach, Kenneth [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Linsky, Jeffrey L. [JILA, University of Colorado and NIST, Boulder, CO 80309-0440 (United States); Savage, Blair D. [Department of Astronomy, University of Wisconsin-Madison, 475 North Charter Street, Madison, WI 53706 (United States); Siegmund, Oswald H. W. [Astronomy Department, University of California, Berkeley, CA 94720 (United States); Spencer, John; Alan Stern, S. [Southwest Research Institute, 1050 Walnut Street, Suite 300, Boulder, CO 80302 (United States); Welsh, Barry [Space Sciences Laboratory, University of California, 7 Gauss Way, Berkeley, CA 94720 (United States); and others

    2012-01-01

    The Cosmic Origins Spectrograph (COS) is a moderate-resolution spectrograph with unprecedented sensitivity that was installed into the Hubble Space Telescope (HST) in 2009 May, during HST Servicing Mission 4 (STS-125). We present the design philosophy and summarize the key characteristics of the instrument that will be of interest to potential observers. For faint targets, with flux F{sub {lambda}} Almost-Equal-To 1.0 Multiplication-Sign 10{sup -14} erg cm{sup -2} s{sup -1} A{sup -1}, COS can achieve comparable signal to noise (when compared to Space Telescope Imaging Spectrograph echelle modes) in 1%-2% of the observing time. This has led to a significant increase in the total data volume and data quality available to the community. For example, in the first 20 months of science operation (2009 September-2011 June) the cumulative redshift pathlength of extragalactic sight lines sampled by COS is nine times than sampled at moderate resolution in 19 previous years of Hubble observations. COS programs have observed 214 distinct lines of sight suitable for study of the intergalactic medium as of 2011 June. COS has measured, for the first time with high reliability, broad Ly{alpha} absorbers and Ne VIII in the intergalactic medium, and observed the He II reionization epoch along multiple sightlines. COS has detected the first CO emission and absorption in the UV spectra of low-mass circumstellar disks at the epoch of giant planet formation, and detected multiple ionization states of metals in extra-solar planetary atmospheres. In the coming years, COS will continue its census of intergalactic gas, probe galactic and cosmic structure, and explore physics in our solar system and Galaxy.

  20. CHARACTERIZING THE CIRCUMGALACTIC MEDIUM OF NEARBY GALAXIES WITH HST/COS AND HST/STIS ABSORPTION-LINE SPECTROSCOPY

    SciTech Connect (OSTI)

    Stocke, John T.; Keeney, Brian A.; Danforth, Charles W.; Shull, J. Michael; Froning, Cynthia S.; Green, James C.; Penton, Steven V. [Center for Astrophysics and Space Astronomy, Department of Astrophysical and Planetary Sciences, University of Colorado, 389 UCB, Boulder, CO 80309 (United States)] [Center for Astrophysics and Space Astronomy, Department of Astrophysical and Planetary Sciences, University of Colorado, 389 UCB, Boulder, CO 80309 (United States); Savage, Blair D., E-mail: john.stocke@colorado.edu [Department of Astronomy, University of Wisconsin, Madison, WI 53706 (United States)

    2013-02-15

    The circumgalactic medium (CGM) of late-type galaxies is characterized using UV spectroscopy of 11 targeted QSO/galaxy pairs at z {<=} 0.02 with the Hubble Space Telescope Cosmic Origins Spectrograph (COS) and {approx}60 serendipitous absorber/galaxy pairs at z {<=} 0.2 with the Space Telescope Imaging Spectrograph. CGM warm cloud properties are derived, including volume filling factors of 3%-5%, cloud sizes of 0.1-30 kpc, masses of 10-10{sup 8} M {sub Sun }, and metallicities of {approx}0.1-1 Z {sub Sun }. Almost all warm CGM clouds within 0.5 R {sub vir} are metal-bearing and many have velocities consistent with being bound, 'galactic fountain' clouds. For galaxies with L {approx}> 0.1 L*, the total mass in these warm CGM clouds approaches 10{sup 10} M {sub Sun }, {approx}10%-15% of the total baryons in massive spirals and comparable to the baryons in their parent galaxy disks. This leaves {approx}> 50% of massive spiral-galaxy baryons 'missing'. Dwarfs (<0.1 L*) have smaller area covering factors and warm CGM masses ({<=}5% baryon fraction), suggesting that many of their warm clouds escape. Constant warm cloud internal pressures as a function of impact parameter (P/k {approx} 10 cm{sup -3} K) support the inference that previous COS detections of broad, shallow O VI and Ly{alpha} absorptions are of an extensive ({approx}400-600 kpc), hot (T Almost-Equal-To 10{sup 6} K), intra-cloud gas which is very massive ({>=}10{sup 11} M {sub Sun }). While the warm CGM clouds cannot account for all the 'missing baryons' in spirals, the hot intra-group gas can, and could account for {approx}20% of the cosmic baryon census at z {approx} 0 if this hot gas is ubiquitous among spiral groups.

  1. HST-COS observations of AGNs. II. Extended survey of ultraviolet composite spectra from 159 active galactic nuclei

    SciTech Connect (OSTI)

    Stevans, Matthew L. [Present address: Astronomy Department, University of Texas, Austin, TX 78712, USA. (United States); Shull, J. Michael [Also at Institute of Astronomy, Cambridge University, Cambridge CB3 OHA, UK. (United Kingdom); Danforth, Charles W.; Tilton, Evan M., E-mail: stevans@astro.as.utexas.edu, E-mail: michael.shull@colorado.edu, E-mail: charles.danforth@colorado.edu, E-mail: evan.tilton@colorado.edu [CASA, Department of Astrophysical and Planetary Sciences, University of Colorado, Boulder, CO 80309 (United States)

    2014-10-10

    The ionizing fluxes from quasars and other active galactic nuclei (AGNs) are critical for interpreting their emission-line spectra and for photoionizing and heating the intergalactic medium. Using far-ultraviolet (FUV) spectra from the Cosmic Origins Spectrograph (COS) on the Hubble Space Telescope (HST), we directly measure the rest-frame ionizing continua and emission lines for 159 AGNs at redshifts 0.001 < z {sub AGN} < 1.476 and construct a composite spectrum from 475 to 1875 . We identify the underlying AGN continuum and strong extreme ultraviolet (EUV) emission lines from ions of oxygen, neon, and nitrogen after masking out absorption lines from the H I Ly? forest, 7 Lyman-limit systems (N{sub H} {sub I}?10{sup 17.2} cm{sup 2}) and 214 partial Lyman-limit systems (14.5

  2. THE IMPACT OF STARBURSTS ON THE CIRCUMGALACTIC MEDIUM

    SciTech Connect (OSTI)

    Borthakur, Sanchayeeta; Heckman, Timothy; Strickland, David [Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218 (United States); Wild, Vivienne [School of Physics and Astronomy, University of St. Andrews, St. Andrews, Fife, KY16 95S (United Kingdom); Scottish Universities Physics Alliance (SUPA) (United Kingdom); Schiminovich, David, E-mail: sanch@pha.jhu.edu [Department of Astronomy, Columbia University, New York, NY 10027 (United States)

    2013-05-01

    We present a study exploring the impact of a starburst on the properties of the surrounding circumgalactic medium (CGM): gas located beyond the galaxy's stellar body and extending out to the virial radius ({approx}200 kpc). We obtained ultraviolet spectroscopic data from the Cosmic Origins Spectrograph (COS) probing the CGM of 20 low-redshift foreground galaxies using background QSOs. Our sample consists of starburst and control galaxies. The latter comprises normal star-forming and passive galaxies with similar stellar masses and impact parameters as the starbursts. We used optical spectra from the Sloan Digital Sky Survey to estimate the properties of the starbursts, inferring average ages of {approx}200 Myr and burst fractions involving {approx}10% of their stellar mass. The COS data reveal highly ionized gas traced by C IV in 80%(4/5) of the starburst and in 17%(2/12) of the control sample. The two control galaxies with C IV absorbers differed from the four starbursts in showing multiple low-ionization transitions and strong saturated Ly{alpha} lines. They therefore appear to be physically different systems. We show that the C IV absorbers in the starburst CGM represent a significant baryon repository. The high detection rate of this highly ionized material in the starbursts suggests that starburst-driven winds can affect the CGM out to radii as large as 200 kpc. This is plausible given the inferred properties of the starbursts and the known properties of starburst-driven winds. This would represent the first direct observational evidence of local starbursts impacting the bulk of their gaseous halos, and as such provides new evidence of the importance of this kind of feedback in the evolution of galaxies.

  3. THE COS-HALOS SURVEY: RATIONALE, DESIGN, AND A CENSUS OF CIRCUMGALACTIC NEUTRAL HYDROGEN

    SciTech Connect (OSTI)

    Tumlinson, Jason; Thom, Christopher; Sembach, Kenneth R. [Space Telescope Science Institute, Baltimore, MD (United States); Werk, Jessica K.; Prochaska, J. Xavier [UCO/Lick Observatory, University of California, Santa Cruz, CA (United States); Tripp, Todd M.; Katz, Neal; Meiring, Joseph D. [Department of Astronomy, University of Massachusetts, Amherst, MA (United States); Dav, Romeel [University of the Western Cape, South African Astronomical Observatories, and African Institute for Mathematical Sciences, Cape Town (South Africa); Oppenheimer, Benjamin D. [Leiden Observatory, Leiden University, 2300 RA Leiden (Netherlands); Ford, Amanda Brady [Steward Observatory, University of Arizona, Tucson, AZ (United States); O'Meara, John M. [Department of Chemistry and Physics, Saint Michael's College, Colchester, VT (United States); Peeples, Molly S. [Center for Galaxy Evolution, University of California Los Angeles, Los Angeles, CA (United States); Weinberg, David H. [Department of Astronomy, The Ohio State University, Columbus, OH (United States)

    2013-11-01

    We present the design and methods of the COS-Halos survey, a systematic investigation of the gaseous halos of 44 z = 0.15-0.35 galaxies using background QSOs observed with the Cosmic Origins Spectrograph aboard the Hubble Space Telescope. This survey has yielded 39 spectra of z{sub em} ? 0.5 QSOs with S/N ?10-15 per resolution element. The QSO sightlines pass within 150 physical kpc of the galaxies, which span early and late types over stellar mass log M{sub *}/M{sub ?} = 9.5-11.5. We find that the circumgalactic medium exhibits strong H I, averaging ? 1 in Ly? equivalent width out to 150 kpc, with 100% covering fraction for star-forming galaxies and 75% covering for passive galaxies. We find good agreement in column densities between this survey and previous studies over similar range of impact parameter. There is weak evidence for a difference between early- and late-type galaxies in the strength and distribution of H I. Kinematics indicate that the detected material is bound to the host galaxy, such that ?> 90% of the detected column density is confined within 200 km s{sup 1} of the galaxies. This material generally exists well below the halo virial temperatures at T ?< 10{sup 5} K. We evaluate a number of possible origin scenarios for the detected material, and in the end favor a simple model in which the bulk of the detected H I arises in a bound, cool, low-density photoionized diffuse medium that is generic to all L* galaxies and may harbor a total gaseous mass comparable to galactic stellar masses.

  4. HST-COS OBSERVATIONS OF AGNs. I. ULTRAVIOLET COMPOSITE SPECTRA OF THE IONIZING CONTINUUM AND EMISSION LINES

    SciTech Connect (OSTI)

    Shull, J. Michael; Stevans, Matthew; Danforth, Charles W., E-mail: michael.shull@colorado.edu, E-mail: matthew.stevans@colorado.edu, E-mail: charles.danforth@colorado.edu [CASA, Department of Astrophysical and Planetary Sciences, University of Colorado, Boulder, CO 80309 (United States)

    2012-06-20

    The ionizing fluxes from quasars and other active galactic nuclei (AGNs) are critical for interpreting the emission-line spectra of AGNs and for photoionization and heating of the intergalactic medium. Using ultraviolet spectra from the Cosmic Origins Spectrograph (COS) on the Hubble Space Telescope (HST), we have directly measured the rest-frame ionizing continua and emission lines for 22 AGNs. Over the redshift range 0.026 < z < 1.44, COS samples the Lyman continuum and many far-UV emission lines (Ly{alpha} {lambda}1216, C IV {lambda}1549, Si IV/O IV] {lambda}1400, N V {lambda}1240, O VI {lambda}1035). Strong EUV emission lines with 14-22 eV excitation energies (Ne VIII {lambda}{lambda}770, 780, Ne V {lambda}569, O II {lambda}834, O III {lambda}833, {lambda}702, O IV {lambda}788, 608, 554, O V {lambda}630, N III {lambda}685) suggest the presence of hot gas in the broad emission-line region. The rest-frame continuum, F{sub {nu}}{proportional_to}{nu}{sup {alpha}{sub {nu}}}, shows a break at wavelengths {lambda} < 1000 A, with spectral index {alpha}{sub {nu}} = -0.68 {+-} 0.14 in the FUV (1200-2000 A) steepening to {alpha}{sub {nu}} = -1.41 {+-} 0.21 in the EUV (500-1000 A). The COS EUV index is similar to that of radio-quiet AGNs in the 2002 HST/FOS survey ({alpha}{sub {nu}} = -1.57 {+-} 0.17). We see no Lyman edge ({tau}{sub HI} < 0.03) or He I {lambda}584 emission in the AGN composite. Our 22 AGNs exhibit a substantial range of FUV/EUV spectral indices and a correlation with AGN luminosity and redshift, likely due to observing below the 1000 A spectral break.

  5. Absorption-line detections of 10{sup 5}-10{sup 6} K gas in spiral-rich groups of galaxies

    SciTech Connect (OSTI)

    Stocke, John T.; Keeney, Brian A.; Danforth, Charles W.; Syphers, David; Yamamoto, H.; Shull, J. Michael; Green, James C.; Froning, Cynthia [Center for Astrophysics and Space Astronomy, Department of Astrophysical and Planetary Sciences, University of Colorado, 389 UCB, Boulder, CO 80309 (United States); Savage, Blair D.; Wakker, Bart; Kim, Tae-Sun [Department of Astronomy, University of Wisconsin, Madison, WI 53706 (United States); Ryan-Weber, Emma V.; Kacprzak, Glenn G., E-mail: john.stocke@colorado.edu [Centre for Astrophysics and Supercomputing, Swinburne University of Technology, VIC 3122 (Australia)

    2014-08-20

    Using the Cosmic Origins Spectrograph (COS) on the Hubble Space Telescope, the COS Science Team has conducted a high signal-to-noise survey of 14 bright QSOs. In a previous paper, these far-UV spectra were used to discover 14 'warm' (T ? 10{sup 5} K) absorbers using a combination of broad Ly? and broad O VI absorptions. A reanalysis of a few of this new class of absorbers using slightly relaxed fitting criteria finds as many as 20 warm absorbers could be present in this sample. A shallow, wide spectroscopic galaxy redshift survey has been conducted around these sight lines to investigate the warm absorber environment, which is found to be spiral-rich groups or cluster outskirts with radial velocity dispersions ? = 250-750 km s{sup 1}. While 2? evidence is presented favoring the hypothesis that these absorptions are associated with the galaxy groups and not with the individual, nearest galaxies, this evidence has considerable systematic uncertainties and is based on a small sample size so it is not entirely conclusive. If the associations are with galaxy groups, the observed frequency of warm absorbers (dN/dz = 3.5-5 per unit redshift) requires them to be very extended as an ensemble on the sky (?1 Mpc in radius at high covering factor). Most likely these warm absorbers are interface gas clouds whose presence implies the existence of a hotter (T ? 10{sup 6.5} K), diffuse, and probably very massive (>10{sup 11} M {sub ?}) intra-group medium which has yet to be detected directly.

  6. The existence and nature of the interstellar bow shock

    SciTech Connect (OSTI)

    Ben-Jaffel, Lotfi; Strumik, M.; Ratkiewicz, R.; Grygorczuk, J.

    2013-12-20

    We report a new diagnosis of two different states of the local interstellar medium (LISM) near our solar system by using a sensitivity study constrained by several distinct and complementary observations of the LISM, solar wind, and inner heliosphere. Assuming the Interstellar Boundary Explorer (IBEX) He flow parameters for the LISM, we obtain a strength of ?2.7 0.2 ?G and a direction pointing away from galactic coordinates (28, 52) 3 for the interstellar magnetic field as a result of fitting Voyager 1 and Voyager 2 in situ plasma measurements and IBEX energetic neutral atoms ribbon. When using Ulysses parameters for the LISM He flow, we recently reported the same direction but with a strength of 2.2 0.1 ?G. First, we notice that with Ulysses He flow, our solution is in the expected hydrogen deflection plane (HDP). In contrast, for the IBEX He flow, the solution is ?20 away from the corresponding HDP plane. Second, the long-term monitoring of the interplanetary H I flow speed shows a value of ?26 km s{sup 1} measured upwind from the Doppler shift in the strong Ly? sky background emission line. All elements of the diagnosis seem therefore to support Ulysses He flow parameters for the interstellar state. In that frame, we argue that reliable discrimination between superfast, subfast, or superslow states of the interstellar flow should be based on most existing in situ and remote observations used together with global modeling of the heliosphere. For commonly accepted LISM ionization rates, we show that a fast interstellar bow shock should be standing off upstream of the heliopause.

  7. Lithium protects against methamphetamine-induced neurotoxicity in PC12 cells via Akt/GSK3β/mTOR pathway

    SciTech Connect (OSTI)

    Wu, Jintao; Zhu, Dexiao; Zhang, Jing; Li, Guibao; Liu, Zengxun; Sun, Jinhao

    2015-09-25

    Methamphetamine (MA) is neurotoxic, especially in dopaminergic neurons. Long-lasting exposure to MA causes psychosis and increases the risk of Parkinson's disease. Lithium (Li) is a known mood stabilizer and has neuroprotective effects. Previous studies suggest that MA exposure decreases the phosphorylation of Akt/GSK3β pathway in vivo, whereas Li facilitates the phosphorylation of Akt/GSK3β pathway. Moreover, GSK3β and mTOR are implicated in the locomotor sensitization induced by psychostimulants and mTOR plays a critical role in MA induced toxicity. However, the effect of MA on Akt/GSK3β/mTOR pathway has not been fully investigated in vitro. Here, we found that MA exposure significantly dephosphorylated Akt/GSK3β/mTOR pathway in PC12 cells. In addition, Li remarkably attenuated the dephosphorylation effect of MA exposure on Akt/GSK3β/mTOR pathway. Furthermore, Li showed obvious protective effects against MA toxicity and LY294002 (Akt inhibitor) suppressed the protective effects of Li. Together, MA exposure dephosphorylates Akt/GSK3β/mTOR pathway in vitro, while lithium protects against MA-induced neurotoxicity via phosphorylation of Akt/GSK3β/mTOR pathway. - Highlights: • Lithium protects against methamphetamine-induced neurotoxicity in vitro. • Methamphetamine exposure dephosphorylates Akt/GSK3β/mTOR pathway. • Lithium attenuates methamphetamine-induced toxicity via phosphorylating Akt/GSK3β/mTOR pathway.

  8. WATER PRODUCTION IN COMETS 2001 Q4 (NEAT) AND 2002 T7 (LINEAR) DETERMINED FROM SOHO/SWAN OBSERVATIONS

    SciTech Connect (OSTI)

    Combi, M. R.; Lee, Y.; Maekinen, J. T. T.; Bertaux, J.-L.; Quemerais, E.

    2009-06-15

    The SWAN all-sky camera on the Solar and Heliospheric Observatory (SOHO) spacecraft detected the hydrogen Lyman-alpha (Ly{alpha}) comae of comets 2001 Q4 NEAT and 2002 T7 LINEAR for large portions of their perihelion apparitions in 2003 and 2004. C/2001 Q4 NEAT was observed from 2003 September 14 through 2004 November 2, covering heliocentric distances from 3.23 AU before perihelion to 2.75 AU after, and C/2002 T7 LINEAR was observed from 2003 December 4 through 2004 August 6, covering heliocentric distances from 2.52 AU before perihelion to 2.09 AU after. We combined the full set of comet specific and full-sky observations and used our time-resolved model (TRM), which enables us to extract continuous values of the daily-average value of the water production rate throughout most of this entire period. The average power-law fit to the production rate variation of C/2001 Q4 NEAT with heliocentric distance, r, gives 3.5 x 10{sup 29} r {sup -1.7} and that for C/2002 T7 LINEAR gives 4.6 x 10{sup 29} r {sup -2.0}. Both comets show roughly a factor of 2 asymmetry in activity about perihelion, being more active before perihelion. C/2001 Q4 NEAT showed a production rate outburst about 30 days before perihelion (2004 April 15) and then a large extended increase above the nominal trend from 50 to 70 days after perihelion (2004 July 5-July 25)

  9. THE MULTI-OBJECT, FIBER-FED SPECTROGRAPHS FOR THE SLOAN DIGITAL SKY SURVEY AND THE BARYON OSCILLATION SPECTROSCOPIC SURVEY

    SciTech Connect (OSTI)

    Smee, Stephen A.; Barkhouser, Robert H.; Gunn, James E.; Carr, Michael A.; Lupton, Robert H.; Loomis, Craig; Uomoto, Alan; Roe, Natalie; Schlegel, David; Rockosi, Constance M.; Leger, French; Owen, Russell; Anderson, Lauren; Dawson, Kyle S.; Olmstead, Matthew D.; Brinkmann, Jon; Long, Dan; Honscheid, Klaus; Harding, Paul; Annis, James; and others

    2013-08-01

    We present the design and performance of the multi-object fiber spectrographs for the Sloan Digital Sky Survey (SDSS) and their upgrade for the Baryon Oscillation Spectroscopic Survey (BOSS). Originally commissioned in Fall 1999 on the 2.5 m aperture Sloan Telescope at Apache Point Observatory, the spectrographs produced more than 1.5 million spectra for the SDSS and SDSS-II surveys, enabling a wide variety of Galactic and extra-galactic science including the first observation of baryon acoustic oscillations in 2005. The spectrographs were upgraded in 2009 and are currently in use for BOSS, the flagship survey of the third-generation SDSS-III project. BOSS will measure redshifts of 1.35 million massive galaxies to redshift 0.7 and Ly{alpha} absorption of 160,000 high redshift quasars over 10,000 deg{sup 2} of sky, making percent level measurements of the absolute cosmic distance scale of the universe and placing tight constraints on the equation of state of dark energy. The twin multi-object fiber spectrographs utilize a simple optical layout with reflective collimators, gratings, all-refractive cameras, and state-of-the-art CCD detectors to produce hundreds of spectra simultaneously in two channels over a bandpass covering the near-ultraviolet to the near-infrared, with a resolving power R = {lambda}/FWHM {approx} 2000. Building on proven heritage, the spectrographs were upgraded for BOSS with volume-phase holographic gratings and modern CCD detectors, improving the peak throughput by nearly a factor of two, extending the bandpass to cover 360 nm < {lambda} < 1000 nm, and increasing the number of fibers from 640 to 1000 per exposure. In this paper we describe the original SDSS spectrograph design and the upgrades implemented for BOSS, and document the predicted and measured performances.

  10. THE SUBARU HIGH-z QUASAR SURVEY: DISCOVERY OF FAINT z ? 6 QUASARS

    SciTech Connect (OSTI)

    Kashikawa, Nobunari; Furusawa, Hisanori; Niino, Yuu [Optical and Infrared Astronomy Division, National Astronomical Observatory, Mitaka, Tokyo 181-8588 (Japan); Ishizaki, Yoshifumi; Onoue, Masafusa; Toshikawa, Jun; Ishikawa, Shogo [Department of Astronomy, School of Science, Graduate University for Advanced Studies, Mitaka, Tokyo 181-8588 (Japan); Willott, Chris J. [Herzberg Institute of Astrophysics, National Research Council, 5071 West Saanich Road, Victoria, BC V9E 2E7 (Canada); Im, Myungshin [Center for the Exploration of the Origin of the Universe (CEOU), Astronomy Program, Department of Physics and Astronomy, Seoul National University, 1 Gwanak-rho, Gwanak-gu, Seoul 151-742 (Korea, Republic of); Shimasaku, Kazuhiro [Department of Astronomy, University of Tokyo, Hongo, Tokyo 113-0033 (Japan); Ouchi, Masami [Institute for Cosmic Ray Research, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8582 (Japan); Hibon, Pascale, E-mail: n.kashikawa@nao.ac.jp [Gemini Observatory, La Serena (Chile)

    2015-01-01

    We present the discovery of one or two extremely faint z ? 6 quasars in 6.5 deg{sup 2} utilizing a unique capability of the wide-field imaging of the Subaru/Suprime-Cam. The quasar selection was made in (i'-z{sub B} ) and (z{sub B} -z{sub R} ) colors, where z{sub B} and z{sub R} are bandpasses with central wavelengths of 8842 and 9841 , respectively. The color selection can effectively isolate quasars at z ? 6 from M/L/T dwarfs without the J-band photometry down to z{sub R} < 24.0, which is 3.5 mag deeper than the Sloan Digital Sky Survey (SDSS). We have selected 17 promising quasar candidates. The follow-up spectroscopy for seven targets identified one apparent quasar at z = 6.156 with M {sub 1450} = 23.10. We also identified one possible quasar at z = 6.041 with a faint continuum of M {sub 1450} = 22.58 and a narrow Ly? emission with HWHM =427 km s{sup 1}, which cannot be distinguished from Lyman ? emitters. We derive the quasar luminosity function at z ? 6 by combining our faint quasar sample with the bright quasar samples by SDSS and CFHQS. Including our data points invokes a higher number density in the faintest bin of the quasar luminosity function than the previous estimate employed. This suggests a steeper faint-end slope than lower z, though it is yet uncertain based on a small number of spectroscopically identified faint quasars, and several quasar candidates still remain to be diagnosed. The steepening of the quasar luminosity function at the faint end does increase the expected emission rate of the ionizing photon; however, it only changes by a factor of approximately two to six. This was found to still be insufficient for the required photon budget of reionization at z ? 6.

  11. Chemical constraints on the contribution of population III stars to cosmic reionization

    SciTech Connect (OSTI)

    Kulkarni, Girish; Hennawi, Joseph F. [Max Planck Institute for Astronomy, Knigstuhl 17, D-69117 Heidelberg (Germany); Rollinde, Emmanuel; Vangioni, Elisabeth, E-mail: girish@mpia-hd.mpg.de [Institut d'Astrophysique de Paris, UMR 7095, UPMC, Paris VI, 98 bis boulevard Arago, F-75014 Paris (France)

    2014-05-20

    Recent studies have highlighted that galaxies at z = 6-8 fall short of producing enough ionizing photons to reionize the intergalactic medium, and suggest that Population III stars could resolve this tension, because their harder spectra can produce ?10 more ionizing photons than Population II. We use a semi-analytic model of galaxy formation, which tracks galactic chemical evolution, to gauge the impact of Population III stars on reionization. Population III supernovae produce distinct metal abundances, and we argue that the duration of the Population III era can be constrained by precise relative abundance measurements in high-z damped Ly? absorbers (DLAs), which provide a chemical record of past star formation. We find that a single generation of Population III stars can self-enrich galaxies above the critical metallicity Z {sub crit} = 10{sup 4} Z {sub ?} for the Population III-to-II transition, on a very short timescale t {sub self-enrich} ? 10{sup 6} yr, owing to the large metal yields and short lifetimes of Population III stars. This subsequently terminates the Population III era, so they contribute ? 50% of the ionizing photons only for z ? 30, and at z = 10 contribute <1%. The Population III contribution can be increased by delaying metal mixing into the interstellar medium. However, comparing the resulting metal abundance pattern to existing measurements in z ? 6 DLAs, we show that the observed [O/Si] ratios of absorbers rule out Population III stars being a major contributor to reionization. Future abundance measurements of z ? 7-8 QSOs and gamma-ray bursts should probe the era when the chemical vestiges of Population III star formation become detectable.

  12. SOLAR RADIATION PRESSURE AND LOCAL INTERSTELLAR MEDIUM FLOW PARAMETERS FROM INTERSTELLAR BOUNDARY EXPLORER LOW ENERGY HYDROGEN MEASUREMENTS

    SciTech Connect (OSTI)

    Schwadron, N. A.; Moebius, E.; Kucharek, H.; Lee, M. A.; French, J.; Saul, L.; Wurz, P.; Bzowski, M.; Fuselier, S. A.; Livadiotis, G.; McComas, D. J.; Frisch, P.; Gruntman, M.; Mueller, H. R.

    2013-10-01

    Neutral hydrogen atoms that travel into the heliosphere from the local interstellar medium (LISM) experience strong effects due to charge exchange and radiation pressure from resonant absorption and re-emission of Ly?. The radiation pressure roughly compensates for the solar gravity. As a result, interstellar hydrogen atoms move along trajectories that are quite different than those of heavier interstellar species such as helium and oxygen, which experience relatively weak radiation pressure. Charge exchange leads to the loss of primary neutrals from the LISM and the addition of new secondary neutrals from the heliosheath. IBEX observations show clear effects of radiation pressure in a large longitudinal shift in the peak of interstellar hydrogen compared with that of interstellar helium. Here, we compare results from the Lee et al. interstellar neutral model with IBEX-Lo hydrogen observations to describe the distribution of hydrogen near 1 AU and provide new estimates of the solar radiation pressure. We find over the period analyzed from 2009 to 2011 that radiation pressure divided by the gravitational force (?) has increased slightly from ? = 0.94 0.04 in 2009 to ? = 1.01 0.05 in 2011. We have also derived the speed, temperature, source longitude, and latitude of the neutral H atoms and find that these parameters are roughly consistent with those of interstellar He, particularly when considering the filtration effects that act on H in the outer heliosheath. Thus, our analysis shows that over the period from 2009 to 2011, we observe signatures of neutral H consistent with the primary distribution of atoms from the LISM and a radiation pressure that increases in the early rise of solar activity.

  13. NGC 1365: A low column density state unveiling a low ionization disk wind

    SciTech Connect (OSTI)

    Braito, V.; Reeves, J. N.; Gofford, J.; Nardini, E.; Porquet, D.; Risaliti, G.

    2014-11-01

    We present the time-resolved spectral analysis of the XMM-Newton data of NGC 1365 collected during one XMM-Newton observation, which caught this 'changing-look' active galactic nucleus in a high flux state characterized also by a low column density (N {sub H} ? 10{sup 22} cm{sup 2}) of the X-ray absorber. During this observation, the low-energy photoelectric cut-off is at about ?1 keV and the primary continuum can be investigated with the XMM-Newton-RGS data, which show strong spectral variability that can be explained as a variable low N {sub H} that decreased from N {sub H} ? 10{sup 23} cm{sup 2} to 10{sup 22} cm{sup 2} in a 100 ks timescale. The spectral analysis of the last segment of the observation revealed the presence of several absorption features that can be associated with an ionized (log ? ? 2 erg cm s{sup 1}) outflowing wind (v {sub out} ? 2000 km s{sup 1}). We detected for the first time a possible P-Cygni profile of the Mg XII Ly? line associated with this mildly ionized absorber indicative of a wide angle outflowing wind. We suggest that this wind is a low ionization zone of the highly ionized wind present in NGC 1365, which is responsible for the iron K absorption lines and is located within the variable X-ray absorber. At the end of the observation, we detected a strong absorption line at E ? 0.76 keV most likely associated with a lower ionization zone of the absorber (log ? ? 0.2 erg cm s{sup 1}, N {sub H} ? 10{sup 22} cm{sup 2}), which suggests that the variable absorber in NGC 1365 could be a low ionization zone of the disk wind.

  14. DES J0454–4448: Discovery of the first luminous z ≥ 6 quasar from the Dark Energy Survey

    SciTech Connect (OSTI)

    Reed, S. L.

    2015-10-28

    We present the first results of a survey for high-redshift, z ≥ 6, quasars using izY multicolour photometric observations from the Dark Energy Survey (DES). Here we report the discovery and spectroscopic confirmation of the zAB, YAB = 20.2, 20.2 (M1450 = –26.5) quasar DES J0454–4448 with a redshift of z = 6.09±0.02 based on the onset of the Ly α forest and an H i near zone size of 4.1+1.1–1.2 proper Mpc. The quasar was selected as an i-band drop out with i–z = 2.46 and zAB < 21.5 from an area of ~300 deg2. It is the brightest of our 43 candidates and was identified for spectroscopic follow-up solely based on the DES i–z and z–Y colours. The quasar is detected by WISE and has W1AB = 19.68. The discovery of one spectroscopically confirmed quasar with 5.7 < z < 6.5 and zAB ≤ 20.2 is consistent with recent determinations of the luminosity function at z ~ 6. DES when completed will have imaged ~5000 deg2 to YAB = 23.0 (5σ point source) and we expect to discover 50–100 new quasars with z > 6 including 3–10 with z > 7 dramatically increasing the numbers of quasars currently known that are suitable for detailed studies.

  15. Bringing simulation and observation together to better understand the intergalactic medium

    SciTech Connect (OSTI)

    Egan, Hilary; Smith, Britton D.; O'Shea, Brian W.; Shull, J. Michael

    2014-08-10

    The methods by which one characterizes the distribution of matter in cosmological simulations is intrinsically different from how one performs the same task observationally. In this paper, we make substantial steps toward comparing simulations and observations of the intergalactic medium (IGM) in a more sensible way. We present a pipeline that generates and fits synthetic QSO absorption spectra using sight lines cast through a cosmological simulation, and simultaneously identifies structure by directly analyzing the variations in H I and O VI number density. We compare synthetic absorption spectra with a less observationally motivated, but more straightforward density threshold-based method for finding absorbers. Our efforts focus on H I and O VI to better characterize the warm/hot IGM, a subset of the IGM that is challenging to conclusively identify observationally. We find that the two methods trace roughly the same quantities of H I and O VI above observable column density limits, but the synthetic spectra typically identify more substructure in absorbers. We use both methods to characterize H I and O VI absorber properties. We find that both integrated and differential column density distributions from both methods generally agree with observations. The distribution of Doppler parameters between the two methods are similar for Ly? and compare reasonably with observational results, but while the two methods agree with each other with O VI systems, they both are systematically different from observations. We find a strong correlation between O VI baryon fraction and O VI column density. We also discuss a possible bimodality in the temperature distribution of the gas traced by O VI.

  16. Overexpression of SnoN/SkiL, amplified at the 3q26.2 locus, in ovarian cancers: A role in ovarian pathogenesis

    SciTech Connect (OSTI)

    Nanjundan, Meera; Cheng, Kwai Wa; Zhang, Fan; Lahad, John; Kuo, Wen-Lin; Schmandt, Rosemarie; Smith-McCune, Karen; Fishman, David; Gray, Joe W.; Mills, Gordon B.

    2008-07-18

    High-resolution array comparative genomic hybridization of 235 serous epithelial ovarian cancers demonstrated a regional increase at 3q26.2 encompassing SnoN/SkiL, a coregulator of SMAD/TGF{beta} signaling. SnoN RNA transcripts were elevated in {approx}80% of advanced stage serous epithelial ovarian cancers. In both immortalized normal (TIOSE) and ovarian carcinoma cell lines (OVCA), SnoN RNA levels were increased by TGF{beta} stimulation and altered by LY294002 and JNK II inhibitor treatment suggesting that the PI3K and JNK signaling pathways may regulate TGF{beta}-induced increases in SnoN RNA. In TIOSE, SnoN protein levels were reduced 15min post TGF{beta}-stimulation, likely by proteosome-mediated degradation. In contrast, in OVCA, SnoN levels were elevated 3h post-stimulation potentially as a result of inhibition of the proteosome. To elucidate the role of SnoN in ovarian tumorigenesis, we explored the effects of both increasing and decreasing SnoN levels. In both TIOSE and OVCA, SnoN siRNA decreased cell growth between 20 and 50% concurrent with increased p21 levels. In TIOSE, transient expression of SnoN repressed TGF{beta} induction of PAI-1 promoters with little effect on the p21 promoter or resultant cell growth. In contrast to the effects of transient expression, stable expression of SnoN in TIOSE led to growth arrest through induction of senescence. Collectively, these results implicate SnoN levels in multiple roles during ovarian carcinogenesis: promoting cellular proliferation in ovarian cancer cells and as a positive mediator of cell cycle arrest and senescence in non-transformed ovarian epithelial cells.

  17. NIR SPECTROSCOPIC OBSERVATION OF MASSIVE GALAXIES IN THE PROTOCLUSTER AT z = 3.09

    SciTech Connect (OSTI)

    Kubo, Mariko; Yamada, Toru; Ichikawa, Takashi; Kajisawa, Masaru; Matsuda, Yuichi; Tanaka, Ichi

    2015-01-20

    We present the results of near-infrared spectroscopic observations of the K-band-selected candidate galaxies in the protocluster at z = 3.09 in the SSA22 field. We observed 67 candidates with K {sub AB} < 24 and confirmed redshifts of the 39 galaxies at 2.0 < z {sub spec} < 3.4. Of the 67 candidates, 24 are certainly protocluster members with 3.04 ? z {sub spec} ? 3.12, which are massive red galaxies that have been unidentified in previous optical observations of the SSA22 protocluster. Many distant red galaxies (J K {sub AB} > 1.4), hyper extremely red objects (J K {sub AB} > 2.1), Spitzer MIPS 24 ?m sources, active galactic nuclei (AGNs) as well as the counterparts of Ly? blobs and the AzTEC/ASTE 1.1 mm sources in the SSA22 field are also found to be protocluster members. The mass of the SSA22 protocluster is estimated to be ?2-5 10{sup 14} M {sub ?}, and this system is plausibly a progenitor of the most massive clusters of galaxies in the current universe. The reddest (J K {sub AB} ? 2.4) protocluster galaxies are massive galaxies with M {sub star} ? 10{sup 11} M {sub ?} showing quiescent star formation activities and plausibly dominated by old stellar populations. Most of these massive quiescent galaxies host moderately luminous AGNs detected by X-ray. There are no significant differences in the [O III] ?5007/H? emission line ratios and [O III] ?5007 line widths and spatial extents of the protocluster galaxies from those of massive galaxies at z ? 2-3 in the general field.

  18. DES J0454–4448: Discovery of the first luminous z ≥ 6 quasar from the Dark Energy Survey

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

    Reed, S. L.

    2015-10-28

    We present the first results of a survey for high-redshift, z ≥ 6, quasars using izY multicolour photometric observations from the Dark Energy Survey (DES). Here we report the discovery and spectroscopic confirmation of the zAB, YAB = 20.2, 20.2 (M1450 = –26.5) quasar DES J0454–4448 with a redshift of z = 6.09±0.02 based on the onset of the Ly α forest and an H i near zone size of 4.1+1.1–1.2 proper Mpc. The quasar was selected as an i-band drop out with i–z = 2.46 and zAB < 21.5 from an area of ~300 deg2. It is the brightestmore » of our 43 candidates and was identified for spectroscopic follow-up solely based on the DES i–z and z–Y colours. The quasar is detected by WISE and has W1AB = 19.68. The discovery of one spectroscopically confirmed quasar with 5.7 < z < 6.5 and zAB ≤ 20.2 is consistent with recent determinations of the luminosity function at z ~ 6. DES when completed will have imaged ~5000 deg2 to YAB = 23.0 (5σ point source) and we expect to discover 50–100 new quasars with z > 6 including 3–10 with z > 7 dramatically increasing the numbers of quasars currently known that are suitable for detailed studies.« less

  19. The OH rotational population and photodissociation of H{sub 2}O in DG Tauri

    SciTech Connect (OSTI)

    Carr, John S.; Najita, Joan R.

    2014-06-10

    We analyze the OH rotational emission in the Spitzer Space Telescope mid-infrared spectrum of the T Tauri star DG Tau. OH is observed in emission from upper level energies of 1900 K to 28,000 K. The rotational diagram cannot be fit with any single combination of temperature and column density and has slopes that correspond to excitation temperatures ranging from 200 K to 6000 K. The relative ?-doublet population within each rotational level is not equal, showing that the OH population is not in thermal equilibrium. The symmetric ?-doublet state is preferred in all rotational states, with an average of 0.5 for the population ratio of the anti-symmetric to symmetric state. We show that the population distribution of the high rotational lines and the ?-doublet ratio are consistent with the formation of OH following the photo-dissociation of H{sub 2}O by FUV photons in the second absorption band of water (?1150-1400 ), which includes Ly?. Other processes, OH formation from either photo-dissociation of water in the first absorption band (1450-1900 ) or the reaction O({sup 1} D) + H{sub 2}, or collisional excitation, cannot explain the observed emission in the high rotational states but could potentially contribute to the population of lower rotational levels. These results demonstrate that the photodissociation of water is active in DG Tau and support the idea that the hot rotational OH emission commonly observed in Classical T Tauri stars is due to the dissociation of H{sub 2}O by FUV radiation.

  20. The O VII X-Ray Forest Toward Markarian 421: Consistency between XMM-Newton and Chandra

    SciTech Connect (OSTI)

    Kaastra, J.S.; Werner, N.; Herder, J.W.A.den; Paerels, F.B.S.; de Plaa, J.; Rasmussen, A.P.; de Vries, C.P.; /SRON, Utrecht

    2006-04-28

    Recently the first detections of highly ionized gas associated with two Warm-Hot Intergalactic Medium (WHIM) filaments have been reported. The evidence is based on X-ray absorption lines due to O VII and other ions observed by Chandra towards the bright blazar Mrk 421. We investigate the robustness of this detection by a re-analysis of the original Chandra LETGS spectra, the analysis of a large set of XMM-Newton RGS spectra of Mrk 421, and additional Chandra observations. We address the reliability of individual spectral features belonging to the absorption components, and assess the significance of the detection of these components. We also use Monte Carlo simulations of spectra. We confirm the apparent strength of several features in the Chandra spectra, but demonstrate that they are statistically not significant. This decreased significance is due to the number of redshift trials that are made and that are not taken into account in the original discovery paper. Therefore these features must be attributed to statistical fluctuations. This is confirmed by the RGS spectra, which have a higher signal to noise ratio than the Chandra spectra, but do not show features at the same wavelengths. Finally, we show that the possible association with a Ly{alpha} absorption system also lacks sufficient statistical evidence. We conclude that there is insufficient observational proof for the existence of the two proposed WHIM filaments towards Mrk 421, the brightest X-ray blazar on the sky. Therefore, the highly ionized component of the WHIM still remains to be discovered.

  1. Hubble space telescope/cosmic origins spectrograph observations of the quasar Q0302–003: Probing the He II reionization epoch and QSO proximity effects

    SciTech Connect (OSTI)

    Syphers, David; Shull, J. Michael

    2014-03-20

    Q0302–003 (z = 3.2860 ± 0.0005) was the first quasar discovered that showed a He II Gunn-Peterson trough, a sign of incomplete helium reionization at z ≳ 2.9. We present its Hubble Space Telescope/Cosmic Origins Spectrograph far-UV medium-resolution spectrum, which resolves many spectral features for the first time, allowing study of the quasar itself, the intergalactic medium, and quasar proximity effects. Q0302–003 has a harder intrinsic extreme-UV spectral index than previously claimed, as determined from both a direct fit to the spectrum (yielding α{sub ν} ≈ –0.8) and the helium-to-hydrogen ion ratio in the quasar's line-of-sight proximity zone. Intergalactic absorption along this sightline shows that the helium Gunn-Peterson trough is largely black in the range 2.87 < z < 3.20, apart from ionization due to local sources, indicating that helium reionization has not completed at these redshifts. However, we tentatively report a detection of nonzero flux in the high-redshift trough when looking at low-density regions, but zero flux in higher-density regions. This constrains the He II fraction to be about 1% in the low-density intergalactic medium (IGM) and possibly a factor of a few higher in the IGM as a whole, suggesting helium reionization has progressed substantially by z ∼ 3.1. The Gunn-Peterson trough recovers to a He II Lyα forest at z < 2.87. We confirm a transmission feature due to the ionization zone around a z = 3.05 quasar just off the sightline, and resolve the feature for the first time. We discover a similar such feature possibly caused by a luminous z = 3.23 quasar further from the sightline, which suggests that this quasar has been luminous for >34 Myr.

  2. Imaging the heliosphere using neutral atoms from solar wind energy down to 15 eV

    SciTech Connect (OSTI)

    Galli, A.; Wurz, P.; Fuselier, S. A.; McComas, D. J.; Bzowski, M.; Sokół, J. M.; Kubiak, M. A.; Möbius, E.

    2014-11-20

    We study the spatial and temporal distribution of hydrogen energetic neutral atoms (ENAs) from the heliosheath observed with the IBEX-Lo sensor of the Interstellar Boundary EXplorer (IBEX) from solar wind energies down to the lowest available energy (15 eV). All available IBEX-Lo data from 2009 January until 2013 June were included. The sky regions imaged when the spacecraft was outside of Earth's magnetosphere and when the Earth was moving toward the direction of observation offer a sufficient signal-to-noise ratio even at very low energies. We find that the ENA ribbon—a 20° wide region of high ENA intensities—is most prominent at solar wind energies whereas it fades at lower energies. The maximum emission in the ribbon is located near the poles for 2 keV and closer to the ecliptic plane for energies below 1 keV. This shift is an evidence that the ENA ribbon originates from the solar wind. Below 0.1 keV, the ribbon can no longer be identified against the globally distributed ENA signal. The ENA measurements in the downwind direction are affected by magnetospheric contamination below 0.5 keV, but a region of very low ENA intensities can be identified from 0.1 keV to 2 keV. The energy spectra of heliospheric ENAs follow a uniform power law down to 0.1 keV. Below this energy, they seem to become flatter, which is consistent with predictions. Due to the subtraction of local background, the ENA intensities measured with IBEX agree with the upper limit derived from Lyα observations.

  3. The mass spectrum of the first stars

    SciTech Connect (OSTI)

    Susa, Hajime; Tominaga, Nozomu; Hasegawa, Kenji

    2014-09-01

    We perform cosmological hydrodynamics simulations with non-equilibrium primordial chemistry to obtain 59 minihalos that host first stars. The obtained minihalos are used as the initial conditions of local three-dimensional radiation hydrodynamics simulations to investigate the formation of the first stars. We find that two-thirds of the minihalos host multiple stars, while the other third has single stars. The mass of the stars found in our simulations are in the range of 1 M {sub ☉} ≲ M ≲ 300 M {sub ☉}, peaking at several× 10 M {sub ☉}. Most of the very massive stars of ≳ 140 M {sub ☉} are born as single stars, although not all of the single stars are very massive. We also find a few stars of ≲ 1 M {sub ☉} that are kicked by the gravitational three body interactions to the position distant from the center of mass. The frequency that a star forming minihalo contains a binary system is ∼50%. We also investigate the abundance pattern of the stellar remnants by summing up the contributions from the first stars in the simulations. Consequently, the pattern is compatible with that of the low metallicity damped Lyα systems or the extremely metal-poor (EMP) stars, if the mass spectrum obtained in our experiment is shifted to the low mass side by 0.2 dex. If we consider the case that an EMP star is born in the remnant of the individual minihalo without mixing with others, the chemical signature of the pair instability supernova is more prominent, because most of them are born as single stars.

  4. THE FIRST HIGH-REDSHIFT QUASAR FROM Pan-STARRS

    SciTech Connect (OSTI)

    Morganson, Eric; De Rosa, Gisella; Decarli, Roberto; Walter, Fabian; Rix, Hans-Walter; Chambers, Ken; Burgett, William; Flewelling, Heather; Hodapp, Klaus; Kaiser, Nick; Magnier, Eugene; Sweeney, Bill; Waters, Christopher; McGreer, Ian; Fan, Xiaohui; Greiner, Jochen; Price, Paul

    2012-06-15

    We present the discovery of the first high-redshift (z > 5.7) quasar from the Panoramic Survey Telescope and Rapid Response System 1 (Pan-STARRS1 or PS1). This quasar was initially detected as an i{sub P1} dropout in PS1, confirmed photometrically with the SAO Wide-field InfraRed Camera at Arizona's Multiple Mirror Telescope (MMT) and the Gamma-Ray Burst Optical/Near-Infrared Detector at the MPG 2.2 m telescope in La Silla. The quasar was verified spectroscopically with the MMT Spectrograph, Red Channel and the Cassegrain Twin Spectrograph at the Calar Alto 3.5 m telescope. Its near-infrared spectrum was taken at the Large Binocular Telescope Observatory (LBT) with the LBT Near-Infrared Spectroscopic Utility with Camera and Integral Field Unit for Extragalactic Research. It has a redshift of 5.73, an AB z{sub P1} magnitude of 19.4, a luminosity of 3.8 Multiplication-Sign 10{sup 47} erg s{sup -1}, and a black hole mass of 6.9 Multiplication-Sign 10{sup 9} M{sub Sun }. It is a broad absorption line quasar with a prominent Ly{beta} peak and a very blue continuum spectrum. This quasar is the first result from the PS1 high-redshift quasar search that is projected to discover more than 100 i{sub P1} dropout quasars and could potentially find more than 10 z{sub P1} dropout (z > 6.8) quasars.

  5. 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}(Ly? and [O III] are likely to probe different regions in the source.

  6. HST/COS OBSERVATIONS OF THE QUASAR HE 2347-4342: PROBING THE EPOCH OF He II PATCHY REIONIZATION AT REDSHIFTS z = 2.4-2.9

    SciTech Connect (OSTI)

    Shull, J. Michael; France, Kevin; Danforth, Charles W.; Smith, Britton [CASA, Department of Astrophysical and Planetary Sciences, University of Colorado, 389-UCB, Boulder, CO 80309 (United States); Tumlinson, Jason, E-mail: michael.shull@colorado.ed, E-mail: danforth@casa.colorado.ed, E-mail: kevin.france@colorado.ed, E-mail: britton.smith@colorado.ed, E-mail: tumlinson@stsci.ed [Space Telescope Science Institute, Baltimore, MD 21218 (United States)

    2010-10-20

    We report ultraviolet spectra of the high-redshift (z{sub em} {approx} 2.9) quasar, HE 2347 - 4342, taken by the Cosmic Origins Spectrograph (COS) on the Hubble Space Telescope. Spectra in the G130M (medium resolution, 1135-1440 A) and G140L (low resolution, 1030-2000 A) gratings exhibit patchy Gunn-Peterson absorption in the 303.78 A Ly{alpha} line of He II between z = 2.39-2.87 (G140L) and z = 2.74-2.90 (G130M). With COS, we obtain better spectral resolution, higher signal-to-noise ratio (S/N), and better determined backgrounds than previous studies, with sensitivity to abundance fractions x{sub He{sub II}} {approx} 0.01 in filaments of the cosmic web. The He II optical depths from COS are higher than those with the Far Ultraviolet Spectroscopic Explorer and range from {tau}{sub He{sub II}} {<=} 0.02 to {tau}{sub He{sub II}} {>=} 5, with a slow recovery in mean optical depth to ({tau}{sub He{sub II}}) {<=} 2 at z < 2.7. The He II/H I optical-depth ratio varies ({eta}{approx} 10-100 for 2.4 < z < 2.73 and {eta} = 5-500 for 2.75 < z < 2.89) on scales {Delta}z {approx}< 0.01 (10.8 Mpc in comoving radial distance at z = 2.8), with numerous flux-transmission windows between 1135 and 1186 A. The He II absorption extends to 1186.26 A (z = 2.905), including associated absorbers with z{sub abs} {approx} z{sub QSO} and minimal 'proximity effect' of flux transmission at the He II edge. We propose a QSO systemic redshift z{sub QSO} = 2.904 {+-} 0.002, some {Delta}z = 0.019 higher than that derived from O I {lambda}1302 emission. Three long troughs (4-10 A or 25-60 Mpc comoving distance) of strong He II absorption between z = 2.75and2.90 are uncharacteristic of the intergalactic medium if He II reionized at z{sub r} {approx} 3. Contrary to recent indirect estimates (z{sub r} = 3.2 {+-} 0.2) from H I optical depths, the epoch of He II reionization may extend to z {approx}< 2.7.

  7. HD/H{sub 2} AS A PROBE OF THE ROLES OF GAS, DUST, LIGHT, METALLICITY, AND COSMIC RAYS IN PROMOTING THE GROWTH OF MOLECULAR HYDROGEN IN THE DIFFUSE INTERSTELLAR MEDIUM

    SciTech Connect (OSTI)

    Liszt, H. S.

    2015-01-20

    We modeled recent observations of UV absorption of HD and H{sub 2} in the Milky Way and toward damped/subdamped Lyα systems at z = 0.18 and z >1.7. N(HD)/N(H{sub 2}) ratios reflect the separate self-shieldings of HD and H{sub 2} and the coupling introduced by deuteration chemistry. Locally, observations are explained by diffuse molecular gas with 16 cm{sup –3} ≲ n(H) ≲ 128 cm{sup –3} if the cosmic-ray ionization rate per H nucleus ζ {sub H} =2 × 10{sup –16} s{sup –1}, as inferred from H{sub 3} {sup +} and OH{sup +}. The dominant influence on N(HD)/N(H{sub 2}) is the cosmic-ray ionization rate with a much weaker downward dependence on n(H) at solar metallicity, but dust extinction can drive N(HD) higher as with N(H{sub 2}). At z > 1.7, N(HD) is comparable to the Galaxy but with 10 times smaller N(H{sub 2}) and somewhat smaller N(H{sub 2})/N(H I). Comparison of our Galaxy with the Magellanic Clouds shows that smaller H{sub 2}/H is expected at subsolar metallicity, and we show by modeling that HD/H{sub 2} increases with density at low metallicity, opposite to the Milky Way. Observations of HD would be explained with higher n(H) at low metallicity, but high-z systems have high HD/H{sub 2} at metallicity 0.04 ≲ Z ≲ 2 solar. In parallel, we trace dust extinction and self-shielding effects. The abrupt H{sub 2} transition to H{sub 2}/H ≈ 1%-10% occurs mostly from self-shielding, although it is assisted by extinction for n(H) ≲ 16 cm{sup –3}. Interior H{sub 2} fractions are substantially increased by dust extinction below ≲ 32 cm{sup –3}. At smaller n(H), ζ {sub H}, small increases in H{sub 2} triggered by dust extinction can trigger abrupt increases in N(HD)

  8. Reduction of metastasis, cell invasion, and adhesion in mouse osteosarcoma by YM529/ONO-5920-induced blockade of the Ras/MEK/ERK and Ras/PI3K/Akt pathway

    SciTech Connect (OSTI)

    Tsubaki, Masanobu; Satou, Takao; Itoh, Tatsuki; Imano, Motohiro; Ogaki, Mitsuhiko; Yanae, Masashi; Depeartment of Pharmacy, Sakai Hospital, Kinki University School of Medicine, Sakai, Osaka 590-0132 ; Nishida, Shozo

    2012-03-15

    Osteosarcoma is one of the most common primary malignant bone tumors in children and adolescents. Some patients continue to have a poor prognosis, because of the metastatic disease. YM529/ONO-5920 is a nitrogen-containing bisphosphonate that has been used for the treatment of osteoporosis. YM529/ONO-5920 has recently been reported to induce apoptosis in various tumors including osteosarcoma. However, the mode of metastasis suppression in osteosarcoma by YM529/ONO-5920 is unclear. In the present study, we investigated whether YM529/ONO-5920 inhibited tumor cell migration, invasion, adhesion, or metastasis in the LM8 mouse osteosarcoma cell line. We found that YM529/ONO-5920 significantly inhibited metastasis, cell migration, invasion, and adhesion at concentrations that did not have antiproliferative effects on LM8 cells. YM529/ONO-5920 also inhibited the mRNA expression and protein activities of matrix metalloproteinases (MMPs). In addition, YM529/ONO-5920 suppressed phosphorylated extracellular signal-regulated kinase 1/2 (ERK1/2) and the serine/threonine protein kinase B (Akt) by the inhibition of Ras prenylation. Moreover, U0126, a mitogen-activated protein kinase kinase (MEK) 1/2 inhibitor, and LY294002, a phosphatidylinositol 3-kinase (PI3K) inhibitor, also inhibited LM8 cell migration, invasion, adhesion, and metastasis, as well as the mRNA expression and protein activities of MMP-1, MMP-2, MMP-9, and MT1-MMP. The results indicated that YM529/ONO-5920 suppressed the Ras/MEK/ERK and Ras/PI3K/Akt pathways, thereby inhibiting LM8 cell migration, invasion, adhesion, and metastasis. These findings suggest that YM529/ONO-5920 has potential clinical applications for the treatment of tumor cell metastasis in osteosarcoma. -- Highlights: ? We investigated whether YM529/ONO-5920 inhibited tumor metastasis in osteosarcoma. ? YM529/ONO-5920 inhibited metastasis, cell migration, invasion, and adhesion. ? YM529/ONO-5920 suppressed Ras signalings. ? YM529/ONO-5920 has potential clinical applications for the treatment in osteosarcoma.

  9. UNDERSTANDING PHYSICAL CONDITIONS IN HIGH-REDSHIFT GALAXIES THROUGH C I FINE STRUCTURE LINES: DATA AND METHODOLOGY

    SciTech Connect (OSTI)

    Jorgenson, Regina A.; Wolfe, Arthur M.; Prochaska, J. Xavier

    2010-10-10

    We probe the physical conditions in high-redshift galaxies, specifically, the damped Ly{alpha} systems (DLAs) using neutral carbon (C I) fine structure lines and molecular hydrogen (H{sub 2}). We report five new detections of C I and analyze the C I in an additional two DLAs with previously published data. We also present one new detection of H{sub 2} in a DLA. We present a new method of analysis that simultaneously constrains both the volume density and the temperature of the gas, as opposed to previous studies that a priori assumed a gas temperature. We use only the column density of C I measured in the fine structure states and the assumption of ionization equilibrium in order to constrain the physical conditions in the gas. We present a sample of 11 C I velocity components in six DLAs and compare their properties to those derived by the global C II* technique. The resulting median values for this sample are (n(H I)) = 69 cm{sup -3}, (T) = 50 K, and (log(P/k)) = 3.86 cm{sup -3} K, with standard deviations, {sigma}{sub n(H{sub i})} = 134 cm{sup -3}, {sigma}{sub T} = 52 K, and {sigma}{sub log(P/k)} = 3.68 cm{sup -3} K. This can be compared with the integrated median values for the same DLAs: (n(H I)) = 2.8 cm{sup -3}, (T) = 139 K, and (log(P/k)) = 2.57 cm{sup -3} K, with standard deviations {sigma}{sub n(H{sub i})} = 3.0 cm{sup -3}, {sigma}{sub T} = 43 K, and {sigma}{sub log(P/k)} = 0.22 cm{sup -3} K. Interestingly, the pressures measured in these high-redshift C I clouds are similar to those found in the Milky Way. We conclude that the C I gas is tracing a higher-density, higher-pressure region, possibly indicative of post-shock gas or a photodissociation region on the edge of a molecular cloud. We speculate that these clouds may be direct probes of the precursor sites of star formation in normal galaxies at high redshift.

  10. DOE/EPRI Electricity Storage Handbook in Collaboration with NRECA.

    SciTech Connect (OSTI)

    Huff, Georgianne; Huff, Georgianne; Akhil, Abbas Ali; Akhil, Abbas Ali; Kaun, Benjamin C; Kaun, Benjamin C; Rastler, Dan M.; Rastler, Dan M.; Chen, Stella Bingqing; Chen, Stella Bingqing; Cotter, Andrew L.; Cotter, Andrew L.; Bradshaw, Dale T.; Bradshaw, Dale T.; Gauntlett, William D.; Gauntlett, William D.; Currier, Aileen B.; Currier, Aileen B.

    2015-02-01

    Th e Electricity Storage Handbook (Handbook) is a how - to guide for utility and rural cooperative engineers, planners , and decision makers to plan and implement energy storage projects . The H andbook also serves as an information resource for investors and venture capitalists , providing the latest develo pments in technologies and tools to guide their evaluation s of energy storage opportunities . It includes a comprehensive database of the cost of current storage systems in a wide variety of electric utility and customer services, along with interconnection schematics . A list of significant past and present energy storage projects is provided for a practical perspective . Th is Handbook, jointly sponsored by the U.S. Department of Energy and the Electric Power Research Institute in collaboration with the National Rural Electric Cooperative Associ ation , is published in electronic form at www.sandia.gov/ess . This Handbook is best viewed online. iii Rev. 1, September 2014 DOE/EPRI Electricity Storage Handbook in Collaboration with NRECA Revision Log Comments, inquiries, corrections, and suggestions can be submitted via the website www.sandia.gov/ess/ , beginning August 1 , 2013. REVISION LOG Rev . Number Date Purpose of Revision Document Number Name or Org. Rev. 0 July 2013 Update and revise the 2003 EPRI - DOE Handbook of Energy Storage for Transmission and Distribution Applications to provide how - to information for various stakeholders. SAND2013 - 5131 DOE (SNL), EPRI, NRECA Rev. 1 Sept. 2014 Chapter 2: * Added information highlighting thermal storage solution. Chapter 3: * Added subchapter highlighting tools available to use to evaluate a Storage solution from a model ing and simulation standpoint. * Added new Subsections 3.3.1 through 3.3.6 . Chapter 4: * With respect to the "AC battery" system: o Added a reference to the patent #4,894,764. o Added a picture of an AC battery . * Added information about KIUC and the RFI and RFP. Appendix A: * Added information regarding ES models and tools. Appendix B: * Expanded on three energy and power cost components. o Calculation of the sum of the energy and power components. o How these costs are highly system dependent and do not scale linear ly. * Expanded on d eri vation of the Total Plant Cost (TPC) and referenced costs that are components of the TPC. * Added explanation of equipment costs . Appendix F: * Added introductory text. Appendix G: * Added reference to AC battery patent . * Removed Hawaii battery projects information. SAND201 5 - XXXX iv Rev. 1, September 201

  11. CANDELS: THE CONTRIBUTION OF THE OBSERVED GALAXY POPULATION TO COSMIC REIONIZATION

    SciTech Connect (OSTI)

    Finkelstein, Steven L.; Pawlik, Andreas H.; Papovich, Casey; Ryan, Russell E.; Ferguson, Henry C.; Koekemoer, Anton M.; Grogin, Norman A.; Dickinson, Mark; Finlator, Kristian; Giavalisco, Mauro; Cooray, Asantha; Dunlop, James S.; Faber, Sandy M.; Kocevski, Dale D.

    2012-10-20

    We present measurements of the specific ultraviolet luminosity density from a sample of 483 galaxies at 6 {approx}< z {approx}< 8. These galaxies were selected from new deep near-infrared Hubble Space Telescope imaging from the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey, Hubble UltraDeep Field 2009, and Wide Field Camera 3 Early Release Science programs. We investigate the contribution to reionization from galaxies that we observe directly, thus sidestepping the uncertainties inherent in complementary studies that have invoked assumptions regarding the intrinsic shape or the faint-end cutoff of the galaxy ultraviolet (UV) luminosity function. Due to our larger survey volume, wider wavelength coverage, and updated assumptions about the clumping of gas in the intergalactic medium (IGM), we find that the observable population of galaxies can sustain a fully reionized IGM at z = 6, if the average ionizing photon escape fraction (f {sub esc}) is {approx}30%. Our result contrasts with a number of previous studies that have measured UV luminosity densities at these redshifts that vary by a factor of five, with many concluding that galaxies could not complete reionization by z = 6 unless a large population of galaxies fainter than the detection limit were invoked, or extremely high values of f {sub esc} were present. The specific UV luminosity density from our observed galaxy samples at z = 7 and 8 is not sufficient to maintain a fully reionized IGM unless f {sub esc} > 50%. We examine the contribution from galaxies in different luminosity ranges and find that the sub-L* galaxies we detect are stronger contributors to the ionizing photon budget than the L > L* population, unless f {sub esc} is luminosity dependent. Combining our observations with constraints on the emission rate of ionizing photons from Ly{alpha} forest observations at z = 6, we find that we can constrain f {sub esc} < 34% (2{sigma}) if the observed galaxies are the only contributors to reionization, or <13% (2{sigma}) if the luminosity function extends to a limiting magnitude of M {sub UV} = -13. These escape fractions are sufficient to sustain an ionized IGM by z = 6. Current constraints on the high-redshift galaxy population imply that the volume ionized fraction of the IGM, while consistent with unity at z {<=} 6, appears to drop at redshifts not much higher than 7, consistent with a number of complementary reionization probes. If faint galaxies dominated the ionizing photon budget at z = 6-7, future extremely deep observations with the James Webb Space Telescope will probe deep enough to directly observe them, providing an indirect constraint on the global ionizing photon escape fraction.

  12. The SDSS-IV extended Baryon Oscillation Spectroscopic Survey: Overview and early data

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

    Kyle S. Dawson

    2016-02-04

    In a six-year program started in 2014 July, the Extended Baryon Oscillation Spectroscopic Survey (eBOSS) will conduct novel cosmological observations using the BOSS spectrograph at Apache Point Observatory. These observations will be conducted simultaneously with the Time Domain Spectroscopic Survey (TDSS) designed for variability studies and the Spectroscopic Identification of eROSITA Sources (SPIDERS) program designed for studies of X-ray sources. In particular, eBOSS will measure with percent-level precision the distance-redshift relation with baryon acoustic oscillations (BAO) in the clustering of matter. eBOSS will use four different tracers of the underlying matter density field to vastly expand the volume covered bymore » BOSS and map the large-scale-structures over the relatively unconstrained redshift range 0.6 < z < 2.2. Using more than 250,000 new, spectroscopically confirmed luminous red galaxies at a median redshift z = 0.72, we project that eBOSS will yield measurements of the angular diameter distance dA(z) to an accuracy of 1.2% and measurements of H(z) to 2.1% when combined with the z > 0.6 sample of BOSS galaxies. With ~195,000 new emission line galaxy redshifts, we expect BAO measurements of dA(z) to an accuracy of 3.1% and H(z) to 4.7% at an effective redshift of z = 0.87. A sample of more than 500,000 spectroscopically confirmed quasars will provide the first BAO distance measurements over the redshift range 0.9 < z < 2.2, with expected precision of 2.8% and 4.2% on dA(z) and H(z), respectively. Finally, with 60,000 new quasars and re-observation of 60,000 BOSS quasars, we will obtain new Lyα forest measurements at redshifts z > 2.1; these new data will enhance the precision of dA(z) and H(z) at z > 2.1 by a factor of 1.44 relative to BOSS. Furthermore, eBOSS will provide improved tests of General Relativity on cosmological scales through redshift-space distortion measurements, improved tests for non-Gaussianity in the primordial density field, and new constraints on the summed mass of all neutrino species. Lastly, we provide an overview of the cosmological goals, spectroscopic target sample, demonstration of spectral quality from early data, and projected cosmological constraints from eBOSS.« less

  13. CO AND H{sub 2} ABSORPTION IN THE AA TAURI CIRCUMSTELLAR DISK

    SciTech Connect (OSTI)

    France, Kevin; Burgh, Eric B.; Schindhelm, Eric; Brown, Alexander; Herczeg, Gregory J.; Yang, Hao; Linsky, Jeffrey L.; Abgrall, Herve; Roueff, Evelyne; Brown, Joanna M.

    2012-01-01

    The direct study of molecular gas in inner protoplanetary disks is complicated by uncertainties in the spatial distribution of the gas, the time variability of the source, and the comparison of observations across a wide range of wavelengths. Some of these challenges can be mitigated with far-ultraviolet spectroscopy. Using new observations obtained with the Hubble Space Telescope Cosmic Origins Spectrograph, we measure column densities and rovibrational temperatures for CO and H{sub 2} observed on the line of sight through the AA Tauri circumstellar disk. CO A - X absorption bands are observed against the far-UV continuum. The CO absorption is characterized by log{sub 10}(N({sup 12}CO)) = 17.5 {+-} 0.5 cm{sup -2} and T{sub rot}(CO) = 500{sup +500}{sub -200} K, although this rotational temperature may underestimate the local kinetic temperature of the CO-bearing gas. We also detect {sup 13}CO in absorption with an isotopic ratio of {approx}20. We do not observe H{sub 2} absorption against the continuum; however, hot H{sub 2} (v > 0) is detected in absorption against the Ly{alpha} emission line. We measure the column densities in eight individual rovibrational states, determining a total log{sub 10}(N(H{sub 2})) = 17.9{sup +0.6}{sub -0.3} cm{sup -2} with a thermal temperature of T(H{sub 2}) = 2500{sup +800}{sub -700} K. The high temperature of the molecules, the relatively small H{sub 2} column density, and the high inclination of the AA Tauri disk suggest that the absorbing gas resides in an inner disk atmosphere. If the H{sub 2} and CO are cospatial within a molecular layer {approx}0.6 AU thick, this region is characterized by {approx} 10{sup 5} cm{sup -3} with an observed (CO/H{sub 2}) ratio of {approx}0.4. We also find evidence for a departure from a purely thermal H{sub 2} distribution, suggesting that excitation by continuum photons and H{sub 2} formation may be altering the level populations in the molecular gas.

  14. Strong chromatic microlensing in HE00471756 and SDSS1155+6346

    SciTech Connect (OSTI)

    Rojas, K.; Motta, V.; Mediavilla, E.; Jimnez-Vicente, J.; Muoz, J. A. E-mail: veronica.motta@uv.cl E-mail: falco@cfa.harvard.edu E-mail: jmunoz@uv.es

    2014-12-10

    We use spectra of the double-lensed quasars HE00471756 and SDSS1155+6346 to study their unresolved structure through the impact of microlensing. There is no significant evidence of microlensing in the emission line profiles except for the Ly? line of SDSS1155+6346, which shows strong differences in the shapes for images A and B. However, the continuum of the B image spectrum in SDSS1155+6346 is strongly contaminated by the lens galaxy, and these differences should be considered with caution. Using the flux ratios of the emission lines for image pairs as a baseline to remove macro-magnification and extinction, we have detected strong chromatic microlensing in the continuum measured by CASTLES (www.cfa.harvard.edu/castles/) in both lens systems, with amplitudes 0.09(?16000) ? |?m| ? 0.8(?5439) for HE00471756, and 0.2(?16000) ? |?m| ? 0.8(?5439) for SDSS1155+6346. Using magnification maps to simulate microlensing and modeling the accretion disk as a Gaussian source (I ? exp(R {sup 2}/2r {sub s}{sup 2})) of size r {sub s} ? ? {sup p}, we find r {sub s} = 2.5{sub ?1.4}{sup +3.0} ?(M/0.3M{sub ?}) lt-day and p = 2.3 0.8 at the rest frame for ? = 2045 for HE00471756 (log prior) and r {sub s} = 5.5{sub ?3.3}{sup +8.2} ?(M/0.3M{sub ?}) lt-day and p = 1.5 0.6 at the rest frame of ? = 1398 for SDSS1155+6346 (log prior). Contrary to other studied lens systems, the chromaticity detected in HE00471756 and SDSS1155+6346 is large enough to fulfill the thin disk prediction. The inferred sizes, however, are very large compared to the predictions of this model, especially in the case of SDSS1155+6346.

  15. ON THE KENNICUTT-SCHMIDT RELATION OF LOW-METALLICITY HIGH-REDSHIFT GALAXIES

    SciTech Connect (OSTI)

    Gnedin, Nickolay Y. [Particle Astrophysics Center, Fermi National Accelerator Laboratory, Batavia, IL 60510 (United States); Kravtsov, Andrey V., E-mail: gnedin@fnal.go, E-mail: andrey@oddjob.uchicago.ed [Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL 60637 (United States)

    2010-05-01

    We present results of self-consistent, high-resolution cosmological simulations of galaxy formation at z {approx} 3. The simulations employ a recently developed recipe for star formation based on the local abundance of molecular hydrogen, which is tracked self-consistently during the course of simulation. The phenomenological H{sub 2} formation model accounts for the effects of dissociating UV radiation of stars in each galaxy, as well as self-shielding and shielding of H{sub 2} by dust, and therefore allows us to explore effects of lower metallicities and higher UV fluxes prevalent in high-redshift galaxies on their star formation. We compare stellar masses, metallicities, and star formation rates of the simulated galaxies to available observations of the Lyman break galaxies (LBGs) and find a reasonable agreement. We find that the Kennicutt-Schmidt (KS) relation exhibited by our simulated galaxies at z {approx} 3 is substantially steeper and has a lower amplitude than the z = 0 relation at {Sigma}{sub H} {approx_lt} 100 M{sub o-dot} pc{sup -2}. The predicted relation, however, is consistent with existing observational constraints for the z {approx} 3 damped Ly{alpha} and LBGs. Our tests show that the main reason for the difference from the local KS relation is lower metallicity of the interstellar medium in high-redshift galaxies. We discuss several implications of the metallicity-dependence of the KS relation for galaxy evolution and interpretation of observations. In particular, we show that the observed size of high-redshift exponential disks depends sensitively on their KS relation. Our results also suggest that significantly reduced star formation efficiency at low gas surface densities can lead to strong suppression of star formation in low-mass high-redshift galaxies and long gas consumption time scales over most of the disks in large galaxies. The longer gas consumption time scales could make disks more resilient to major and minor mergers and could help explain the prevalence of the thin stellar disks in the local universe.

  16. Functional Toll-like receptor 4 expressed in lactotrophs mediates LPS-induced proliferation in experimental pituitary hyperplasia

    SciTech Connect (OSTI)

    Sabatino, Mara Eugenia; Sosa, Liliana del Valle; Petiti, Juan Pablo; Mukdsi, Jorge Humberto; Mascanfroni, Ivn Daro; Pellizas, Claudia Gabriela; Gutirrez, Silvina; Torres, Alicia Ins; De Paul, Ana Luca

    2013-11-15

    Toll like receptor 4 (TLR4) has been characterized for its ability to recognize bacterial endotoxin lipopolysaccharide (LPS). Considering that infections or inflammatory processes might contribute to the progression of pituitary tumors, we analyzed the TLR4 functional role by evaluating the LPS effect on lactotroph proliferation in primary cultures from experimental pituitary tumors, and examined the involvement of PI3K-Akt and NF-?B activation in this effect. In addition, the role of 17?-estradiol as a possible modulator of LPS-induced PRL cell proliferation was further investigated. In estrogen-induced hyperplasic pituitaries, LPS triggered lactotroph cell proliferation. However, endotoxin failed to increase the number of lactotrophs taking up BrdU in normal pituitaries. Moreover, incubation with anti-TLR4 antibody significantly reduced LPS-induced lactotroph proliferation, suggesting a functional role of this receptor. As a sign of TLR4 activation, an LPS challenge increased IL-6 release in normal and tumoral cells. By flow cytometry, TLR4 baseline expression was revealed at the plasma membrane of tumoral lactotrophs, without changes noted in the percentage of double PRL/TLR4 positive cells after LPS stimulus. Increases in TLR4 intracellular expression were detected as well as rises in CD14, p-Akt and NF-?B after an LPS challenge, as assessed by western blotting. The TLR4/PRL and PRL/NF-?B co-localization was also corroborated by immunofluorescence and the involvement of PI3K/Akt signaling in lactotroph proliferation and IL-6 release was revealed through the PI3K inhibitor Ly-294002. In addition, 17?-estradiol attenuated the LPS-evoked increase in tumoral lactotroph proliferation and IL-6 release. Collectively these results demonstrate the presence of functional TLR4 in lactotrophs from estrogen-induced hyperplasic pituitaries, which responded to the proliferative stimulation and IL-6 release induced by LPS through TLR4/CD14, with a contribution of the PI3K-Akt and NF-?B signaling pathways. - Highlights: In hyperplastic pituitaries, LPS triggered the lactotroph cell proliferation and IL-6 release. Functional Toll-like receptor 4 (TLR4) is expressed at the plasma membrane of tumoral lactotrophs. Increases in TLR4 and CD14 intracellular expression levels were detected after an LPS challenge. The proliferative stimulation and IL-6 release involved the PI3K-Akt pathway and NF-?B activation. 17?-estradiol attenuated the LPS-evoked tumoral lactotroph proliferation and IL-6 secretion.

  17. Search for [C II] emission in z = 6.5-11 star-forming galaxies

    SciTech Connect (OSTI)

    Gonzlez-Lpez, Jorge; Infante, Leopoldo; Riechers, Dominik A. E-mail: linfante@astro.puc.cl; and others

    2014-04-01

    We present the search for the [C II] emission line in three z > 6.5 Ly? emitters (LAEs) and one J-dropout galaxy using the Combined Array for Research in Millimeter-wave Astronomy and the Plateau de Bure Interferometer. We observed three bright z ? 6.5-7 LAEs discovered in the Subaru Deep Field (SDF) and the multiple imaged lensed z ? 11 galaxy candidate found behind the galaxy cluster MACSJ0647.7+7015. For the LAEs IOK-1 (z = 6.965), SDF J132415.7+273058 (z = 6.541), and SDF J132408.3+271543 (z = 6.554) we find upper limits for the [C II] line luminosity of <2.05, <4.52, and <10.56 10{sup 8} L {sub ?}, respectively. We find upper limits to the far-IR (FIR) luminosity of the galaxies using a spectral energy distribution template of the local galaxy NGC 6946 and taking into account the effects of the cosmic microwave background on the millimeter observations. For IOK-1, SDF J132415.7+273058, and SDF J132408.3+271543 we find upper limits for the FIR luminosity of <2.33, 3.79, and 7.72 10{sup 11} L {sub ?}, respectively. For the lensed galaxy MACS0647-JD, one of the highest-redshift galaxy candidates to date with z{sub ph}=10.7{sub ?0.4}{sup +0.6}, we put an upper limit in the [C II] emission of <1.36 10{sup 8} (?/15){sup 1} L {sub ?} and an upper limit in the FIR luminosity of <6.1 10{sup 10} (?/15){sup 1} L {sub ?} (where ? is the magnification factor). We explore the different conditions relevant for the search for [C II] emission in high-redshift galaxies as well as the difficulties for future observations with the Atacama Large Millimeter/submillimeter Array (ALMA) and the Cerro Chajnantor Atacama Telescope (CCAT).

  18. NEW PERSPECTIVE ON GALAXY OUTFLOWS FROM THE FIRST DETECTION OF BOTH INTRINSIC AND TRAVERSE METAL-LINE ABSORPTION

    SciTech Connect (OSTI)

    Kacprzak, Glenn G.; Cooke, Jeff; Martin, Crystal L.; Ho, Stephanie H.; Bouch, Nicolas; LeReun, Audrey; Schroetter, Ilane; Churchill, Christopher W.; Klimek, Elizabeth

    2014-09-01

    We present the first observation of a galaxy (z = 0.2) that exhibits metal-line absorption back-illuminated by the galaxy (down-the-barrel) and transversely by a background quasar at a projected distance of 58 kpc. Both absorption systems, traced by Mg II, are blueshifted relative to the galaxy systemic velocity. The quasar sight line, which resides almost directly along the projected minor axis of the galaxy, probes Mg I and Mg II absorption obtained from the Keck/Low Resolution Imaging Spectrometer as well as Ly?, Si II, and Si III absorption obtained from the Hubble Space Telescope/Cosmic Origins Spectrograph. For the first time, we combine two independent models used to quantify the outflow properties for down-the-barrel and transverse absorption. We find that the modeled down-the-barrel deprojected outflow velocities range between V {sub dtb} = 45-255 km s{sup 1}. The transverse bi-conical outflow model, assuming constant-velocity flows perpendicular to the disk, requires wind velocities V {sub outflow} = 40-80 km s{sup 1} to reproduce the transverse Mg II absorption kinematics, which is consistent with the range of V {sub dtb}. The galaxy has a metallicity, derived from H? and N II, of [O/H] = 0.21 0.08, whereas the transverse absorption has [X/H] = 1.12 0.02. The galaxy star formation rate is constrained between 4.6-15 M {sub ?} yr{sup 1} while the estimated outflow rate ranges between 1.6-4.2 M {sub ?} yr{sup 1} and yields a wind loading factor ranging between 0.1-0.9. The galaxy and gas metallicities, the galaxy-quasar sight-line geometry, and the down-the-barrel and transverse modeled outflow velocities collectively suggest that the transverse gas originates from ongoing outflowing material from the galaxy. The ?1 dex decrease in metallicity from the base of the outflow to the outer halo suggests metal dilution of the gas by the time it reached 58 kpc.

  19. Carbon Dioxide Sealing Capacity: Textural or Compositional Controls?

    SciTech Connect (OSTI)

    Cranganu, Constantin; Soleymani, Hamidreza; Sadiqua, Soleymani; Watson, Kieva

    2013-11-30

    This research project is aiming to assess the carbon dioxide sealing capacity of most common seal-rocks, such as shales and non-fractured limestones, by analyzing the role of textural and compositional parameters of those rocks. We hypothesize that sealing capacity is controlled by textural and/or compositional pa-rameters of caprocks. In this research, we seek to evaluate the importance of textural and compositional parameters affecting the sealing capacity of caprocks. The conceptu-al framework involves two testable end-member hypotheses concerning the sealing ca-pacity of carbon dioxide reservoir caprocks. Better understanding of the elements controlling sealing quality will advance our knowledge regarding the sealing capacity of shales and carbonates. Due to relatively low permeability, shale and non-fractured carbonate units are considered relatively imper-meable formations which can retard reservoir fluid flow by forming high capillary pres-sure. Similarly, these unites can constitute reliable seals for carbon dioxide capture and sequestration purposes. This project is a part of the comprehensive project with the final aim of studying the caprock sealing properties and the relationship between microscopic and macroscopic characteristics of seal rocks in depleted gas fields of Oklahoma Pan-handle. Through this study we examined various seal rock characteristics to infer about their respective effects on sealing capacity in special case of replacing reservoir fluid with super critical carbon dioxide (scCO{sub 2}). To assess the effect of textural and compositional properties on scCO{sub 2} maximum reten-tion column height we collected 30 representative core samples in caprock formations in three counties (Cimarron, Texas, Beaver) in Oklahoma Panhandle. Core samples were collected from various seal formations (e.g., Cherokee, Keys, Morrowan) at different depths. We studied the compositional and textural properties of the core samples using several techniques. Mercury Injection Porosimetry (MIP), Scanning Electron Microsco-py SEM, and Sedigraph measurements are used to assess the pore-throat-size distribu-tion, sorting, texture, and grain size of the samples. Also, displacement pressure at 10% mercury saturation (Pd) and graphically derived threshold pressure (Pc) were deter-mined by MIP technique. SEM images were used for qualitative study of the minerals and pores texture of the core samples. Moreover, EDS (Energy Dispersive X-Ray Spec-trometer), BET specific surface area, and Total Organic Carbon (TOC) measurements were performed to study various parameters and their possible effects on sealing capaci-ty of the samples. We found that shales have the relatively higher average sealing threshold pressure (Pc) than carbonate and sandstone samples. Based on these observations, shale formations could be considered as a promising caprock in terms of retarding scCO{sub 2} flow and leak-age into above formations. We hypothesized that certain characteristics of shales (e.g., 3 fine pore size, pore size distribution, high specific surface area, and strong physical chemical interaction between wetting phase and mineral surface) make them an effi-cient caprock for sealing super critical CO{sub 2}. We found that the displacement pressure at 10% mercury saturation could not be the ultimate representative of the sealing capacity of the rock sample. On the other hand, we believe that graphical method, introduced by Cranganu (2004) is a better indicator of the true sealing capacity. Based on statistical analysis of our samples from Oklahoma Panhandle we assessed the effects of each group of properties (textural and compositional) on maximum supercriti-cal CO{sub 2} height that can be hold by the caprock. We conclude that there is a relatively strong positive relationship (+.40 to +.69) between supercritical CO{sub 2} column height based on Pc and hard/ soft mineral content index (ratio of minerals with Mohs hardness more than 5 over minerals with Mohs hardness less than 5) in both shales and limestone samples. Average median pore radius and porosity display a strong negative correlation with supercritical CO{sub 2} retention column height. Also, increasing bulk density is positive-ly correlated with the supercritical CO{sub 2} retention column height. One of the most im-portant factors affecting sealing capacity and consequently the height of supercritical CO{sub 2} column is sorting of the pore throats. We observed a strong positive correlation be-tween pore throat sorting and height of CO{sub 2} retention column, especially in shales. This correlation could not be observed in limestone samples. It suggests that the pore throat sorting is more controlling the sealing capacity in shales and shales with well sorted pore throats are the most reliable lithology as seal. We observed that Brunauer–Emmett–Teller (BET) surface area shows a very strong correlation with CO{sub 2} retention column height in limestone samples while BET surface area did not display significant correlation in shales. Pore structure based on SEM mi-crographs exhibits strong correlation with CO{sub 2} retention column height in limestones. Both intercrystalline and vuggy structures have negative correlations while intergranu-lar texture has positive correlation in limestone with respect to CO{sub 2} retention column height. Textural effects observed on SEM micrographs did not show statistically signifi-cant correlation with supercritical CO{sub 2} retention column height in shale samples. Finally, we showed that increasing hard/soft mineral index is strongly correlated with the displacement pressure in limestone samples. Vuggy texture displays a relatively strong and negative correlation with displacement pressure values at 10% mercury satu-ration in shale samples.