National Library of Energy BETA

Sample records for group supernova cosmology

  1. Cosmological and supernova neutrinos

    SciTech Connect

    Kajino, T. [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan Department of Astronomy, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033 (Japan); Aoki, W. [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Balantekin, A. B. [Department of Physics, University of Wisconsin - Madison, Wisconsin 53706 (United States); Cheoun, M.-K. [Department of Physics, Soongsil University, Seoul 156-743 (Korea, Republic of); Hayakawa, T. [Japan Atomic Energy Agency, Shirakara-Shirane 2-4, Tokai-mura, Ibaraki 319-1195 (Japan); Hidaka, J. [National Astronomical Observatory, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Hirai, Y.; Shibagaki, S. [National Astronomical Observatory, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan and Department of Astronomy, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033 (Japan); Kusakabe, M. [School of Liberal Arts and Science, Korea Aerospace University, Goyang 412-791 (Korea, Republic of); Mathews, G. J. [Department of Physics, University of Notre Dame, IN 46556 (United States); Nakamura, K. [Waseda University, Ohkubo 3-4-1, Shinjuku, Tokyo 169-8555 (Japan); Pehlivan, Y. [Mimar Sinan GS, Department of Physics, ?i?li, ?stanbul 34380 (Turkey); Suzuki, T. [Nihon University, Sakurajosui 3-25-40, Setagaya-ku, Tokyo 156-8550 (Japan)

    2014-06-24

    The Big Bang nucleosynthesis (BBN) and the cosmic microwave background (CMB) anisotropies are the pillars of modern cosmology. It has recently been suggested that axion which is a dark matter candidate in the framework of the standard model could condensate in the early universe and induce photon cooling before the epoch of the photon last scattering. Although this may render a solution to the overproduction problem of primordial {sup 7}Li abundance, there arises another serious difficulty of overproducing D abundance. We propose a hybrid dark matter model with both axions and relic supersymmetric (SUSY) particles to solve both overproduction problems of the primordial D and {sup 7}Li abundances simultaneously. The BBN also serves to constrain the nature of neutrinos. Considering non-thermal photons produced in the decay of the heavy sterile neutrinos due to the magnetic moment, we explore the cosmological constraint on the strength of neutrino magnetic moment consistent with the observed light element abundances. Core-collapse supernovae eject huge flux of energetic neutrinos which affect explosive nucleosynthesis of rare isotopes like {sup 7}Li, {sup 11}B, {sup 92}Nb, {sup 138}La and {sup 180}Ta and r-process elements. Several isotopes depend strongly on the neutrino flavor oscillation due to the Mikheyev-Smirnov-Wolfenstein (MSW) effect. Combining the recent experimental constraints on ?{sub 13} with predicted and observed supernova-produced abundance ratio {sup 11}B/{sup 7}Li encapsulated in the presolar grains from the Murchison meteorite, we show a marginal preference for an inverted neutrino mass hierarchy. We also discuss supernova relic neutrinos (SRN) that may indicate the softness of the equation of state (EoS) of nuclear matter and adiabatic conditions of the neutrino oscillation.

  2. Ideal bandpasses for type Ia supernova cosmology

    SciTech Connect

    Davis, Tamara M.; Schmidt, Brian P.; Kim, Alex G.

    2005-10-24

    To use type Ia supernovae as standard candles for cosmologywe need accurate broadband magnitudes. In practice the observed magnitudemay differ from the ideal magnitude-redshift relationship either throughintrinsic inhomogeneities in the type Ia supernova population or throughobservational error. Here we investigate how we can choose filterbandpasses to reduce the error caused by both these effects. We find thatbandpasses with large integral fluxes and sloping wings are best able tominimise several sources of observational error, and are also leastsensitive to intrinsic differences in type Ia supernovae. The mostimportant feature of a complete filter set for type Ia supernovacosmology is that each bandpass be a redshifted copy of the first. Wedesign practical sets of redshifted bandpasses that are matched totypical high resistivity CCD and HgCdTe infra-red detector sensitivities.These are designed to minimise systematic error in well observedsupernovae, final designs for specific missions should also considersignal-to-noise requirements and observing strategy. In addition wecalculate how accurately filters need to be calibrated in order toachieve the required photometric accuracy of future supernova cosmologyexperiments such as the SuperNova-Acceleration-Probe (SNAP), which is onepossible realisation of the Joint Dark-Energy mission (JDEM). We considerthe effect of possible periodic miscalibrations that may arise from theconstruction of an interference filter.

  3. COSMOLOGICAL PARAMETERS FROM SUPERNOVAE ASSOCIATED WITH GAMMA-RAY BURSTS

    SciTech Connect

    Li, Xue; Hjorth, Jens; Wojtak, Rados?aw, E-mail: lixue@dark-cosmology.dk [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark)

    2014-11-20

    We report estimates of the cosmological parameters ? {sub m} and ?{sub ?} obtained using supernovae (SNe) associated with gamma-ray bursts (GRBs) at redshifts up to 0.606. Eight high-fidelity GRB-SNe with well-sampled light curves across the peak are used. We correct their peak magnitudes for a luminosity-decline rate relation to turn them into accurate standard candles with dispersion ? = 0.18mag. We also estimate the peculiar velocity of the low-redshift host galaxy of SN 1998bw using constrained cosmological simulations. In a flat universe, the resulting Hubble diagram leads to best-fit cosmological parameters of (?{sub m},?{sub ?})=(0.58{sub ?0.25}{sup +0.22},0.42{sub ?0.22}{sup +0.25}). This exploratory study suggests that GRB-SNe can potentially be used as standardizable candles to high redshifts to measure distances in the universe and constrain cosmological parameters.

  4. Consistent use of type Ia supernovae highly magnified by galaxy clusters to constrain the cosmological parameters

    SciTech Connect

    Zitrin, Adi [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, MS 249-17, Pasadena, CA 91125 (United States); Redlich, Matthias [Universitt Heidelberg, Zentrum fr Astronomie, Institut fr Theoretische Astrophysik, Philosophenweg 12, D-69120 Heidelberg (Germany); Broadhurst, Tom, E-mail: adizitrin@gmail.com [Department of Theoretical Physics, University of Basque Country UPV/EHU, Bilbao (Spain)

    2014-07-01

    We discuss how Type Ia supernovae (SNe) strongly magnified by foreground galaxy clusters should be self-consistently treated when used in samples fitted for the cosmological parameters. While the cluster lens magnification of a SN can be well constrained from sets of multiple images of various background galaxies with measured redshifts, its value is typically dependent on the fiducial set of cosmological parameters used to construct the mass model. In such cases, one should not naively demagnify the observed SN luminosity by the model magnification into the expected Hubble diagram, which would create a bias, but instead take into account the cosmological parameters a priori chosen to construct the mass model. We quantify the effect and find that a systematic error of typically a few percent, up to a few dozen percent per magnified SN may be propagated onto a cosmological parameter fit unless the cosmology assumed for the mass model is taken into account (the bias can be even larger if the SN is lying very near the critical curves). We also simulate how such a bias propagates onto the cosmological parameter fit using the Union2.1 sample supplemented with strongly magnified SNe. The resulting bias on the deduced cosmological parameters is generally at the few percent level, if only few biased SNe are included, and increases with the number of lensed SNe and their redshift. Samples containing magnified Type Ia SNe, e.g., from ongoing cluster surveys, should readily account for this possible bias.

  5. Optimal Extraction of Cosmological Information from Supernova Datain the Presence of Calibration Uncertainties

    SciTech Connect

    Kim, Alex G.; Miquel, Ramon

    2005-09-26

    We present a new technique to extract the cosmological information from high-redshift supernova data in the presence of calibration errors and extinction due to dust. While in the traditional technique the distance modulus of each supernova is determined separately, in our approach we determine all distance moduli at once, in a process that achieves a significant degree of self-calibration. The result is a much reduced sensitivity of the cosmological parameters to the calibration uncertainties. As an example, for a strawman mission similar to that outlined in the SNAP satellite proposal, the increased precision obtained with the new approach is roughly equivalent to a factor of five decrease in the calibration uncertainty.

  6. Supernova Simulations from the T-6 Group at Los Alamos National...

    Office of Scientific and Technical Information (OSTI)

    Supernova Simulations from the T-6 Group at Los Alamos National Laboratory (LANL) Title: Supernova Simulations from the T-6 Group at Los Alamos National Laboratory (LANL) LANL's ...

  7. Supernova Simulations from the T-6 Group at Los Alamos National...

    Office of Scientific and Technical Information (OSTI)

    Data Explorer Search Results Supernova Simulations from the T-6 Group at Los Alamos National Laboratory (LANL) Title: Supernova Simulations from the T-6 Group at Los Alamos ...

  8. Stochastic gravitational-wave background from cosmological supernovae

    SciTech Connect

    Buonanno, Alessandra; Sigl, Guenter; Raffelt, Georg G.; Janka, Hans-Thomas; Mueller, Ewald

    2005-10-15

    Based on new developments in the understanding of supernovae (SNe) as gravitational-wave (GW) sources we estimate the GW background from all cosmic SNe. For a broad range of frequencies around 1 Hz, this background is crudely comparable to the GW background expected from standard inflationary models. While our estimate remains uncertain within several orders of magnitude, the SN GW background may become detectable by second-generation space-based interferometers such as the proposed Big Bang Observatory (BBO). By the same token, the SN GWs may become a foreground for searches of the inflationary GWs, in particular, for sub-Hz frequencies where the SN background is Gaussian and where the BBO will be most sensitive. SN simulations lasting far beyond the usual cutoff of about 1 s are needed for more robust predictions in the sub-Hz frequency band. An even larger GW background can arise from a hypothetical early population of massive stars, although their GW source strength as well as their abundance are currently poorly understood.

  9. Supernova Simulations from the T-6 Group at Los Alamos National Laboratory

    Office of Scientific and Technical Information (OSTI)

    (LANL) () | Data Explorer Simulations from the T-6 Group at Los Alamos National Laboratory (LANL) Title: Supernova Simulations from the T-6 Group at Los Alamos National Laboratory (LANL) LANL's primary effort to numerically model supernova explosions is based in the Theoretical Astrophysics Group (T-6). Both thermonuclear supernovae and core- collapse supernovae are studied, with special emphasis placed on multi-dimensional simulations. Both types of supernova require a wide range of input

  10. Type IIP supernovae as cosmological probes: A SEAM distance to SN1999em

    SciTech Connect

    Baron, E.; Nugent, Peter E.; Branch, David; Hauschildt, Peter H.

    2004-06-01

    Because of their intrinsic brightness, supernovae make excellent cosmological probes. We describe the spectral-fitting expanding atmosphere method (SEAM) for obtaining distances to Type IIP supernovae (SNe IIP) and present a distance to SN 1999em for which a Cepheid distance exists. Our models give results consistent with the Cepheid distance, even though we have not attempted to tune the underlying hydrodynamical model but have simply chosen the best fits. This is in contradistinction to the expanding photosphere method (EPM), which yields a distance to SN 1999em that is 50 percent smaller than the Cepheid distance. We emphasize the differences between the SEAM and the EPM. We show that the dilution factors used in the EPM analysis were systematically too small at later epochs. We also show that the EPM blackbody assumption is suspect. Since SNe IIP are visible to redshifts as high as z {approx}< 6, with the James Webb Space Telescope, the SEAM may be a valuable probe of the early universe.

  11. Cosmological parameter uncertainties from SALT-II type Ia supernova light curve models

    SciTech Connect

    Mosher, J.; Sako, M. [Department of Physics and Astronomy, University of Pennsylvania, 209 South 33rd Street, Philadelphia, PA 19104 (United States); Guy, J.; Astier, P.; Betoule, M.; El-Hage, P.; Pain, R.; Regnault, N. [LPNHE, CNRS/IN2P3, Universit Pierre et Marie Curie Paris 6, Universi Denis Diderot Paris 7, 4 place Jussieu, F-75252 Paris Cedex 05 (France); Kessler, R.; Frieman, J. A. [Kavli Institute for Cosmological Physics, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 (United States); Marriner, J. [Center for Particle Astrophysics, Fermi National Accelerator Laboratory, P.O. Box 500, Batavia, IL 60510 (United States); Biswas, R.; Kuhlmann, S. [Argonne National Laboratory, 9700 South Cass Avenue, Lemont, IL 60439 (United States); Schneider, D. P., E-mail: kessler@kicp.chicago.edu [Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802 (United States)

    2014-09-20

    We use simulated type Ia supernova (SN Ia) samples, including both photometry and spectra, to perform the first direct validation of cosmology analysis using the SALT-II light curve model. This validation includes residuals from the light curve training process, systematic biases in SN Ia distance measurements, and a bias on the dark energy equation of state parameter w. Using the SN-analysis package SNANA, we simulate and analyze realistic samples corresponding to the data samples used in the SNLS3 analysis: ?120 low-redshift (z < 0.1) SNe Ia, ?255 Sloan Digital Sky Survey SNe Ia (z < 0.4), and ?290 SNLS SNe Ia (z ? 1). To probe systematic uncertainties in detail, we vary the input spectral model, the model of intrinsic scatter, and the smoothing (i.e., regularization) parameters used during the SALT-II model training. Using realistic intrinsic scatter models results in a slight bias in the ultraviolet portion of the trained SALT-II model, and w biases (w {sub input} w {sub recovered}) ranging from 0.005 0.012 to 0.024 0.010. These biases are indistinguishable from each other within the uncertainty; the average bias on w is 0.014 0.007.

  12. Grouping normal type Ia supernovae by UV to optical color differences

    SciTech Connect

    Milne, Peter A.; Brown, Peter J.; Roming, Peter W. A.; Bufano, Filomena; Gehrels, Neil

    2013-12-10

    Observations of many Type Ia supernovae (SNe Ia) for multiple epochs per object with the Swift Ultraviolet Optical Telescope instrument have revealed that there exists order to the differences in the UV-optical colors of optically normal supernovae (SNe). We examine UV-optical color curves for 23 SNe Ia, dividing the SNe into four groups, and find that roughly one-third of 'NUV-blue' SNe Ia have bluer UV-optical colors than the larger 'NUV-red' group. Two minor groups are recognized, 'MUV-blue' and 'irregular' SNe Ia. While we conclude that the latter group is a subset of the NUV-red group, containing the SNe with the broadest optical peaks, we conclude that the 'MUV-blue' group is a distinct group. Separating into the groups and accounting for the time evolution of the UV-optical colors lowers the scatter in two NUV-optical colors (e.g., u – v and uvw1 – v) to the level of the scatter in b – v. This finding is promising for extending the cosmological utilization of SNe Ia into the NUV. We generate spectrophotometry of 33 SNe Ia and determine the correct grouping for each. We argue that there is a fundamental spectral difference in the 2900-3500 Å wavelength range, a region suggested to be dominated by absorption from iron-peak elements. The NUV-blue SNe Ia feature less absorption than the NUV-red SNe Ia. We show that all NUV-blue SNe Ia in this sample also show evidence of unburned carbon in optical spectra, whereas only one NUV-red SN Ia features that absorption line. Every NUV-blue event also exhibits a low gradient of the Si II λ6355 absorption feature. Many NUV-red events also exhibit a low gradient, perhaps suggestive that NUV-blue events are a subset of the larger low-velocity gradient group.

  13. On silicon group elements ejected by supernovae type IA

    SciTech Connect

    De, Soma; Timmes, F. X. [School of Earth and Space Exploration, Arizona State University, Tempe, AZ (United States); Brown, Edward F. [Joint Institute for Nuclear Astrophysics, University of Notre Dame, IN 46556 (United States); Calder, Alan C. [Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY (United States); Townsley, Dean M. [Department of Physics and Astronomy, The University of Alabama, Tuscaloosa, AL (United States); Athanassiadou, Themis [Swiss National Supercomputing Centre, Via Trevano 131, 6900 Lugano (Switzerland); Chamulak, David A. [Physics Division, Argonne National Laboratory, Argonne, IL (United States); Hawley, Wendy [Laboratoire d'Astrophysique de Marseille, Marseille cedex 13 F-13388 (France); Jack, Dennis, E-mail: somad@asu.edu [Departamento de Astronoma, Universidad de Guanajuato, Apartado Postal 144, 36000 Guanajuato (Mexico)

    2014-06-01

    There is evidence that the peak brightness of a Type Ia supernova is affected by the electron fraction Y {sub e} at the time of the explosion. The electron fraction is set by the aboriginal composition of the white dwarf and the reactions that occur during the pre-explosive convective burning. To date, determining the makeup of the white dwarf progenitor has relied on indirect proxies, such as the average metallicity of the host stellar population. In this paper, we present analytical calculations supporting the idea that the electron fraction of the progenitor systematically influences the nucleosynthesis of silicon group ejecta in Type Ia supernovae. In particular, we suggest the abundances generated in quasi-nuclear statistical equilibrium are preserved during the subsequent freeze-out. This allows potential recovery of Y {sub e} at explosion from the abundances recovered from an observed spectra. We show that measurement of {sup 28}Si, {sup 32}S, {sup 40}Ca, and {sup 54}Fe abundances can be used to construct Y {sub e} in the silicon-rich regions of the supernovae. If these four abundances are determined exactly, they are sufficient to recover Y {sub e} to 6%. This is because these isotopes dominate the composition of silicon-rich material and iron-rich material in quasi-nuclear statistical equilibrium. Analytical analysis shows the {sup 28}Si abundance is insensitive to Y {sub e}, the {sup 32}S abundance has a nearly linear trend with Y {sub e}, and the {sup 40}Ca abundance has a nearly quadratic trend with Y {sub e}. We verify these trends with post-processing of one-dimensional models and show that these trends are reflected in the model's synthetic spectra.

  14. Supernova Simulations from the T-6 Group at Los Alamos National Laboratory (LANL)

    DOE Data Explorer

    Woosley, Stanford

    LANL's primary effort to numerically model supernova explosions is based in the Theoretical Astrophysics Group (T-6). Both thermonuclear supernovae and core- collapse supernovae are studied, with special emphasis placed on multi-dimensional simulations. Both types of supernova require a wide range of input physics, which is provided by research efforts throughout the lab. In particular this research benefits from other LANL efforts studying massive star evolution, equations of state and aspects of neutrino physics. [From http://laastro.lanl.gov/science/computation.html

  15. Systematic uncertainties associated with the cosmological analysis of the first Pan-STARRS1 type Ia supernova sample

    SciTech Connect

    Scolnic, D.; Riess, A.; Brout, D.; Rodney, S. [Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States); Rest, A. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Huber, M. E.; Tonry, J. L. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Foley, R. J.; Chornock, R.; Berger, E.; Soderberg, A. M.; Stubbs, C. W.; Kirshner, R. P.; Challis, P.; Czekala, I.; Drout, M. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Narayan, G. [Department of Physics, Harvard University, 17 Oxford Street, Cambridge, MA 02138 (United States); Smartt, S. J.; Botticella, M. T. [Astrophysics Research Centre, School of Mathematics and Physics, Queens University Belfast, Belfast BT7 1NN (United Kingdom); Schlafly, E. [Max Planck Institute for Astronomy, Konigstuhl 17, D-69117 Heidelberg (Germany); and others

    2014-11-01

    We probe the systematic uncertainties from the 113 Type Ia supernovae (SN Ia) in the Pan-STARRS1 (PS1) sample along with 197 SN Ia from a combination of low-redshift surveys. The companion paper by Rest et al. describes the photometric measurements and cosmological inferences from the PS1 sample. The largest systematic uncertainty stems from the photometric calibration of the PS1 and low-z samples. We increase the sample of observed Calspec standards from 7 to 10 used to define the PS1 calibration system. The PS1 and SDSS-II calibration systems are compared and discrepancies up to ?0.02 mag are recovered. We find uncertainties in the proper way to treat intrinsic colors and reddening produce differences in the recovered value of w up to 3%. We estimate masses of host galaxies of PS1 supernovae and detect an insignificant difference in distance residuals of the full sample of 0.037 0.031 mag for host galaxies with high and low masses. Assuming flatness and including systematic uncertainties in our analysis of only SNe measurements, we find w =?1.120{sub ?0.206}{sup +0.360}(Stat){sub ?0.291}{sup +0.269}(Sys). With additional constraints from Baryon acoustic oscillation, cosmic microwave background (CMB) (Planck) and H {sub 0} measurements, we find w=?1.166{sub ?0.069}{sup +0.072} and ?{sub m}=0.280{sub ?0.012}{sup +0.013} (statistical and systematic errors added in quadrature). The significance of the inconsistency with w = 1 depends on whether we use Planck or Wilkinson Microwave Anisotropy Probe measurements of the CMB: w{sub BAO+H0+SN+WMAP}=?1.124{sub ?0.065}{sup +0.083}.

  16. THE KINEMATICS OF THE LOCAL GROUP IN A COSMOLOGICAL CONTEXT

    SciTech Connect

    Forero-Romero, J. E.; Hoffman, Y.; Bustamante, S.; Gottloeber, S.; Yepes, G.

    2013-04-10

    Recent observations constrained the tangential velocity of M31 with respect to the Milky Way to be v{sub M31,tan} < 34.4 km s{sup -1}and the radial velocity to be in the range v{sub M31,rad} = -109 {+-} 4.4 km s{sup -1}. In this study we use a large volume high-resolution N-body cosmological simulation (Bolshoi) together with three constrained simulations to statistically study this kinematics in the context of the {Lambda} cold dark matter ({Lambda}CDM). The comparison of the ensembles of simulated pairs with the observed Local Group (LG) at the 1{sigma} level in the uncertainties has been done with respect to the radial and tangential velocities, the reduced orbital energy (e{sub tot}), angular momentum (l{sub orb}), and the dimensionless spin parameter, {lambda}. Our main results are (1) the preferred radial and tangential velocities for pairs in {Lambda}CDM are v{sub r} = -80 {+-} 20 km s{sup -1} and v{sub t} = 50 {+-} 10 km s{sup -1}, (2) pairs around that region are 3-13 times more common than pairs within the observational values, (3) 15%-24% of LG-like pairs in {Lambda}CDM have energy and angular momentum consistent with observations, while (4) 9%-13% of pairs in the same sample show similar values in the inferred dimensionless spin parameter. It follows that within current observational uncertainties the quasi-conserved quantities that characterize the orbit of the LG, i.e., e{sub tot}, l{sub orb}, and {lambda}, do not challenge the standard {Lambda}CDM model, but the model is in tension with regard to the actual values of the radial and tangential velocities. This might hint to a problem of the {Lambda}CDM model to reproduce the observed LG.

  17. Systematic Effects in Type-1a Supernovae Surveys from Host Galaxy...

    Office of Scientific and Technical Information (OSTI)

    Systematic Effects in Type-1a Supernovae Surveys from Host Galaxy Spectra Strauss, Michael A. Princeton University 79 ASTRONOMY AND ASTROPHYSICS Cosmology, supernovae, stellar...

  18. Cosmological constraints from measurements of type Ia supernovae discovered during the first 1.5 yr of the Pan-STARRS1 survey

    SciTech Connect

    Rest, A.; Scolnic, D.; Riess, A.; Rodney, S.; Brout, D.; Foley, R. J.; Chornock, R.; Berger, E.; Soderberg, A. M.; Stubbs, C. W.; Kirshner, R. P.; Challis, P.; Czekala, I.; Drout, M.; Huber, M. E.; Tonry, J. L.; Narayan, G.; Smartt, S. J.; Schlafly, E.; Botticella, M. T.; and others

    2014-11-01

    We present griz {sub P1} light curves of 146 spectroscopically confirmed Type Ia supernovae (SNe Ia; 0.03 < z < 0.65) discovered during the first 1.5 yr of the Pan-STARRS1 Medium Deep Survey. The Pan-STARRS1 natural photometric system is determined by a combination of on-site measurements of the instrument response function and observations of spectrophotometric standard stars. We find that the systematic uncertainties in the photometric system are currently 1.2% without accounting for the uncertainty in the Hubble Space Telescope Calspec definition of the AB system. A Hubble diagram is constructed with a subset of 113 out of 146 SNe Ia that pass our light curve quality cuts. The cosmological fit to 310 SNe Ia (113 PS1 SNe Ia + 222 light curves from 197 low-z SNe Ia), using only supernovae (SNe) and assuming a constant dark energy equation of state and flatness, yields w=−1.120{sub −0.206}{sup +0.360}(Stat){sub −0.291}{sup +0.269}(Sys). When combined with BAO+CMB(Planck)+H {sub 0}, the analysis yields Ω{sub M}=0.280{sub −0.012}{sup +0.013} and w=−1.166{sub −0.069}{sup +0.072} including all identified systematics. The value of w is inconsistent with the cosmological constant value of –1 at the 2.3σ level. Tension endures after removing either the baryon acoustic oscillation (BAO) or the H {sub 0} constraint, though it is strongest when including the H {sub 0} constraint. If we include WMAP9 cosmic microwave background (CMB) constraints instead of those from Planck, we find w=−1.124{sub −0.065}{sup +0.083}, which diminishes the discord to <2σ. We cannot conclude whether the tension with flat ΛCDM is a feature of dark energy, new physics, or a combination of chance and systematic errors. The full Pan-STARRS1 SN sample with ∼three times as many SNe should provide more conclusive results.

  19. Supernova Twins: Making Standard Candles More Standard Than Ever

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    Supernova Twins: Making Standard Candles More Standard Than Ever Supernova Twins: Making Standard Candles More Standard Than Ever New Modeling Method Measures Cosmological Distances With Far Greater Accuracy January 13, 2016 Contact: Paul Preuss, paul_preuss@lbl.gov, +1 415 272 3253 supernovatwins From left, Greg Aldering, Kyle Boone, Hannah Fakhouri and Saul Perlmutter of the Nearby Supernova Factory. Behind them is a poster of a supernova spectrum. Matching spectra among different supernovae

  20. The Distant Type Ia Supernova Rate

    DOE R&D Accomplishments

    Pain, R.; Fabbro, S.; Sullivan, M.; Ellis, R. S.; Aldering, G.; Astier, P.; Deustua, S. E.; Fruchter, A. S.; Goldhaber, G.; Goobar, A.; Groom, D. E.; Hardin, D.; Hook, I. M.; Howell, D. A.; Irwin, M. J.; Kim, A. G.; Kim, M. Y.; Knop, R. A.; Lee, J. C.; Perlmutter, S.; Ruiz-Lapuente, P.; Schahmaneche, K.; Schaefer, B.; Walton, N. A.

    2002-05-28

    We present a measurement of the rate of distant Type Ia supernovae derived using 4 large subsets of data from the Supernova Cosmology Project. Within this fiducial sample, which surveyed about 12 square degrees, thirty-eight supernovae were detected at redshifts 0.25--0.85. In a spatially flat cosmological model consistent with the results obtained by the Supernova Cosmology Project, we derive a rest-frame Type Ia supernova rate at a mean red shift z {approx_equal} 0.55 of 1.53 {sub -0.25}{sub -0.31}{sup 0.28}{sup 0.32} x 10{sup -4} h{sup 3} Mpc{sup -3} yr{sup -1} or 0.58{sub -0.09}{sub -0.09}{sup +0.10}{sup +0.10} h{sup 2} SNu(1 SNu = 1 supernova per century per 10{sup 10} L{sub B}sun), where the first uncertainty is statistical and the second includes systematic effects. The dependence of the rate on the assumed cosmological parameters is studied and the redshift dependence of the rate per unit comoving volume is contrasted with local estimates in the context of possible cosmic star formation histories and progenitor models.

  1. Defining photometric peculiar type Ia supernovae

    SciTech Connect

    González-Gaitán, S.; Pignata, G.; Förster, F.; Gutiérrez, C. P.; Bufano, F.; Galbany, L.; Hamuy, M.; De Jaeger, T.; Hsiao, E. Y.; Phillips, M. M.; Folatelli, G.; Anderson, J. P.

    2014-11-10

    We present a new photometric identification technique for SN 1991bg-like type Ia supernovae (SNe Ia), i.e., objects with light curve characteristics such as later primary maxima and the absence of a secondary peak in redder filters. This method is capable of selecting this sub-group from the normal type Ia population. Furthermore, we find that recently identified peculiar sub-types such as SNe Iax and super-Chandrasekhar SNe Ia have photometric characteristics similar to 91bg-like SNe Ia, namely, the absence of secondary maxima and shoulders at longer wavelengths, and can also be classified with our technique. The similarity of these different SN Ia sub-groups perhaps suggests common physical conditions. This typing methodology permits the photometric identification of peculiar SNe Ia in large upcoming wide-field surveys either to study them further or to obtain a pure sample of normal SNe Ia for cosmological studies.

  2. Testing the copernican principle via cosmological observations

    SciTech Connect

    Bolejko, Krzysztof; Wyithe, J. Stuart B. E-mail: swyithe@unimelb.edu.au

    2009-02-15

    Observations of distances to Type-Ia supernovae can be explained by cosmological models that include either a gigaparsec-scale void, or a cosmic flow, without the need for Dark Energy. Instead of invoking dark energy, these inhomogeneous models instead violate the Copernican Principle. we show that current cosmological observations (Supernovae, Baryon Acoustic Oscillations and estimates of the Hubble parameters based on the age of the oldest stars) are not able to rule out inhomogeneous anti-Copernican models. The next generation of surveys for baryonic acoustic oscillations will be sufficiently precise to either validate the Copernican Principle or determine the existence of a local Gpc scale inhomogeneity.

  3. Scrutinizing Exotic Cosmological Models Using ESSENCE Supernova...

    Office of Scientific and Technical Information (OSTI)

    and Akaike information criteria are applied to gauge the worth of models. These statistics favor models that give a good fit with fewer parameters. Based on this analysis, the...

  4. Scrutinizing Exotic Cosmological Models Using ESSENCE Supernova...

    Office of Scientific and Technical Information (OSTI)

    ; Schmidt, B.P. ; Bohr Inst. Stockholm U. Washington U., Seattle, Astron. Dept. Harvard-Smithsonian Ctr. Astrophys. Chile U., Catolica UC, Berkeley, Astron. Dept. Notre...

  5. Cosmology with matter diffusion

    SciTech Connect

    Calogero, Simone; Velten, Hermano E-mail: velten@cce.ufes.br

    2013-11-01

    We construct a viable cosmological model based on velocity diffusion of matter particles. In order to ensure the conservation of the total energy-momentum tensor in the presence of diffusion, we include a cosmological scalar field ? which we identify with the dark energy component of the universe. The model is characterized by only one new degree of freedom, the diffusion parameter ?. The standard ?CDM model can be recovered by setting ? = 0. If diffusion takes place (? > 0) the dynamics of the matter and of the dark energy fields are coupled. We argue that the existence of a diffusion mechanism in the universe may serve as a theoretical motivation for interacting models. We constrain the background dynamics of the diffusion model with Supernovae, H(z) and BAO data. We also perform a perturbative analysis of this model in order to understand structure formation in the universe. We calculate the impact of diffusion both on the CMB spectrum, with particular attention to the integrated Sachs-Wolfe signal, and on the matter power spectrum P(k). The latter analysis places strong constraints on the magnitude of the diffusion mechanism but does not rule out the model.

  6. Observational constraints on late-time {lambda}(t) cosmology

    SciTech Connect

    Carneiro, S.; Pigozzo, C.; Dantas, M. A.; Alcaniz, J. S.

    2008-04-15

    The cosmological constant {lambda}, i.e., the energy density stored in the true vacuum state of all existing fields in the Universe, is the simplest and the most natural possibility to describe the current cosmic acceleration. However, despite its observational successes, such a possibility exacerbates the well-known {lambda} problem, requiring a natural explanation for its small, but nonzero, value. In this paper we study cosmological consequences of a scenario driven by a varying cosmological term, in which the vacuum energy density decays linearly with the Hubble parameter, {lambda}{proportional_to}H. We test the viability of this scenario and study a possible way to distinguish it from the current standard cosmological model by using recent observations of type Ia supernova (Supernova Legacy Survey Collaboration), measurements of the baryonic acoustic oscillation from the Sloan Digital Sky Survey, and the position of the first peak of the cosmic microwave background angular spectrum from the three-year Wilkinson Microwave Anisotropy Probe.

  7. SUPERNOVA SIMULATIONS AND STRATEGIES FOR THE DARK ENERGY SURVEY

    SciTech Connect

    Bernstein, J. P.; Kuhlmann, S.; Biswas, R.; Kovacs, E.; Crane, I.; Hufford, T.; Kessler, R.; Frieman, J. A.; Aldering, G.; Kim, A. G.; Nugent, P.; D'Andrea, C. B.; Nichol, R. C.; Finley, D. A.; Marriner, J.; Reis, R. R. R.; Jarvis, M. J.; Mukherjee, P.; Parkinson, D.; Sako, M.; and others

    2012-07-10

    We present an analysis of supernova light curves simulated for the upcoming Dark Energy Survey (DES) supernova search. The simulations employ a code suite that generates and fits realistic light curves in order to obtain distance modulus/redshift pairs that are passed to a cosmology fitter. We investigated several different survey strategies including field selection, supernova selection biases, and photometric redshift measurements. Using the results of this study, we chose a 30 deg{sup 2} search area in the griz filter set. We forecast (1) that this survey will provide a homogeneous sample of up to 4000 Type Ia supernovae in the redshift range 0.05 supernova with an identified host galaxy will be obtained from spectroscopic observations of the host. A supernova spectrum will be obtained for a subset of the sample, which will be utilized for control studies. In addition, we have investigated the use of combined photometric redshifts taking into account data from both the host and supernova. We have investigated and estimated the likely contamination from core-collapse supernovae based on photometric identification, and have found that a Type Ia supernova sample purity of up to 98% is obtainable given specific assumptions. Furthermore, we present systematic uncertainties due to sample purity, photometric calibration, dust extinction priors, filter-centroid shifts, and inter-calibration. We conclude by estimating the uncertainty on the cosmological parameters that will be measured from the DES supernova data.

  8. Supernova Hunting with Supercomputers

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    Supernova Hunting with Supercomputers Supernova Hunting with Supercomputers Berkeley researchers provide "roadmap" and tools for finding and studying Type Ia supernovae in their natural habitat May 20, 2015 Contact: Linda Vu, +1 510 495 2402, lvu@lbl.gov sn-star.jpg Simulation of the expanding debris from a supernova explosion (shown in red) running over and shredding a nearby star (shown in blue). Image credit: Daniel Kasen, Berkeley Lab/ UC Berkeley Type Ia supernovae are famous for

  9. Stability analysis in tachyonic potential chameleon cosmology

    SciTech Connect

    Farajollahi, H.; Salehi, A.; Tayebi, F.; Ravanpak, A. E-mail: a.salehi@guilan.ac.ir E-mail: aravanpak@guilan.ac.ir

    2011-05-01

    We study general properties of attractors for tachyonic potential chameleon scalar-field model which possess cosmological scaling solutions. An analytic formulation is given to obtain fixed points with a discussion on their stability. The model predicts a dynamical equation of state parameter with phantom crossing behavior for an accelerating universe. We constrain the parameters of the model by best fitting with the recent data-sets from supernovae and simulated data points for redshift drift experiment generated by Monte Carlo simulations.

  10. Supernova Hunting with Supercomputers

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    star, allowing them to determine the stellar system from which the supernova was born. ... (NERSC), he showed that if a supernova is born in a binary star system, the collision of ...

  11. Evolution of density perturbations in decaying vacuum cosmology

    SciTech Connect

    Borges, H. A.; Pigozzo, C.; Carneiro, S.; Fabris, J. C.

    2008-02-15

    We study cosmological perturbations in the context of an interacting dark energy model, in which the cosmological term decays linearly with the Hubble parameter, with concomitant matter production. A previous joint analysis of the redshift-distance relation for type Ia supernovas, barionic acoustic oscillations, and the position of the first peak in the anisotropy spectrum of the cosmic microwave background has led to acceptable values for the cosmological parameters. Here we present our analysis of small perturbations, under the assumption that the cosmological term, and therefore the matter production, are strictly homogeneous. Such a homogeneous production tends to dilute the matter contrast, leading to a late-time suppression in the power spectrum. Nevertheless, an excellent agreement with the observational data can be achieved by using a higher matter density as compared to the concordance value previously obtained. This may indicate that our hypothesis of homogeneous matter production must be relaxed by allowing perturbations in the interacting cosmological term.

  12. Supernova Discoveries from the Nearby Supernova Factory (SNfactory) () |

    Office of Scientific and Technical Information (OSTI)

    Data Explorer Discoveries from the Nearby Supernova Factory (SNfactory) Title: Supernova Discoveries from the Nearby Supernova Factory (SNfactory) The Nearby Supernova Factory is an experiment designed to collect data on more Type Ia supernovae than have ever been studied in a single project before, and in so doing, to answer some fundamental questions about the nature of the universe. Type Ia supernovae are extraordinarily bright, remarkably uniform objects which make excellent

  13. supernova.jpg | OSTI, US Dept of Energy Office of Scientific and Technical

    Office of Scientific and Technical Information (OSTI)

    Information supernova

  14. Nuclear and Particle Physics, Astrophysics, and Cosmology

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    2 Nuclear and Particle Physics, Astrophysics, and Cosmology Providing scientific and technical leadership in fundamental and applied theoretical research on nuclear, particle, astrophysics, and cosmology theory and simulations Leadership Group Leader Joe Carlson Email Deputy Group Leader Gerry Hale Email Contact Us Administrator Kay Grady Email Administrator Karla Jackson Email Dark sky Simulation of the cosmic web of the dark matter mass distribution. This region represents about 1/10,000 of

  15. Power-law cosmology, SN Ia, and BAO

    SciTech Connect

    Dolgov, Aleksander; Halenka, Vitali; Tkachev, Igor E-mail: vithal@umich.edu

    2014-10-01

    We revise observational constraints on the class of models of modified gravity which at low redshifts lead to a power-law cosmology. To this end we use available public data on Supernova Ia and on baryon acoustic oscillations. We show that the expansion regime a(t)?t{sup ?} with ? close to 3/2 in a spatially flat universe is a good fit to these data.

  16. Supernova Neutrinos, LSND

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    Supernova Neutrinos, LSND and MiniBooNE * Constraints on neutrino oscillations from supernovæ * MiniBooNE as a supernova neutrino detector * MiniBooNE status Michel Sorel Columbia U./MiniBooNE Moriond EW 2002 1 Three good reasons to look for supernova (SN) neutrinos 1. High-energy astrophysicists can learn much about core-collapse SN explosion mechanism from neutrinos ⇒ 99% of SN energy is released in neutrinos 2. Particle physicists can learn much about neutrino masses and mixings 3.

  17. Nucleosynthesis in Thermonuclear Supernovae

    SciTech Connect

    Claudia, Travaglio; Hix, William Raphael

    2013-01-01

    We review our understanding of the nucleosynthesis that occurs in thermonuclear supernovae and their contribution to Galactic Chemical evolution. We discuss the prospects to improve the modeling of the nucleosynthesis within simulations of these events.

  18. Evolution of density perturbations in decaying vacuum cosmology: The case of nonzero perturbations in the cosmological term

    SciTech Connect

    Borges, H. A.; Carneiro, S.; Fabris, J. C.

    2008-12-15

    We extend the results of a previous paper where a model of interacting dark energy, with a cosmological term decaying linearly with the Hubble parameter, is tested against the observed mass power spectrum. In spite of the agreement with observations of type Ia supernovas, baryonic acoustic oscillations, and the cosmic microwave background, we had shown previously that no good concordance is achieved if we include the mass power spectrum. However, our analysis was based on the ad hoc assumption that the interacting cosmological term is strictly homogeneous. Now we perform a more complete analysis, by perturbing such a term. Although our conclusions are still based on a particular, scale-invariant choice of the primordial spectrum of dark energy perturbations, we show that a cosmological term decaying linearly with the Hubble parameter is indeed disfavored as compared to the standard model.

  19. The Carnegie Supernova Project: Intrinsic colors of type Ia supernovae

    SciTech Connect

    Burns, Christopher R.; Persson, S. E.; Freedman, Wendy L.; Madore, Barry F. [Observatories of the Carnegie Institution for Science, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Stritzinger, Maximilian; Contreras, Carlos [Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C (Denmark); Phillips, M. M.; Hsiao, E. Y.; Boldt, Luis; Campillay, Abdo; Castelln, Sergio; Morrell, Nidia; Salgado, Francisco [Carnegie Institution of Washington, Las Campanas Observatory, Colina El Pino, Casilla 601 (Chile); Folatelli, Gaston [Kavli Institute for the Physics and Mathematics of the Universe, Todai Institutes for Advanced Study, the University of Tokyo, 277-8583 Kashiwa (Japan); Suntzeff, Nicholas B. [George P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy, Texas A and M University, Department of Physics and Astronomy, College Station, TX 77843 (United States)

    2014-07-01

    We present an updated analysis of the intrinsic colors of Type Ia supernova (SNe Ia) using the latest data release of the Carnegie Supernova Project. We introduce a new light-curve parameter very similar to stretch that is better suited for fast-declining events, and find that these peculiar types can be seen as extensions to the population of 'normal' SNe Ia. With a larger number of objects, an updated fit to the Lira relation is presented along with evidence for a dependence on the late-time slope of the B V light-curves with stretch and color. Using the full wavelength range from u to H band, we place constraints on the reddening law for the sample as a whole and also for individual events/hosts based solely on the observed colors. The photometric data continue to favor low values of R{sub V} , though with large variations from event to event, indicating an intrinsic distribution. We confirm the findings of other groups that there appears to be a correlation between the derived reddening law, R{sub V} , and the color excess, E(B V), such that larger E(B V) tends to favor lower R{sub V} . The intrinsic u-band colors show a relatively large scatter that cannot be explained by variations in R{sub V} or by the Goobar power-law for circumstellar dust, but rather is correlated with spectroscopic features of the supernova and is therefore likely due to metallicity effects.

  20. STANDARDIZING TYPE Ia SUPERNOVA ABSOLUTE MAGNITUDES USING GAUSSIAN PROCESS DATA REGRESSION

    SciTech Connect

    Kim, A. G.; Aldering, G.; Aragon, C.; Bailey, S.; Childress, M.; Fakhouri, H. K.; Nordin, J.; Thomas, R. C.; Antilogus, P.; Bongard, S.; Canto, A.; Cellier-Holzem, F.; Guy, J.; Baltay, C.; Buton, C.; Kerschhaggl, M.; Kowalski, M.; Chotard, N.; Copin, Y.; Gangler, E.; and others

    2013-04-01

    We present a novel class of models for Type Ia supernova time-evolving spectral energy distributions (SEDs) and absolute magnitudes: they are each modeled as stochastic functions described by Gaussian processes. The values of the SED and absolute magnitudes are defined through well-defined regression prescriptions, so that data directly inform the models. As a proof of concept, we implement a model for synthetic photometry built from the spectrophotometric time series from the Nearby Supernova Factory. Absolute magnitudes at peak B brightness are calibrated to 0.13 mag in the g band and to as low as 0.09 mag in the z = 0.25 blueshifted i band, where the dispersion includes contributions from measurement uncertainties and peculiar velocities. The methodology can be applied to spectrophotometric time series of supernovae that span a range of redshifts to simultaneously standardize supernovae together with fitting cosmological parameters.

  1. Supernova hunting with supercomputers

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    Supernova hunting with supercomputers Click to share on Facebook (Opens in new window) Click to share on Twitter (Opens in new window) Click to share on Reddit (Opens in new window) Click to share on Pinterest (Opens in new window) A new avenue for studying the life and death of stars opens up. This simulation of the expanding debris from a supernova explosion (shown in red) running over and shredding a nearby star (shown in blue). (Image: Daniel Kasen, Berkeley Lab/UC Berkeley) More » Solitary

  2. FUZZY SUPERNOVA TEMPLATES. II. PARAMETER ESTIMATION

    SciTech Connect

    Rodney, Steven A.; Tonry, John L. E-mail: jt@ifa.hawaii.ed

    2010-05-20

    Wide-field surveys will soon be discovering Type Ia supernovae (SNe) at rates of several thousand per year. Spectroscopic follow-up can only scratch the surface for such enormous samples, so these extensive data sets will only be useful to the extent that they can be characterized by the survey photometry alone. In a companion paper we introduced the Supernova Ontology with Fuzzy Templates (SOFT) method for analyzing SNe using direct comparison to template light curves, and demonstrated its application for photometric SN classification. In this work we extend the SOFT method to derive estimates of redshift and luminosity distance for Type Ia SNe, using light curves from the Sloan Digital Sky Survey (SDSS) and Supernova Legacy Survey (SNLS) as a validation set. Redshifts determined by SOFT using light curves alone are consistent with spectroscopic redshifts, showing an rms scatter in the residuals of rms{sub z} = 0.051. SOFT can also derive simultaneous redshift and distance estimates, yielding results that are consistent with the currently favored {Lambda}CDM cosmological model. When SOFT is given spectroscopic information for SN classification and redshift priors, the rms scatter in Hubble diagram residuals is 0.18 mag for the SDSS data and 0.28 mag for the SNLS objects. Without access to any spectroscopic information, and even without any redshift priors from host galaxy photometry, SOFT can still measure reliable redshifts and distances, with an increase in the Hubble residuals to 0.37 mag for the combined SDSS and SNLS data set. Using Monte Carlo simulations, we predict that SOFT will be able to improve constraints on time-variable dark energy models by a factor of 2-3 with each new generation of large-scale SN surveys.

  3. Essential Ingredients in Core-collapse Supernovae

    DOE PAGES [OSTI]

    Hix, William Raphael; Lentz, E. J.; Endeve, Eirik; Baird, Mark L.; Chertkow, Merek A.; Harris, James A.; Messer, Bronson; Mezzacappa, Anthony; Bruenn, S. W.; Blondin, J. M.

    2014-03-27

    Marking the inevitable death of a massive star, and the birth of a neutron star or black hole, core-collapse supernovae bring together physics at a wide range in spatial scales, from kilometer-sized hydrodynamic motions (eventually growing to gigameter scale) down to femtometer scale nuclear reactions. Carrying 10more » $$^{44}$$ joules of kinetic energy and a rich-mix of newly synthesized atomic nuclei, core-collapse supernovae are the preeminent foundries of the nuclear species which make up ourselves and our solar system. We will discuss our emerging understanding of the convectively unstable, neutrino-driven explosion mechanism, based on increasingly realistic neutrino-radiation hydrodynamic simulations that include progressively better nuclear and particle physics. Recent multi-dimensional models with spectral neutrino transport from several research groups, which slowly develop successful explosions for a range of progenitors, have motivated changes in our understanding of the neutrino reheating mechanism. In a similar fashion, improvements in nuclear physics, most notably explorations of weak interactions on nuclei and the nuclear equation of state, continue to refine our understanding of how supernovae explode. Recent progress on both the macroscopic and microscopic effects that affect core-collapse supernovae are discussed.« less

  4. Particle Theory & Cosmology

    SciTech Connect

    Shafi, Qaisar; Barr, Steven; Gaisser, Thomas; Stanev, Todor

    2015-03-31

    1. Executive Summary (April 1, 2012 - March 31, 2015) Title: Particle Theory, Particle Astrophysics and Cosmology Qaisar Shafi University of Delaware (Principal Investigator) Stephen M. Barr, University of Delaware (Co-Principal Investigator) Thomas K. Gaisser, University of Delaware (Co-Principal Investigator) Todor Stanev, University of Delaware (Co-Principal Investigator) The proposed research was carried out at the Bartol Research included Professors Qaisar Shafi Stephen Barr, Thomas K. Gaisser, and Todor Stanev, two postdoctoral fellows (Ilia Gogoladze and Liucheng Wang), and several graduate students. Five students of Qaisar Shafi completed their PhD during the period August 2011 - August 2014. Measures of the group’s high caliber performance during the 2012-2015 funding cycle included pub- lications in excellent refereed journals, contributions to working groups as well as white papers, and conference activities, which together provide an exceptional record of both individual performance as well as overall strength. Another important indicator of success is the outstanding quality of the past and current cohort of graduate students. The PhD students under our supervision regularly win the top departmental and university awards, and their publications records show excellence both in terms of quality and quantity. The topics covered under this grant cover the frontline research areas in today’s High Energy Theory & Phenomenology. For Professors Shafi and Barr they include LHC related topics including supersymmetry, collider physics, fl vor physics, dark matter physics, Higgs boson and seesaw physics, grand unifi and neutrino physics. The LHC two years ago discovered the Standard Model Higgs boson, thereby at least partially unlocking the secrets behind electroweak symmetry breaking. We remain optimistic that new and exciting physics will be found at LHC 14, which explain our focus on physics beyond the Standard Model. Professors Shafi continued his

  5. Emergent cosmology revisited

    SciTech Connect

    Bag, Satadru; Sahni, Varun; Shtanov, Yuri; Unnikrishnan, Sanil E-mail: varun@iucaa.ernet.in E-mail: sanil@lnmiit.ac.in

    2014-07-01

    We explore the possibility of emergent cosmology using the effective potential formalism. We discover new models of emergent cosmology which satisfy the constraints posed by the cosmic microwave background (CMB). We demonstrate that, within the framework of modified gravity, the emergent scenario can arise in a universe which is spatially open/closed. By contrast, in general relativity (GR) emergent cosmology arises from a spatially closed past-eternal Einstein Static Universe (ESU). In GR the ESU is unstable, which creates fine tuning problems for emergent cosmology. However, modified gravity models including Braneworld models, Loop Quantum Cosmology (LQC) and Asymptotically Free Gravity result in a stable ESU. Consequently, in these models emergent cosmology arises from a larger class of initial conditions including those in which the universe eternally oscillates about the ESU fixed point. We demonstrate that such an oscillating universe is necessarily accompanied by graviton production. For a large region in parameter space graviton production is enhanced through a parametric resonance, casting serious doubts as to whether this emergent scenario can be past-eternal.

  6. A Massive Stellar Burst Before the Supernova

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    A Massive Stellar Burst Before the Supernova A Massive Stellar Burst Before the Supernova February 6, 2013 Contact: Linda Vu, lvu@lbl.gov, +1 510 495 2402 An automated supernova ...

  7. Supernova Science Center

    SciTech Connect

    S. E. Woosley

    2008-05-05

    The Supernova Science Center (SNSC) was founded in 2001 to carry out theoretical and computational research leading to a better understanding of supernovae and related transients. The SNSC, a four-institutional collaboration, included scientists from LANL, LLNL, the University of Arizona (UA), and the University of California at Santa Cruz (UCSC). Intitially, the SNSC was funded for three years of operation, but in 2004 an opportunity was provided to submit a renewal proposal for two years. That proposal was funded and subsequently, at UCSC, a one year no-cost extension was granted. The total operational time of the SNSC was thus July 15, 2001 - July 15, 2007. This document summarizes the research and findings of the SNSC and provides a cummulative publication list.

  8. Supernova Discoveries from the Nearby Supernova Factory (SNfactory)

    DOE Data Explorer

    SNfactory International Collaboration,

    The Nearby Supernova Factory is an experiment designed to collect data on more Type Ia supernovae than have ever been studied in a single project before, and in so doing, to answer some fundamental questions about the nature of the universe. Type Ia supernovae are extraordinarily bright, remarkably uniform objects which make excellent "standard candles" for measuring the expansion rate of the universe. However, such stellar explosions are very rare, occurring only a couple of times per millenium in a typical galaxy, and remaining bright enough to detect only for a few weeks. Previous studies of Type Ia supernovae led to the discovery of the mysterious "dark energy" that is causing the universe to expand at an accelerating rate. To reduce the statistical uncertainties in previous experimental data, extensive spectral and photometric monitoring of more Type Ia supernovae is required. The SNfactory collaboration has built an automated system consisting of specialized software and custom-built hardware that systematically searches the sky for new supernovae, screens potential candidates, then performs multiple spectral and photometric observations on each supernova. These observations are stored in a database to be made available to supernova researchers world-wide for further study and analysis [copied from http://snfactory.lbl.gov/snf/snf-about.html]. Users must register and agree to the open access honor system. Finding charts are in FITS format and may not be accessible through normal browser settings.

  9. First-Year Spectroscopy for the SDSS-II Supernova Survey

    SciTech Connect

    Zheng, Chen; Romani, Roger W.; Sako, Masao; Marriner, John; Bassett, Bruce; Becker, Andrew; Choi, Changsu; Cinabro, David; DeJongh, Fritz; Depoy, Darren L.; Dilday, Ben; Doi, Mamoru; Frieman, Joshua A.; Garnavich, Peter M.; Hogan, Craig J.; Holtzman, Jon; Im, Myungshin; Jha, Saurabh; Kessler, Richard; Konishi, Kohki; Lampeitl, Hubert

    2008-03-25

    This paper presents spectroscopy of supernovae discovered in the first season of the Sloan Digital Sky Survey-II Supernova Survey. This program searches for and measures multi-band light curves of supernovae in the redshift range z = 0.05-0.4, complementing existing surveys at lower and higher redshifts. Our goal is to better characterize the supernova population, with a particular focus on SNe Ia, improving their utility as cosmological distance indicators and as probes of dark energy. Our supernova spectroscopy program features rapid-response observations using telescopes of a range of apertures, and provides confirmation of the supernova and host-galaxy types as well as precise redshifts. We describe here the target identification and prioritization, data reduction, redshift measurement, and classification of 129 SNe Ia, 16 spectroscopically probable SNe Ia, 7 SNe Ib/c, and 11 SNe II from the first season. We also describe our efforts to measure and remove the substantial host galaxy contamination existing in the majority of our SN spectra.

  10. Pair-instability supernovae in the local universe

    SciTech Connect

    Whalen, Daniel J. [Zentrum fr Astronomie, Institut fr Theoretische Astrophysik, Universitt Heidelberg, Albert-Ueberle-Str. 2, D-69120 Heidelberg (Germany); Smidt, Joseph [CCS-2, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Heger, Alexander [Monash Centre for Astrophysics, Monash University, Victoria 3800 (Australia); Hirschi, Raphael [Astrophysics Group, EPSAM, University of Keele, Lennard-Jones Labs, Keele ST5 5BG (United Kingdom); Yusof, Norhasliza [Department of Physics, University of Malaysia, 50603 Kuala Lampur (Malaysia); Even, Wesley; Fryer, Chris L. [T-2, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Stiavelli, Massimo [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Chen, Ke-Jung [Department of Astronomy and Astrophysics, UCSC, Santa Cruz, CA 95064 (United States); Joggerst, Candace C. [XTD-3, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2014-12-10

    The discovery of 150-300 M {sub ?} stars in the Local Group and pair-instability supernova candidates at low redshifts has excited interest in this exotic explosion mechanism. Realistic light curves for pair-instability supernovae at near-solar metallicities are key to identifying and properly interpreting these events as more are found. We have modeled pair-instability supernovae of 150-500 M {sub ?} Z ? 0.1-0.4 Z {sub ?} stars. These stars lose up to 80% of their mass to strong line-driven winds and explode as bare He cores. We find that their light curves and spectra are quite different from those of Population III pair-instability explosions, which therefore cannot be used as templates for low-redshift events. Although non-zero metallicity pair-instability supernovae are generally dimmer than their Population III counterparts, in some cases they will be bright enough to be detected at the earliest epochs at which they can occur, the formation of the first galaxies at z ? 10-15. Others can masquerade as dim, short duration supernovae that are only visible in the local universe and that under the right conditions could be hidden in a wide variety of supernova classes. We also report for the first time that some pair-instability explosions can create black holes with masses of ?100 M {sub ?}.

  11. Collective neutrino oscillations in supernovae

    SciTech Connect

    Duan, Huaiyu [Department of Physics and Astronomy, University of New Mexico, Albuquerque, NM 87131 (United States)

    2014-06-24

    In a dense neutrino medium neutrinos can experience collective flavor transformation through the neutrino-neutrino forward scattering. In this talk we present some basic features of collective neutrino flavor transformation in the context in core-collapse supernovae. We also give some qualitative arguments for why and when this interesting phenomenon may occur and how it may affect supernova nucleosynthesis.

  12. TYPE Ia SUPERNOVA DISTANCE MODULUS BIAS AND DISPERSION FROM K-CORRECTION ERRORS: A DIRECT MEASUREMENT USING LIGHT CURVE FITS TO OBSERVED SPECTRAL TIME SERIES

    SciTech Connect

    Saunders, C.; Aldering, G.; Aragon, C.; Bailey, S.; Childress, M.; Fakhouri, H. K.; Kim, A. G.; Antilogus, P.; Bongard, S.; Canto, A.; Cellier-Holzem, F.; Guy, J.; Baltay, C.; Buton, C.; Chotard, N.; Copin, Y.; Gangler, E.; and others

    2015-02-10

    We estimate systematic errors due to K-corrections in standard photometric analyses of high-redshift Type Ia supernovae. Errors due to K-correction occur when the spectral template model underlying the light curve fitter poorly represents the actual supernova spectral energy distribution, meaning that the distance modulus cannot be recovered accurately. In order to quantify this effect, synthetic photometry is performed on artificially redshifted spectrophotometric data from 119 low-redshift supernovae from the Nearby Supernova Factory, and the resulting light curves are fit with a conventional light curve fitter. We measure the variation in the standardized magnitude that would be fit for a given supernova if located at a range of redshifts and observed with various filter sets corresponding to current and future supernova surveys. We find significant variation in the measurements of the same supernovae placed at different redshifts regardless of filters used, which causes dispersion greater than ∼0.05 mag for measurements of photometry using the Sloan-like filters and a bias that corresponds to a 0.03 shift in w when applied to an outside data set. To test the result of a shift in supernova population or environment at higher redshifts, we repeat our calculations with the addition of a reweighting of the supernovae as a function of redshift and find that this strongly affects the results and would have repercussions for cosmology. We discuss possible methods to reduce the contribution of the K-correction bias and uncertainty.

  13. Supernova Discoveries from the Nearby Supernova Factory (SNfactory...

    Office of Scientific and Technical Information (OSTI)

    data on more Type Ia supernovae than have ever been studied in a single project before, and in so doing, to answer some fundamental questions about the nature of the universe. ...

  14. Topics in inflationary cosmologies

    SciTech Connect

    Mahajan, S.

    1986-04-01

    Several aspects of inflationary cosmologies are discussed. An introduction to the standard hot big bang cosmological model is reviewed, and some of the problems associated with it are presented. A short review of the proposals for solving the cosmological conundrums of the big bang model is presented. Old and the new inflationary scenarios are discussed and shown to be unacceptable. Some alternative scenarios especially those using supersymmetry are reviewed briefly. A study is given of inflationary models where the same set of fields that breaks supersymmetry is also responsible for inflation. In these models, the scale of supersymmetry breaking is related to the slope of the potential near the origin and can thus be kept low. It is found that a supersymmetry breaking scale of the order of the weak breaking scale. The cosmology obtained from the simplest of such models is discussed in detail and it is shown that there are no particular problems except a low reheating temperature and a violation of the thermal constraint. A possible solution to the thermal constraint problem is given by introducing a second field, and the role played by this second field in the scenario is discussed. An alternative mechanism for the generation of baryon number within the framework of supergravity inflationary models is studied using the gravitational couplings of the heavy fields with the hidden sector (the sector which breaks supersymmetry). This mechanism is applied to two specific models - one with and one without supersymmetry breaking. The baryon to entropy ratio is found to be dependent on parameters which are model dependent. Finally, the effect of direct coupling between the two sectors on results is related, 88 refs., 6 figs.

  15. Nearby Supernova Factory Observations of SN 2005gj: Another TypeIa Supernova in a Massive Circumstellar Envelope

    SciTech Connect

    Aldering, G.; Antilogus, P.; Bailey, S.; Baltay, C.; Bauer, A.; Blanc, N.; Bongard, S.; Copin, Y.; Gangler, E.; Gilles, S.; Kessler, R.; Kocevski, D.; Lee, B.C.; Loken, S.; Nugent, P.; Pain, R.; Pecontal, E.; Pereira, R.; Perlmutter, S.; Rabinowitz, D.; Rigaudier, G.; Scalzo, R.; Smadja, G.; Thomas, R.C.; Wang, L.; Weaver, B.A.; Rabinowitz, D.; Bauer, A.

    2006-06-01

    began roughly 200 {+-} 70 Myr ago. We discuss the implications of these observations for progenitor models and cosmology using Type Ia supernovae.

  16. Nuclear & Particle Physics, Astrophysics, Cosmology

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    Nuclear & Particle Physics, Astrophysics, Cosmology National security depends on science ... The United States relies on Los Alamos National Laboratory for the best of both. Nuclear ...

  17. The supernova that destroyed a galaxy

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    The supernova that destroyed a galaxy The supernova that destroyed a galaxy The research may solve the long-standing puzzle of how supermassive black holes were formed in the...

  18. Cosmological constraints on extended Galileon models

    SciTech Connect

    Felice, Antonio De; Tsujikawa, Shinji E-mail: shinji@rs.kagu.tus.ac.jp

    2012-03-01

    The extended Galileon models possess tracker solutions with de Sitter attractors along which the dark energy equation of state is constant during the matter-dominated epoch, i.e. w{sub DE} = ?1?s, where s is a positive constant. Even with this phantom equation of state there are viable parameter spaces in which the ghosts and Laplacian instabilities are absent. Using the observational data of the supernovae type Ia, the cosmic microwave background (CMB), and baryon acoustic oscillations, we place constraints on the tracker solutions at the background level and find that the parameter s is constrained to be s = 0.034{sub ?0.034}{sup +0.327} (95 % CL) in the flat Universe. In order to break the degeneracy between the models we also study the evolution of cosmological density perturbations relevant to the large-scale structure (LSS) and the Integrated-Sachs-Wolfe (ISW) effect in CMB. We show that, depending on the model parameters, the LSS and the ISW effect is either positively or negatively correlated. It is then possible to constrain viable parameter spaces further from the observational data of the ISW-LSS cross-correlation as well as from the matter power spectrum.

  19. Baryonic matter perturbations in decaying vacuum cosmology

    SciTech Connect

    Marttens, R.F. vom; Zimdahl, W.; Hiplito-Ricaldi, W.S. E-mail: wiliam.ricaldi@ufes.br

    2014-08-01

    We consider the perturbation dynamics for the cosmic baryon fluid and determine the corresponding power spectrum for a ?(t)CDM model in which a cosmological term decays into dark matter linearly with the Hubble rate. The model is tested by a joint analysis of data from supernovae of type Ia (SNIa) (Constitution and Union 2.1), baryonic acoustic oscillations (BAO), the position of the first peak of the anisotropy spectrum of the cosmic microwave background (CMB) and large-scale-structure (LSS) data (SDSS DR7). While the homogeneous and isotropic background dynamics is only marginally influenced by the baryons, there are modifications on the perturbative level if a separately conserved baryon fluid is included. Considering the present baryon fraction as a free parameter, we reproduce the observed abundance of the order of 5% independently of the dark-matter abundance which is of the order of 32% for this model. Generally, the concordance between background and perturbation dynamics is improved if baryons are explicitly taken into account.

  20. Improving Data Mobility & Management for International Cosmology...

    Office of Scientific and Technical Information (OSTI)

    Improving Data Mobility & Management for International Cosmology Citation Details In-Document Search Title: Improving Data Mobility & Management for International Cosmology In February ...

  1. Cosmology with Mimetic Matter

    SciTech Connect

    Chamseddine, Ali H.; Mukhanov, Viatcheslav; Vikman, Alexander E-mail: viatcheslav.Mukhanov@lmu.de

    2014-06-01

    We consider minimal extensions of the recently proposed Mimetic Dark Matter and show that by introducing a potential for the mimetic non-dynamical scalar field we can mimic nearly any gravitational properties of the normal matter. In particular, the mimetic matter can provide us with inflaton, quintessence and even can lead to a bouncing nonsingular universe. We also investigate the behaviour of cosmological perturbations due to a mimetic matter. We demonstrate that simple mimetic inflation can produce red-tilted scalar perturbations which are largely enhanced over gravity waves.

  2. Inflationary Axion Cosmology

    DOE R&D Accomplishments

    Wilczek, Frank; Turner, Michael S.

    1990-09-01

    If Peccei-Quinn (PQ) symmetry is broken after inflation, the initial axion angle is a random variable on cosmological scales; based on this fact, estimates of the relic-axion mass density give too large a value if the axion mass is less than about 10-6 eV. This bound can be evaded if the Universe underwent inflation after PQ symmetry breaking and if the observable Universe happens to be a region where the initial axion angle was atypically small, .1 . (ma/10-6eV)0.59. We show consideration of fluctuations induced during inflation severely constrains the latter alternative.

  3. Supernova Remnants And GLAST

    SciTech Connect

    Slane, Patrick; /Harvard-Smithsonian Ctr. Astrophys.

    2011-11-29

    It has long been speculated that supernova remnants represent a major source of cosmic rays in the Galaxy. Observations over the past decade have ceremoniously unveiled direct evidence of particle acceleration in SNRs to energies approaching the knee of the cosmic ray spectrum. Nonthermal X-ray emission from shell-type SNRs reveals multi-TeV electrons, and the dynamical properties of several SNRs point to efficient acceleration of ions. Observations of TeV gamma-ray emission have confirmed the presence of energetic particles in several remnants as well, but there remains considerable debate as to whether this emission originates with high energy electrons or ions. Equally uncertain are the exact conditions that lead to efficient particle acceleration. Based on the catalog of EGRET sources, we know that there is a large population of Galactic gamma-ray sources whose distribution is similar to that of SNRs.With the increased resolution and sensitivity of GLAST, the gamma-ray SNRs from this population will be identified. Their detailed emission structure, along with their spectra, will provide the link between their environments and their spectra in other wavebands to constrain emission models and to potentially identify direct evidence of ion acceleration in SNRs. Here I summarize recent observational and theoretical work in the area of cosmic ray acceleration by SNRs, and discuss the contributions GLAST will bring to our understanding of this problem.

  4. A Massive Stellar Burst Before the Supernova

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    A Massive Stellar Burst Before the Supernova A Massive Stellar Burst Before the Supernova February 6, 2013 Contact: Linda Vu, lvu@lbl.gov, +1 510 495 2402 An automated supernova hunt is shedding new light on the death sequence of massive stars-specifically, the kind that self-destruct in Type IIn supernova explosions. Digging through the Palomar Transient Factory (PTF) data archive housed at the Department of Energy's National Energy Research Scientific Computing Center (NERSC) at Lawrence

  5. What We Know About Dark Energy From Supernovae

    ScienceCinema

    Filippenko, Alex [University of California, Berkeley, California, United States

    2016-07-12

    The measured distances of type Ia (white dwarf) supernovae as a function of redshift (z) have shown that the expansion of the Universe is currently accelerating, probably due to the presence of dark energy (X) having a negative pressure. Combining all of the data with existing results from large-scale structure surveys, we find a best fit for Omega M and Omega X of 0.28 and 0.72 (respectively), in excellent agreement with the values derived independently from WMAP measurements of the cosmic microwave background radiation. Thus far, the best-fit value for the dark energy equation-of-state parameter is -1, and its first derivative is consistent with zero, suggesting that the dark energy may indeed be Einstein's cosmological constant.

  6. Particle physics and cosmology

    SciTech Connect

    Kolb, E.W.

    1986-10-01

    This series of lectures is about the role of particle physics in physical processes that occurred in the very early stages of the bug gang. Of particular interest is the role of particle physics in determining the evolution of the early Universe, and the effect of particle physics on the present structure of the Universe. The use of the big bang as a laboratory for placing limits on new particle physics theories will also be discussed. Section 1 reviews the standard cosmology, including primordial nucleosynthesis. Section 2 reviews the decoupling of weakly interacting particles in the early Universe, and discusses neutrino cosmology and the resulting limits that may be placed on the mass and lifetime of massive neutrinos. Section 3 discusses the evolution of the vacuum through phase transitions in the early Universe and the formation of topological defects in the transitions. Section 4 covers recent work on the generation of the baryon asymmetry by baryon-number violating reactions in Grand Unified Theories, and mentions some recent work on baryon number violation effects at the electroweak transition. Section 5 is devoted to theories of cosmic inflation. Finally, Section 6 is a discussion of the role of extra spatial dimensions in the evolution of the early Universe. 78 refs., 32 figs., 6 tabs.

  7. Supernova neutrinos and explosive nucleosynthesis

    SciTech Connect

    Kajino, T. [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan and Department of Astronomy, Graduate School of Science, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033 (Japan); Aoki, W. [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Cheoun, M.-K. [Department of Physics, Soongsil University, Seoul 156-743 (Korea, Republic of); Hayakawa, T. [Japan Atomic Energy Agency, Shirakara-Shirane 2-4, Tokai-mura, Ibaraki 319-1195 (Japan); Hidaka, J.; Hirai, Y.; Shibagaki, S. [National Astronomical Observatory, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Mathews, G. J. [Center for Astrophysics, Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Nakamura, K. [Faculty of Science and Engineering, Waseda University, Ohkubo 3-4-1, Shinjuku, Tokyo 169-8555 (Japan); Suzuki, T. [Department of Physics, College of Humanities and Sciences, Nihon University, Sakurajosui 3-25-40, Setagaya-ku, Tokyo 156-8550 (Japan)

    2014-05-09

    Core-collapse supernovae eject huge amount of flux of energetic neutrinos. We studied the explosive nucleosyn-thesis in supernovae and found that several isotopes {sup 7}Li, {sup 11}B, {sup 92}Nb, {sup 138}La and {sup 180}Ta as well as r-process nuclei are affected by the neutrino interactions. The abundance of these isotopes therefore depends strongly on the neutrino flavor oscillation due to the Mikheyev-Smirnov-Wolfenstein (MSW) effect. We discuss first how to determine the neutrino temperatures in order to explain the observed solar system abundances of these isotopes, combined with Galactic chemical evolution of the light nuclei and the heavy r-process elements. We then study the effects of neutrino oscillation on their abundances, and propose a novel method to determine the still unknown neutrino oscillation parameters, mass hierarchy and ?{sub 13}, simultaneously. There is recent evidence that SiC X grains from the Murchison meteorite may contain supernova-produced light elements {sup 11}B and {sup 7}Li encapsulated in the presolar grains. Combining the recent experimental constraints on ?{sub 13}, we show that our method sug-gests at a marginal preference for an inverted neutrino mass hierarchy. Finally, we discuss supernova relic neutrinos that may indicate the softness of the equation of state (EoS) of nuclear matter as well as adiabatic conditions of the neutrino oscillation.

  8. Computational Cosmology | Argonne National Laboratory

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    Computational Cosmology Computational Cosmology To study the mysterious dark sector we use powerful simulations on state-of-the-art high-performance computers, run at Argonne and elsewhere. By developing specialized codes for these supercomputers, and by comparing their results to observations from deep surveys of the sky, we aim to answer some of the most fundamental questions in physics: What is dark matter made of? What is the nature of dark energy? Does general relativity need to be

  9. Solar and supernova neutrino interactions

    SciTech Connect

    Haxton, W.C.

    1990-11-01

    Two topics are addressed, the interactions of neutrinos during a type II supernova and the effect of current eddies on solar neutrino oscillations. The supernova discussion focuses on the nucleosynthesis that accompanies inelastic neutral current interactions of neutrinos in the mantle of a collapsing star, and on the effect of neutrino down-scattering'' and preheating on the explosion mechanism. The second half of the talk deals with the influence of solar turbulence (or density fluctuations) on the neutrino effective mass and the possibility that a time-varying neutrino flux could result. The effects of harmonic density or three-current perturbations on the oscillation probability are explored analytically and numerically. 15 refs., 5 figs.

  10. The supernova that destroyed a galaxy

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    The supernova that destroyed a galaxy The supernova that destroyed a galaxy The research may solve the long-standing puzzle of how supermassive black holes were formed in the centers of some galaxies less then a billion years after the Big Bang. August 5, 2013 Supernova of a 55,000 solar-mass star in a primitive galaxy (explosion in a low-density region) Supernova of a 55,000 solar-mass star in a primitive galaxy (explosion in a low-density region) The Los Alamos simulation is the most realistic

  11. The supernova that destroyed a galaxy

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    The supernova that destroyed a galaxy The supernova that destroyed a galaxy The research may solve the long-standing puzzle of how supermassive black holes were formed in the centers of some galaxies less then a billion years after the Big Bang. August 5, 2013 Supernova of a 55,000 solar-mass star in a primitive galaxy (explosion in a low-density region) Supernova of a 55,000 solar-mass star in a primitive galaxy (explosion in a low-density region) The Los Alamos simulation is the most realistic

  12. Multigroup Radiation Transport in Supernova Light Curve Calculations...

    Office of Scientific and Technical Information (OSTI)

    Technical Report: Multigroup Radiation Transport in Supernova Light Curve Calculations Citation Details In-Document Search Title: Multigroup Radiation Transport in Supernova Light ...

  13. Core-Collapse Supernovae and Host Galaxy Stellar Populations...

    Office of Scientific and Technical Information (OSTI)

    Core-Collapse Supernovae and Host Galaxy Stellar Populations Citation Details In-Document Search Title: Core-Collapse Supernovae and Host Galaxy Stellar Populations Authors: Kelly, ...

  14. Machine learning helps discover the most luminous supernova in...

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    host galaxy of the supernova. (Credit: Beijing Planetarium Jin Ma) An artist's ... host galaxy of the supernova. (Credit: Beijing Planetarium Jin Ma) Contact Laura ...

  15. ASTRONOMY AND ASTROPHYSICS Dark Energy, Type Ia supernovae, radiative

    Office of Scientific and Technical Information (OSTI)

    of Oklahoma Univ. of Oklahoma 79 ASTRONOMY AND ASTROPHYSICS Dark Energy, Type Ia supernovae, radiative transfer, Dark Energy, Type Ia supernovae, radiative transfer, The...

  16. Type Ia Supernova Hubble Residuals and Host-Galaxy Properties...

    Office of Scientific and Technical Information (OSTI)

    Tao, C.; Thomas, R. C.; Weaver, B. A. 79 ASTRONOMY AND ASTROPHYSICS distance scale, supernovae: general distance scale, supernovae: general Kim et al. (2013) K13 introduced a...

  17. Constraining Cosmic Evolution of Type Ia Supernovae (Journal...

    Office of Scientific and Technical Information (OSTI)

    Constraining Cosmic Evolution of Type Ia Supernovae Citation Details In-Document Search Title: Constraining Cosmic Evolution of Type Ia Supernovae We present the first large-scale...

  18. FUZZY SUPERNOVA TEMPLATES. I. CLASSIFICATION

    SciTech Connect

    Rodney, Steven A.; Tonry, John L. E-mail: jt@ifa.hawaii.ed

    2009-12-20

    Modern supernova (SN) surveys are now uncovering stellar explosions at rates that far surpass what the world's spectroscopic resources can handle. In order to make full use of these SN data sets, it is necessary to use analysis methods that depend only on the survey photometry. This paper presents two methods for utilizing a set of SN light-curve templates to classify SN objects. In the first case, we present an updated version of the Bayesian Adaptive Template Matching program (BATM). To address some shortcomings of that strictly Bayesian approach, we introduce a method for Supernova Ontology with Fuzzy Templates (SOFT), which utilizes fuzzy set theory for the definition and combination of SN light-curve models. For well-sampled light curves with a modest signal-to-noise ratio (S/N >10), the SOFT method can correctly separate thermonuclear (Type Ia) SNe from core collapse SNe with >=98% accuracy. In addition, the SOFT method has the potential to classify SNe into sub-types, providing photometric identification of very rare or peculiar explosions. The accuracy and precision of the SOFT method are verified using Monte Carlo simulations as well as real SN light curves from the Sloan Digital Sky Survey and the SuperNova Legacy Survey. In a subsequent paper, the SOFT method is extended to address the problem of parameter estimation, providing estimates of redshift, distance, and host galaxy extinction without any spectroscopy.

  19. Systematic corrections to the measured cosmological constant as a result of local inhomogeneity

    SciTech Connect

    Vanderveld, R. Ali; Flanagan, Eanna E.; Wasserman, Ira

    2007-10-15

    We explicitly calculate the lowest order systematic inhomogeneity-induced corrections to the cosmological constant that one would infer from an analysis of the luminosities and redshifts of type Ia supernovae, assuming a homogeneous universe. The calculation entails a post-Newtonian expansion within the framework of second-order perturbation theory, wherein we consider the effects of subhorizon density perturbations in a flat, dust-dominated universe. Within this formalism, we calculate luminosity distances and redshifts along the past light cone of an observer. The luminosity distance-redshift relation is then averaged over viewing angles and ensemble averaged, assuming that density fluctuations at a given cosmic time are a homogeneous random process. The resulting relation is fit to that of a homogeneous model containing dust and a cosmological constant, in order to deduce the best-fit cosmological constant density {omega}{sub {lambda}}. We find that the luminosity distance-redshift relation is indeed modified, even for large sample sizes, but only by a very small fraction, of order 10{sup -5} for z{approx}0.1. This lowest order deviation depends on the peculiar velocities of the source and the observer. However, when fitting this perturbed relation to that of a homogeneous universe, via maximizing a likelihood function, we find that the inferred cosmological constant can be surprisingly large, depending on the range of redshifts sampled. For a sample of supernovae extending from z{sub min}=0.02 out to a limiting redshift z{sub max}=0.15, we find that {omega}{sub {lambda}}{approx_equal}0.004. The value of {omega}{sub {lambda}} has a large variance, and its magnitude tends to get progressively larger as the limiting redshift z{sub max} gets smaller, implying that precision measurements of {omega}{sub {lambda}} from nearby supernova data will require taking this effect into account. This effect has been referred to in the past as the 'fitting problem', and more

  20. Double field theory inspired cosmology

    SciTech Connect

    Wu, Houwen; Yang, Haitang E-mail: hyanga@scu.edu.cn

    2014-07-01

    Double field theory proposes a generalized spacetime action possessing manifest T-duality on the level of component fields. We calculate the cosmological solutions of double field theory with vanishing Kalb-Ramond field. It turns out that double field theory provides a more consistent way to construct cosmological solutions than the standard string cosmology. We construct solutions for vanishing and non-vanishing symmetry preserving dilaton potentials. The solutions assemble the pre- and post-big bang evolutions in one single line element. Our results show a smooth evolution from an anisotropic early stage to an isotropic phase without any special initial conditions in contrast to previous models. In addition, we demonstrate that the contraction of the dual space automatically leads to both an inflation phase and a decelerated expansion of the ordinary space during different evolution stages.

  1. Constraining Lorentz Violation with Cosmology

    SciTech Connect

    Zuntz, J. A.; Ferreira, P. G.; Zlosnik, T. G

    2008-12-31

    The Einstein-aether theory provides a simple, dynamical mechanism for breaking Lorentz invariance. It does so within a generally covariant context and may emerge from quantum effects in more fundamental theories. The theory leads to a preferred frame and can have distinct experimental signatures. In this Letter, we perform a comprehensive study of the cosmological effects of the Einstein-aether theory and use observational data to constrain it. Allied to previously determined consistency and experimental constraints, we find that an Einstein-aether universe can fit experimental data over a wide range of its parameter space, but requires a specific rescaling of the other cosmological densities.

  2. The Supernova Legacy Survey: Measurement of Omega_M, Omega_Lambda, and w from the First Year Data Set

    DOE R&D Accomplishments

    Astier, P.; Guy, J.; Regnault, N.; Pain, R.; Aubourg, E.; Balam, D.; Basa, S.; Carlberg, R. G.; Fabbro, S.; Fouchez, D.; Hook, I. M.; Howell, D. A.; Lafoux, H.; Neill, J. D.; Palanque-Delabrouille, N.; Perrett, K.; Pritchet, C. J.; Rich, J.; Sullivan, M.; Taillet, R.; Aldering, G.; Antilogus, P.; Arsenijevic, V.; Balland, C.; Baumont, S.; Bronder, J.; Courtois, H.; Ellis, R. S.; Filiol, M.; Goncalves, A. C.; Goobar, A.; Guide, D.; Hardin, D.; Lusset, V.; Lidman, C.; McMahon, R.; Mouchet, M.; Mourao, A.; Perlmutter, S.; Ripoche, P.; Tao, C.; Walton, N.

    2005-10-14

    We present distance measurements to 71 high redshift type Ia supernovae discovered during the first year of the 5-year Supernova Legacy Survey (SNLS). These events were detected and their multi-color light-curves measured using the MegaPrime/MegaCam instrument at the Canada-France-Hawaii Telescope (CFHT), by repeatedly imaging four one-square degree fields in four bands. Follow-up spectroscopy was performed at the VLT, Gemini and Keck telescopes to confirm the nature of the supernovae and to measure their redshift. With this data set, we have built a Hubble diagram extending to z = 1, with all distance measurements involving at least two bands. Systematic uncertainties are evaluated making use of the multiband photometry obtained at CFHT. Cosmological fits to this first year SNLS Hubble diagram give the following results: {Omega}{sub M} = 0.263 {+-} 0.042 (stat) {+-} 0.032 (sys) for a flat {Lambda}CDM model; and w = -1.023 {+-} 0.090 (stat) {+-} 0.054 (sys) for a flat cosmology with constant equation of state w when combined with the constraint from the recent Sloan Digital Sky Survey measurement of baryon acoustic oscillations.

  3. The Multi-Dimensional Character of Core-Collapse Supernovae

    SciTech Connect

    Hix, William Raphael; Lentz, E. J.; Bruenn, S. W.; Mezzacappa, Anthony; Messer, Bronson; Endeve, Eirik; Blondin, J. M.; Harris, James Austin; Marronetti, Pedro; Yakunin, Konstantin N

    2016-01-01

    Core-collapse supernovae, the culmination of massive stellar evolution, are spectacular astronomical events and the principle actors in the story of our elemental origins. Our understanding of these events, while still incomplete, centers around a neutrino-driven central engine that is highly hydrodynamically unstable. Increasingly sophisticated simulations reveal a shock that stalls for hundreds of milliseconds before reviving. Though brought back to life by neutrino heating, the development of the supernova explosion is inextricably linked to multi-dimensional fluid flows. In this paper, the outcomes of three-dimensional simulations that include sophisticated nuclear physics and spectral neutrino transport are juxtaposed to learn about the nature of the three dimensional fluid flow that shapes the explosion. Comparison is also made between the results of simulations in spherical symmetry from several groups, to give ourselves confidence in the understanding derived from this juxtaposition.

  4. Dark D-brane cosmology

    SciTech Connect

    Koivisto, Tomi; Wills, Danielle; Zavala, Ivonne E-mail: d.e.wills@durham.ac.uk

    2014-06-01

    Disformally coupled cosmologies arise from Dirac-Born-Infeld actions in Type II string theories, when matter resides on a moving hidden sector D-brane. Since such matter interacts only very weakly with the standard model particles, this scenario can provide a natural origin for the dark sector of the universe with a clear geometrical interpretation: dark energy is identified with the scalar field associated to the D-brane's position as it moves in the internal space, acting as quintessence, while dark matter is identified with the matter living on the D-brane, which can be modelled by a perfect fluid. The coupling functions are determined by the (warped) extra-dimensional geometry, and are thus constrained by the theory. The resulting cosmologies are studied using both dynamical system analysis and numerics. From the dynamical system point of view, one free parameter controls the cosmological dynamics, given by the ratio of the warp factor and the potential energy scales. The disformal coupling allows for new scaling solutions that can describe accelerating cosmologies alleviating the coincidence problem of dark energy. In addition, this scenario may ameliorate the fine-tuning problem of dark energy, whose small value may be attained dynamically, without requiring the mass of the dark energy field to be unnaturally low.

  5. Finding the first cosmic explosions. IV. 90–140 $$\\;{{M}_{\\odot }}$$ pair-stability supernovae

    DOE PAGES [OSTI]

    Smidt, Joseph; Whalen, Daniel J.; Chatzopoulos, E.; Wiggins, Brandon; Chen, Ke-Jung; Kozyreva, Alexandra; Even, Wesley

    2015-05-19

    Population III stars that die as pair-instability supernovae are usually thought to fall in the mass range of 140 - 260 M⊙. However, several lines of work have now shown that rotation can build up the He cores needed to encounter the pair instability at stellar masses as low as 90 M⊙. Depending on the slope of the initial mass function of Population III stars, there could be 4 - 5 times as many stars from 90 - 140 M⊙ in the primordial universe than in the usually accepted range. We present numerical simulations of the pair-instability explosions of suchmore » stars performed with the MESA, FLASH and RAGE codes. We find that they will be visible to supernova factories such as Pan-STARRS and LSST in the optical out to z ~ 1-2 and JWST and the 30 m-class telescopes in the NIR out to z ~ 7-10. Such explosions will thus probe the stellar populations of the first galaxies and cosmic star formation rates in the era of cosmological reionization. These supernovae are also easily distinguished from more massive pair-instability explosions, underscoring the fact that there is far greater variety to the light curves of these events than previously understood.« less

  6. Finding the first cosmic explosions. IV. 90–140 $\\;{{M}_{\\odot }}$ pair-stability supernovae

    SciTech Connect

    Smidt, Joseph; Whalen, Daniel J.; Chatzopoulos, E.; Wiggins, Brandon; Chen, Ke-Jung; Kozyreva, Alexandra; Even, Wesley

    2015-05-19

    Population III stars that die as pair-instability supernovae are usually thought to fall in the mass range of 140 - 260 M. However, several lines of work have now shown that rotation can build up the He cores needed to encounter the pair instability at stellar masses as low as 90 M. Depending on the slope of the initial mass function of Population III stars, there could be 4 - 5 times as many stars from 90 - 140 M in the primordial universe than in the usually accepted range. We present numerical simulations of the pair-instability explosions of such stars performed with the MESA, FLASH and RAGE codes. We find that they will be visible to supernova factories such as Pan-STARRS and LSST in the optical out to z ~ 1-2 and JWST and the 30 m-class telescopes in the NIR out to z ~ 7-10. Such explosions will thus probe the stellar populations of the first galaxies and cosmic star formation rates in the era of cosmological reionization. These supernovae are also easily distinguished from more massive pair-instability explosions, underscoring the fact that there is far greater variety to the light curves of these events than previously understood.

  7. Stellar Evolution/Supernova Research Data Archives from the SciDAC...

    Office of Scientific and Technical Information (OSTI)

    and ground based supernova searches; 4) core collapse supernovae; 5) gamma-ray bursts; ... codes to study Type 1Amore and core-collapse supernovae. (Taken from http:...

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

    SciTech Connect

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

    2014-08-01

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

  9. Supernova / Acceleration Probe: a Satellite Experiment to Study the Nature of the Dark Energy

    SciTech Connect

    Aldering, G.; Althouse, W.; Amanullah, R.; Annis, J.; Astier, P.; Baltay, C.; Barrelet, E.; Basa, S.; Bebek, C.; Bergstrom, L.; Bernstein, G.; Bester, M.; Bigelow, B.; Blandford, R.; Bohlin, R.; Bonissent, A.; Bower, C.; Brown, M.; Campbell, M.; Carithers, W.; Commins, E.; /LBL, Berkeley /SLAC /Stockholm U. /Fermilab /Paris U., VI-VII /Yale U. /Pennsylvania U. /UC, Berkeley /Michigan U. /Baltimore, Space Telescope Sci. /Marseille, CPPM /Indiana U. /American Astron. Society /Caltech /Case Western Reserve U. /Cambridge U. /Saclay /Lyon, IPN

    2005-08-15

    , including discrimination of vacuum energy due to the cosmological constant and various classes of dynamical scalar fields. If we assume we live in a cosmological-constant-dominated Universe, the matter density, dark energy density, and flatness of space can all be measured with SNAP supernova and weak-lensing measurements to a systematics-limited accuracy of 1%. For a flat universe, the density-to-pressure ratio of dark energy or equation of state w(z) can be similarly measured to 5% for the present value w{sub 0} and {approx} 0.1 for the time variation w' {triple_bond} dw/d ln a|{sub z=1}. For a fiducial SUGRA-inspired universe, w{sub 0} and w' can be measured to an even tighter uncertainty of 0.03 and 0.06 respectively. Note that no external priors are needed. As more accurate theoretical predictions for the small-scale weak-lensing shear develop, the conservative estimates adopted here for space-based systematics should improve, allowing even tighter constraints. While the survey strategy is tailored for supernova and weak gravitational lensing observations, the large survey area, depth, spatial resolution, time-sampling, and nine-band optical to NIR photometry will support additional independent and/or complementary dark-energy measurement approaches as well as a broad range of auxiliary science programs.

  10. Supernova/Acceleration Probe: A Satellite Experiment to Study the Nature of the Dark Energy

    SciTech Connect

    Aldering, G.; Althouse, W.; Amanullah, R.; Annis, J.; Astier, P.; Baltay, C.; Barrelet, E.; Basa, E.; Bebek, C.; Bergstrom, L.; Bernstein, G.; Bester, M.; Bigelow, C.; Blandford, R.; Bohlin, R.; Bonissent, A.; Bower, C.; Brown, M.; Campbell, M.; Carithers, W.; Commins, E.; Craig, W.; Day, C.; DeJongh, F.; Deustua, S.; Diehl, T.; Dodelson, S.; Ealet, A.; Ellis, R.; Emmet, W.; Fouchez, D.; Frieman, J.; Fruchter, A.; Gerdes, D.; Gladney, L.; Goldhaber, G.; Goobar, A.; Groom, D.; Heetderks, H.; Hoff, M.; Holland, S.; Huffer, M.; Hui, L.; Huterer, D.; Jain, B.; Jelinsky, P.; Karcher, A.; Kent, S.; Kahn, S.; Kim, A.; Kolbe, W.; Krieger, B.; Kushner, G.; Kuznetsova, N.; Lafever, R.; Lamoureux, J.; Lampton, M.; Le Fevre, O.; Levi, M.; Limon, P.; Lin, H.; Linder, E.; Loken, S.; Lorenzon, W.; Malina, R.; Marriner, J.; Marshall, P.; Massey, R.; Mazure, A.; McKay, T.; McKee, S.; Miquel, R.; Morgan, N.; Mortsell, E.; Mostek, N.; Mufson, S.; Musser, J.; Nugent, P.; Oluseyi, H.; Pain, R.; Palaio, N.; Pankow, D.; Peoples, J.; Perlmutter, S.; Prieto, E.; Rabinowitz, D.; Refregier, A.; Rhodes, J.; Roe, N.; Rusin, D.; Scarpine, V.; Schubnell, M.; Sholl, M.; Samdja, G.; Smith, R.M.; Smoot, G.; Snyder, J.; Spadafora, A.; Stebbine, A.; Stoughton, C.; Szymkowiak, A.; Tarle, G.; Taylor, K.; Tilquin, A.; Tomasch, A.; Tucker, D.; Vincent, D.; von der Lippe, H.; Walder, J-P.; Wang, G.; Wester, W.

    2004-05-12

    , including discrimination of vacuum energy due to the cosmological constant and various classes of dynamical scalar fields. If we assume we live in a cosmological-constant-dominated Universe, the matter density, dark energy density, and flatness of space can all be measured with SNAP supernova and weak-lensing measurements to a systematics-limited accuracy of 1 percent. For a flat universe, the density-to-pressure ratio of dark energy or equation of state w(z) can be similarly measured to 5 percent for the present value w0 and {approx} 0.1 for the time variation w' is defined as dw/d ln a bar z = 1. For a fiducial SUGRA-inspired universe, w0 and w' can be measured to an even tighter uncertainty of 0.03 and 0.06 respectively. Note that no external priors are needed. As more accurate theoretical predictions for the small-scale weak-lensing shear develop, the conservative estimates adopted here for space-based systematics should improve, allowing even tighter constraints. While the survey strategy is tailored for supernova and weak gravitational lensing observations, the large survey area, depth, spatial resolution, time-sampling, and nine-band optical to NIR photometry will support additional independent and/or complementary dark-energy measurement approaches as well as a broad range of auxiliary science programs.

  11. Supernova relic neutrinos and the supernova rate problem: Analysis of uncertainties and detectability of ONeMg and failed supernovae

    SciTech Connect

    Mathews, Grant J. [Center for Astrophysics, Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Hidaka, Jun; Kajino, Toshitaka; Suzuki, Jyutaro [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan)

    2014-08-01

    Direct measurements of the core collapse supernova rate (R{sub SN}) in the redshift range 0 ? z ? 1 appear to be about a factor of two smaller than the rate inferred from the measured cosmic massive star formation rate (SFR). This discrepancy would imply that about one-half of the massive stars that have been born in the local observed comoving volume did not explode as luminous supernovae. In this work, we explore the possibility that one could clarify the source of this 'supernova rate problem' by detecting the energy spectrum of supernova relic neutrinos with a next generation 10{sup 6} ton water ?erenkov detector like Hyper-Kamiokande. First, we re-examine the supernova rate problem. We make a conservative alternative compilation of the measured SFR data over the redshift range 0 ?z ? 7. We show that by only including published SFR data for which the dust obscuration has been directly determined, the ratio of the observed massive SFR to the observed supernova rate R{sub SN} has large uncertainties ?1.8{sub ?0.6}{sup +1.6} and is statistically consistent with no supernova rate problem. If we further consider that a significant fraction of massive stars will end their lives as faint ONeMg SNe or as failed SNe leading to a black hole remnant, then the ratio reduces to ?1.1{sub ?0.4}{sup +1.0} and the rate problem is essentially solved. We next examine the prospects for detecting this solution to the supernova rate problem. We first study the sources of uncertainty involved in the theoretical estimates of the neutrino detection rate and analyze whether the spectrum of relic neutrinos can be used to independently identify the existence of a supernova rate problem and its source. We consider an ensemble of published and unpublished core collapse supernova simulation models to estimate the uncertainties in the anticipated neutrino luminosities and temperatures. We illustrate how the spectrum of detector events might be used to establish the average neutrino

  12. Effective perfect fluids in cosmology

    SciTech Connect

    Ballesteros, Guillermo; Bellazzini, Brando E-mail: brando.bellazzini@pd.infn.it

    2013-04-01

    We describe the cosmological dynamics of perfect fluids within the framework of effective field theories. The effective action is a derivative expansion whose terms are selected by the symmetry requirements on the relevant long-distance degrees of freedom, which are identified with comoving coordinates. The perfect fluid is defined by requiring invariance of the action under internal volume-preserving diffeomorphisms and general covariance. At lowest order in derivatives, the dynamics is encoded in a single function of the entropy density that characterizes the properties of the fluid, such as the equation of state and the speed of sound. This framework allows a neat simultaneous description of fluid and metric perturbations. Longitudinal fluid perturbations are closely related to the adiabatic modes, while the transverse modes mix with vector metric perturbations as a consequence of vorticity conservation. This formalism features a large flexibility which can be of practical use for higher order perturbation theory and cosmological parameter estimation.

  13. Cosmological perturbations in unimodular gravity

    SciTech Connect

    Gao, Caixia; Brandenberger, Robert H.; Cai, Yifu; Chen, Pisin E-mail: rhb@hep.physics.mcgill.ca E-mail: chen@slac.stanford.edu

    2014-09-01

    We study cosmological perturbation theory within the framework of unimodular gravity. We show that the Lagrangian constraint on the determinant of the metric required by unimodular gravity leads to an extra constraint on the gauge freedom of the metric perturbations. Although the main equation of motion for the gravitational potential remains the same, the shift variable, which is gauge artifact in General Relativity, cannot be set to zero in unimodular gravity. This non-vanishing shift variable affects the propagation of photons throughout the cosmological evolution and therefore modifies the Sachs-Wolfe relation between the relativistic gravitational potential and the microwave temperature anisotropies. However, for adiabatic fluctuations the difference between the result in General Relativity and unimodular gravity is suppressed on large angular scales. Thus, no strong constraints on the theory can be derived.

  14. Cosmological solution moduli of bigravity

    SciTech Connect

    Yılmaz, Nejat Tevfik

    2015-09-29

    We construct the complete set of metric-configuration solutions of the ghost-free massive bigravity for the scenario in which the g−metric is the Friedmann-Lemaitre-Robertson-Walker (FLRW) one, and the interaction Lagrangian between the two metrics contributes an effective ideal fluid energy-momentum tensor to the g-metric equations. This set corresponds to the exact background cosmological solution space of the theory.

  15. Signatures of a companion star in type Ia supernovae

    SciTech Connect

    Maeda, Keiichi; Kutsuna, Masamichi; Shigeyama, Toshikazu

    2014-10-10

    Although type Ia supernovae (SNe Ia) have been used as precise cosmological distance indicators, their progenitor systems remain unresolved. One of the key questions is whether there is a nondegenerate companion star at the time of a thermonuclear explosion of a white dwarf. In this paper, we investigate whether an interaction between the SN ejecta and the companion star may result in observable footprints around the maximum brightness and thereafter, by performing multidimensional radiation transfer simulations based on hydrodynamic simulations of the interaction. We find that such systems result in variations in various observational characteristics due to different viewing directions, and the predicted behaviors (redder and fainter for the companion direction) are the opposite of what were suggested by the previous study. The variations are generally modest and within observed scatters. However, the model predicts trends between some observables different from those observationally derived, so a large sample of SNe Ia with small calibration errors may be used to constrain the existence of such a companion star. The variations in different colors in optical band passes can be mimicked by external extinctions, so such an effect could be a source of scatter in the peak luminosity and derived distance. After the peak, hydrogen-rich materials expelled from the companion will manifest themselves in hydrogen lines, but Hα is extremely difficult to identify. Alternatively, we find that P{sub β} in postmaximum near-infrared spectra can potentially provide a powerful diagnostic.

  16. ANTIPROTONS PRODUCED IN SUPERNOVA REMNANTS

    SciTech Connect

    Berezhko, E. G.; Ksenofontov, L. T.

    2014-08-20

    We present the energy spectrum of an antiproton cosmic ray (CR) component calculated on the basis of the nonlinear kinetic model of CR production in supernova remnants (SNRs). The model includes the reacceleration of antiprotons already existing in the interstellar medium as well as the creation of antiprotons in nuclear collisions of accelerated protons with gas nuclei and their subsequent acceleration by SNR shocks. It is shown that the production of antiprotons in SNRs produces a considerable effect in their resultant energy spectrum, making it essentially flatter above 10 GeV so that the spectrum at TeV energies increases by a factor of 5. The calculated antiproton spectrum is consistent with the PAMELA data, which correspond to energies below 100 GeV. As a consistency check, we have also calculated within the same model the energy spectra of secondary nuclei and show that the measured boron-to-carbon ratio is consistent with the significant SNR contribution.

  17. Supercomputing and the search for supernovae

    ScienceCinema

    Nugent, Peter

    2016-07-12

    Berkeley Lab's Peter Nugent discusses "Supercomputing and the search for supernovae" in this Oct. 28, 2013 talk, which is part of a Science at the Theater event entitled Eight Big Ideas.

  18. How to See a Recently Discovered Supernova

    ScienceCinema

    Nugent, Peter

    2013-05-29

    Berkeley Lab scientist Peter Nugent discusses a recently discovered supernova that is closer to Earth ? approximately 21 million light-years away ? than any other of its kind in a generation. Astronomers believe they caught the supernova within hours of its explosion, a rare feat made possible with a specialized survey telescope and state-of-the-art computational tools. The finding of such a supernova so early and so close has energized the astronomical community as they are scrambling to observe it with as many telescopes as possible, including the Hubble Space Telescope. More info on how to see it: http://newscenter.lbl.gov/feature-stories/2011/08/31/glimpse-cosmic-explosion/ News release: http://newscenter.lbl.gov/feature-stories/2011/08/25/supernova/

  19. Supernova cooling in a dark matter smog

    SciTech Connect

    Zhang, Yue

    2014-11-27

    A light hidden gauge boson with kinetic mixing with the usual photon is a popular setup in theories of dark matter. The supernova cooling via radiating the hidden boson is known to put an important constraint on the mixing. I consider the possible role dark matter, which under reasonable assumptions naturally exists inside supernova, can play in the cooling picture. Because the interaction between the hidden gauge boson and DM is likely unsuppressed, even a small number of dark matter compared to protons inside the supernova could dramatically shorten the free streaming length of the hidden boson. A picture of a dark matter “smog” inside the supernova, which substantially relaxes the cooling constraint, is discussed in detail.

  20. Emergent cosmological constant from colliding electromagnetic waves

    SciTech Connect

    Halilsoy, M.; Mazharimousavi, S. Habib; Gurtug, O. E-mail: habib.mazhari@emu.edu.tr

    2014-11-01

    In this study we advocate the view that the cosmological constant is of electromagnetic (em) origin, which can be generated from the collision of em shock waves coupled with gravitational shock waves. The wave profiles that participate in the collision have different amplitudes. It is shown that, circular polarization with equal amplitude waves does not generate cosmological constant. We also prove that the generation of the cosmological constant is related to the linear polarization. The addition of cross polarization generates no cosmological constant. Depending on the value of the wave amplitudes, the generated cosmological constant can be positive or negative. We show additionally that, the collision of nonlinear em waves in a particular class of Born-Infeld theory also yields a cosmological constant.

  1. Cosmology & Astrophysics | Argonne National Laboratory

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    Cosmology & Astrophysics Cosmology & Astrophysics For centuries, scientists have tried to fully describe the formation and evolution of our universe, as well as its composition. At Argonne, scientists study the cosmic background radiation that formed as a result of the big bang as well as the mysterious dark matter and dark energy which combine to form more than 90 percent of our universe. Cosmology, the study of the origins and working of our universe, not only gives us answers that

  2. Nuclear and Particle Physics, Astrophysics, and Cosmology

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    Nuclear and Particle Physics, Astrophysics, and Cosmology Providing scientific and technical leadership in fundamental and applied theoretical research on nuclear, particle, ...

  3. The Effective Field Theory of Cosmological Large Scale Structures...

    Office of Scientific and Technical Information (OSTI)

    The Effective Field Theory of Cosmological Large Scale Structures Citation Details In-Document Search Title: The Effective Field Theory of Cosmological Large Scale Structures...

  4. Cosmological singularities in Born-Infeld determinantal gravity...

    Office of Scientific and Technical Information (OSTI)

    Cosmological singularities in Born-Infeld determinantal gravity Citation Details In-Document Search Title: Cosmological singularities in Born-Infeld determinantal gravity Authors: ...

  5. Cosmology from large scale galaxy clustering and galaxy-galaxy lensing with Dark Energy Survey Science Verification data

    DOE PAGES [OSTI]

    Kwan, J.

    2016-10-05

    Here, we present cosmological constraints from the Dark Energy Survey (DES) using a combined analysis of angular clustering of red galaxies and their cross-correlation with weak gravitational lensing of background galaxies. We use a 139 square degree contiguous patch of DES data from the Science Verification (SV) period of observations. Using large scale measurements, we constrain the matter density of the Universe as Ωm = 0.31 ± 0.09 and the clustering amplitude of the matter power spectrum as σ8 = 0.74 ± 0.13 after marginalizing over seven nuisance parameters and three additional cosmological parameters. This translates into S8 Ξ σ8more » (Ωm/0.3)0.16 = 0.74 ± 0.12 for our fiducial lens redshift bin at 0.35 < z < 0.5, while S8 = 0.78 ± 0.09 using two bins over the range 0.2 < z < 0.5. We study the robustness of the results under changes in the data vectors, modelling and systematics treatment, including photometric redshift and shear calibration uncertainties, and find consistency in the derived cosmological parameters. We show that our results are consistent with previous cosmological analyses from DES and other data sets and conclude with a joint analysis of DES angular clustering and galaxy-galaxy lensing with Planck CMB data, Baryon Accoustic Oscillations and Supernova type Ia measurements.« less

  6. No hair theorem for inhomogeneous cosmologies

    SciTech Connect

    Jensen, L.G.; Stein-Schabes, J.A.

    1986-03-01

    We show that under very general conditions any inhomogeneous cosmological model with a positive cosmological constant, that can be described in a synchronous reference system will tend asymptotically in time towards the de Sitter solution. This is shown to be relevant in the context of inflationary models as it makes inflation very weakly dependent on initial conditions. 8 refs.

  7. Cosmic Rays from Supernovae Proven to Hit Earth

    Energy.gov [DOE]

    A new study confirms that cosmic rays are born in the violent aftermath of supernovas, exploding stars throughout the galaxy.

  8. Horava-Lifshitz Theory and Applications to Cosmology and Astrophysics

    SciTech Connect

    Wang, Anzhong

    2014-08-14

    This final report describes the activities of the Baylor University Gravity, Cosmology and Astroparticle Physics (GCAP) group on the project: Horava-Lifshitz Theory and Applications to Cosmology and Astrophysics, during the time, August 15, 2010 - August 14, 2014. We are grateful for the financial support provided by the U.S. Department of Energy for this research, which leads to our exceptional success. We are very proud to say that we have achieved all the goals set up in our project and made significant contributions to the understanding of the field. In particular, with this DOE support, we have published 38 articles in the prestigious national/international journals, which have already received about 1000 citations so far.

  9. Tidally-Induced Thermonuclear Supernovae

    SciTech Connect

    Rosswog, S.; Ramirez-Ruiz, E.; Hix, William Raphael

    2009-01-01

    We discuss the results of 3D simulations of tidal disruptions of white dwarfs by moderate-mass black holes as they may exist in the cores of globular clusters or dwarf galaxies. Our simulations follow self-consistently the hydrodynamic and nuclear evolution from the initial parabolic orbit over the disruption to the build-up of an accretion disk around the black hole. For strong enough encounters (pericentre distances smaller than about 1/3 of the tidal radius) the tidal compression is reversed by a shock and finally results in a thermonuclear explosion. These explosions are not restricted to progenitor masses close to the Chandrasekhar limit, we find exploding examples throughout the whole white dwarf mass range. There is, however, a restriction on the masses of the involved black holes: black holes more massive than 2x105M{circle_dot} swallow a typical 0.6M{circle_dot} white dwarf before their tidal forces can overwhelm the star's selfgravity. Therefore, this mechanism is characteristic for black holes of moderate masses. The material that remains bound to the black hole settles into an accretion disk and produces an Xray flare close to the Eddington limit of L{sub Edd} {approx} 10{sup 41}erg/s (Mbh/1000M{circle_dot}), typically lasting for a few months. The combination of a peculiar thermonuclear supernova together with an X-ray flare thus whistle-blows the existence of such moderate-mass black holes. The next generation of wide field space-based instruments should be able to detect such events.

  10. Nuclear Physics in Core-Collapse Supernovae

    SciTech Connect

    Liebendoerfer, Matthias; Fischer, T.; Froelich, C.; Hix, William Raphael; Langanke, Karlheinz; Martinez-Pinedo, Gabriel; Mezzacappa, Anthony; Scheidegger, Simon; Thielemann, Friedrich-Karl W.; Whitehouse, Stuart

    2008-01-01

    Core-collapse and the launch of a supernova explosion form a very short episode of few seconds in the evolution of a massive star, during which an enormous gravitational energy of several times 1053 erg is transformed into observable neutrino-, kinetic-, and electromagnetic radiation energy. We emphasize the wide range of matter conditions that prevail in a supernova event and sort the conditions into distinct regimes in the density and entropy phase diagram to briefly discuss their different impact on the neutrino signal, gravitational wave emission, and ejecta.

  11. Nuclear Physics in Core-Collapse Supernovae

    SciTech Connect

    Liebendoerfer, M.; Fischer, T.; Froelich, C.; Hix, William Raphael; Langanke, Karlheinz; Mart�nez-Pinedo, Gabriel; Mezzacappa, Anthony; Scheidegger, Simon; Thielemann, F.-K.; Whitehouse, S.

    2008-10-01

    Core collapse and the launch of a supernova explosion form a very short episode of a few seconds in the evolution of a massive star, during which an enormous gravitational energy of several times 10^{51} erg is transformed into observable neutrino, kinetic, and optical energy. We emphasize the wide range of matter conditions that prevail in a supernova event and sort the conditions into distinct regimes in the density and entropy phase diagram to briefly discuss their different impact on the neutrino signal, gravitational wave emission, and ejecta.

  12. Type Ia supernova rate studies from the SDSS-II Supernova Study

    SciTech Connect

    Dilday, Benjamin

    2008-08-01

    The author presents new measurements of the type Ia SN rate from the SDSS-II Supernova Survey. The SDSS-II Supernova Survey was carried out during the Fall months (Sept.-Nov.) of 2005-2007 and discovered ~ 500 spectroscopically confirmed SNe Ia with densely sampled (once every ~ 4 days), multi-color light curves. Additionally, the SDSS-II Supernova Survey has discovered several hundred SNe Ia candidates with well-measured light curves, but without spectroscopic confirmation of type. This total, achieved in 9 months of observing, represents ~ 15-20% of the total SNe Ia discovered worldwide since 1885. The author describes some technical details of the SN Survey observations and SN search algorithms that contributed to the extremely high-yield of discovered SNe and that are important as context for the SDSS-II Supernova Survey SN Ia rate measurements.

  13. Core-collapse supernova neutrinos and neutrino properties

    SciTech Connect

    Gava, J.; Volpe, C.

    2008-08-29

    Core-collapse supernovae are powerful neutrino sources. The observation of a future (extra-)galactic supernova explosion or of the relic supernova neutrinos might provide important information on the supernova dynamics, on the supernova formation rate and on neutrino properties. One might learn more about unknown neutrino properties either from indirect effects in the supernova (e.g. on the explosion or on in the r-process) or from modifications of the neutrino time or energy distributions in a detector on Earth. Here we will discuss in particular possible effects of CP violation in the lepton sector. We will also mention the interest of future neutrino-nucleus interaction measurements for the precise knowledge of supernova neutrino detector response to electron neutrinos.

  14. Properties of optically selected supernova remnant candidates in M33

    SciTech Connect

    Lee, Jong Hwan; Lee, Myung Gyoon E-mail: mglee@astro.snu.ac.kr

    2014-10-01

    Narrowband images covering strong emission lines are efficient for surveying supernova remnants (SNRs) in nearby galaxies. Using the narrowband images provided by the Local Group Galaxy Survey, we searched for SNRs in M33. Culling the objects with enhanced [S II]/Hα and round morphology in the continuum-subtracted Hα and [S II] images, we produced a list of 199 sources. Among them, 79 are previously unknown. Their progenitor and morphology types were classified. A majority of the sample (170 objects) are likely remnants of core-collapse supernovae (SNe), and 29 are remnants of Type Ia SNe. The cumulative size distribution of these objects is found to be similar to that of the M31 remnants derived in a similar way. We obtain a power-law slope, α = 2.38 ± 0.05. Thus, a majority of the sources are considered to be in the Sedov-Taylor phase, consistent with previous findings. The histogram of the emission-line ratio ([S II]/Hα) of the remnants has two concentrations at [S II]/Hα ∼ 0.55 and ∼0.8, as in M31. Interestingly, L {sub X} (and L {sub 20cm}) of the compact center-bright objects are correlated with their optical luminosity. The remnants with X-ray emission have brighter optical surface brightnesses and smaller diameters than those without X-ray emission.

  15. COSMOLOGICAL SIMULATIONS OF INTERGALACTIC MEDIUM EVOLUTION. I. TEST OF THE SUBGRID CHEMICAL ENRICHMENT MODEL

    SciTech Connect

    Côté, Benoit; Martel, Hugo; Drissen, Laurent

    2013-11-10

    We present a one-zone galactic chemical enrichment model that takes into account the contribution of stellar winds from massive stars under the effect of rotation, Type II supernovae, hypernovae, stellar winds from low- and intermediate-mass stars, and Type Ia supernovae. This enrichment model will be implemented in a galactic model designed to be used as a subgrid treatment for galaxy evolution and outflow generation in large-scale cosmological simulations, in order to study the evolution of the intergalactic medium. We test our enrichment prescription by comparing its predictions with the metallicity distribution function and the abundance patterns of 14 chemical elements observed in the Milky Way stars. To do so, we combine the effect of many stellar populations created from the star formation history of the Galaxy in the solar neighborhood. For each stellar population, we keep track of its specific mass, initial metallicity, and age. We follow the time evolution of every population in order to respect the time delay between the various stellar phases. Our model is able to reproduce the observed abundances of C, O, Na, Mg, Al, S, and Ca. For Si, Cr, Mn, Ni, Cu, and Zn, the fits are still reasonable, but improvements are needed. We marginally reproduce the nitrogen abundance in very low metallicity stars. Overall, our results are consistent with the predicted abundance ratios seen in previous studies of the enrichment history of the Milky Way. We have demonstrated that our semi-analytic one-zone model, which cannot deal with spatial information such as the metallicity gradient, can nevertheless successfully reproduce the global Galactic enrichment evolution obtained by more complex models, at a fraction of the computational cost. This model is therefore suitable for a subgrid treatment of chemical enrichment in large-scale cosmological simulations.

  16. Multipole expansion method for supernova neutrino oscillations

    SciTech Connect

    Duan, Huaiyu; Shalgar, Shashank, E-mail: duan@unm.edu, E-mail: shashankshalgar@unm.edu [Department of Physics and Astronomy, University of New Mexico, Albuquerque, NM 87131 (United States)

    2014-10-01

    We demonstrate a multipole expansion method to calculate collective neutrino oscillations in supernovae using the neutrino bulb model. We show that it is much more efficient to solve multi-angle neutrino oscillations in multipole basis than in angle basis. The multipole expansion method also provides interesting insights into multi-angle calculations that were accomplished previously in angle basis.

  17. COSMOLOGICAL ADAPTIVE MESH REFINEMENT MAGNETOHYDRODYNAMICS WITH ENZO

    SciTech Connect

    Collins, David C.; Xu Hao; Norman, Michael L.; Li Hui; Li Shengtai

    2010-02-01

    In this work, we present EnzoMHD, the extension of the cosmological code Enzo to include the effects of magnetic fields through the ideal magnetohydrodynamics approximation. We use a higher order Godunov method for the computation of interface fluxes. We use two constrained transport methods to compute the electric field from those interface fluxes, which simultaneously advances the induction equation and maintains the divergence of the magnetic field. A second-order divergence-free reconstruction technique is used to interpolate the magnetic fields in the block-structured adaptive mesh refinement framework already extant in Enzo. This reconstruction also preserves the divergence of the magnetic field to machine precision. We use operator splitting to include gravity and cosmological expansion. We then present a series of cosmological and non-cosmological test problems to demonstrate the quality of solution resulting from this combination of solvers.

  18. Cosmology at the Beach Lecture: Anne Green

    ScienceCinema

    Ann Green

    2016-07-12

    The lecture was delivered as part of the "Cosmology at the Beach" winter school organized by Berkeley Lab's George Smoot in Los Cabos, Mexico from Jan. 12-16, 2009.  

  19. Cosmology on the Beach: Kendrick Smith

    ScienceCinema

    George Smoot

    2016-07-12

    The lecture was delivered as part of the "Cosmology at the Beach" winter school organized by Berkeley Lab's George Smoot in Los Cabos, Mexico from Jan. 12-16, 2009.

  20. Primordial nucleosynthesis: A cosmological point of view

    SciTech Connect

    Mathews, G. J.; Kusakabe, M.; Cheoun, M.-K.

    2014-05-09

    Primordial nucleosynthesis remains as one of the pillars of modern cosmology. It is the test-ing ground upon which all cosmological models must ultimately rest. It is our only probe of the universe during the first few minutes of cosmic expansion and in particular during the important radiation-dominated epoch. These lectures review the basic equations of space-time, cosmology, and big bang nucleosynthesis. We will then review the current state of observational constraints on primordial abundances along with the key nuclear reactions and their uncertainties. We summarize which nuclear measure-ments are most crucial during the big bang. We also review various cosmological models and their constraints. In particular, we summarize the constraints that big bang nucleosynthesis places upon the possible time variation of fundamental constants, along with constraints on the nature and origin of dark matter and dark energy, long-lived supersymmetric particles, gravity waves, and the primordial magnetic field.

  1. Cosmology at the Beach Lecture: Simon White

    ScienceCinema

    Simon White

    2016-07-12

    The lecture was delivered as part of the "Cosmology at the Beach" winter school organized by Berkeley Lab's George Smoot in Los Cabos, Mexico from Jan. 12-16, 2009.

  2. Cosmology at the Beach Lecture: David Hughes

    ScienceCinema

    David Hughes

    2016-07-12

    The lecture was delivered as part of the "Cosmology at the Beach" winter school organized by Berkeley Lab's George Smoot in Los Cabos, Mexico from Jan. 12-16, 2009.

  3. Cosmology on the Beach - George Smoot

    ScienceCinema

    George Smoot

    2016-07-12

    The lecture was delivered as part of the "Cosmology at the Beach" winter school organized by Berkeley Lab's George Smoot in Los Cabos, Mexico from Jan. 12-16, 2009.

  4. Improving Data Mobility & Management for International Cosmology

    SciTech Connect

    Borrill, Julian; Dart, Eli; Gore, Brooklin; Habib, Salman; Myers, Steven T.; Nugent, Peter; Petravick, Don; Thomas, Rollin

    2015-10-02

    In February 2015 the third workshop in the CrossConnects series, with a focus on Improving Data Mobility & Management for International Cosmology, was held at Lawrence Berkeley National Laboratory. Scientists from fields including astrophysics, cosmology, and astronomy collaborated with experts in computing and networking to outline strategic opportunities for enhancing scientific productivity and effectively managing the ever-increasing scale of scientific data.

  5. First trillion particle cosmological simulation completed

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    First trillion particle cosmological simulation completed First trillion particle cosmological simulation completed A team of astrophysicists and computer scientists has created high-resolution cyber images of our cosmos. January 8, 2015 Simulation of the cosmic web of the dark matter mass distribution. This region represents about 1/10,000 of the total simulation volume. Simulation of the cosmic web of the dark matter mass distribution. This region represents about 1/10,000 of the total

  6. A NEW COSMOLOGICAL DISTANCE MEASURE USING ACTIVE GALACTIC NUCLEUS X-RAY VARIABILITY

    SciTech Connect

    Franca, Fabio La; Bianchi, Stefano; Branchini, Enzo; Matt, Giorgio [Dipartimento di Matematica e Fisica, Universit Roma Tre, Via della Vasca Navale 84, I-00146, Roma (Italy); Ponti, Gabriele, E-mail: lafranca@fis.uniroma3.it [Max-Planck-Institut fr Extraterrestrische Physik, Giessenbachstrasse 1, D-85748 Garching bei Mnchen (Germany)

    2014-05-20

    We report the discovery of a luminosity distance estimator using active galactic nuclei (AGNs). We combine the correlation between the X-ray variability amplitude and the black hole (BH) mass with the single-epoch spectra BH mass estimates which depend on the AGN luminosity and the line width emitted by the broad-line region. We demonstrate that significant correlations do exist that allow one to predict the AGN (optical or X-ray) luminosity as a function of the AGN X-ray variability and either the H? or the Pa? line widths. In the best case, when the Pa? is used, the relationship has an intrinsic dispersion of ?0.6dex. Although intrinsically more disperse than supernovae Ia, this relation constitutes an alternative distance indicator potentially able to probe, in an independent way, the expansion history of the universe. With respect to this, we show that the new mission concept Athena should be able to measure the X-ray variability of hundreds of AGNs and then constrain the distance modulus with uncertainties of 0.1mag up to z ? 0.6. We also discuss how our estimator has the prospect of becoming a cosmological probe even more sensitive than the current supernovae Ia samples by using a new dedicated wide-field X-ray telescope able to measure the variability of thousands of AGNs.

  7. THE REDDENING TOWARD CASSIOPEIA A's SUPERNOVA: CONSTRAINING THE...

    Office of Scientific and Technical Information (OSTI)

    Country of Publication: United States Language: English Subject: 79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; 99 GENERAL AND MISCELLANEOUSMATHEMATICS, COMPUTING, AND INFORMATION ...

  8. Weak-interaction processes in core-collapse supernovae

    SciTech Connect

    Langanke, K.

    2015-02-24

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

  9. Computational Astrophysics Consortium 3 - Supernovae, Gamma-Ray Bursts and

    Office of Scientific and Technical Information (OSTI)

    Nucleosynthesis (Technical Report) | SciTech Connect Computational Astrophysics Consortium 3 - Supernovae, Gamma-Ray Bursts and Nucleosynthesis Citation Details In-Document Search Title: Computational Astrophysics Consortium 3 - Supernovae, Gamma-Ray Bursts and Nucleosynthesis Final project report for UCSC's participation in the Computational Astrophysics Consortium - Supernovae, Gamma-Ray Bursts and Nucleosynthesis. As an appendix, the report of the entire Consortium is also appended.

  10. Supernovae and gamma-ray bursts connection

    SciTech Connect

    Valle, Massimo Della

    2015-12-17

    I’ll review the status of the Supernova/Gamma-Ray Burst connection. Several pieces of evidence suggest that long duration Gamma-ray Bursts are associated with bright SNe-Ic. However recent works suggest that GRBs might be produced in tight binary systems composed of a massive carbon-oxygen cores and a neutron star companion. Current estimates of the SN and GRB rates yield a ratio GRB/SNe-Ibc in the range ∼ 0.4% − 3%.

  11. Multigroup Radiation Transport in Supernova Light Curve Calculations...

    Office of Scientific and Technical Information (OSTI)

    SciTech Connect Search Results Technical Report: Multigroup Radiation Transport in Supernova Light Curve Calculations Citation Details In-Document Search Title: Multigroup ...

  12. New approaches for modeling type Ia supernovae (Conference) ...

    Office of Scientific and Technical Information (OSTI)

    Type Ia supernovae (SNe Ia) are the largest thermonuclearexplosions in the Universe. Their light output can be seen across greatstances and has led to the discovery that the ...

  13. Type Ia Supernova Hubble Residuals and Host-Galaxy Properties...

    Office of Scientific and Technical Information (OSTI)

    SciTech Connect Search Results Journal Article: Type Ia Supernova Hubble Residuals and ... as distinguished from previous works that use magnitude corrections as a ...

  14. SUPERNOVA NEUTRINO LIGHT CURVES AND SPECTRA FOR VARIOUS PROGENITOR...

    Office of Scientific and Technical Information (OSTI)

    FROM CORE COLLAPSE TO PROTO-NEUTRON STAR COOLING Citation Details In-Document Search Title: SUPERNOVA NEUTRINO LIGHT CURVES AND SPECTRA FOR VARIOUS PROGENITOR STARS: FROM CORE ...

  15. Saul Perlmutter, Distant Supernovae, Dark Energy, and the Accelerating...

    Office of Scientific and Technical Information (OSTI)

    Saul Perlmutter, Distant Supernovae, Dark Energy, and the Accelerating Expansion of the ... studies to determine the nature of dark energy.'1 'The accelerating expansion means that ...

  16. HUBBLE RESIDUALS OF NEARBY TYPE Ia SUPERNOVAE ARE CORRELATED...

    Office of Scientific and Technical Information (OSTI)

    ... MASS; RED SHIFT; SUPERNOVAE BINARY STARS; ERUPTIVE VARIABLE STARS; OPTICAL PROPERTIES; PHYSICAL PROPERTIES; STARS; VARIABLE STARS Word Cloud More Like This Full Text Journal ...

  17. CEPHEID CALIBRATIONS OF MODERN TYPE Ia SUPERNOVAE: IMPLICATIONS...

    Office of Scientific and Technical Information (OSTI)

    CEPHEID CALIBRATIONS OF MODERN TYPE Ia SUPERNOVAE: IMPLICATIONS FOR THE HUBBLE CONSTANT ... Country of Publication: United States Language: English Subject: 79 ASTROPHYSICS, ...

  18. Turbulence-Flame Interactions in Type Ia Supernovae (Journal...

    Office of Scientific and Technical Information (OSTI)

    turbulent intensity and l is the integral scale. For the larger integral scales characteristic of a real supernova, the flame structure is predicted to become complex and unsteady. ...

  19. Multigroup Radiation Transport in Supernova Light Curve Calculations...

    Office of Scientific and Technical Information (OSTI)

    Multigroup Radiation Transport in Supernova Light Curve Calculations Even, Wesley P. Los Alamos National Laboratory; Frey, Lucille H. Los Alamos National Laboratory; Fryer,...

  20. Confirmed: Stellar Behemoth Self-Destructs in Type IIb Supernova

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    Confirmed: Stellar Behemoth Self-Destructs in Type IIb Supernova Confirmed: Stellar Behemoth Self-Destructs in Type IIb Supernova Berkeley Researchers Help Catch a Wolf-Rayet Hours After it Goes Supernova May 21, 2014 Contact: Linda Vu, +1 510 495 2402, lvu@lbl.gov SN2013cu-.jpg A star in a distant galaxy explodes as a supernova: While observing a galaxy known as UGC 9379 (left; image from the Sloan Digital Sky Survey; SDSS) located about 360 million light years away from Earth, the team

  1. Lab helps to discover supernova ASAS-SN

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    Lab helps to discover supernova ASAS-SN Lab helps to discover supernova ASAS-SN Machine-learning technology developed at Los Alamos National Laboratory helps power ASAS-SN, providing the software that picks out these events from the images the project spots. January 15, 2016 ASSASN An artist's impression of the record-breakingly powerful, superluminous supernova ASASSN-15lh as it would appear from an exoplanet located about 10,000 light years away in the host galaxy of the supernova. (Credit:

  2. Systematic Effects in Type-1a Supernovae Surveys from Host Galaxy...

    Office of Scientific and Technical Information (OSTI)

    of supernovae, and correlations between the progenitor stellar populations and the nature of the supernova light curves. Authors: Strauss, Michael A. 1 + Show Author...

  3. Stellar Evolution/Supernova Research Data Archives from the SciDAC...

    Office of Scientific and Technical Information (OSTI)

    The team has developed and used supernovae simulation codes to study Type 1Amore and core-collapse supernovae. (Taken from http:www.scidac.govphysicsgrb.html) The ...

  4. Systematic Effects in Type-1a Supernovae Surveys from Host Galaxy...

    Office of Scientific and Technical Information (OSTI)

    This grant found strong evidence for two distinct populations of supernovae, and correlations between the progenitor stellar populations and the nature of the supernova light ...

  5. High Statistics Study of Nearby Type 1a Supernovae. QUEST Camera...

    Office of Scientific and Technical Information (OSTI)

    Statistics Study of Nearby Type 1a Supernovae. QUEST Camera Short Term Maintenance: Final Technical Report Baltay, Charles 79 ASTRONOMY AND ASTROPHYSICS Study of Type 1a Supernovae...

  6. Neutrino-induced nucleosynthesis in supernovae

    SciTech Connect

    Hayakawa, Takehito

    2012-11-12

    The neutrino-induced reactions in supernova explosions produce some rare odd-odd nuclides. We have made a new time-dependent calculation of the supernova production ratio of the long-lived isomeric state of {sup 180}Ta. This time-dependent solution is crucial for understanding the production and survival of this isotope. We find that the explicit time evolution of the synthesis of {sup 180}Ta using the available nuclear data avoids the overproduction relative to {sup 138}La for a {nu}-process neutrino temperature of 4 MeV. An unstable isotope {sup 92}Nb decays to {sup 92}Zr with a half-life of 3.47 Multiplication-Sign 10{sup 7} years. We have proposed the {nu}-process origin for {sup 92}Nb. We calculate key neutrino-induced reactions and supernova {nu}-process. Our calculated result shows that the abundance of {sup 92}Nb can be explained by the {nu}-process.

  7. The core collapse supernova rate from the SDSS-II supernova survey

    SciTech Connect

    Taylor, Matt; Cinabro, David [Department of Physics and Astronomy, Wayne State University, Detroit, MI 48202 (United States); Dilday, Ben [Spokane, WA 99203 (United States); Galbany, Lluis [Millennium Institute of Astrophysics, Universidad de Chile, Casilla 36-D, Santiago (Chile); Gupta, Ravi R. [Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104 (United States); Kessler, R. [Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL 60637 (United States); Marriner, John [Center for Particle Astrophysics, Fermi National Accelerator Laboratory, P.O. Box 500, Batavia, IL 60510 (United States); Nichol, Robert C. [Institute of Cosmology and Gravitation, Dennis Sciama Building, University of Portsmouth, Portsmouth PO1 2FX (United Kingdom); Richmond, Michael [School of Physics and Astronomy, Rochester Institute of Technology, Rochester, NY 14623 (United States); Schneider, Donald P. [Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802 (United States); Sollerman, Jesper, E-mail: cinabro@physics.wayne.edu [The Oskar Klein Centre, Department of Astronomy, AlbaNova, SE-106 91 Stockholm (Sweden)

    2014-09-10

    We use the Sloan Digital Sky Survey II Supernova Survey (SDSS-II SNS) data to measure the volumetric core collapse supernova (CCSN) rate in the redshift range (0.03 < z < 0.09). Using a sample of 89 CCSN, we find a volume-averaged rate of 1.06 0.19 10{sup 4}((h/0.7){sup 3}/(yr Mpc{sup 3})) at a mean redshift of 0.072 0.009. We measure the CCSN luminosity function from the data and consider the implications on the star formation history.

  8. The new cosmology (Conference) | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    The new cosmology Citation Details In-Document Search Title: The new cosmology You are accessing a document from the Department of Energy's (DOE) SciTech Connect. This site is a ...

  9. The new cosmology (Conference) | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    The new cosmology Citation Details In-Document Search Title: The new cosmology Over the past three years we have determined the basic features of our Universe. It is spatially ...

  10. Cosmological Simulations for Large-Scale Sky Surveys | Argonne...

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    The focus of cosmology today is on its two mysterious pillars, dark matter and dark energy. Large-scale sky surveys are the current drivers of precision cosmology and have been ...

  11. Cosmological Simulations for Large-Scale Sky Surveys | Argonne...

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    The focus of cosmology today revolves around two mysterious pillars, dark matter and dark energy. Large-scale sky surveys are the current drivers of precision cosmology and have ...

  12. Cosmological Behavior of a Parity and Charge-Parity Violating...

    Office of Scientific and Technical Information (OSTI)

    Cosmological Behavior of a Parity and Charge-Parity Violating Varying Alpha Theory Citation Details In-Document Search Title: Cosmological Behavior of a Parity and Charge-Parity ...

  13. Cosmological behavior of a parity and charge-parity violating...

    Office of Scientific and Technical Information (OSTI)

    Cosmological behavior of a parity and charge-parity violating varying alpha theory Citation Details In-Document Search Title: Cosmological behavior of a parity and charge-parity ...

  14. Rescuing the Born rule for quantum cosmology

    SciTech Connect

    Cooperman, Joshua H.

    2011-02-01

    Page has recently argued that the Born rule does not suffice for computing all probabilities in quantum cosmology. He further asserts that the Born rule's failure gives rise to the cosmological measure problem. Here I contend that Page's result stems from his use of an overly restrictive definition of the Born rule. In particular, I demonstrate that all of the probabilities he wishes to compute follow from the Born rule when generalized measurements are permitted. I also register two comments on Page's theoretical setting, relating respectively to Hilbert space dimensionality and permutation symmetry. These considerations lead me to conclude that the claimed insufficiency of the Born rule is by no means specific to the cosmological context.

  15. Quantum cosmological consistency condition for inflation

    SciTech Connect

    Calcagni, Gianluca; Kiefer, Claus; Steinwachs, Christian F. E-mail: kiefer@thp.uni-koeln.de

    2014-10-01

    We investigate the quantum cosmological tunneling scenario for inflationary models. Within a path-integral approach, we derive the corresponding tunneling probability distribution. A sharp peak in this distribution can be interpreted as the initial condition for inflation and therefore as a quantum cosmological prediction for its energy scale. This energy scale is also a genuine prediction of any inflationary model by itself, as the primordial gravitons generated during inflation leave their imprint in the B-polarization of the cosmic microwave background. In this way, one can derive a consistency condition for inflationary models that guarantees compatibility with a tunneling origin and can lead to a testable quantum cosmological prediction. The general method is demonstrated explicitly for the model of natural inflation.

  16. Inflation after COBE: Lectures on inflationary cosmology

    SciTech Connect

    Turner, M.S. [Chicago Univ., IL (United States). Enrico Fermi Inst.]|[Fermi National Accelerator Lab., Batavia, IL (United States)

    1992-12-31

    In these lectures I review the standard hot big-bang cosmology, emphasizing its successes, its shortcomings, and its major challenge-a detailed understanding of the formation of structure in the Universe. I then discuss the motivations for and the fundamentals of inflationary cosmology, particularly emphasizing the quantum origin of metric (density and gravity-wave) perturbations. Inflation addresses the shortcomings of the standard cosmology and provides the ``initial data`` for structure formation. I conclude by addressing the implications of inflation for structure formation, evaluating the various cold dark matter models in the light of the recent detection of temperature anisotropies in the cosmic background radiation by COBE. In the near term, the study of structure formation offers a powerful probe of inflation, as well as specific inflationary models.

  17. CosmoSIS: Modular cosmological parameter estimation

    SciTech Connect

    Zuntz, J.; Paterno, M.; Jennings, E.; Rudd, D.; Manzotti, A.; Dodelson, S.; Bridle, S.; Sehrish, S.; Kowalkowski, J.

    2015-06-09

    Cosmological parameter estimation is entering a new era. Large collaborations need to coordinate high-stakes analyses using multiple methods; furthermore such analyses have grown in complexity due to sophisticated models of cosmology and systematic uncertainties. In this paper we argue that modularity is the key to addressing these challenges: calculations should be broken up into interchangeable modular units with inputs and outputs clearly defined. Here we present a new framework for cosmological parameter estimation, CosmoSIS, designed to connect together, share, and advance development of inference tools across the community. We describe the modules already available in CosmoSIS, including CAMB, Planck, cosmic shear calculations, and a suite of samplers. Lastly, we illustrate it using demonstration code that you can run out-of-the-box with the installer available at http://bitbucket.org/joezuntz/cosmosis

  18. CosmoSIS: Modular cosmological parameter estimation

    DOE PAGES [OSTI]

    Zuntz, J.; Paterno, M.; Jennings, E.; Rudd, D.; Manzotti, A.; Dodelson, S.; Bridle, S.; Sehrish, S.; Kowalkowski, J.

    2015-06-09

    Cosmological parameter estimation is entering a new era. Large collaborations need to coordinate high-stakes analyses using multiple methods; furthermore such analyses have grown in complexity due to sophisticated models of cosmology and systematic uncertainties. In this paper we argue that modularity is the key to addressing these challenges: calculations should be broken up into interchangeable modular units with inputs and outputs clearly defined. Here we present a new framework for cosmological parameter estimation, CosmoSIS, designed to connect together, share, and advance development of inference tools across the community. We describe the modules already available in CosmoSIS, including CAMB, Planck, cosmicmore » shear calculations, and a suite of samplers. Lastly, we illustrate it using demonstration code that you can run out-of-the-box with the installer available at http://bitbucket.org/joezuntz/cosmosis« less

  19. Gravitational collapse and the cosmological constant

    SciTech Connect

    Deshingkar, S. S.; Jhingan, S.; Chamorro, A.; Joshi, P. S.

    2001-06-15

    We consider here the effects of a nonvanishing cosmological term on the final fate of a spherical inhomogeneous collapsing dust cloud. It is shown that, depending on the nature of the initial data from which the collapse evolves, and for a positive value of the cosmological constant, we can have a globally regular evolution where a bounce develops within the cloud. We characterize precisely the initial data causing such a bounce in terms of the initial density and velocity profiles for the collapsing cloud. In the cases otherwise, the result of collapse is either the formation of a black hole or a naked singularity resulting as the end state of collapse. We also show here that a positive cosmological term can cover a part of the singularity spectrum which is visible in the corresponding dust collapse models for the same initial data.

  20. Our Universe from the cosmological constant

    SciTech Connect

    Barrau, Aurlien; Linsefors, Linda E-mail: linda.linsefors@lpsc.in2p3.fr

    2014-12-01

    The issue of the origin of the Universe and of its contents is addressed in the framework of bouncing cosmologies, as described for example by loop quantum gravity. If the current acceleration is due to a true cosmological constant, this constant is naturally conserved through the bounce and the Universe should also be in a (contracting) de Sitter phase in the remote past. We investigate here the possibility that the de Sitter temperature in the contracting branch fills the Universe with radiation that causes the bounce and the subsequent inflation and reheating. We also consider the possibility that this gives rise to a cyclic model of the Universe and suggest some possible tests.

  1. Cosmology as Science?: From Inflation to Eternity

    ScienceCinema

    None

    2016-07-12

    The last decade or two have represented the golden age of observational cosmology, producing a revolution in our picture of the Universe on its largest scales, and perhaps also its smallest ones. I will argue that these recent development bring to the forefront some vexing questions about whether various fundamental assumptions about the universe are in fact falsifiable. I will focus on 3 issues: (1) "Proving" Inflation, (2) Dark Energy and Anthropic Arguments, and (3) Cosmology of the far future.Interview with Lawrence M. Krauss

  2. New Cosmologies on the Horizon. Cosmology and Holography in bigravity and massive gravity

    SciTech Connect

    Tolley, Andrew James

    2013-03-31

    The goal of this research program is to explore the cosmological dynamics, the nature of cosmological and black hole horizons, and the role of holography in a new class of infrared modified theories of gravity. This will capitalize of the considerable recent progress in our understanding of the dynamics of massive spin two fields on curved spacetimes, culminating in the formulation of the first fully consistent theories of massive gravity and bigravity/bimetric theories.

  3. Cosmology at the Beach Lecture: Wayne Hu

    ScienceCinema

    Wayne Hu

    2016-07-12

    Wayne Hu lectures on Secondary Anisotropy in the CMB. The lecture is the first in a series of 3 he delivered as part of the "Cosmology at the Beach" winter school organized by Berkeley Lab's George Smoot in Los Cabos, Mexico from Jan. 12-16, 2009.

  4. Primordial magnetic field limits from cosmological data

    SciTech Connect

    Kahniashvili, Tina [McWilliams Center for Cosmology and Department of Physics, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213 (United States); Department of Physics, Laurentian University, Ramsey Lake Road, Sudbury, Ontario P3E 2C (Canada); Abastumani Astrophysical Observatory, Ilia State University, 2A Kazbegi Ave, Tbilisi, GE-0160 (Georgia); Tevzadze, Alexander G. [Abastumani Astrophysical Observatory, Ilia State University, 2A Kazbegi Ave, Tbilisi, GE-0160 (Georgia); Faculty of Exact and Natural Sciences, Tbilisi State University, 1 Chavchavadze Avenue, Tbilisi, GE-0128 (Georgia); Sethi, Shiv K. [McWilliams Center for Cosmology and Department of Physics, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213 (United States); Raman Research Institute, Sadashivanagar, Bangalore 560080 (India); Pandey, Kanhaiya [Raman Research Institute, Sadashivanagar, Bangalore 560080 (India); Ratra, Bharat [Department of Physics, Kansas State University, 116 Cardwell Hall, Manhattan, Kansas 66506 (United States)

    2010-10-15

    We study limits on a primordial magnetic field arising from cosmological data, including that from big bang nucleosynthesis, cosmic microwave background polarization plane Faraday rotation limits, and large-scale structure formation. We show that the physically relevant quantity is the value of the effective magnetic field, and limits on it are independent of how the magnetic field was generated.

  5. Cosmology: Clarence Chang | Argonne National Laboratory

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    Cosmology: Clarence Chang Share Browse By - Any - General Argonne Information Energy -Energy efficiency --Vehicles ---Alternative fuels ---Automotive engineering ---Diesel ---Electric drive technology ---Hybrid & electric vehicles ---Hydrogen & fuel cells ---Internal combustion ---Powertrain research --Building design ---Construction --Manufacturing -Energy sources --Renewable energy ---Bioenergy ---Solar energy --Fossil fuels ---Natural Gas --Nuclear energy ---Nuclear energy modeling

  6. Cosmology and astrophysics with galaxy clusters

    SciTech Connect

    Nagai, Daisuke

    2014-11-20

    Galaxy clusters are the largest gravitationally bound objects in the universe, whose formation is driven by dark energy and dark matter. The majority of the baryonic mass in clusters resides in the hot X-ray emitting plasma, which also leaves imprints in the cosmic microwave background radiation. Recent X-ray and microwave observations have revealed detailed thermodynamic structure of the hot X-ray emitting plasma from their cores to the virial radii, making comparisons of baryonic component in simulations to observations a strong cosmological probe. However, the statistical power of these future surveys can only be exploited for cosmology if and only if we are able to measure the cluster mass with a very high precision. I will discuss recent progress and future challenges for the use of galaxy clusters as precise cosmological probes, with highlights on (1) the importance of understanding thermodynamics and plasma physics in the outskirts of galaxy clusters and (2) prospects for improving the power of cluster-based cosmological measurements using numerical simulations and multi-wavelength observations.

  7. CfA3: 185 TYPE Ia SUPERNOVA LIGHT CURVES FROM THE CfA

    SciTech Connect

    Hicken, Malcolm; Challis, Peter; Kirshner, Robert P.; Bakos, Gaspar; Berlind, Perry; Brown, Warren R.; Caldwell, Nelson; Calkins, Mike; Cho, Richard; Contreras, Maria; Jha, Saurabh; Matheson, Tom; Modjaz, Maryam; Rest, Armin; Michael Wood-Vasey, W.; Barton, Elizabeth J.; Bragg, Ann; Briceno, Cesar; Ciupik, Larry; Dendy, Kristi-Concannon E-mail: kirshner@cfa.harvard.edu

    2009-07-20

    We present multiband photometry of 185 type-Ia supernovae (SNe Ia), with over 11,500 observations. These were acquired between 2001 and 2008 at the F. L. Whipple Observatory of the Harvard-Smithsonian Center for Astrophysics (CfA). This sample contains the largest number of homogeneously observed and reduced nearby SNe Ia (z {approx}< 0.08) published to date. It more than doubles the nearby sample, bringing SN Ia cosmology to the point where systematic uncertainties dominate. Our natural system photometry has a precision of {approx}<0.02 mag in BVRIr'i' and {approx}<0.04 mag in U for points brighter than 17.5 mag. We also estimate a systematic uncertainty of 0.03 mag in our SN Ia standard system BVRIr'i' photometry and 0.07 mag for U. Comparisons of our standard system photometry with published SN Ia light curves and comparison stars, where available for the same SN, reveal agreement at the level of a few hundredths mag in most cases. We find that 1991bg-like SNe Ia are sufficiently distinct from other SNe Ia in their color and light-curve-shape/luminosity relation that they should be treated separately in light-curve/distance fitter training samples. The CfA3 sample will contribute to the development of better light-curve/distance fitters, particularly in the few dozen cases where near-infrared photometry has been obtained and, together, can help disentangle host-galaxy reddening from intrinsic supernova color, reducing the systematic uncertainty in SN Ia distances due to dust.

  8. Supernova Simulations with Boltzmann Neutrino Transport: A Comparison of Methods

    SciTech Connect

    Liebendoerfer, M.; Rampp, M.; Janka, H.-Th.; Mezzacappa, Anthony

    2005-02-01

    Accurate neutrino transport has been built into spherically symmetric simulations of stellar core collapse and postbounce evolution. The results of such simulations agree that spherically symmetric models with standard microphysical input fail to explode by the delayed, neutrino-driven mechanism. Independent groups implemented fundamentally different numerical methods to tackle the Boltzmann neutrino transport equation. Here we present a direct and detailed comparison of such neutrino radiation-hydrodynamics simulations for two codes, AGILE-BOLTZTRAN of the Oak Ridge-Basel group and VERTEX of the Garching group. The former solves the Boltzmann equation directly by an implicit, general relativistic discrete-angle method on the adaptive grid of a conservative implicit hydrodynamics code with second-order TVD advection. In contrast, the latter couples a variable Eddington factor technique with an explicit, moving-grid, conservative high-order Riemann solver with important relativistic effects treated by an effective gravitational potential. The presented study is meant to test our neutrino radiation-hydrodynamics implementations and to provide a data basis for comparisons and verifications of supernova codes to be developed in the future. Results are discussed for simulations of the core collapse and postbounce evolution of a 13 M{sub {circle_dot}} star with Newtonian gravity and a 15 M{sub {circle_dot}} star with relativistic gravity.

  9. VHE Gamma-ray Supernova Remnants

    SciTech Connect

    Funk, Stefan; /KIPAC, Menlo Park

    2007-01-22

    Increasing observational evidence gathered especially in X-rays and {gamma}-rays during the course of the last few years support the notion that Supernova remnants (SNRs) are Galactic particle accelerators up to energies close to the ''knee'' in the energy spectrum of Cosmic rays. This review summarizes the current status of {gamma}-ray observations of SNRs. Shell-type as well as plerionic type SNRs are addressed and prospect for observations of these two source classes with the upcoming GLAST satellite in the energy regime above 100 MeV are given.

  10. Supernovae as Nuclear and Particle Physics Laboratories

    SciTech Connect

    Liebendoerfer, Matthias; Fischer, T.; Hempel, M.; Mezzacappa, Anthony; Pagliara, G.; Sagert, I.; Schaffner-Bielich, J.; Scheidegger, Simon; Thielemann, Friedrich-Karl W.; Whitehouse, Stuart

    2009-01-01

    In the interior of supernovae, temperatures and densities exceed the range that is easily accessible by terrestrial experiments. With the improving sensitivities of neutrino and gravitational wave detectors, the chance of obtaining observations providing a deep view into the heart of a close-by supernova explosion is steadily increasing. Based on computational models, we investigate the imprint of the nuclear equation of state on the emission of neutrinos and gravitational waves. If a QCD phase transition to quark matter occurs during the immediate postbounce accretion phase, a strong second shock front is formed at a radius of order 10 km. Neutronized hadronic outer layers of the protoneutron star fall into it, are shock-heated, and lead to a rapid acceleration of the second shock wave. As soon as this shock reduces the electron degeneracy at the neutrinospheres, a sharp second neutrino burst is emitted, dominated by electron antineutrinos. Together with the abruptly increasing mean energies of {mu}- and {tau}-neutrinos, it may serve as a clear signature of the phase transition of the protoneutron star core to a more compact state.

  11. Could there be a hole in type Ia supernovae?

    SciTech Connect

    Kasen, Daniel; Nugent, Peter; Thomas, R.C.; Wang, Lifan

    2004-04-23

    In the favored progenitor scenario, Type Ia supernovae (SNe Ia) arise from a white dwarf accreting material from a non-degenerate companion star. Soon after the white dwarf explodes, the ejected supernova material engulfs the companion star; two-dimensional hydrodynamical simulations by Marietta et al. (2001) show that, in the interaction, the companion star carves out a conical hole of opening angle 30-40 degrees in the supernova ejecta. In this paper we use multi-dimensional Monte Carlo radiative transfer calculations to explore the observable consequences of an ejecta-hole asymmetry. We calculate the variation of the spectrum, luminosity, and polarization with viewing angle for the aspherical supernova near maximum light. We find that the supernova looks normal from almost all viewing angles except when one looks almost directly down the hole. In the latter case, one sees into the deeper, hotter layers of ejecta. The supernova is relatively brighter and has a peculiar spectrum characterized by more highly ionized species, weaker absorption features, and lower absorption velocities. The spectrum viewed down the hole is comparable to the class of SN 1991T-like supernovae. We consider how the ejecta-hole asymmetry may explain the current spectropolarimetric observations of SNe Ia, and suggest a few observational signatures of the geometry. Finally, we discuss the variety currently seen in observed SNe Ia and how an ejecta-hole asymmetry may fit in as one of several possible sources of diversity.

  12. The Rise and Fall of Core-Collapse Supernovae

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    The Rise and Fall of Core-Collapse Supernovae The Rise and Fall of Core-Collapse Supernovae 2D and 3D Models Shed New Light on What Fuels an Exploding Star July 2, 2015 Contact: Kathy Kincade, kkincade@lbl.gov,+1 510 495 2124 corecollapse3 2D simulations of the evolution of the entropy (upper half) and radial velocity (lower half) of a supernovae explosion at 150, 300 and 600 milliseconds. Red material is moving outward, blue material is moving inward. Simulations run at NERSC (Hopper and

  13. A cosmological study in massive gravity theory

    SciTech Connect

    Pan, Supriya Chakraborty, Subenoy

    2015-09-15

    A detailed study of the various cosmological aspects in massive gravity theory has been presented in the present work. For the homogeneous and isotropic FLRW model, the deceleration parameter has been evaluated, and, it has been examined whether there is any transition from deceleration to acceleration in recent past, or not. With the proper choice of the free parameters, it has been shown that the massive gravity theory is equivalent to Einstein gravity with a modified Newtonian gravitational constant together with a negative cosmological constant. Also, in this context, it has been examined whether the emergent scenario is possible, or not, in massive gravity theory. Finally, we have done a cosmographic analysis in massive gravity theory.

  14. Numerical Cosmology: Building a Dynamical Universe

    SciTech Connect

    Garrison, David

    2010-10-11

    In this talk I discuss an often over-looked aspect of most cosmological models, dynamical interactions caused by gravitational waves. I begin by reviewing our current state of cosmological knowledge and gravitational waves. Then, I review work done to understand the nature of primordial magnetic fields. Finally, I combine the ideas of gravitational wave theory and plasma turbulence to develop a new theory of cosmic structure formation. Eventually, this work could help to explain the distribution of mass-energy in the observable universe as well as the anisotropies in the Cosmic Microwave Background without a heavy dependence on dark matter. This work seeks to explain how the dense, hot, turbulent plasma of protons, neutrons, electrons and neutrinos cooled in the presence of gravitational waves to form into structures and develop a statistical mechanics to describe this dynamical system.

  15. Conformal symmetries of adiabatic modes in cosmology

    SciTech Connect

    Hinterbichler, Kurt; Khoury, Justin; Hui, Lam E-mail: lhui@astro.columbia.edu

    2012-08-01

    We remark on the existence of non-linearly realized conformal symmetries for scalar adiabatic perturbations in cosmology. These conformal symmetries are present for any cosmological background, beyond any slow-roll or quasi-de Sitter approximation. The dilatation transformation shifts the curvature perturbation by a constant, and corresponds to the well-known symmetry under spatial rescaling. We argue that the scalar sector is also invariant under special conformal transformations, which shift the curvature perturbation by a term linear in the spatial coordinates. We discuss whether these conformal symmetries can be extended to include tensor perturbations. Tensor modes introduce their own set of non-linearly realized symmetries. We identify an infinite set of large gauge transformations which maintain the transverse, traceless gauge condition, while shifting the tensor mode non-trivially.

  16. Spacetime Average Density (SAD) cosmological measures

    SciTech Connect

    Page, Don N.

    2014-11-01

    The measure problem of cosmology is how to obtain normalized probabilities of observations from the quantum state of the universe. This is particularly a problem when eternal inflation leads to a universe of unbounded size so that there are apparently infinitely many realizations or occurrences of observations of each of many different kinds or types, making the ratios ambiguous. There is also the danger of domination by Boltzmann Brains. Here two new Spacetime Average Density (SAD) measures are proposed, Maximal Average Density (MAD) and Biased Average Density (BAD), for getting a finite number of observation occurrences by using properties of the Spacetime Average Density (SAD) of observation occurrences to restrict to finite regions of spacetimes that have a preferred beginning or bounce hypersurface. These measures avoid Boltzmann brain domination and appear to give results consistent with other observations that are problematic for other widely used measures, such as the observation of a positive cosmological constant.

  17. Neutrinos and cosmology: a lifetime relationship

    SciTech Connect

    Serpico, Pasquale D.; /Fermilab

    2008-06-01

    We consider the example of neutrino decays to illustrate the profound relation between laboratory neutrino physics and cosmology. Two case studies are presented: In the first one, we show how the high precision cosmic microwave background spectral data collected by the FIRAS instrument on board of COBE, when combined with Lab data, have greatly changed bounds on the radiative neutrino lifetime. In the second case, we speculate on the consequence for neutrino physics of the cosmological detection of neutrino masses even as small as {approx}0.06 eV, the lower limit guaranteed by neutrino oscillation experiments. We show that a detection at that level would improve by many orders of magnitude the existing limits on neutrino lifetime, and as a consequence on some models of neutrino secret interactions.

  18. Electron-capture supernovae of super-asymptotic giant branch stars and the Crab supernova 1054

    SciTech Connect

    Nomoto, Ken'ichi [Kavli Institute for Physics and Mathematics of the Universe (WPI), The University of Tokyo, Kashiwa, Chiba 277-8583 (Japan); Tominaga, Nozomu [Department of Physics, Faculty of Science and Engineering, Konan University, 8-9-1 Okamoto, Kobe, Hyogo 658-8501, Japan and Kavli Institute for Physics and Mathematics of the Universe (WPI), The University of Tokyo, Kashiwa, Chiba 277-8583 (Japan); Blinnikov, Sergei I. [Institute for Theoretical and Experimental Physics (ITEP), Moscow 117218, Russia and Kavli Institute for Physics and Mathematics of the Universe (WPI), The University of Tokyo, Kashiwa, Chiba 277-8583 (Japan)

    2014-05-02

    An electron-capture supernova (ECSN) is a core-collapse supernova explosion of a super-asymptotic giant branch (SAGB) star with a main-sequence mass M{sub Ms} ? 7 - 9.5M{sub ?}. The explosion takes place in accordance with core bounce and subsequent neutrino heating and is a unique example successfully produced by first-principle simulations. This allows us to derive a first self-consistent multicolor light curves of a core-collapse supernova. Adopting the explosion properties derived by the first-principle simulation, i.e., the low explosion energy of 1.5 10{sup 50} erg and the small {sup 56}Ni mass of 2.5 10{sup ?3} M{sub ?}, we perform a multigroup radiation hydrodynamics calculation of ECSNe and present multicolor light curves of ECSNe of SAGB stars with various envelope mass and hydrogen abundance. We demonstrate that a shock breakout has peak luminosity of L ? 2 10{sup 44} erg s{sup ?1} and can evaporate circumstellar dust up to R ? 10{sup 17} cm for a case of carbon dust, that plateau luminosity and plateau duration of ECSNe are L ? 10{sup 42} erg s{sup ?1} and {sup t} ? 60 - 100 days, respectively, and that a plateau is followed by a tail with a luminosity drop by ? 4 mag. The ECSN shows a bright and short plateau that is as bright as typical Type II plateau supernovae, and a faint tail that might be influenced by spin-down luminosity of a newborn pulsar. Furthermore, the theoretical models are compared with ECSN candidates: SN 1054 and SN 2008S. We find that SN 1054 shares the characteristics of the ECSNe. For SN 2008S, we find that its faint plateau requires a ECSN model with a significantly low explosion energy of E ? 10{sup 48} erg.

  19. Cosmic strings in hidden sectors: 2. Cosmological and astrophysical signatures

    SciTech Connect

    Long, Andrew J.; Vachaspati, Tanmay

    2014-12-18

    Cosmic strings can arise in hidden sector models with a spontaneously broken Abelian symmetry group. We have studied the couplings of the Standard Model fields to these so-called dark strings in the companion paper. Here we survey the cosmological and astrophysical observables that could be associated with the presence of dark strings in our universe with an emphasis on low-scale models, perhaps TeV. Specifically, we consider constraints from nucleosynthesis and CMB spectral distortions, and we calculate the predicted fluxes of diffuse gamma ray cascade photons and cosmic rays. For strings as light as TeV, we find that the predicted level of these signatures is well below the sensitivity of the current experiments, and therefore low scale cosmic strings in hidden sectors remain unconstrained. Heavier strings with a mass scale in the range 10{sup 13} GeV to 10{sup 15} GeV are at tension with nucleosynthesis constraints.

  20. Cosmic strings in hidden sectors: 2. Cosmological and astrophysical signatures

    SciTech Connect

    Long, Andrew J.; Vachaspati, Tanmay E-mail: tvachasp@asu.edu

    2014-12-01

    Cosmic strings can arise in hidden sector models with a spontaneously broken Abelian symmetry group. We have studied the couplings of the Standard Model fields to these so-called dark strings in the companion paper. Here we survey the cosmological and astrophysical observables that could be associated with the presence of dark strings in our universe with an emphasis on low-scale models, perhaps TeV . Specifically, we consider constraints from nucleosynthesis and CMB spectral distortions, and we calculate the predicted fluxes of diffuse gamma ray cascade photons and cosmic rays. For strings as light as TeV, we find that the predicted level of these signatures is well below the sensitivity of the current experiments, and therefore low scale cosmic strings in hidden sectors remain unconstrained. Heavier strings with a mass scale in the range 10{sup 13} GeV to 10{sup 15} GeV are at tension with nucleosynthesis constraints.

  1. The Explosion Mechanism of Core-Collapse Supernovae: Progress in Supernova Theory and Experiments

    SciTech Connect

    Foglizzo, Thierry; Kazeroni, Rémi; Guilet, Jérôme; Masset, Frédéric; González, Matthias; Krueger, Brendan K.; Novak, Jérôme; Faure, Julien; Martin, Noël; Blottiau, Patrick; Peres, Bruno; Durand, Gilles

    2015-03-17

    The explosion of core-collapse supernova depends on a sequence of events taking place in less than a second in a region of a few hundred kilometers at the center of a supergiant star, after the stellar core approaches the Chandrasekhar mass and collapses into a proto-neutron star, and before a shock wave is launched across the stellar envelope. Theoretical efforts to understand stellar death focus on the mechanism which transforms the collapse into an explosion. Progress in understanding this mechanism is reviewed with particular attention to its asymmetric character. We highlight a series of successful studies connecting observations of supernova remnants and pulsars properties to the theory of core-collapse using numerical simulations. The encouraging results from first principles models in axisymmetric simulations is tempered by new puzzles in 3D. The diversity of explosion paths and the dependence on the pre-collapse stellar structure is stressed, as well as the need to gain a better understanding of hydrodynamical and MHD instabilities such as SASI and neutrino-driven convection. The shallow water analogy of shock dynamics is presented as a comparative system where buoyancy effects are absent. This dynamical system can be studied numerically and also experimentally with a water fountain. Lastly, we analyse the potential of this complementary research tool for supernova theory. We also review its potential for public outreach in science museums.

  2. Combined cosmological tests of a bivalent tachyonic dark energy scalar field model

    SciTech Connect

    Keresztes, Zoltán; Gergely, László Á. E-mail: gergely@physx.u-szeged.hu

    2014-11-01

    A recently investigated tachyonic scalar field dark energy dominated universe exhibits a bivalent future: depending on initial parameters can run either into a de Sitter exponential expansion or into a traversable future soft singularity followed by a contraction phase. We also include in the model (i) a tiny amount of radiation, (ii) baryonic matter (Ω{sub b}h{sup 2} = 0.022161, where the Hubble constant is fixed as h = 0.706) and (iii) cold dark matter (CDM). Out of a variety of six types of evolutions arising in a more subtle classification, we identify two in which in the past the scalar field effectively degenerates into a dust (its pressure drops to an insignificantly low negative value). These are the evolutions of type IIb converging to de Sitter and type III hitting the future soft singularity. We confront these background evolutions with various cosmological tests, including the supernova type Ia Union 2.1 data, baryon acoustic oscillation distance ratios, Hubble parameter-redshift relation and the cosmic microwave background (CMB) acoustic scale. We determine a subset of the evolutions of both types which at 1σ confidence level are consistent with all of these cosmological tests. At perturbative level we derive the CMB temperature power spectrum to find the best agreement with the Planck data for Ω{sub CDM} = 0.22. The fit is as good as for the ΛCDM model at high multipoles, but the power remains slightly overestimated at low multipoles, for both types of evolutions. The rest of the CDM is effectively generated by the tachyonic field, which in this sense acts as a combined dark energy and dark matter model.

  3. The crossing statistic: dealing with unknown errors in the dispersion of Type Ia supernovae

    SciTech Connect

    Shafieloo, Arman; Clifton, Timothy; Ferreira, Pedro E-mail: tclifton@astro.ox.ac.uk

    2011-08-01

    We propose a new statistic that has been designed to be used in situations where the intrinsic dispersion of a data set is not well known: The Crossing Statistic. This statistic is in general less sensitive than χ{sup 2} to the intrinsic dispersion of the data, and hence allows us to make progress in distinguishing between different models using goodness of fit to the data even when the errors involved are poorly understood. The proposed statistic makes use of the shape and trends of a model's predictions in a quantifiable manner. It is applicable to a variety of circumstances, although we consider it to be especially well suited to the task of distinguishing between different cosmological models using type Ia supernovae. We show that this statistic can easily distinguish between different models in cases where the χ{sup 2} statistic fails. We also show that the last mode of the Crossing Statistic is identical to χ{sup 2}, so that it can be considered as a generalization of χ{sup 2}.

  4. Fermi Large Area Telescope Observations of the Supernova Remnant...

    Office of Scientific and Technical Information (OSTI)

    Fermi Large Area Telescope Observations of the Supernova Remnant G8.7-0.1 Citation Details ... Language: English Subject: 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 72 PHYSICS ...

  5. Object Classification at the Nearby Supernova Factory (Journal...

    Office of Scientific and Technical Information (OSTI)

    Nearby Supernova Factory Citation Details In-Document ... Report Number(s): LBNL-696E TRN: US200815%%72 DOE Contract Number: DE-AC02-05CH11231 Resource Type: Journal Article ...

  6. Probing Late Neutrino Mass Properties With SupernovaNeutrinos...

    Office of Scientific and Technical Information (OSTI)

    Journal Article: Probing Late Neutrino Mass Properties With SupernovaNeutrinos Citation ... DOE Contract Number: DE-AC02-05CH11231 Resource Type: Journal Article Resource Relation: ...

  7. The Nearby Supernova Factory: Toward A High-Precision Spectro...

    Office of Scientific and Technical Information (OSTI)

    The goal is to acquire for each supernova and over its full life-time (more than 10 epochs) high spectro-photometric quality spectra over the extended optical range (320-1000 nm).I ...

  8. Supernovae of the Same Brightness, Cut From Vastly Different...

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    that the progenitor system of a Type 1a supernova, called PTF 11kx, contains a red giant star. They also show that the system previously underwent at least one much...

  9. Type Ia Supernova Hubble Residuals and Host-Galaxy Properties...

    Office of Scientific and Technical Information (OSTI)

    The K13 Hubble residual step with host mass is 0.013 ? 0.031 mag for a supernova subsample with data coverage corresponding to the K13 training; at ? 1?, the step is not ...

  10. Improved Distances to Type Ia Supernovae withMulticolor Light...

    Office of Scientific and Technical Information (OSTI)

    We present an updated version of the Multicolor Light Curve Shape method to measure distances to type Ia supernovae (SN Ia), incorporating new procedures for K-correction and ...

  11. Classifying supernovae using only galaxy data

    SciTech Connect

    Foley, Ryan J.; Mandel, Kaisey

    2013-12-01

    We present a new method for probabilistically classifying supernovae (SNe) without using SN spectral or photometric data. Unlike all previous studies to classify SNe without spectra, this technique does not use any SN photometry. Instead, the method relies on host-galaxy data. We build upon the well-known correlations between SN classes and host-galaxy properties, specifically that core-collapse SNe rarely occur in red, luminous, or early-type galaxies. Using the nearly spectroscopically complete Lick Observatory Supernova Search sample of SNe, we determine SN fractions as a function of host-galaxy properties. Using these data as inputs, we construct a Bayesian method for determining the probability that an SN is of a particular class. This method improves a common classification figure of merit by a factor of >2, comparable to the best light-curve classification techniques. Of the galaxy properties examined, morphology provides the most discriminating information. We further validate this method using SN samples from the Sloan Digital Sky Survey and the Palomar Transient Factory. We demonstrate that this method has wide-ranging applications, including separating different subclasses of SNe and determining the probability that an SN is of a particular class before photometry or even spectra can. Since this method uses completely independent data from light-curve techniques, there is potential to further improve the overall purity and completeness of SN samples and to test systematic biases of the light-curve techniques. Further enhancements to the host-galaxy method, including additional host-galaxy properties, combination with light-curve methods, and hybrid methods, should further improve the quality of SN samples from past, current, and future transient surveys.

  12. THE ENGINES BEHIND SUPERNOVAE AND GAMMA-RAY BURSTS

    SciTech Connect

    FRYER, CHRISTOPHER LEE

    2007-01-23

    The authors review the different engines behind supernova (SNe) and gamma-ray bursts (GRBs), focusing on those engines driving explosions in massive stars: core-collapse SNe and long-duration GRBs. Convection and rotation play important roles in the engines of both these explosions. They outline the basic physics and discuss the wide variety of ways scientists have proposed that this physics can affect the supernova explosion mechanism, concluding with a review of the current status in these fields.

  13. Multigroup Radiation Transport in Supernova Light Curve Calculations

    Office of Scientific and Technical Information (OSTI)

    (Technical Report) | SciTech Connect Multigroup Radiation Transport in Supernova Light Curve Calculations Citation Details In-Document Search Title: Multigroup Radiation Transport in Supernova Light Curve Calculations Authors: Even, Wesley P. [1] ; Frey, Lucille H. [1] ; Fryer, Christopher L. [1] ; Young, Patrick [2] + Show Author Affiliations Los Alamos National Laboratory Arizona State University Publication Date: 2013-04-29 OSTI Identifier: 1077017 Report Number(s): LA-UR-13-23060 DOE

  14. Petascale Simulation of Magnetorotational Core-Collapse Supernovae |

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    Argonne Leadership Computing Facility Magnetohydrodynamic turbulence powered by neutrino driven convection Magnetohydrodynamic turbulence powered by neutrino driven convection behind the stalled shock of a core-collapse supernova simulation. This simulation shows that the presence of rotation and weak magnetic fields dramatically impacts the development of the supernova mechanism as compared to non-rotating, non-magnetic stars. The nascent neutron star is just barely visible in the center of

  15. Verification of the Time Evolution of Cosmological Simulations...

    Office of Scientific and Technical Information (OSTI)

    Country of Publication: United States Language: English Subject: 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ACCURACY; ALGORITHMS; COSMOLOGY; SIMULATION; VERIFICATION Word ...

  16. Cosmological Behavior of a Parity and Charge-Parity Violating...

    Office of Scientific and Technical Information (OSTI)

    Violating Varying Alpha Theory Citation Details In-Document Search Title: Cosmological Behavior of a Parity and Charge-Parity Violating Varying Alpha Theory Authors: Maity, ...

  17. Formation of Compact Clusters from High Resolution Hybrid Cosmological...

    Office of Scientific and Technical Information (OSTI)

    Formation of Compact Clusters from High Resolution Hybrid Cosmological Simulations Citation Details In-Document Search Title: Formation of Compact Clusters from High Resolution ...

  18. Astrophysics and Cosmology with TeV Gamma Rays

    SciTech Connect

    Aharonian, Felix

    2005-07-13

    I will discuss the astrophysical and cosmological implications of recent exciting discoveries of TeV gamma-rays from objects representing several Galactic and Extragalactic source populations.

  19. Multi-Scale Initial Conditions For Cosmological Simulations ...

    Office of Scientific and Technical Information (OSTI)

    Journal Article: Multi-Scale Initial Conditions For Cosmological Simulations Citation ... OSTI Identifier: 1028674 Report Number(s): SLAC-PUB-14463 Journal ID: ISSN 0035-8711; ...

  20. Cosmology at the frontier of neutrino physics (Journal Article...

    Office of Scientific and Technical Information (OSTI)

    SciTech Connect Search Results Journal Article: Cosmology at the frontier of neutrino ... OSTI Identifier: 22068967 Resource Type: Journal Article Resource Relation: Journal Name: ...

  1. PDACS - A Portal for Data Analysis Services for Cosmological...

    Office of Scientific and Technical Information (OSTI)

    Conference: PDACS - A Portal for Data Analysis Services for Cosmological Simulations Citation Details In-Document Search Title: PDACS - A Portal for Data Analysis Services for ...

  2. Verification of the Time Evolution of Cosmological Simulations...

    Office of Scientific and Technical Information (OSTI)

    Journal Article: Verification of the Time Evolution of Cosmological Simulations via Hypothesis-Driven Comparative and Quantitative Visualization Citation Details In-Document Search...

  3. PARALLEL HOP: A SCALABLE HALO FINDER FOR MASSIVE COSMOLOGICAL...

    Office of Scientific and Technical Information (OSTI)

    Center for Astrophysics and Space Sciences, University of California, San Diego, CA 92093 ... Subject: 79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; DATA ANALYSIS; DISTRIBUTION; GALAXIES; ...

  4. Neutrino flavor instabilities in a time-dependent supernova model

    DOE PAGES [OSTI]

    Abbar, Sajad; Duan, Huaiyu

    2015-10-19

    In this study, a dense neutrino medium such as that inside a core-collapse supernova can experience collective flavor conversion or oscillations because of the neutral-current weak interaction among the neutrinos. This phenomenon has been studied in a restricted, stationary supernova model which possesses the (spatial) spherical symmetry about the center of the supernova and the (directional) axial symmetry around the radial direction. Recently it has been shown that these spatial and directional symmetries can be broken spontaneously by collective neutrino oscillations. In this letter we analyze the neutrino flavor instabilities in a time-dependent supernova model. Our results show that collectivemore »neutrino oscillations start at approximately the same radius in both the stationary and time-dependent supernova models unless there exist very rapid variations in local physical conditions on timescales of a few microseconds or shorter. Our results also suggest that collective neutrino oscillations can vary rapidly with time in the regimes where they do occur which need to be studied in time-dependent supernova models.« less

  5. Sloan Digital Sky Survey II (SDSS-II) Supernova Data

    DOE Data Explorer

    The Sloan Digital Sky Survey (SDSS) is a series of three interlocking imaging and spectroscopic surveys, carried out over an eight-year period with a dedicated 2.5m telescope located at Apache Point Observatory in Southern New Mexico. The SDSS Supernova Survey was one of those three components of SDSS and SDSS-II, a 3-year extension of the original SDSS that operated from July 2005 to July 2008. The Supernova Survey was a time-domain survey, involving repeat imaging of the same region of sky every other night, weather permitting. The primary scientific motivation was to detect and measure light curves for several hundred supernovae through repeat scans of the SDSS Southern equatorial stripe 82 (about 2.5? wide by ~120? long). Over the course of three 3-month campaigns SDSS-II SN discovered and measured multi-band lightcurves for ~500 spectroscopically confirmed Type Ia supernovae in the redshift range z=0.05-0.4. In addition, the project harvested a few hundred light curves for SNe Ia and discovered about 80 spectroscopically confirmed core-collapse supernovae (supernova types Ib/c and II).

  6. THE ULTRAVIOLET BRIGHTEST TYPE Ia SUPERNOVA 2011de

    SciTech Connect

    Brown, Peter J., E-mail: pbrown@physics.tamu.edu [George P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy, Texas A and M University, Department of Physics and Astronomy, 4242 TAMU, College Station, TX 77843 (United States)

    2014-11-20

    We present and discuss the ultraviolet (UV)/optical photometric light curves and absolute magnitudes of the TypeIa supernova (SN Ia) 2011de from the Swift Ultraviolet/Optical Telescope. We find it to be the UV brightest SN Ia yet observedmore than a factor of 10 brighter than normal SNe Ia in the mid-ultraviolet. We find that the UV/optical brightness and broad light curve evolution can be modeled with additional flux from the shock of the ejecta hitting a relatively large red giant companion separated by 6 10{sup 13} cm. However, the post-maximum behavior of other UV-bright SNe Ia can also be modeled in a similar manner, including objects with UV spectroscopy or pre-maximum photometry which is inconsistent with this model. This suggests that similar UV luminosities can be intrinsic or caused by other forms of shock interaction. The high velocities reported for SN 2011de make it distinct from the UV-bright ''super-Chandrasekhar'' SNe Ia and the NUV-blue group of normal SNe Ia. SN 2011de is an extreme example of the UV variations in SNe Ia.

  7. Uniqueness of measures in loop quantum cosmology

    SciTech Connect

    Hanusch, Maximilian

    2015-09-15

    In Ashtekar and Campiglia [Classical Quantum Gravity 29, 242001 (2012)], residual diffeomorphisms have been used to single out the standard representation of the reduced holonomy-flux algebra in homogeneous loop quantum cosmology (LQC). We show that, in the homogeneous isotropic case, unitarity of the translations with respect to the extended ℝ-action (exponentiated reduced fluxes in the standard approach) singles out the Bohr measure on both the standard quantum configuration space ℝ{sub Bohr} as well as on the Fleischhack one (ℝ⊔ℝ{sub Bohr}). Thus, in both situations, the same condition singles out the standard kinematical Hilbert space of LQC.

  8. Vector fields and Loop Quantum Cosmology

    SciTech Connect

    Artymowski, Michał; Lalak, Zygmunt E-mail: Zygmunt.Lalak@fuw.edu.pl

    2011-09-01

    In the context of the Loop Quantum Cosmology we have analysed the holonomy correction to the classical evolution of the simplified Bianchi I model in the presence of vector fields. For the Universe dominated by a massive vector field or by a combination of a scalar field and a vector field a smooth transition between Kasner-like and Kasner-unlike solutions for a Bianchi I model has been demonstrated. In this case a lack of initial curvature singularity and a finite maximal energy density appear already at the level of General Relativity, which simulates a classical Big Bounce.

  9. Some cosmological consequences of Weyl invariance

    SciTech Connect

    Alvarez, Enrique; González-Martín, Sergio; Herrero-Valea, Mario

    2015-03-19

    We examine some Weyl invariant cosmological models in the framework of generalized dilaton gravity, in which the action is made of a set of N conformally coupled scalar fields. It will be shown that when the FRW ansatz for the spacetime metric is assumed, the Ward identity for conformal invariance guarantees that the gravitational equations hold whenever the scalar fields EM do so. It follows that any scale factor can solve the theory provided a non-trivial profile for a dilaton field. In particular, accelerated expansion is a natural solution to the full set of equations.

  10. A note on entropic force and brane cosmology

    SciTech Connect

    Ling, Yi; Wu, Jian-Pin E-mail: jianpinwu@yahoo.com.cn

    2010-08-01

    Recently Verlinde proposed that gravity is an entropic force caused by information changes when a material body moves away from the holographic screen. In this note we apply this argument to brane cosmology, and show that the cosmological equation can be derived from this holographic scenario.

  11. Cosmology as Science: From Inflation to the Future

    ScienceCinema

    Krass, Lawrence [Case Western Reserve

    2016-07-12

    Recent developments in cosmology bring to the forefront fundamental questions about our ability to falsify various fundamental assumptions about the universe.  I will discuss three issues that reflect different aspects of these questions:  (1) "Proving" Inflation (2) Anthropic "Explanations" (3) Cosmology of the far future.

  12. DIVERSITY OF TYPE Ia SUPERNOVAE IMPRINTED IN CHEMICAL ABUNDANCES

    SciTech Connect

    Tsujimoto, Takuji [National Astronomical Observatory of Japan, Mitaka-shi, Tokyo 181-8588 (Japan); Shigeyama, Toshikazu, E-mail: taku.tsujimoto@nao.ac.jp [Research Center for the Early Universe, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)

    2012-12-01

    A time delay of Type Ia supernova (SN Ia) explosions hinders the imprint of their nucleosynthesis on stellar abundances. However, some occasional cases give birth to stars that avoid enrichment of their chemical compositions by massive stars and thereby exhibit an SN-Ia-like elemental feature including a very low [Mg/Fe] ( Almost-Equal-To - 1). We highlight the elemental feature of Fe-group elements for two low-Mg/Fe objects detected in nearby galaxies, and propose the presence of a class of SNe Ia that yield the low abundance ratios of [Cr, Mn, Ni/Fe]. Our novel models of chemical evolution reveal that our proposed class of SNe Ia (slow SNe Ia) is associated with ones exploding on a long timescale after their stellar birth and give a significant impact on the chemical enrichment in the Large Magellanic Cloud (LMC). In the Galaxy, on the other hand, this effect is unseen due to the overwhelming enrichment by the major class of SNe Ia that explode promptly (prompt SNe Ia) and eject a large amount of Fe-group elements. This nicely explains the different [Cr, Mn, Ni/Fe] features between the two galaxies as well as the puzzling feature seen in the LMC stars exhibiting very low Ca but normal Mg abundances. Furthermore, the corresponding channel of slow SN Ia is exemplified by performing detailed nucleosynthesis calculations in the scheme of SNe Ia resulting from a 0.8 + 0.6 M{sub Sun} white dwarf merger.

  13. A STUDY OF CARBON FEATURES IN TYPE Ia SUPERNOVA SPECTRA (Journal...

    Office of Scientific and Technical Information (OSTI)

    A STUDY OF CARBON FEATURES IN TYPE Ia SUPERNOVA SPECTRA Citation Details In-Document Search Title: A STUDY OF CARBON FEATURES IN TYPE Ia SUPERNOVA SPECTRA One of the major ...

  14. The host galaxies of fast-ejecta core-collapse supernovae (Journal...

    Office of Scientific and Technical Information (OSTI)

    The host galaxies of fast-ejecta core-collapse supernovae Citation Details In-Document Search Title: The host galaxies of fast-ejecta core-collapse supernovae Spectra of broad-lined ...

  15. f(T,T) gravity and cosmology

    SciTech Connect

    Harko, Tiberiu; Lobo, Francisco S.N.; Otalora, G.; Saridakis, Emmanuel N. E-mail: flobo@cii.fc.ul.pt

    2014-12-01

    We present an extension of f(T) gravity, allowing for a general coupling of the torsion scalar T with the trace of the matter energy-momentum tensor T. The resulting f(T,T) theory is a new modified gravity, since it is different from all the existing torsion or curvature based constructions. Applied to a cosmological framework, it leads to interesting phenomenology. In particular, one can obtain a unified description of the initial inflationary phase, the subsequent non-accelerating, matter-dominated expansion, and then the transition to a late-time accelerating phase. Additionally, the effective dark energy sector can be quintessence or phantom-like, or exhibit the phantom-divide crossing during the evolution. Moreover, in the far future the universe results either to a de Sitter exponential expansion, or to eternal power-law accelerated expansions. Finally, a detailed study of the scalar perturbations at the linear level reveals that f(T,T) cosmology can be free of ghosts and instabilities for a wide class of ansatzes and model parameters.

  16. TRANSPARENT HELIUM IN STRIPPED ENVELOPE SUPERNOVAE

    SciTech Connect

    Piro, Anthony L.; Morozova, Viktoriya S., E-mail: piro@caltech.edu [Theoretical Astrophysics, California Institute of Technology, 1200 E. California Blvd., M/C 350-17, Pasadena, CA 91125 (United States)

    2014-09-01

    Using simple arguments based on photometric light curves and velocity evolution, we propose that some stripped envelope supernovae (SNe) show signs that a significant fraction of their helium is effectively transparent. The main pieces of evidence are the relatively low velocities with little velocity evolution, as are expected deep inside an exploding star, along with temperatures that are too low to ionize helium. This means that the helium should not contribute to the shaping of the main SN light curve, and thus the total helium mass may be difficult to measure from simple light curve modeling. Conversely, such modeling may be more useful for constraining the mass of the carbon/oxygen core of the SN progenitor. Other stripped envelope SNe show higher velocities and larger velocity gradients, which require an additional opacity source (perhaps the mixing of heavier elements or radioactive nickel) to prevent the helium from being transparent. We discuss ways in which similar analysis can provide insights into the differences and similarities between SNe Ib and Ic, which will lead to a better understanding of their respective formation mechanisms.

  17. The first Fermi LAT supernova remnant catalog

    DOE PAGES [OSTI]

    Acero, F.

    2016-05-16

    To uniformly determine the properties of supernova remnants (SNRs) at high energies, we have developed the first systematic survey at energies from 1 to 100 GeV using data from the Fermi Large Area Telescope. Based on the spatial overlap of sources detected at GeV energies with SNRs known from radio surveys, we classify 30 sources as likely GeV SNRs. We also report 14 marginal associations and 245 flux upper limits. A mock catalog in which the positions of known remnants are scrambled in Galactic longitude, allows us to determine an upper limit of 22% on the number of GeV candidatesmore » falsely identified as SNRs. We have also developed a method to estimate spectral and spatial systematic errors arising from the diffuse interstellar emission model, a key component of all Galactic Fermi LAT analyses. By studying remnants uniformly in aggregate, we measure the GeV properties common to these objects and provide a crucial context for the detailed modeling of individual SNRs. Combining our GeV results with multiwavelength (MW) data, including radio, X-ray, and TeV, demonstrates the need for improvements to previously sufficient, simple models describing the GeV and radio emission from these objects. As a result, we model the GeV and MW emission from SNRs in aggregate to constrain their maximal contribution to observed Galactic cosmic rays.« less

  18. How to See the Supernova Berkeley Lab Just Discovered | Department of

    Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)

    Energy See the Supernova Berkeley Lab Just Discovered How to See the Supernova Berkeley Lab Just Discovered September 1, 2011 - 10:12am Addthis Berkeley Lab scientist Peter Nugent discusses a recently discovered supernova that is closer to Earth - approximately 21 million light-years away - than any other of its kind in a generation. Linda Vu Skywatchers -- grab your binoculars and telescopes, and head for some clear dark skies. A new supernova has been discovered near the Big Dipper.

  19. Systematic Effects in Type-1a Supernovae Surveys from Host Galaxy Spectra

    Office of Scientific and Technical Information (OSTI)

    (Technical Report) | SciTech Connect Systematic Effects in Type-1a Supernovae Surveys from Host Galaxy Spectra Citation Details In-Document Search Title: Systematic Effects in Type-1a Supernovae Surveys from Host Galaxy Spectra The physical relation between the properties of Type Ia supernovae and their host galaxies is investigated. Such supernovae are used to constrain the properties of dark energy, making it crucial to understand their physical properties and to check for systematic

  20. Progress Report on the Berkeley/Anglo-Australian Observatory High-redshift Supernova Search

    DOE R&D Accomplishments

    Goldhaber, G.; Perlmutter, S.; Pennypacker, C.; Marvin, H.; Muller, R. A.; Couch, W.; Boyle, B.

    1990-11-01

    There are two main efforts related to supernovae in progress at Berkeley. The first is an automated supernova search for nearby supernovae, which was already discussed by Carl Pennypacker at this conference. The second is a search for distant supernovae, in the z = 0.3 to 0.5 region, aimed at measuring {Omega}. It is the latter that I want to discuss in this paper.

  1. The Explosion Mechanism of Core-Collapse Supernovae: Progress in Supernova Theory and Experiments

    DOE PAGES [OSTI]

    Foglizzo, Thierry; Kazeroni, Rémi; Guilet, Jérôme; Masset, Frédéric; González, Matthias; Krueger, Brendan K.; Novak, Jérôme; Oertel, Micaela; Margueron, Jérôme; Faure, Julien; et al

    2015-03-17

    The explosion of core-collapse supernova depends on a sequence of events taking place in less than a second in a region of a few hundred kilometers at the center of a supergiant star, after the stellar core approaches the Chandrasekhar mass and collapses into a proto-neutron star, and before a shock wave is launched across the stellar envelope. Theoretical efforts to understand stellar death focus on the mechanism which transforms the collapse into an explosion. Progress in understanding this mechanism is reviewed with particular attention to its asymmetric character. We highlight a series of successful studies connecting observations of supernovamore » remnants and pulsars properties to the theory of core-collapse using numerical simulations. The encouraging results from first principles models in axisymmetric simulations is tempered by new puzzles in 3D. The diversity of explosion paths and the dependence on the pre-collapse stellar structure is stressed, as well as the need to gain a better understanding of hydrodynamical and MHD instabilities such as SASI and neutrino-driven convection. The shallow water analogy of shock dynamics is presented as a comparative system where buoyancy effects are absent. This dynamical system can be studied numerically and also experimentally with a water fountain. Lastly, we analyse the potential of this complementary research tool for supernova theory. We also review its potential for public outreach in science museums.« less

  2. Neutrino probe comparisons of supernovae as a function of redshift

    SciTech Connect

    Fryer, Christopher Lee

    2009-01-01

    We compare aspects of supernova explosions produced in the current epoch against those produced in the first round of star formation. Although the total final mass of stars can change dramatically between these two epochs due to different mass-loss rates from winds, their cores remam very similar. The core structure is more sensitive to the stellar evolution code than it is to the amount of metals. As such, current stellar models produce supernovae from first stars that look very similar to that of stars produced in the current epoch. The neutrino signal, a powerful probe of the inner core, is identical to the few percent level for both star formation epochs. A change in the neutrino signal in the supernova population between these two star formation epochs will only arise if the initial mass function is altered.

  3. TYPE Ia SUPERNOVA COLORS AND EJECTA VELOCITIES: HIERARCHICAL BAYESIAN REGRESSION WITH NON-GAUSSIAN DISTRIBUTIONS

    SciTech Connect

    Mandel, Kaisey S.; Kirshner, Robert P. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Foley, Ryan J., E-mail: kmandel@cfa.harvard.edu [Astronomy Department, University of Illinois at Urbana-Champaign, 1002 West Green Street, Urbana, IL 61801 (United States)

    2014-12-20

    We investigate the statistical dependence of the peak intrinsic colors of Type Ia supernovae (SNe Ia) on their expansion velocities at maximum light, measured from the Si II ?6355 spectral feature. We construct a new hierarchical Bayesian regression model, accounting for the random effects of intrinsic scatter, measurement error, and reddening by host galaxy dust, and implement a Gibbs sampler and deviance information criteria to estimate the correlation. The method is applied to the apparent colors from BVRI light curves and Si II velocity data for 79 nearby SNe Ia. The apparent color distributions of high-velocity (HV) and normal velocity (NV) supernovae exhibit significant discrepancies for B V and B R, but not other colors. Hence, they are likely due to intrinsic color differences originating in the B band, rather than dust reddening. The mean intrinsic B V and B R color differences between HV and NV groups are 0.06 0.02 and 0.09 0.02 mag, respectively. A linear model finds significant slopes of 0.021 0.006 and 0.030 0.009 mag (10{sup 3} km s{sup 1}){sup 1} for intrinsic B V and B R colors versus velocity, respectively. Because the ejecta velocity distribution is skewed toward high velocities, these effects imply non-Gaussian intrinsic color distributions with skewness up to +0.3. Accounting for the intrinsic-color-velocity correlation results in corrections to A{sub V} extinction estimates as large as 0.12 mag for HV SNe Ia and +0.06 mag for NV events. Velocity measurements from SN Ia spectra have the potential to diminish systematic errors from the confounding of intrinsic colors and dust reddening affecting supernova distances.

  4. Constraining Cosmic Evolution of Type Ia Supernovae

    SciTech Connect

    Foley, Ryan J.; Filippenko, Alexei V.; Aguilera, C.; Becker, A.C.; Blondin, S.; Challis, P.; Clocchiatti, A.; Covarrubias, R.; Davis, T.M.; Garnavich, P.M.; Jha, S.; Kirshner, R.P.; Krisciunas, K.; Leibundgut, B.; Li, W.; Matheson, T.; Miceli, A.; Miknaitis, G.; Pignata, G.; Rest, A.; Riess, A.G.; /UC, Berkeley, Astron. Dept. /Cerro-Tololo InterAmerican Obs. /Washington U., Seattle, Astron. Dept. /Harvard-Smithsonian Ctr. Astrophys. /Chile U., Catolica /Bohr Inst. /Notre Dame U. /KIPAC, Menlo Park /Texas A-M /European Southern Observ. /NOAO, Tucson /Fermilab /Chile U., Santiago /Harvard U., Phys. Dept. /Baltimore, Space Telescope Sci. /Johns Hopkins U. /Res. Sch. Astron. Astrophys., Weston Creek /Stockholm U. /Hawaii U. /Illinois U., Urbana, Astron. Dept.

    2008-02-13

    We present the first large-scale effort of creating composite spectra of high-redshift type Ia supernovae (SNe Ia) and comparing them to low-redshift counterparts. Through the ESSENCE project, we have obtained 107 spectra of 88 high-redshift SNe Ia with excellent light-curve information. In addition, we have obtained 397 spectra of low-redshift SNe through a multiple-decade effort at Lick and Keck Observatories, and we have used 45 ultraviolet spectra obtained by HST/IUE. The low-redshift spectra act as a control sample when comparing to the ESSENCE spectra. In all instances, the ESSENCE and Lick composite spectra appear very similar. The addition of galaxy light to the Lick composite spectra allows a nearly perfect match of the overall spectral-energy distribution with the ESSENCE composite spectra, indicating that the high-redshift SNe are more contaminated with host-galaxy light than their low-redshift counterparts. This is caused by observing objects at all redshifts with similar slit widths, which corresponds to different projected distances. After correcting for the galaxy-light contamination, subtle differences in the spectra remain. We have estimated the systematic errors when using current spectral templates for K-corrections to be {approx}0.02 mag. The variance in the composite spectra give an estimate of the intrinsic variance in low-redshift maximum-light SN spectra of {approx}3% in the optical and growing toward the ultraviolet. The difference between the maximum-light low and high-redshift spectra constrain SN evolution between our samples to be < 10% in the rest-frame optical.

  5. Emergent universe in spatially flat cosmological model

    SciTech Connect

    Zhang, Kaituo; Yu, Hongwei; Wu, Puxun E-mail: wpx0227@gmail.com

    2014-01-01

    The scenario of an emergent universe provides a promising resolution to the big bang singularity in universes with positive or negative spatial curvature. It however remains unclear whether the scenario can be successfully implemented in a spatially flat universe which seems to be favored by present cosmological observations. In this paper, we study the stability of Einstein static state solutions in a spatially flat Shtanov-Sahni braneworld scenario. With a negative dark radiation term included and assuming a scalar field as the only matter energy component, we find that the universe can stay at an Einstein static state past eternally and then evolve to an inflation phase naturally as the scalar field climbs up its potential slowly. In addition, we also propose a concrete potential of the scalar field that realizes this scenario.

  6. Cosmological constraints on neutrinos with Planck data

    SciTech Connect

    Spinelli, M.

    2015-07-15

    Neutrinos take part in the dance of the evolving Universe influencing its history from leptogenesis, to Big Bang nucleosynthesis, until late time structure formation. This makes cosmology, and in particular one of its primary observables the Cosmic Microwave Background (CMB), an unusual but valuable tool for testing Neutrino Physics. The best measurement to date of full-sky CMB anisotropies comes from the Planck satellite launched in 2009 by the European Space Agency (ESA) and successful follower of COBE and WMAP. Testing Planck data against precise theoretical predictions allow us to shed light on various interesting open questions such as the value of the absolute scale of neutrino masses or their energy density. We revise here the results concerning neutrinos obtained by the Planck Collaboration in the 2013 data release.

  7. The Raychaudhuri equation in homogeneous cosmologies

    SciTech Connect

    Albareti, F.D.; Cembranos, J.A.R.; Cruz-Dombriz, A. de la; Dobado, A. E-mail: cembra@fis.ucm.es E-mail: dobado@fis.ucm.es

    2014-03-01

    In this work we address the issue of studying the conditions required to guarantee the Focusing Theorem for both null and timelike geodesic congruences by using the Raychaudhuri equation. In particular we study the case of Friedmann-Robertson-Walker as well as more general Bianchi Type I spacetimes. The fulfillment of the Focusing Theorem is mandatory in small scales since it accounts for the attractive character of gravity. However, the Focusing Theorem is not satisfied at cosmological scales due to the measured negative deceleration parameter. The study of the conditions needed for congruences convergence is not only relevant at the fundamental level but also to derive the viability conditions to be imposed on extended theories of gravity describing the different expansion regimes of the universe. We illustrate this idea for f(R) gravity theories.

  8. Cosmology of bigravity with doubly coupled matter

    SciTech Connect

    Comelli, D.; Crisostomi, M.; Koyama, K.; Pilo, L.; Tasinato, G.

    2015-04-20

    We study cosmology in the bigravity formulation of the dRGT model where matter couples to both metrics. At linear order in perturbation theory two mass scales emerge: an hard one from the dRGT potential, and an environmental dependent one from the coupling of bigravity with matter. At early time, the dynamics is dictated by the second mass scale which is of order of the Hubble scale. The set of gauge invariant perturbations that couples to matter follow closely the same behaviour as in GR. The remaining perturbations show no issue in the scalar sector, while problems arise in the tensor and vector sectors. During radiation domination, a tensor mode grows power-like at super-horizon scales. More dangerously, the only propagating vector mode features an exponential instability on sub-horizon scales. We discuss the consequences of such instabilities and speculate on possible ways to deal with them.

  9. Escape fraction of ionizing photons during reionization: Effects due to supernova feedback and runaway ob stars

    SciTech Connect

    Kimm, Taysun; Cen, Renyue

    2014-06-20

    The fraction of hydrogen ionizing photons escaping from galaxies into the intergalactic medium is a critical ingredient in the theory of reionization. We use two zoomed-in, high-resolution (4 pc), cosmological radiation hydrodynamic simulations with adaptive mesh refinement to investigate the impact of two physical mechanisms (supernova, SN, feedback, and runaway OB stars) on the escape fraction (f {sub esc}) at the epoch of reionization (z ? 7). We implement a new, physically motivated SN feedback model that can approximate the Sedov solutions at all (from the free expansion to snowplow) stages. We find that there is a significant time delay of about ten million years between the peak of star formation and that of escape fraction, due to the time required for the build-up and subsequent destruction of the star-forming cloud by SN feedback. Consequently, the photon number-weighted mean escape fraction for dwarf galaxies in halos of mass 10{sup 8}-10{sup 10.5} M {sub ?} is found to be ?f{sub esc}??11%, although instantaneous values of f {sub esc} > 20% are common when star formation is strongly modulated by the SN explosions. We find that the inclusion of runaway OB stars increases the mean escape fraction by 22% to ?f{sub esc}??14%. As SNe resulting from runaway OB stars tend to occur in less dense environments, the feedback effect is enhanced and star formation is further suppressed in halos with M{sub vir}?10{sup 9} M{sub ?} in the simulation with runaway OB stars compared with the model without them. While both our models produce enough ionizing photons to maintain a fully ionized universe at z ? 7 as observed, a still higher amount of ionizing photons at z ? 9 appears necessary to accommodate the high observed electron optical depth inferred from cosmic microwave background observations.

  10. Ultraviolet observations of Super-Chandrasekhar mass type Ia supernova candidates with swift UVOT

    SciTech Connect

    Brown, Peter J.; Smitka, Michael T.; Krisciunas, Kevin; Wang, Lifan; Kuin, Paul; De Pasquale, Massimiliano; Scalzo, Richard; Holland, Stephen; Milne, Peter

    2014-05-20

    Among Type Ia supernovae (SNe Ia), a class of overluminous objects exist whose ejecta mass is inferred to be larger than the canonical Chandrasekhar mass. We present and discuss the UV/optical photometric light curves, colors, absolute magnitudes, and spectra of three candidate Super-Chandrasekhar mass SNe—2009dc, 2011aa, and 2012dn—observed with the Swift Ultraviolet/Optical Telescope. The light curves are at the broad end for SNe Ia, with the light curves of SN 2011aa being among the broadest ever observed. We find all three to have very blue colors which may provide a means of excluding these overluminous SNe from cosmological analysis, though there is some overlap with the bluest of 'normal' SNe Ia. All three are overluminous in their UV absolute magnitudes compared to normal and broad SNe Ia, but SNe 2011aa and 2012dn are not optically overluminous compared to normal SNe Ia. The integrated luminosity curves of SNe 2011aa and 2012dn in the UVOT range (1600-6000 Å) are only half as bright as SN 2009dc, implying a smaller {sup 56}Ni yield. While it is not enough to strongly affect the bolometric flux, the early time mid-UV flux makes a significant contribution at early times. The strong spectral features in the mid-UV spectra of SNe 2009dc and 2012dn suggest a higher temperature and lower opacity to be the cause of the UV excess rather than a hot, smooth blackbody from shock interaction. Further work is needed to determine the ejecta and {sup 56}Ni masses of SNe 2011aa and 2012dn and to fully explain their high UV luminosities.

  11. Cosmology on the Beach - Chung-Pei Ma, Lecture 3

    ScienceCinema

    Chung-Pei Ma

    2016-07-12

    The lecture was delivered as part of the "Cosmology at the Beach" winter school organized by Berkeley Lab's George Smoot in Los Cabos, Mexico from Jan. 12-16, 2009.

  12. Cosmology on the Beach: Eric Linder, lecture 3

    ScienceCinema

    Eric Linder

    2016-07-12

    The lecture was delivered as part of the "Cosmology at the Beach" winter school organized by Berkeley Lab's George Smoot in Los Cabos, Mexico from Jan. 12-16, 2009.

  13. Constraints on Cosmology from the Cosmic Microwave Background...

    Office of Scientific and Technical Information (OSTI)

    from the Cosmic Microwave Background Power Spectrum of the 2500-square degree SPT-SZ Survey Citation Details In-Document Search Title: Constraints on Cosmology from the Cosmic...

  14. Cosmology on the Beach - Carlos Frenk: Lecture 1

    ScienceCinema

    Carlos Frenk

    2016-07-12

    The lecture was delivered as part of the "Cosmology at the Beach" winter school organized by Berkeley Lab's George Smoot in Los Cabos, Mexico from Jan. 12-16, 2009.

  15. Cosmology on the Beach - Chung-Pei Ma: Lecture 2

    ScienceCinema

    Chung-Pei Ma

    2016-07-12

    The lecture was delivered as part of the "Cosmology at the Beach" winter school organized by Berkeley Lab's George Smoot in Los Cabos, Mexico from Jan. 12-16, 2009

  16. Cosmology at the Beach Lecture: Chung-Pei Ma

    ScienceCinema

    Chung-Pei Ma

    2016-07-12

    The lecture was delivered as part of the "Cosmology at the Beach" winter school organized by Berkeley Lab's George Smoot in Los Cabos, Mexico from Jan. 12-16, 2009.

  17. Cosmology on the Beach - Simon White, Lecture 3

    ScienceCinema

    Simon White

    2016-07-12

    The lecture was delivered as part of the "Cosmology at the Beach" winter school organized by Berkeley Lab's George Smoot in Los Cabos, Mexico from Jan. 12-16, 2009.

  18. Cosmology on the Beach - Eric Linder: Lecture 1

    ScienceCinema

    Eric Linder

    2016-07-12

    The lecture was delivered as part of the "Cosmology at the Beach" winter school organized by Berkeley Lab's George Smoot in Los Cabos, Mexico from Jan. 12-16, 2009.

  19. Cosmology on the Beach - Carlos Frenk, Lecture 2

    ScienceCinema

    Carlos Frenk

    2016-07-12

    The lecture was delivered as part of the "Cosmology at the Beach" winter school organized by Berkeley Lab's George Smoot in Los Cabos, Mexico from Jan. 12-16, 2009.

  20. Constraints on Cosmology from the Cosmic Microwave Background...

    Office of Scientific and Technical Information (OSTI)

    Power Spectrum of the 2500-square degree SPT-SZ Survey Citation Details In-Document Search Title: Constraints on Cosmology from the Cosmic Microwave Background Power Spectrum of ...

  1. Cosmology on the Beach - Carlos Frenk, Lecture 3

    ScienceCinema

    Carlos Frenk

    2016-07-12

    The lecture was delivered as part of the "Cosmology at the Beach" winter school organized by Berkeley Lab's George Smoot in Los Cabos, Mexico from Jan. 12-16, 2009.

  2. Cosmology on the Beach - Wayne Hu: Lecture 2

    ScienceCinema

    Wayne Hu

    2016-07-12

    The lecture was delivered as part of the "Cosmology at the Beach" winter school organized by Berkeley Lab's George Smoot in Los Cabos, Mexico from Jan. 12-16, 2009.

  3. Cosmology on the Beach - Eric Linder, Lecture 2

    ScienceCinema

    Eric Linder

    2016-07-12

    The lecture was delivered as part of the "Cosmology at the Beach" winter school organized by Berkeley Lab's George Smoot in Los Cabos, Mexico from Jan. 12-16, 2009.  

  4. Pair instability supernovae of very massive population III stars

    SciTech Connect

    Chen, Ke-Jung; Woosley, Stan; Heger, Alexander; Almgren, Ann; Whalen, Daniel J.

    2014-09-01

    Numerical studies of primordial star formation suggest that the first stars in the universe may have been very massive. Stellar models indicate that non-rotating Population III stars with initial masses of 140-260 M {sub ☉} die as highly energetic pair-instability supernovae. We present new two-dimensional simulations of primordial pair-instability supernovae done with the CASTRO code. Our simulations begin at earlier times than previous multidimensional models, at the onset of core contraction, to capture any dynamical instabilities that may be seeded by core contraction and explosive burning. Such instabilities could enhance explosive yields by mixing hot ash with fuel, thereby accelerating nuclear burning, and affect the spectra of the supernova by dredging up heavy elements from greater depths in the star at early times. Our grid of models includes both blue supergiants and red supergiants over the range in progenitor mass expected for these events. We find that fluid instabilities driven by oxygen and helium burning arise at the upper and lower boundaries of the oxygen shell ∼20-100 s after core bounce. Instabilities driven by burning freeze out after the SN shock exits the helium core. As the shock later propagates through the hydrogen envelope, a strong reverse shock forms that drives the growth of Rayleigh-Taylor instabilities. In red supergiant progenitors, the amplitudes of these instabilities are sufficient to mix the supernova ejecta.

  5. A fast contour descriptor algorithm for supernova imageclassification

    SciTech Connect

    Aragon, Cecilia R.; Aragon, David Bradburn

    2006-07-16

    We describe a fast contour descriptor algorithm and its application to a distributed supernova detection system (the Nearby Supernova Factory) that processes 600,000 candidate objects in 80 GB of image data per night. Our shape-detection algorithm reduced the number of false positives generated by the supernova search pipeline by 41% while producing no measurable impact on running time. Fourier descriptors are an established method of numerically describing the shapes of object contours, but transform-based techniques are ordinarily avoided in this type of application due to their computational cost. We devised a fast contour descriptor implementation for supernova candidates that meets the tight processing budget of the application. Using the lowest-order descriptors (F{sub 1} and F{sub -1}) and the total variance in the contour, we obtain one feature representing the eccentricity of the object and another denoting its irregularity. Because the number of Fourier terms to be calculated is fixed and small, the algorithm runs in linear time, rather than the O(n log n) time of an FFT. Constraints on object size allow further optimizations so that the total cost of producing the required contour descriptors is about 4n addition/subtraction operations, where n is the length of the contour.

  6. SCoPE: an efficient method of Cosmological Parameter Estimation

    SciTech Connect

    Das, Santanu; Souradeep, Tarun E-mail: tarun@iucaa.ernet.in

    2014-07-01

    Markov Chain Monte Carlo (MCMC) sampler is widely used for cosmological parameter estimation from CMB and other data. However, due to the intrinsic serial nature of the MCMC sampler, convergence is often very slow. Here we present a fast and independently written Monte Carlo method for cosmological parameter estimation named as Slick Cosmological Parameter Estimator (SCoPE), that employs delayed rejection to increase the acceptance rate of a chain, and pre-fetching that helps an individual chain to run on parallel CPUs. An inter-chain covariance update is also incorporated to prevent clustering of the chains allowing faster and better mixing of the chains. We use an adaptive method for covariance calculation to calculate and update the covariance automatically as the chains progress. Our analysis shows that the acceptance probability of each step in SCoPE is more than 95% and the convergence of the chains are faster. Using SCoPE, we carry out some cosmological parameter estimations with different cosmological models using WMAP-9 and Planck results. One of the current research interests in cosmology is quantifying the nature of dark energy. We analyze the cosmological parameters from two illustrative commonly used parameterisations of dark energy models. We also asses primordial helium fraction in the universe can be constrained by the present CMB data from WMAP-9 and Planck. The results from our MCMC analysis on the one hand helps us to understand the workability of the SCoPE better, on the other hand it provides a completely independent estimation of cosmological parameters from WMAP-9 and Planck data.

  7. Quantum Newtonian cosmology and the biconfluent Heun functions

    SciTech Connect

    Vieira, H. S.; Bezerra, V. B.

    2015-09-15

    We obtain the exact solution of the Schrödinger equation for a particle (galaxy) moving in a Newtonian universe with a cosmological constant, which is given in terms of the biconfluent Heun functions. The first six Heun polynomials of the biconfluent function are written explicitly. The energy spectrum which resembles the one corresponding to the isotropic harmonic oscillator is also obtained. The wave functions as well as the energy levels codify the role played by the cosmological constant.

  8. Next-Generation Cosmology Simulations with HACC: Challenges from Baryons |

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    Argonne Leadership Computing Facility Simulated cluster strong lensing image based on a large halo extracted from the Outer Rim simulation Simulated cluster strong lensing image based on a large halo extracted from the Outer Rim simulation. The Outer Rim simulation was carried out on Mira and is one of the largest cosmological simulations worldwide. Lindsey Bleem, Nan Li, and the HACC team, Argonne National Laboratory; Mike Gladders, University of Chicago Next-Generation Cosmology

  9. Future singularities and teleparallelism in loop quantum cosmology

    SciTech Connect

    Bamba, Kazuharu; Haro, Jaume de; Odintsov, Sergei D. E-mail: jaime.haro@upc.edu

    2013-02-01

    We demonstrate how holonomy corrections in loop quantum cosmology (LQC) prevent the Big Rip singularity by introducing a quadratic modification in terms of the energy density ? in the Friedmann equation in the Friedmann-Lematre-Robertson-Walker (FLRW) space-time in a consistent and useful way. In addition, we investigate whether other kind of singularities like Type II,III and IV singularities survive or are avoided in LQC when the universe is filled by a barotropic fluid with the state equation P = ???f(?), where P is the pressure and f(?) a function of ?. It is shown that the Little Rip cosmology does not happen in LQC. Nevertheless, the occurrence of the Pseudo-Rip cosmology, in which the phantom universe approaches the de Sitter one asymptotically, is established, and the corresponding example is presented. It is interesting that the disintegration of bound structures in the Pseudo-Rip cosmology in LQC always takes more time than that in Einstein cosmology. Our investigation on future singularities is generalized to that in modified teleparallel gravity, where LQC and Brane Cosmology in the Randall-Sundrum scenario are the best examples. It is remarkable that F(T) gravity may lead to all the kinds of future singularities including Little Rip.

  10. Cosmology in general massive gravity theories

    SciTech Connect

    Comelli, D.; Nesti, F.; Pilo, L. E-mail: fabrizio.nesti@aquila.infn.it

    2014-05-01

    We study the cosmological FRW flat solutions generated in general massive gravity theories. Such a model are obtained adding to the Einstein General Relativity action a peculiar non derivative potentials, function of the metric components, that induce the propagation of five gravitational degrees of freedom. This large class of theories includes both the case with a residual Lorentz invariance as well as the case with rotational invariance only. It turns out that the Lorentz-breaking case is selected as the only possibility. Moreover it turns out that that perturbations around strict Minkowski or dS space are strongly coupled. The upshot is that even though dark energy can be simply accounted by massive gravity modifications, its equation of state w{sub eff} has to deviate from -1. Indeed, there is an explicit relation between the strong coupling scale of perturbations and the deviation of w{sub eff} from -1. Taking into account current limits on w{sub eff} and submillimiter tests of the Newton's law as a limit on the possible strong coupling scale, we find that it is still possible to have a weakly coupled theory in a quasi dS background. Future experimental improvements on short distance tests of the Newton's law may be used to tighten the deviation of w{sub eff} form -1 in a weakly coupled massive gravity theory.

  11. Observational tests for ?(t)CDM cosmology

    SciTech Connect

    Pigozzo, C.; Carneiro, S.; Dantas, M.A.; Alcaniz, J.S. E-mail: aldinez@on.br E-mail: alcaniz@on.br

    2011-08-01

    We investigate the observational viability of a class of cosmological models in which the vacuum energy density decays linearly with the Hubble parameter, resulting in a production of cold dark matter particles at late times. Similarly to the flat ?CDM case, there is only one free parameter to be adjusted by the data in this class of ?(t)CDM scenarios, namely, the matter density parameter. To perform our analysis we use three of the most recent SNe Ia compilation sets (Union2, SDSS and Constitution) along with the current measurements of distance to the BAO peaks at z = 0.2 and z = 0.35 and the position of the first acoustic peak of the CMB power spectrum. We show that in terms of ?{sup 2} statistics both models provide good fits to the data and similar results. A quantitative analysis discussing the differences in parameter estimation due to SNe light-curve fitting methods (SALT2 and MLCS2k2) is studied using the current SDSS and Constitution SNe Ia compilations. A matter power spectrum analysis using the 2dFGRS is also performed, providing a very good concordance with the constraints from the SDSS and Constitution MLCS2k2 data.

  12. Cosmological data and indications for new physics

    SciTech Connect

    Benetti, Micol; Gerbino, Martina; Melchiorri, Alessandro; Pagano, Luca; Kinney, William H.; Kolb, Edward W.; Lattanzi, Massimiliano; Riotto, Antonio E-mail: martina.gerbino@roma1.infn.it E-mail: Rocky.Kolb@uchicago.edu E-mail: alessandro.melchiorri@roma1.infn.it E-mail: antonio.riotto@unige.ch

    2013-10-01

    Data from the Atacama Cosmology Telescope (ACT) and the South Pole Telescope (SPT), combined with the nine-year data release from the WMAP satellite, provide very precise measurements of the cosmic microwave background (CMB) angular anisotropies down to very small angular scales. Augmented with measurements from Baryonic Acoustic Oscillations surveys and determinations of the Hubble constant, we investigate whether there are indications for new physics beyond a Harrison-Zel'dovich model for primordial perturbations and the standard number of relativistic degrees of freedom at primordial recombination. All combinations of datasets point to physics beyond the minimal Harrison-Zel'dovich model in the form of either a scalar spectral index different from unity or additional relativistic degrees of freedom at recombination (e.g., additional light neutrinos). Beyond that, the extended datasets including either ACT or SPT provide very different indications: while the extended-ACT (eACT) dataset is perfectly consistent with the predictions of standard slow-roll inflation, the extended-SPT (eSPT) dataset prefers a non-power-law scalar spectral index with a very large variation with scale of the spectral index. Both eACT and eSPT favor additional light degrees of freedom on top of the Harrison-Zel'dovich model. eACT is consistent with zero neutrino masses, while eSPT favors nonzero neutrino masses at more than 95% confidence.

  13. Finite Cosmology and a CMB Cold Spot

    SciTech Connect

    Adler, R.J.; Bjorken, J.D.; Overduin, J.M.; /Stanford U., HEPL

    2006-03-20

    The standard cosmological model posits a spatially flat universe of infinite extent. However, no observation, even in principle, could verify that the matter extends to infinity. In this work we model the universe as a finite spherical ball of dust and dark energy, and obtain a lower limit estimate of its mass and present size: the mass is at least 5 x 10{sup 23}M{sub {circle_dot}} and the present radius is at least 50 Gly. If we are not too far from the dust-ball edge we might expect to see a cold spot in the cosmic microwave background, and there might be suppression of the low multipoles in the angular power spectrum. Thus the model may be testable, at least in principle. We also obtain and discuss the geometry exterior to the dust ball; it is Schwarzschild-de Sitter with a naked singularity, and provides an interesting picture of cosmogenesis. Finally we briefly sketch how radiation and inflation eras may be incorporated into the model.

  14. SUPERNOVAE AND AGN DRIVEN GALACTIC OUTFLOWS

    SciTech Connect

    Sharma, Mahavir; Nath, Biman B. E-mail: biman@rri.res.in

    2013-01-20

    We present analytical solutions for winds from galaxies with a Navarro-Frank-White (NFW) dark matter halo. We consider winds driven by energy and mass injection from multiple supernovae (SNe), as well as momentum injection due to radiation from a central black hole. We find that the wind dynamics depends on three velocity scales: (1) v{sub *}{approx}( E-dot / 2 M-dot ){sup 1/2} describes the effect of starburst activity, with E-dot and M-dot as energy and mass injection rate in a central region of radius R; (2) v {sub .} {approx} (GM {sub .}/2R){sup 1/2} for the effect of a central black hole of mass M {sub .} on gas at distance R; and (3) v{sub s}=(GM{sub h} / 2Cr{sub s}){sup 1/2}, which is closely related to the circular speed (v{sub c} ) for an NFW halo, where r{sub s} is the halo scale radius and C is a function of the halo concentration parameter. Our generalized formalism, in which we treat both energy and momentum injection from starbursts and radiation from the central active galactic nucleus (AGN), allows us to estimate the wind terminal speed to be (4v {sup 2} {sub *} + 6({Gamma} - 1)v {sub .} {sup 2} - 4v {sup 2} {sub s}){sup 1/2}, where {Gamma} is the ratio of force due to radiation pressure to gravity of the central black hole. Our dynamical model also predicts the following: (1) winds from quiescent star-forming galaxies cannot escape from 10{sup 11.5} M {sub Sun} {<=} M{sub h} {<=} 10{sup 12.5} M {sub Sun} galaxies; (2) circumgalactic gas at large distances from galaxies should be present for galaxies in this mass range; (3) for an escaping wind, the wind speed in low- to intermediate-mass galaxies is {approx}400-1000 km s{sup -1}, consistent with observed X-ray temperatures; and (4) winds from massive galaxies with AGNs at Eddington limit have speeds {approx}> 1000 km s{sup -1}. We also find that the ratio [2v {sup 2} {sub *} - (1 - {Gamma})v {sub .} {sup 2}]/v {sup 2} {sub c} dictates the amount of gas lost through winds. Used in conjunction with

  15. High Statistics Study of Nearby Type 1a Supernovae. QUEST Camera Short Term

    Office of Scientific and Technical Information (OSTI)

    Maintenance: Final Technical Report (Technical Report) | SciTech Connect High Statistics Study of Nearby Type 1a Supernovae. QUEST Camera Short Term Maintenance: Final Technical Report Citation Details In-Document Search Title: High Statistics Study of Nearby Type 1a Supernovae. QUEST Camera Short Term Maintenance: Final Technical Report The Quest Camera was installed at the Palomar Obervatory in California. The camera was used to carry out a survey of low redshift Type 1a supernovae.The

  16. Stellar Evolution/Supernova Research Data Archives from the SciDAC

    Office of Scientific and Technical Information (OSTI)

    Computational Astrophysics Consortium () | Data Explorer Stellar Evolution/Supernova Research Data Archives from the SciDAC Computational Astrophysics Consortium Title: Stellar Evolution/Supernova Research Data Archives from the SciDAC Computational Astrophysics Consortium Theoretical high-energy astrophysics studies the most violent explosions in the universe - supernovae (the massive explosions of dying stars) and gamma ray bursts (mysterious blasts of intense radiation). The evolution of

  17. Type Ia Supernova Hubble Residuals and Host-Galaxy Properties (Journal

    Office of Scientific and Technical Information (OSTI)

    Article) | SciTech Connect Journal Article: Type Ia Supernova Hubble Residuals and Host-Galaxy Properties Citation Details In-Document Search Title: Type Ia Supernova Hubble Residuals and Host-Galaxy Properties Kim et al. (2013) [K13] introduced a new methodology for determining peak- brightness absolute magnitudes of type Ia supernovae from multi-band light curves. We examine the relation between their parameterization of light curves and Hubble residuals, based on photometry synthesized

  18. Gamma-Ray Emission From Crushed Clouds in Supernova Remnants

    SciTech Connect

    Uchiyama, Yasunobu; Blandford, Roger D.; Funk, Stefan; Tajima, Hiroyasu; Tanaka, Takaaki; /KIPAC, Menlo Park

    2010-10-27

    It is shown that the radio and gamma-ray emission observed from newly-found 'GeV-bright' supernova remnants (SNRs) can be explained by a model, in which a shocked cloud and shock-accelerated cosmic rays (CRs) frozen in it are simultaneously compressed by the supernova blastwave as a result of formation of a radiative cloud shock. Simple reacceleration of pre-existing CRs is generally sufficient to power the observed gamma-ray emission through the decays of {pi}{sup 0}-mesons produced in hadronic interactions between high-energy protons (nuclei) and gas in the compressed-cloud layer. This model provides a natural account of the observed synchrotron radiation in SNRs W51C, W44 and IC 443 with flat radio spectral index, which can be ascribed to a combination of secondary and reaccelerated electrons and positrons.

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

    SciTech Connect

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

    2014-10-20

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

  20. Research in nuclear astrophysics: Stellar collapse and supernovae

    SciTech Connect

    Lattimer, J.M.; Yahil, A.

    1992-01-01

    This progress report describes the nuclear astrophysics research activities in the Earth and Space Sciences Department at Stony Brook during the last year. Our research focused on three aspects of nuclear astrophysics: (1) the equation of state of hot, dense matter, (2) the origin of supernovae and neutron stars, (3) the early cooling epoch of neutron stars. The following contains detailed reports which summarize each completed project.

  1. GRB 020410: A Gamma-ray burst afterglow discovered by its supernova...

    Office of Scientific and Technical Information (OSTI)

    We present the discovery and monitoring of the optical transient (OT) associated with GRB ... AND RADIATION PHYSICS; AFTERGLOW; COLOR; MONITORING; TELESCOPES; TRANSIENTS GRB supernova

  2. Fermi-LAT Observation of Supernova Remnant S147 (Journal Article...

    Office of Scientific and Technical Information (OSTI)

    Fermi-LAT Observation of Supernova Remnant S147 Citation Details In-Document Search Title: ... Subject: 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; 71 CLASSICAL AND QUANTUM ...

  3. Stellar Evolution/Supernova Research Data Archives from the SciDAC Computational Astrophysics Consortium

    DOE Data Explorer

    Woosley, Stan [University of California, Santa Cruz

    Theoretical high-energy astrophysics studies the most violent explosions in the universe - supernovae (the massive explosions of dying stars) and gamma ray bursts (mysterious blasts of intense radiation). The evolution of massive stars and their explosion as supernovae and/or gamma ray bursts describes how the "heavy" elements needed for life, such as oxygen and iron, are forged (nucleosynthesis) and ejected to later form new stars and planets. The Computational Astrophysics Consortium's project includes a Science Application Partnership on Adaptive Algorithms that develops software involved. The principal science topics are - in order of priority - 1) models for Type Ia supernovae, 2) radiation transport, spectrum formation, and nucleosynthesis in model supernovae of all types; 3) the observational implications of these results for experiments in which DOE has an interest, especially the Joint Dark Energy Mission, Supernova/Acceleration Probe (SNAP) satellite observatory, the Large Synoptic Survey Telescope (LSST), and ground based supernova searches; 4) core collapse supernovae; 5) gamma-ray bursts; 6) hypernovae from Population III stars; and 7) x-ray bursts. Models of these phenomena share a common need for nuclear reactions and radiation transport coupled to multi-dimensional fluid flow. The team has developed and used supernovae simulation codes to study Type 1A and core-collapse supernovae. (Taken from http://www.scidac.gov/physics/grb.html) The Stellar Evolution Data Archives contains more than 225 Pre-SN models that can be freely accessed.

  4. High Statistics Study of Nearby Type 1a Supernovae. QUEST Camera...

    Office of Scientific and Technical Information (OSTI)

    QUEST Camera Short Term Maintenance: Final Technical Report Citation Details In-Document Search Title: High Statistics Study of Nearby Type 1a Supernovae. QUEST Camera Short Term ...

  5. The Atacama Cosmology Telescope: cosmological parameters from three seasons of data

    SciTech Connect

    Sievers, Jonathan L.; Appel, John William; Hlozek, Renée A.; Nolta, Michael R.; Battaglia, Nick; Bond, J. Richard; Acquaviva, Viviana; Addison, Graeme E.; Amiri, Mandana; Battistelli, Elia S.; Burger, Bryce; Ade, Peter A. R.; Aguirre, Paula; Barrientos, L. Felipe; Brown, Ben; Calabrese, Erminia; Chervenak, Jay; Das, Sudeep; Devlin, Mark J.; and others

    2013-10-01

    We present constraints on cosmological and astrophysical parameters from high-resolution microwave background maps at 148 GHz and 218 GHz made by the Atacama Cosmology Telescope (ACT) in three seasons of observations from 2008 to 2010. A model of primary cosmological and secondary foreground parameters is fit to the map power spectra and lensing deflection power spectrum, including contributions from both the thermal Sunyaev-Zeldovich (tSZ) effect and the kinematic Sunyaev-Zeldovich (kSZ) effect, Poisson and correlated anisotropy from unresolved infrared sources, radio sources, and the correlation between the tSZ effect and infrared sources. The power ℓ{sup 2}C{sub ℓ}/2π of the thermal SZ power spectrum at 148 GHz is measured to be 3.4±1.4  μK{sup 2} at ℓ = 3000, while the corresponding amplitude of the kinematic SZ power spectrum has a 95% confidence level upper limit of 8.6  μK{sup 2}. Combining ACT power spectra with the WMAP 7-year temperature and polarization power spectra, we find excellent consistency with the LCDM model. We constrain the number of effective relativistic degrees of freedom in the early universe to be N{sub eff} = 2.79±0.56, in agreement with the canonical value of N{sub eff} = 3.046 for three massless neutrinos. We constrain the sum of the neutrino masses to be Σm{sub ν} < 0.39 eV at 95% confidence when combining ACT and WMAP 7-year data with BAO and Hubble constant measurements. We constrain the amount of primordial helium to be Y{sub p} = 0.225±0.034, and measure no variation in the fine structure constant α since recombination, with α/α{sub 0} = 1.004±0.005. We also find no evidence for any running of the scalar spectral index, dn{sub s}/dln k = −0.004±0.012.

  6. Cutting-edge issues of core-collapse supernova theory

    SciTech Connect

    Kotake, Kei; Nakamura, Ko; Kuroda, Takami; Takiwaki, Tomoya

    2014-05-02

    Based on multi-dimensional neutrino-radiation hydrodynamic simulations, we report several cutting-edge issues about the long-veiled explosion mechanism of core-collapse supernovae (CCSNe). In this contribution, we pay particular attention to whether three-dimensional (3D) hydrodynamics and/or general relativity (GR) would or would not help the onset of explosions. By performing 3D simulations with spectral neutrino transport, we show that it is more difficult to obtain an explosion in 3D than in 2D. In addition, our results from the first generation of full general relativistic 3D simulations including approximate neutrino transport indicate that GR can foster the onset of neutrino-driven explosions. Based on our recent parametric studies using a light-bulb scheme, we discuss impacts of nuclear energy deposition behind the supernova shock and stellar rotation on the neutrino-driven mechanism, both of which have yet to be included in the self-consistent 3D supernova models. Finally we give an outlook with a summary of the most urgent tasks to extract the information about the explosion mechanisms from multi-messenger CCSN observables.

  7. Parallel halo finding in N-body cosmology simulations

    SciTech Connect

    Pfitzner, D.W.; Salmon, J.K.

    1996-12-31

    Cosmological N-body simulations on parallel computers produce large datasets - about five hundred Megabytes at a single output time, or tens of Gigabytes over the course of a simulation. These large datasets require further analysis before they can be compared to astronomical observations. We have implemented two methods for performing halo finding, a key part of the knowledge discovery process, on parallel machines. One of these is a parallel implementation of the friends of friends (FOF) algorithm, widely used in the field of N-body cosmology. The new isodensity (ID) method has been developed to overcome some of the shortcomings of FOR Both have been implemented on a variety of computer systems, and successfully used to extract halos from simulations with up to 256{sup 3} (or about 16.8 million) particles, which axe among the largest N-body cosmology simulations in existence.

  8. Theoretical Research in Cosmology, High-Energy Physics and String Theory

    SciTech Connect

    Ng, Y Jack; Dolan, Louise; Mersini-Houghton, Laura; Frampton, Paul

    2013-07-29

    The research was in the area of Theoretical Physics: Cosmology, High-Energy Physics and String Theory

  9. Classical and quantum aspects of brane-world cosmology

    SciTech Connect

    Cordero, Ruben; Rojas, Efrain

    2011-10-14

    We give a brief overview of several models in brane-world cosmology. In particular, we focus on the asymmetric DGP and Regge-Teiltelboim models. We present the associated equations of motion governing the dynamics of the brane and their corresponding Friedmann-like equations. In order to develop the quantum Regge-Teiltelboim type cosmology we construct its Ostrogradski Hamiltonian formalism which naturally leads to the corresponding Wheeler-DeWitt equation. In addition, we comment on possible generalizations for these models including second order derivative geometrical terms.

  10. Implementing the DC Mode in Cosmological Simulations with Supercomoving Variables

    DOE PAGES [OSTI]

    Gnedin, Nickolay Y; Kravtsov, Andrey V; Rudd, Douglas H

    2011-06-02

    As emphasized by previous studies, proper treatment of the density fluctuation on the fundamental scale of a cosmological simulation volume - the 'DC mode' - is critical for accurate modeling of spatial correlations on scales ~> 10% of simulation box size. We provide further illustration of the effects of the DC mode on the abundance of halos in small boxes and show that it is straightforward to incorporate this mode in cosmological codes that use the 'supercomoving' variables. The equations governing evolution of dark matter and baryons recast with these variables are particularly simple and include the expansion factor, andmorehence the effect of the DC mode, explicitly only in the Poisson equation.less

  11. Cosmological neutrino mass detection: The Best probe of neutrino lifetime

    SciTech Connect

    Serpico, Pasquale D.; /Fermilab

    2007-01-01

    Future cosmological data may be sensitive to the effects of a finite sum of neutrino masses even as small as {approx}0.06 eV, the lower limit guaranteed by neutrino oscillation experiments. We show that a cosmological detection of neutrino mass at that level would improve by many orders of magnitude the existing limits on neutrino lifetime, and as a consequence on neutrino secret interactions with (quasi-)massless particles as in majoron models. On the other hand, neutrino decay may provide a way-out to explain a discrepancy {approx}< 0.1 eV between cosmic neutrino bounds and Lab data.

  12. Duality linking standard and tachyon scalar field cosmologies

    SciTech Connect

    Avelino, P. P.; Bazeia, D.; Losano, L.; Oliveira, J. C. R. E.; Pavan, A. B.

    2010-09-15

    In this work we investigate the duality linking standard and tachyon scalar field homogeneous and isotropic cosmologies in N+1 dimensions. We determine the transformation between standard and tachyon scalar fields and between their associated potentials, corresponding to the same background evolution. We show that, in general, the duality is broken at a perturbative level, when deviations from a homogeneous and isotropic background are taken into account. However, we find that for slow-rolling fields the duality is still preserved at a linear level. We illustrate our results with specific examples of cosmological relevance, where the correspondence between scalar and tachyon scalar field models can be calculated explicitly.

  13. Group X

    SciTech Connect

    Fields, Susannah

    2007-08-16

    This project is currently under contract for research through the Department of Homeland Security until 2011. The group I was responsible for studying has to remain confidential so as not to affect the current project. All dates, reference links and authors, and other distinguishing characteristics of the original group have been removed from this report. All references to the name of this group or the individual splinter groups has been changed to 'Group X'. I have been collecting texts from a variety of sources intended for the use of recruiting and radicalizing members for Group X splinter groups for the purpose of researching the motivation and intent of leaders of those groups and their influence over the likelihood of group radicalization. This work included visiting many Group X websites to find information on splinter group leaders and finding their statements to new and old members. This proved difficult because the splinter groups of Group X are united in beliefs, but differ in public opinion. They are eager to tear each other down, prove their superiority, and yet remain anonymous. After a few weeks of intense searching, a list of eight recruiting texts and eight radicalizing texts from a variety of Group X leaders were compiled.

  14. CONSTRAINING PHYSICAL PROPERTIES OF TYPE IIn SUPERNOVAE THROUGH RISE TIMES AND PEAK LUMINOSITIES

    SciTech Connect

    Moriya, Takashi J.; Maeda, Keiichi

    2014-08-01

    We investigate the diversity in the wind density, supernova ejecta energy, and ejecta mass in Type IIn supernovae based on their rise times and peak luminosities. We show that the wind density and supernova ejecta properties can be estimated independently if both the rise time and peak luminosity are observed. The peak luminosity is mostly determined by the supernova properties and the rise time can be used to estimate the wind density. We find that the ejecta energies of Type IIn supernovae need to vary by factors of 0.2-5 from the average if their ejecta masses are similar. The diversity in the observed rise times indicates that their wind densities vary by factors of 0.2-2 from the average. We show that Type IIn superluminous supernovae should have not only large wind density but also large ejecta energy and/or small ejecta mass to explain their large luminosities and the rise times at the same time. We also note that shock breakout does not necessarily occur in the wind even if it is optically thick, except for the case of superluminous supernovae, and we analyze the observational data both with and without assuming that the shock breakout occurs in the dense wind of Type IIn supernovae.

  15. Superluminous supernovae as standardizable candles and high-redshift distance probes

    SciTech Connect

    Inserra, C.; Smartt, S. J.

    2014-12-01

    We investigate the use of type Ic superluminous supernovae (SLSN Ic) as standardizable candles and distance indicators. Their appeal as cosmological probes stems from their remarkable peak luminosities, hot blackbody temperatures, and bright rest-frame ultraviolet emission. We present a sample of 16 published SLSN, from redshifts 0.1 to 1.2, and calculate accurate K corrections to determine uniform magnitudes in 2 synthetic rest-frame filter bandpasses with central wavelengths at 400 nm and 520 nm. At 400 nm, we find an encouragingly low scatter in their uncorrected, raw mean magnitudes with M(400) = –21.86 ± 0.35 mag for the full sample of 16 objects. We investigate the correlation between their decline rates and peak magnitude and find that the brighter events appear to decline more slowly. In a manner similar to the Phillips relation for type Ia SNe (SNe Ia), we define a ΔM {sub 20} decline relation. This correlates peak magnitude and decline over 20 days and can reduce the scatter in standardized peak magnitudes to ±0.22 mag. We further show that M(400) appears to have a strong color dependence. Redder objects are fainter and also become redder faster. Using this peak magnitudecolor evolution relation, a surprisingly low scatter of between ±0.08 mag and ±0.13 mag can be found in peak magnitudes, depending on sample selection. However, we caution that only 8 to 10 objects currently have enough data to test this peak magnitudecolor evolution relation. We conclude that SLSN Ic are promising distance indicators in the high-redshift universe in regimes beyond those possible with SNe Ia. Although the empirical relationships are encouraging, the unknown progenitor systems, how they may evolve with redshift, and the uncertain explosion physics are of some concern. The two major measurement uncertainties are the limited numbers of low-redshift, well-studied objects available to test these relationships and internal dust extinction in the host galaxies.

  16. FRW quantum cosmology with a generalized Chaplygin gas

    SciTech Connect

    Bouhmadi-Lopez, Mariam; Moniz, Paulo Vargas

    2005-03-15

    Cosmologies with a Chaplygin gas have recently been explored with the objective of explaining the transition from a dust dominated epoch towards an accelerating expansion stage. In this context, we consider the hypothesis that this transition involves a quantum mechanical process. Our analysis is entirely analytical, with the objective of finding explicit mathematical expressions for the different quantum mechanical states and their cosmological implications. We employ a Friedmann-Robertson-Walker (FRW) minisuperspace model, characterized by two Lorentzian sectors, separated by a classically forbidden region. This is the configuration associated with the evolution of a generalized Chaplygin gas in a FRW universe. The Hartle-Hawking and Vilenkin wave functions are then computed, together with the transition amplitudes towards the accelerating epoch. Furthermore, for specific initial conditions we found that the generalized Chaplygin gas parameters become related through an expression involving an integer n. We also introduce a phenomenological association between some brane-world scenarios and a FRW minisuperspace cosmology with a generalized Chaplygin gas. The aim is to promote a discussion and subsequent research on the quantum creation of brane cosmologies from such a perspective. Additional results in this paper suggest that the brane tension would become related with the generalized Chaplygin gas parameters through another expression involving an integer.

  17. Disformal theories of gravity: from the solar system to cosmology

    SciTech Connect

    Sakstein, Jeremy

    2014-12-01

    This paper is concerned with theories of gravity that contain a scalar coupled both conformally and disformally to matter through the metric. By systematically deriving the non-relativistic limit, it is shown that no new non-linear screening mechanisms are present beyond the Vainshtein mechanism and chameleon-like screening. If one includes the cosmological expansion of the universe, disformal effects that are usually taken to be absent can be present in the solar system. When the conformal factor is absent, fifth-forces can be screened on all scales when the cosmological field is slowly-rolling. We investigate the cosmology of these models and use local tests of gravity to place new constraints on the disformal coupling and find M?>O(eV), which is not competitive with laboratory tests. Finally, we discuss the future prospects for testing these theories and the implications for other theories of modified gravity. In particular, the Vainshtein radius of solar system objects can be altered from the static prediction when cosmological time-derivatives are non-negligible.

  18. Bimetric gravity doubly coupled to matter: theory and cosmological implications

    SciTech Connect

    Akrami, Yashar; Koivisto, Tomi S.; Mota, David F.; Sandstad, Marit E-mail: t.s.koivisto@astro.uio.no E-mail: marit.sandstad@astro.uio.no

    2013-10-01

    A ghost-free theory of gravity with two dynamical metrics both coupled to matter is shown to be consistent and viable. Its cosmological implications are studied, and the models, in particular in the context of partially massless gravity, are found to explain the cosmic acceleration without resorting to dark energy.

  19. Detecting a Lorentz-violating field in cosmology

    SciTech Connect

    Li Baojiu; Barrow, John D.; Mota, David F.

    2008-01-15

    We consider cosmology in the Einstein-Aether theory (the generally covariant theory of gravitation coupled to a dynamical timelike Lorentz-violating vector field) with a linear Ae-Lagrangian. The 3+1 spacetime splitting approach is used to derive covariant and gauge invariant perturbation equations which are valid for a general class of Lagrangians. Restricting attention to the parameter space of these theories which is consistent with local gravity experiments, we show that there are tracking behaviors for the Ae field, both in the background cosmology and at the linear perturbation level. The primordial power spectrum of scalar perturbations in this model is shown to be the same as that predicted by standard general relativity. However, the power spectrum of tensor perturbation is different from that in general relativity, but has a smaller amplitude and so cannot be detected at present. We also study the implications for late-time cosmology and find that the evolution of photon and neutrino anisotropic stresses can source the Ae field perturbation during the radiation and matter dominated epochs, and as a result the CMB and matter power spectra are modified. However, these effects are degenerate with respect to other cosmological parameters, such as neutrino masses and the bias parameter in the observed galaxy spectrum.

  20. Distance-redshift relations in an anisotropic cosmological model

    SciTech Connect

    Menezes, R. S. Jr.; Pigozzo, C.; Carneiro, S. E-mail: cpigozzo@ufba.br

    2013-03-01

    In this paper we study an anisotropic model generated from a particular Bianchi type-III metric, which is a generalization of Gdel's metric and an exact solution of Einstein's field equations. We analyse type Ia supernova data, namely the SDSS sample calibrated with the MLCS2k2 fitter, and we verify in which ranges of distances and redshifts the anisotropy could be observed. We also consider, in a joint analysis, the position of the first peak in the CMB anisotropy spectrum, as well as current observational constraints on the Hubble constant. We conclude that a small anisotropy is permitted by the data, and that more accurate measurements of supernova distances above z = 2 might indicate the existence of such anisotropy in the universe.

  1. Type Ia Supernova Hubble Residuals and Host-Galaxy Properties

    SciTech Connect

    Nearby Supernova Factory; Kim, A. G.; Aldering, G.; Antilogus, P.; Aragon, C.; Bailey, S.; Baltay, C.; Bongard, S.; Buton, C.; Canto, A.; Cellier-Holzem, F.; Childress, M.; Chotard, N.; Copin, Y.; Fakhouri, H. K.; Feindt, U.; Fleury, M.; Gangler, E.; Greskovic, P.; Guy, J.; Kowalski, M.; Lombardo, S.; Nordin, J.; Nugent, P.; Pain, R.; Pecontal, E.; Pereira, R.; Perlmutter, S.; Rabinowitz, D.; Rigault, M.; Runge, K.; Saunders, C.; Scalzo, R.; Smadja, G.; Tao, C.; Thomas, R. C.; Weaver, B. A.

    2014-01-17

    Kim et al. (2013) [K13] introduced a new methodology for determining peak- brightness absolute magnitudes of type Ia supernovae from multi-band light curves. We examine the relation between their parameterization of light curves and Hubble residuals, based on photometry synthesized from the Nearby Supernova Factory spec- trophotometric time series, with global host-galaxy properties. The K13 Hubble residual step with host mass is 0.013 ? 0.031 mag for a supernova subsample with data coverage corresponding to the K13 training; at ? 1?, the step is not significant and lower than previous measurements. Relaxing the data coverage requirement the Hubble residual step with host mass is 0.045 ? 0.026 mag for the larger sample; a calculation using the modes of the distributions, less sensitive to outliers, yields a step of 0.019 mag. The analysis of this article uses K13 inferred luminosities, as distinguished from previous works that use magnitude corrections as a function of SALT2 color and stretch param- eters: Steps at> 2? significance are found in SALT2 Hubble residuals in samples split by the values of their K13 x(1) and x(2) light-curve parameters. x(1) affects the light- curve width and color around peak (similar to the∆m15 and stretch parameters), and x(2) affects colors, the near-UV light-curve width, and the light-curve decline 20 to 30 days after peak brightness. The novel light-curve analysis, increased parameter set, and magnitude corrections of K13 may be capturing features of SN Ia diversity arising from progenitor stellar evolution.

  2. Type Ia supernova Hubble residuals and host-galaxy properties

    SciTech Connect

    Kim, A. G.; Aldering, G.; Aragon, C.; Bailey, S.; Fakhouri, H. K.; Antilogus, P.; Bongard, S.; Canto, A.; Cellier-Holzem, F.; Fleury, M.; Guy, J.; Baltay, C.; Buton, C.; Feindt, U.; Greskovic, P.; Kowalski, M.; Childress, M.; Chotard, N.; Copin, Y.; Gangler, E. [Université de Lyon, F-69622 Lyon; Université de Lyon 1, Villeurbanne; CNRS and others

    2014-03-20

    Kim et al. introduced a new methodology for determining peak-brightness absolute magnitudes of type Ia supernovae from multi-band light curves. We examine the relation between their parameterization of light curves and Hubble residuals, based on photometry synthesized from the Nearby Supernova Factory spectrophotometric time series, with global host-galaxy properties. The K13 Hubble residual step with host mass is 0.013 ± 0.031 mag for a supernova subsample with data coverage corresponding to the K13 training; at <<1σ, the step is not significant and lower than previous measurements. Relaxing the data coverage requirement of the Hubble residual step with the host mass is 0.045 ± 0.026 mag for the larger sample; a calculation using the modes of the distributions, less sensitive to outliers, yields a step of 0.019 mag. The analysis of this article uses K13 inferred luminosities, as distinguished from previous works that use magnitude corrections as a function of SALT2 color and stretch parameters: steps at >2σ significance are found in SALT2 Hubble residuals in samples split by the values of their K13 x(1) and x(2) light-curve parameters. x(1) affects the light-curve width and color around peak (similar to the Δm {sub 15} and stretch parameters), and x(2) affects colors, the near-UV light-curve width, and the light-curve decline 20-30 days after peak brightness. The novel light-curve analysis, increased parameter set, and magnitude corrections of K13 may be capturing features of SN Ia diversity arising from progenitor stellar evolution.

  3. Effects of Ion Correlations in Supernovae and Neutron Star Crusts

    SciTech Connect

    Caballero, O. L.; Horowitz, C. J.

    2007-10-26

    Core-collapse supernovae are some of the most energetic explosions in the Universe. During the collapse 99 % of the energy is lost by neutrino emission. The dynamics of the explosion is highly sensitive to neutrino scattering from the stellar medium. We use molecular dynamics simulations to calculate ion structure factors, neutrino-nucleus scattering cross sections, and neutrino mean free paths. We find clear differences in the neutrino mean free path when the medium is composed of a mixture of ions compared with a medium composed of a single ion species.

  4. Bolometric and UV light curves of core-collapse supernovae

    SciTech Connect

    Pritchard, T. A.; Roming, P. W. A.; Brown, Peter J.; Bayless, Amanda J.; Frey, Lucille H.

    2014-06-01

    The Swift UV-Optical Telescope (UVOT) has been observing core-collapse supernovae (CCSNe) of all subtypes in the UV and optical since 2005. Here we present 50 CCSNe observed with the Swift UVOT, analyzing their UV properties and behavior. Where we have multiple UV detections in all three UV filters (λ {sub c} = 1928-2600 Å), we generate early time bolometric light curves, analyze the properties of these light curves and the UV contribution to them, and derive empirical corrections for the UV-flux contribution to optical-IR based bolometric light curves.

  5. Galaxy groups

    SciTech Connect

    Brent Tully, R.

    2015-02-01

    Galaxy groups can be characterized by the radius of decoupling from cosmic expansion, the radius of the caustic of second turnaround, and the velocity dispersion of galaxies within this latter radius. These parameters can be a challenge to measure, especially for small groups with few members. In this study, results are gathered pertaining to particularly well-studied groups over four decades in group mass. Scaling relations anticipated from theory are demonstrated and coefficients of the relationships are specified. There is an update of the relationship between light and mass for groups, confirming that groups with mass of a few times 10{sup 12}M{sub ?} are the most lit up while groups with more and less mass are darker. It is demonstrated that there is an interesting one-to-one correlation between the number of dwarf satellites in a group and the group mass. There is the suggestion that small variations in the slope of the luminosity function in groups are caused by the degree of depletion of intermediate luminosity systems rather than variations in the number per unit mass of dwarfs. Finally, returning to the characteristic radii of groups, the ratio of first to second turnaround depends on the dark matter and dark energy content of the universe and a crude estimate can be made from the current observations of ?{sub matter}?0.15 in a flat topology, with a 68% probability of being less than 0.44.

  6. Model-independent plotting of the cosmological scale factor as a function of lookback time

    SciTech Connect

    Ringermacher, H. I.; Mead, L. R., E-mail: ringerha@gmail.com, E-mail: Lawrence.mead@usm.edu [Department of Physics and Astronomy, University of Southern Mississippi, Hattiesburg, MS 39406 (United States)

    2014-11-01

    In this work we describe a model-independent method of developing a plot of scale factor a(t) versus lookback time t{sub L} from the usual Hubble diagram of modulus data against redshift. This is the first plot of this type. We follow the model-independent methodology of Daly and Djorgovski used for their radio-galaxy data. Once the a(t)data plot is completed, any model can be applied and will display as described in the standard literature. We then compile an extensive data set to z = 1.8 by combining Type Ia supernovae (SNe Ia) data from SNLS3 of Conley et al., high-z SNe data of Riess et al., and radio-galaxy data of Daly and Djorgovski to validate the new plot. We first display these data on a standard Hubble diagram to confirm the best fit for ?CDM cosmology, and thus validate the joined data set. The scale factor plot is then developed from the data and the ?CDM model is again displayed from a least-squares fit. The fit parameters are in agreement with the Hubble diagram fit confirming the validity of the new plot. Of special interest is the transition time of the universe, which in the scale factor plot will appear as an inflection point in the data set. Noise is more visible in this presentation, which is particularly sensitive to inflection points of any model displayed in the plot, unlike on a modulus-z diagram, where there are no inflection points and the transition-z is not at all obvious by inspection. We obtain a lower limit of z ? 0.6. It is evident from this presentation that there is a dearth of SNe data in the range z = 1-2, exactly the range necessary to confirm a ?CDM transition-z around z = 0.76. We then compare a 'toy model' wherein dark matter is represented as a perfect fluid with an equation of state p = (1/3) ? to demonstrate the plot sensitivity to model choice. Its density varies as 1/t {sup 2} and it enters the Friedmann equations as ?{sub dark}/t {sup 2}, replacing only the ?{sub dark}/a {sup 3} term. The toy model is a close match to

  7. Exploring the Outer Solar System with the ESSENCE Supernova Survey

    SciTech Connect

    Becker, A.C.; Arraki, K.; Kaib, N.A.; Wood-Vasey, W.M.; Aguilera, C.; Blackman, J.W.; Blondin, S.; Challis, P.; Clocchiatti, A.; Covarrubias, R.; Damke, G.; Davis, T.M.; Filippenko, A.V.; Foley, R.J.; Garg, A.; Garnavich, P.M.; Hicken, M.; Jha, S.; Kirshner, R.P.; Krisciunas, K.; Leibundgut, B.; /Munich, Tech. U. /UC, Berkeley /NOAO, Tucson /Washington U., Seattle, Astron. Dept. /Fermilab /Harvard-Smithsonian Ctr. Astrophys. /Harvard U. /Chile U., Santiago /Ohio State U. /Cerro-Tololo InterAmerican Obs. /Harvard U. /Baltimore, Space Telescope Sci. /Johns Hopkins U. /Australian Natl. U., Canberra /Australian Natl. U., Canberra /Cerro-Tololo InterAmerican Obs. /Munich, Tech. U. /Harvard-Smithsonian Ctr. Astrophys. /Harvard U. /Cerro-Tololo InterAmerican Obs. /Texas A-M /Cerro-Tololo InterAmerican Obs.

    2011-11-10

    We report the discovery and orbital determination of 14 trans-Neptunian objects (TNOs) from the ESSENCE Supernova Survey difference imaging data set. Two additional objects discovered in a similar search of the SDSS-II Supernova Survey database were recovered in this effort. ESSENCE repeatedly observed fields far from the solar system ecliptic (-21{sup o} < {beta} < -5{sup o}), reaching limiting magnitudes per observation of I {approx} 23.1 and R {approx} 23.7. We examine several of the newly detected objects in detail, including 2003 UC{sub 414}, which orbits entirely between Uranus and Neptune and lies very close to a dynamical region that would make it stable for the lifetime of the solar system. 2003 SS{sub 422} and 2007 TA{sub 418} have high eccentricities and large perihelia, making them candidate members of an outer class of TNOs. We also report a new member of the 'extended' or 'detached' scattered disk, 2004 VN{sub 112}, and verify the stability of its orbit using numerical simulations. This object would have been visible to ESSENCE for only {approx}2% of its orbit, suggesting a vast number of similar objects across the sky. We emphasize that off-ecliptic surveys are optimal for uncovering the diversity of such objects, which in turn will constrain the history of gravitational influences that shaped our early solar system.

  8. Search for surviving companions in type Ia supernova remnants

    SciTech Connect

    Pan, Kuo-Chuan; Ricker, Paul M.; Taam, Ronald E. E-mail: pmricker@illinois.edu E-mail: taam@asiaa.sinica.edu.tw

    2014-09-01

    The nature of the progenitor systems of type Ia supernovae (SNe Ia) is still unclear. One way to distinguish between the single-degenerate scenario and double-degenerate scenario for their progenitors is to search for the surviving companions (SCs). Using a technique that couples the results from multi-dimensional hydrodynamics simulations with calculations of the structure and evolution of main-sequence- (MS-) and helium-rich SCs, the color and magnitude of MS- and helium-rich SCs are predicted as functions of time. The SC candidates in Galactic type Ia supernova remnants (Ia SNR) and nearby extragalactic Ia SNRs are discussed. We find that the maximum detectable distance of MS SCs (helium-rich SCs) is 0.6-4 Mpc (0.4-16 Mpc), if the apparent magnitude limit is 27 in the absence of extinction, suggesting that the Large and Small Magellanic Clouds and the Andromeda Galaxy are excellent environments in which to search for SCs. However, only five Ia SNRs have been searched for SCs, showing little support for the standard channels in the singe-degenerate scenario. To better understand the progenitors of SNe Ia, we encourage the search for SCs in other nearby Ia SNRs.

  9. CAN STELLAR MIXING EXPLAIN THE LACK OF TYPE Ib SUPERNOVAE IN...

    Office of Scientific and Technical Information (OSTI)

    Country of Publication: United States Language: English Subject: 79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ALGORITHMS; CONVECTION; COSMIC GAMMA BURSTS; HELIUM; MIXING; SPECTRA; ...

  10. Improved Dark Energy Constraints From ~ 100 New CfA Supernova...

    Office of Scientific and Technical Information (OSTI)

    Kirshner, Robert P.; Harvard-Smithsonian Ctr. Astrophys. 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ACCURACY; COLOR; COSMOLOGICAL CONSTANT; LUMINOSITY; PHOTOMETRY;...

  11. IMPROVED DARK ENERGY CONSTRAINTS FROM {approx}100 NEW CfA SUPERNOVA...

    Office of Scientific and Technical Information (OSTI)

    of Physics and Astronomy, Rutgers, the State University of New Jersey, Piscataway, NJ 08854 (United States) Kavli Institute for Particle Astrophysics and Cosmology, Stanford ...

  12. Spectroscopic Determination of the Low Redshift Type Ia Supernova Rate from the Sloan Digital Sky Survey

    SciTech Connect

    Krughoff, K. S.; Connolly, Andrew J.; Frieman, Joshua; SubbaRao, Mark; Kilper, Gary; Schneider, Donald P.

    2011-04-10

    Supernova rates are directly coupled to high mass stellar birth and evolution. As such, they are one of the few direct measures of the history of cosmic stellar evolution. In this paper we describe an probabilistic technique for identifying supernovae within spectroscopic samples of galaxies. We present a study of 52 type Ia supernovae ranging in age from -14 days to +40 days extracted from a parent sample of \\simeq 50,000 spectra from the SDSS DR5. We find a Supernova Rate (SNR) of 0.472^{+0.048}_{-0.039}(Systematic)^{+0.081}_{-0.071}(Statistical)SNu at a redshift of = 0.1. This value is higher than other values at low redshift at the 1{\\sigma}, but is consistent at the 3{\\sigma} level. The 52 supernova candidates used in this study comprise the third largest sample of supernovae used in a type Ia rate determination to date. In this paper we demonstrate the potential for the described approach for detecting supernovae in future spectroscopic surveys.

  13. Cosmological viability conditions for f(T) dark energy models

    SciTech Connect

    Setare, M.R.; Mohammadipour, N. E-mail: N.Mohammadipour@uok.ac.ir

    2012-11-01

    Recently f(T) modified teleparallel gravity where T is the torsion scalar has been proposed as the natural gravitational alternative for dark energy. We perform a detailed dynamical analysis of these models and find conditions for the cosmological viability of f(T) dark energy models as geometrical constraints on the derivatives of these models. We show that in the phase space exists two cosmologically viable trajectory which (i) The universe would start from an unstable radiation point, then pass a saddle standard matter point which is followed by accelerated expansion de sitter point. (ii) The universe starts from a saddle radiation epoch, then falls onto the stable matter era and the system can not evolve to the dark energy dominated epoch. Finally, for a number of f(T) dark energy models were proposed in the more literature, the viability conditions are investigated.

  14. Cosmological moduli problem in large volume scenario and thermal inflation

    SciTech Connect

    Choi, Kiwoon; Park, Wan-Il; Shin, Chang Sub E-mail: wipark@kias.re.kr

    2013-03-01

    We show that in a large volume scenario of type IIB string or F-theory compactifications, single thermal inflation provides only a partial solution to the cosmological problem of the light volume modulus. We then clarify the conditions for double thermal inflation, being a simple extension of the usual single thermal inflation scenario, to solve the cosmological moduli problem in the case of relatively light moduli masses. Using a specific example, we demonstrate that double thermal inflation can be realized in large volume scenario in a natural manner, and the problem of the light volume modulus can be solved for the whole relevant mass range. We also find that right amount of baryon asymmetry and dark matter can be obtained via a late-time Affleck-Dine mechanism and the decays of the visible sector NLSP to flatino LSP.

  15. Cosmological and astrophysical constraints on superconducting cosmic strings

    SciTech Connect

    Miyamoto, Koichi; Nakayama, Kazunori E-mail: kazunori@hep-th.phys.s.u-tokyo.ac.jp

    2013-07-01

    We investigate the cosmological and astrophysical constraints on superconducting cosmic strings (SCSs). SCS loops emit strong bursts of electromagnetic waves, which might affect various cosmological and astrophysical observations. We take into account the effect on the CMB anisotropy, CMB blackbody spectrum, BBN, observational implications on radio wave burst and X-ray or ?-ray events, and stochastic gravitational wave background measured by pulsar timing experiments. We then derive constraints on the parameters of SCS from current observations and estimate prospects for detecting SCS signatures in on-going observations. As a result, we find that these constraints exclude broad parameter regions, and also that on-going radio wave observations can probe large parameter space.

  16. The adhesion model as a field theory for cosmological clustering

    SciTech Connect

    Rigopoulos, Gerasimos

    2015-01-01

    The adhesion model has been proposed in the past as an improvement of the Zel'dovich approximation, providing a good description of the formation of the cosmic web. We recast the model as a field theory for cosmological large scale structure, adding a stochastic force to account for power generated from very short, highly non-linear scales that is uncorrelated with the initial power spectrum. The dynamics of this Stochastic Adhesion Model (SAM) is reminiscent of the well known Kardar-Parisi-Zhang equation with the difference that the viscosity and the noise spectrum are time dependent. Choosing the viscosity proportional to the growth factor D restricts the form of noise spectrum through a 1-loop renormalization argument. For this choice, the SAM field theory is renormalizable to one loop. We comment on the suitability of this model for describing the non-linear regime of the CDM power spectrum and its utility as a relatively simple approach to cosmological clustering.

  17. Nuclear and particle physics, astrophysics and cosmology (NPAC) capability review

    SciTech Connect

    Redondo, Antonio

    2010-01-01

    The present document represents a summary self-assessment of the status of the Nuclear and Particle Physics, Astrophysics and Cosmology (NPAC) capability across Los Alamos National Laboratory (LANL). For the purpose of this review, we have divided the capability into four theme areas: Nuclear Physics, Particle Physics, Astrophysics and Cosmology, and Applied Physics. For each theme area we have given a general but brief description of the activities under the area, a list of the Laboratory divisions involved in the work, connections to the goals and mission of the Laboratory, a brief description of progress over the last three years, our opinion of the overall status of the theme area, and challenges and issues.

  18. Cosmological Ohm's law and dynamics of non-minimal electromagnetism

    SciTech Connect

    Hollenstein, Lukas; Jain, Rajeev Kumar; Urban, Federico R. E-mail: jain@cp3.dias.sdu.dk

    2013-01-01

    The origin of large-scale magnetic fields in cosmic structures and the intergalactic medium is still poorly understood. We explore the effects of non-minimal couplings of electromagnetism on the cosmological evolution of currents and magnetic fields. In this context, we revisit the mildly non-linear plasma dynamics around recombination that are known to generate weak magnetic fields. We use the covariant approach to obtain a fully general and non-linear evolution equation for the plasma currents and derive a generalised Ohm law valid on large scales as well as in the presence of non-minimal couplings to cosmological (pseudo-)scalar fields. Due to the sizeable conductivity of the plasma and the stringent observational bounds on such couplings, we conclude that modifications of the standard (adiabatic) evolution of magnetic fields are severely limited in these scenarios. Even at scales well beyond a Mpc, any departure from flux freezing behaviour is inhibited.

  19. Supernova 2010as: the lowest-velocity member of a family of flat-velocity type IIb supernovae

    SciTech Connect

    Folatelli, Gastn; Bersten, Melina C.; Nomoto, Ken'ichi [Kavli Institute for the Physics and Mathematics of the Universe (WPI), The University of Tokyo, Kashiwa, Chiba 277-8583 (Japan); Kuncarayakti, Hanindyo; Hamuy, Mario [Departamento de Astronoma, Universidad de Chile, Casilla 36-D, Santiago (Chile); Olivares Estay, Felipe; Pignata, Giuliano [Departamento de Ciencias Fisicas, Universidad Andres Bello, Avda. Republica 252, Santiago (Chile); Anderson, Joseph P. [European Southern Observatory, Alonso de Cordova 3107, Vitacura, Santiago (Chile); Holmbo, Simon; Stritzinger, Maximilian [Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C (Denmark); Maeda, Keiichi [Department of Astronomy, Kyoto University, Kitashirakawa-Oiwake-cho, Sakyo-ku, Kyoto 606-8502 (Japan); Morrell, Nidia; Contreras, Carlos; Phillips, Mark M. [Las Campanas Observatory, Carnegie Observatories, Casilla 601, La Serena (Chile); Frster, Francisco [Center for Mathematical Modelling, Universidad de Chile, Avenida Blanco Encalada 2120 Piso 7, Santiago (Chile); Prieto, Jos Luis [Department of Astrophysical Sciences, Princeton University, 4 Ivy Lane, Peyton Hall, Princeton, NJ 08544 (United States); Valenti, Stefano [Las Cumbres Observatory Global Telescope Network, 6740 Cortona Drive, Suite 102, Goleta, CA 93117 (United States); Afonso, Paulo; Altenmller, Konrad; Elliott, Jonny, E-mail: gaston.folatelli@ipmu.jp [Max-Planck-Institut fr extraterrestrische Physik, Giessenbachstrae 1, D-85740 Garching (Germany); and others

    2014-09-01

    We present extensive optical and near-infrared photometric and spectroscopic observations of the stripped-envelope supernova SN 2010as. Spectroscopic peculiarities such as initially weak helium features and low expansion velocities with a nearly flat evolution place this object in the small family of events previously identified as transitional Type Ib/c supernovae (SNe). There is ubiquitous evidence of hydrogen, albeit weak, in this family of SNe, indicating that they are in fact a peculiar kind of Type IIb SNe that we name 'flat-velocity' Type IIb. The flat-velocity evolutionwhich occurs at different levels between 6000 and 8000 km s{sup 1} for different SNesuggests the presence of a dense shell in the ejecta. Despite the spectroscopic similarities, these objects show surprisingly diverse luminosities. We discuss the possible physical or geometrical unification picture for such diversity. Using archival Hubble Space Telescope images, we associate SN 2010as with a massive cluster and derive a progenitor age of ?6 Myr, assuming a single star-formation burst, which is compatible with a Wolf-Rayet progenitor. Our hydrodynamical modeling, on the contrary, indicates that the pre-explosion mass was relatively low, ?4 M {sub ?}. The seeming contradiction between a young age and low pre-SN mass may be solved by a massive interacting binary progenitor.

  20. Inflation in Kaluza-Klein cosmology. 2; Freidmann models

    SciTech Connect

    Bleyer, U. ); Schmidt, H.J. )

    1990-12-20

    The conformal relation between scale- invariant fourth-order gravity and Kaluza-Klein models as derived is applied to Friedmann cosmological models. Especially, the results that power-law inflation is an attractor solution can be carried over, but the conformal transformation brings power-law inflation to de Sitter-like exponential inflation, or power-law inflation a {approx} t. This paper reports that results depend essentially on the dimension of the internal space.

  1. Self-Consistent Cosmological Simulations of DGP Braneworld Gravity

    SciTech Connect

    Schmidt, Fabian; /Chicago U., Astron. Astrophys. Ctr. /KICP, Chicago

    2009-09-01

    We perform cosmological N-body simulations of the Dvali-Gabadadze-Porrati braneworld model, by solving the full non-linear equations of motion for the scalar degree of freedom in this model, the brane bending mode. While coupling universally to matter, the brane-bending mode has self-interactions that become important as soon as the density field becomes non-linear. These self-interactions lead to a suppression of the field in high-density environments, and restore gravity to General Relativity. The code uses a multi-grid relaxation scheme to solve the non-linear field equation in the quasi-static approximation. We perform simulations of a flat self-accelerating DGP model without cosmological constant. However, the type of non-linear interactions of the brane-bending mode, which are the focus of this study, are generic to a wide class of braneworld cosmologies. The results of the DGP simulations are compared with standard gravity simulations assuming the same expansion history, and with DGP simulations using the linearized equation for the brane bending mode. This allows us to isolate the effects of the non-linear self-couplings of the field which are noticeable already on quasi-linear scales. We present results on the matter power spectrum and the halo mass function, and discuss the behavior of the brane bending mode within cosmological structure formation. We find that, independently of CMB constraints, the self-accelerating DGP model is strongly constrained by current weak lensing and cluster abundance measurements.

  2. Improved Dark Energy Constraints From ~ 100 New CfA Supernova Type Ia Light

    Office of Scientific and Technical Information (OSTI)

    Curves (Journal Article) | SciTech Connect Journal Article: Improved Dark Energy Constraints From ~ 100 New CfA Supernova Type Ia Light Curves Citation Details In-Document Search Title: Improved Dark Energy Constraints From ~ 100 New CfA Supernova Type Ia Light Curves We combine the CfA3 supernovae Type Ia (SN Ia) sample with samples from the literature to calculate improved constraints on the dark energy equation of state parameter, w. The CfA3 sample is added to the Union set of Kowalski

  3. Non-minimal Higgs inflation and frame dependence in cosmology

    SciTech Connect

    Steinwachs, Christian F.; Kamenshchik, Alexander Yu.

    2013-02-21

    We investigate a very general class of cosmological models with scalar fields non-minimally coupled to gravity. A particular representative in this class is given by the non-minimal Higgs inflation model in which the Standard Model Higgs boson and the inflaton are described by one and the same scalar particle. While the predictions of the non-minimal Higgs inflation scenario come numerically remarkably close to the recently discovered mass of the Higgs boson, there remains a conceptual problem in this model that is associated with the choice of the cosmological frame. While the classical theory is independent of this choice, we find by an explicit calculation that already the first quantum corrections induce a frame dependence. We give a geometrical explanation of this frame dependence by embedding it into a more general field theoretical context. From this analysis, some conceptional points in the long lasting cosmological debate: 'Jordan frame vs. Einstein frame' become more transparent and in principle can be resolved in a natural way.

  4. Cosmology from Cosmic Shear with DES Science Verification Data

    SciTech Connect

    Abbott, T.

    2015-07-20

    We present the first constraints on cosmology from the Dark Energy Survey (DES), using weak lensing measurements from the preliminary Science Verification (SV) data. We use 139 square degrees of SV data, which is less than 3% of the full DES survey area. Using cosmic shear 2-point measurements over three redshift bins we find ?8(m=0.3)0.5 = 0:81 0:06 (68% confidence), after marginalising over 7 systematics parameters and 3 other cosmological parameters. Furthermore, we examine the robustness of our results to the choice of data vector and systematics assumed, and find them to be stable. About 20% of our error bar comes from marginalising over shear and photometric redshift calibration uncertainties. The current state-of-the-art cosmic shear measurements from CFHTLenS are mildly discrepant with the cosmological constraints from Planck CMB data. Our results are consistent with both datasets. Our uncertainties are ~30% larger than those from CFHTLenS when we carry out a comparable analysis of the two datasets, which we attribute largely to the lower number density of our shear catalogue. We investigate constraints on dark energy and find that, with this small fraction of the full survey, the DES SV constraints make negligible impact on the Planck constraints. The moderate disagreement between the CFHTLenS and Planck values of ?8(?m=0.3)0.5 is present regardless of the value of w.

  5. Cosmological stability bound in massive gravity and bigravity

    SciTech Connect

    Fasiello, Matteo; Tolley, Andrew J. E-mail: andrew.j.tolley@case.edu

    2013-12-01

    We give a simple derivation of a cosmological bound on the graviton mass for spatially flat FRW solutions in massive gravity with an FRW reference metric and for bigravity theories. This bound comes from the requirement that the kinetic term of the helicity zero mode of the graviton is positive definite. The bound is dependent only on the parameters in the massive gravity potential and the Hubble expansion rate for the two metrics. We derive the decoupling limit of bigravity and FRW massive gravity, and use this to give an independent derivation of the cosmological bound. We recover our previous results that the tension between satisfying the Friedmann equation and the cosmological bound is sufficient to rule out all observationally relevant FRW solutions for massive gravity with an FRW reference metric. In contrast, in bigravity this tension is resolved due to different nature of the Vainshtein mechanism. We find that in bigravity theories there exists an FRW solution with late-time self-acceleration for which the kinetic terms for the helicity-2, helicity-1 and helicity-0 are generically nonzero and positive making this a compelling candidate for a model of cosmic acceleration. We confirm that the generalized bound is saturated for the candidate partially massless (bi)gravity theories but the existence of helicity-1/helicity-0 interactions implies the absence of the conjectured partially massless symmetry for both massive gravity and bigravity.

  6. NUMERICAL STUDY OF THE VISHNIAC INSTABILITY IN SUPERNOVA REMNANTS

    SciTech Connect

    Michaut, C.; Cavet, C.; Bouquet, S. E.; Roy, F.; Nguyen, H. C.

    2012-11-10

    The Vishniac instability is thought to explain the complex structure of radiative supernova remnants in their Pressure-Driven Thin Shell (PDTS) phase after a blast wave (BW) has propagated from a central explosion. In this paper, the propagation of the BW and the evolution of the PDTS stage are studied numerically with the two-dimensional (2D) code HYDRO-MUSCL for a finite-thickness shell expanding in the interstellar medium (ISM). Special attention is paid to the adiabatic index, {gamma}, and three distinct values are taken for the cavity ({gamma}{sub 1}), the shell ({gamma}{sub 2}), and the ISM ({gamma}{sub 3}) with the condition {gamma}{sub 2} < {gamma}{sub 1}, {gamma}{sub 3}. This low value of {gamma}{sub 2} accounts for the high density in the shell achieved by a strong radiative cooling. Once the spherical background flow is obtained, the evolution of a 2D-axisymmetric perturbation is computed from the linear to the nonlinear regime. The overstable mechanism, previously demonstrated theoretically by E. T. Vishniac in 1983, is recovered numerically in the linear stage and is expected to produce and enhance anisotropies and clumps on the shock front, leading to the disruption of the shell in the nonlinear phase. The period of the increasing oscillations and the growth rate of the instability are derived from several points of view (the position of the perturbed shock front, mass fluxes along the shell, and density maps), and the most unstable mode differing from the value given by Vishniac is computed. In addition, the influence of several parameters (the Mach number, amplitude and wavelength of the perturbation, and adiabatic index) is examined and for wavelengths that are large enough compared to the shell thickness, the same conclusion arises: in the late stage of the evolution of the radiative supernova remnant, the instability is dampened and the angular initial deformation of the shock front is smoothed while the mass density becomes uniform with the

  7. Consequences of CCD imperfections for cosmology determined by weak lensing surveys: from laboratory measurements to cosmological parameter bias

    DOE PAGES [OSTI]

    Okura, Yuki; Petri, Andrea; May, Morgan; Plazas, Andrés A.; Tamagawa, Toru

    2016-06-27

    Weak gravitational lensing causes subtle changes in the apparent shapes of galaxies due to the bending of light by the gravity of foreground masses. By measuring the shapes of large numbers of galaxies (millions in recent surveys, up to tens of billions in future surveys) we can infer the parameters that determine cosmology. Imperfections in the detectors used to record images of the sky can introduce changes in the apparent shape of galaxies, which in turn can bias the inferred cosmological parameters. Here in this paper we consider the effect of two widely discussed sensor imperfections: tree-rings, due to impuritymore » gradients which cause transverse electric fields in the Charge-Coupled Devices (CCD), and pixel-size variation, due to periodic CCD fabrication errors. These imperfections can be observed when the detectors are subject to uniform illumination (flat field images). We develop methods to determine the spurious shear and convergence (due to the imperfections) from the flat-field images. We calculate how the spurious shear when added to the lensing shear will bias the determination of cosmological parameters. We apply our methods to candidate sensors of the Large Synoptic Survey Telescope (LSST) as a timely and important example, analyzing flat field images recorded with LSST prototype CCDs in the laboratory. In conclusion, we find that tree-rings and periodic pixel-size variation present in the LSST CCDs will introduce negligible bias to cosmological parameters determined from the lensing power spectrum, specifically w,Ωm and σ8.« less

  8. Exact analytical solution of the linear structure growth rate in {Lambda}CDM cosmology and its cosmological applications

    SciTech Connect

    Zhang Pengjie [Key Laboratory for Research in Galaxies and Cosmology, Shanghai Astronomical Observatory, Chinese Academy of Science, 80 Nandan Road, Shanghai, China, 200030 (China)

    2011-03-15

    We derive the exact analytical solution of the linear structure growth rate in {Lambda}CDM cosmology with flat or curved geometry, under the Newtonian gauge. Unlike the well known solution under the Newtonian limit [D. J. Heath, Mon. Not. R. Astron. Soc. 179, 351 (1977)], our solution takes all general relativistic corrections into account and is hence valid at both the sub- and superhorizon scales. With this exact solution, we evaluate cosmological impacts induced by these relativistic corrections. (1) General relativistic corrections alter the density growth from z=100 to z=0 by 10% at k=0.01 h/Mpc and the impact becomes stronger toward larger scales. We caution the readers that the overdensity is not gauge invariant and the above statement is restrained to the Newtonian gauge. (2) Relativistic corrections introduce a k{sup -2} scale dependence in the density fluctuation. It mimics a primordial non-Gaussianity of the local type with f{sub NL}{sup local{approx}}1. This systematical error may become non-negligible for future all sky deep galaxy surveys. (3) Cosmological simulations with box size greater than 1 Gpc are also affected by these relativistic corrections. We provide a postprocessing recipe to correct for these effects. (4) These relativistic corrections affect the redshift distortion. However, at redshifts and scales relevant to redshift distortion measurements, such effect is negligible.

  9. Type Ia Supernova Spectral Line Ratios as LuminosityIndicators

    SciTech Connect

    Bongard, Sebastien; Baron, E.; Smadja, G.; Branch, David; Hauschildt, Peter H.

    2005-12-07

    Type Ia supernovae have played a crucial role in thediscovery of the dark energy, via the measurement of their light curvesand the determination of the peak brightness via fitting templates to theobserved lightcurve shape. Two spectroscopic indicators are also known tobe well correlated with peak luminosity. Since the spectroscopicluminosity indicators are obtained directly from observed spectra, theywill have different systematic errors than do measurements usingphotometry. Additionally, these spectroscopic indicators may be usefulfor studies of effects of evolution or age of the SNe~;Ia progenitorpopulation. We present several new variants of such spectroscopicindicators which are easy to automate and which minimize the effects ofnoise. We show that these spectroscopic indicators can be measured byproposed JDEM missions such as snap and JEDI.

  10. Spectrum of supernova neutrinos in ultra-pure scintillators

    SciTech Connect

    Lujan-Peschard, C.; Pagliaroli, G.; Vissani, F., E-mail: carolup@fisica.ugto.mx, E-mail: giulia.pagliaroli@lngs.infn.it, E-mail: francesco.vissani@lngs.infn.it [Laboratori Nazionali del Gran Sasso, INFN, Assergi (AQ) (Italy)

    2014-07-01

    There is a great interest in measuring the non-electronic component of neutrinos from core collapse supernovae by observing, for the first time, also neutral-current reactions. In order to assess the physics potential of the ultra-pure scintillators in this respect, we study the entire expected energy spectrum in the Borexino, KamLAND and SNO+ detectors. We examine the various sources of uncertainties in the expectations, and in particular, those due to specific detector features and to the relevant cross sections. We discuss the possibility to identify the different neutrino flavors, and we quantify the effect of confusion, due to other components of the energy spectrum, overlapped with the neutral-current reactions of interest.

  11. GRB 020410: A Gamma-ray burst afterglow discovered by its supernova...

    Office of Scientific and Technical Information (OSTI)

    Journal Article: GRB 020410: A Gamma-ray burst afterglow discovered by its supernova light Citation Details In-Document Search Title: GRB 020410: A Gamma-ray burst afterglow ...

  12. Improved Dark Energy Constraints From ~ 100 New CfA Supernova...

    Office of Scientific and Technical Information (OSTI)

    Journal Article: Improved Dark Energy Constraints From 100 New CfA Supernova Type Ia Light Curves Citation Details In-Document Search Title: Improved Dark Energy Constraints From ...

  13. Luminous blue variables and superluminous supernovae from binary mergers

    SciTech Connect

    Justham, Stephen; Podsiadlowski, Philipp; Vink, Jorick S. E-mail: podsi@astro.ox.ac.uk

    2014-12-01

    Evidence suggests that the direct progenitor stars of some core-collapse supernovae (CCSNe) are luminous blue variables (LBVs), perhaps including some Type II 'superluminous supernovae' (SLSNe). We examine models in which massive stars gain mass soon after the end of core hydrogen burning. These are mainly intended to represent mergers following a brief contact phase during early Case B mass transfer, but may also represent stars which gain mass in the Hertzsprung Gap or extremely late during the main-sequence phase for other reasons. The post-accretion stars spend their core helium-burning phase as blue supergiants (BSGs), and many examples are consistent with being LBVs at the time of core collapse. Other examples are yellow supergiants at explosion. We also investigate whether such post-accretion stars may explode successfully after core collapse. The final core properties of post-accretion models are broadly similar to those of single stars with the same initial mass as the pre-merger primary star. More surprisingly, when early Case B accretion does affect the final core properties, the effect appears likely to favor a successful SN explosion, i.e., to make the core properties more like those of a lower-mass single star. However, the detailed structures of these cores sometimes display qualitative differences to any single-star model we have calculated. The rate of appropriate binary mergers may match the rate of SNe with immediate LBV progenitors; for moderately optimistic assumptions we estimate that the progenitor birthrate is ?1% of the CCSN rate.

  14. Nucleosynthesis in Early Supernova Winds II: The Role of Neutrinos

    SciTech Connect

    Pruet, J; Hoffman, R; Woosley, S; Janka, H; Buras, R

    2005-11-04

    One of the outstanding unsolved riddles of nuclear astrophysics is the origin of the so called ''p-process'' nuclei from A = 92 to 126. Both the lighter and heavier p-process nuclei are adequately produced in the neon and oxygen shells of ordinary Type II supernovae, but the origin of these intermediate isotopes, especially {sup 92,94}Mo and {sup 96,98}Ru, has long been mysterious. Here we explore the production of these nuclei in the neutrino-driven wind from a young neutron star. We consider such early times that the wind still contains a proton excess because the rates for {nu}{sub e} and positron captures on neutrons are faster than those for the inverse captures on protons. Following a suggestion by Froehlich et al. (2005), they also include the possibility that, in addition to the protons, {alpha}-particles, and heavy seed, a small flux of neutrons is maintained by the reaction p({bar {nu}}{sub e}, e{sup +})n. This flux of neutrons is critical in bridging the long waiting points along the path of the rp-process by (n,p) and (n,{gamma}) reactions. Using the unmodified ejecta histories from a recent two-dimensional supernova model by Janka, Buras, and Rampp (2003), they find synthesis of p-rich nuclei up to {sup 102}Pd. However, if the entropy of these ejecta is increased by a factor of two, the synthesis extends to {sup 120}Te. Still larger increases in entropy, that might reflect the role of magnetic fields or vibrational energy input neglected in the hydrodynamical model, result in the production of numerous r-, s-, and p-process nuclei up to A {approx} 170, even in winds that are proton-rich.

  15. Recombining plasma in the gamma-ray-emitting mixed-morphology supernova remnant 3C 391

    SciTech Connect

    Ergin, T.; Sezer, A.; Saha, L.; Majumdar, P.; Chatterjee, A.; Bayirli, A.; Ercan, E. N.

    2014-07-20

    A group of middle-aged mixed-morphology (MM) supernova remnants (SNRs) interacting with molecular clouds (MCs) has been discovered to be strong GeV gamma-ray emitters by the Large Area Telescope (LAT) on board the Fermi Gamma-Ray Space Telescope (Fermi-LAT). The recent observations of the Suzaku X-ray satellite have revealed that some of these interacting gamma-ray-emitting SNRs, such as IC443, W49B, W44, and G359.1-0.5, have overionized plasmas. 3C 391 (G31.9+0.0) is another Galactic MM SNR interacting with MCs. It was observed in GeV gamma rays by Fermi-LAT as well as in the 0.3-10.0 keV X-ray band by Suzaku. In this work, 3C 391 was detected in GeV gamma rays with a significance of ?18? and we showed that the GeV emission is point-like in nature. The GeV gamma-ray spectrum was shown to be best explained by the decay of neutral pions assuming that the protons follow a broken power-law distribution. We revealed radiative recombination structures of silicon and sulfur from 3C 391 using Suzaku data. In this paper, we discuss the possible origin of this type of radiative plasma and hadronic gamma rays.

  16. FIRST EVIDENCE OF GLOBULAR CLUSTER FORMATION FROM THE EJECTA OF PROMPT TYPE Ia SUPERNOVAE

    SciTech Connect

    Tsujimoto, Takuji [National Astronomical Observatory of Japan, Mitaka-shi, Tokyo 181-8588 (Japan); Bekki, Kenji, E-mail: taku.tsujimoto@nao.ac.jp [ICRAR, M468, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009 (Australia)

    2012-06-01

    Recent spectroscopic observations of globular clusters (GCs) in the Large Magellanic Cloud (LMC) have discovered that one of the intermediate-age GCs, NGC 1718, with [Fe/H] = -0.7 has an extremely low [Mg/Fe] ratio of {approx}-0.9. We propose that NGC 1718 was formed from the ejecta of Type Ia supernovae mixed with very metal-poor ([Fe/H] <-1.3) gas about {approx}2 Gyr ago. The proposed scenario is shown to be consistent with the observed abundances of Fe-group elements such as Cr, Mn, and Ni. In addition, compelling evidence for asymptotic giant branch stars playing a role in chemical enrichment during this GC formation is found. We suggest that the origin of the metal-poor gas is closely associated with efficient gas transfer from the outer gas disk of the Small Magellanic Cloud to the LMC disk. We anticipate that the outer part of the LMC disk contains field stars exhibiting significantly low [Mg/Fe] ratios, formed through the same process as NGC 1718.

  17. Group Members

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    Group Leader Sherry Yennello See full cv Assistant Research Scientist Alan B. McIntosh 2010-presentalanmcintosh at tamu.edu Current Post Docs Meirong Huang 2015-present Current Graduate Students Lauren Heilborn PhD Expected 2015 Andrew Zarrella PhD Expected 2016 Andrea Jedele PhD Expected 2018 Current Undergraduate Students Christine Lawrence 2015-Present Continuing Collaborators George Souliotis Past Post Docs Mike Youngs 2013-2016 Ellen Mccleskey 2014-2016 Justin Mabiala 2011-2014 Paola Marini

  18. Group Publications

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    Publications Background Literature Group: Publications, Annual Reports, Theses, Conference Proceedings Title Lead Author Reference and Link Novel technique to extract experimental symmetry free energy information for nuclear matter J. Mabiala Phys. Rev. C 92, 024605 (2015) Studying heavy-ion collisions with coverage near zero degrees with FAUST-QTS P. Cammarata NIMA 792 61 (2015) Isoscaling of heavy projectile residues and N/Z equilibration in peripheral heavy-ion collisions below the Fermi

  19. The halo model in a massive neutrino cosmology

    SciTech Connect

    Massara, Elena; Villaescusa-Navarro, Francisco; Viel, Matteo E-mail: villaescusa@oats.inaf.it

    2014-12-01

    We provide a quantitative analysis of the halo model in the context of massive neutrino cosmologies. We discuss all the ingredients necessary to model the non-linear matter and cold dark matter power spectra and compare with the results of N-body simulations that incorporate massive neutrinos. Our neutrino halo model is able to capture the non-linear behavior of matter clustering with a ?20% accuracy up to very non-linear scales of k=10 h/Mpc (which would be affected by baryon physics). The largest discrepancies arise in the range k=0.51 h/Mpc where the 1-halo and 2-halo terms are comparable and are present also in a massless neutrino cosmology. However, at scales k<0.2 h/Mpc our neutrino halo model agrees with the results of N-body simulations at the level of 8% for total neutrino masses of <0.3 eV. We also model the neutrino non-linear density field as a sum of a linear and clustered component and predict the neutrino power spectrum and the cold dark matter-neutrino cross-power spectrum up to k=1 h/Mpc with ?30% accuracy. For masses below 0.15 eV the neutrino halo model captures the neutrino induced suppression, casted in terms of matter power ratios between massive and massless scenarios, with a 2% agreement with the results of N-body/neutrino simulations. Finally, we provide a simple application of the halo model: the computation of the clustering of galaxies, in massless and massive neutrinos cosmologies, using a simple Halo Occupation Distribution scheme and our halo model extension.

  20. Viscous gravitational aether and the cosmological constant problem

    SciTech Connect

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

    2009-10-01

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

  1. Statefinder hierarchy of bimetric and galileon models for concordance cosmology

    SciTech Connect

    Myrzakulov, R.; Shahalam, M. E-mail: mdshahalam@ctp-jamia.res.in

    2013-10-01

    In this paper, we use Statefinder hierarchy method to distinguish between bimetric theory of massive gravity, galileon modified gravity and DGP models applied to late time expansion of the universe. We also carry out comparison between bimetric and DGP models using Statefinder pairs (r,s) and (r,q). We show that statefinder diagnostic can differentiate between ?CDM and above mentioned cosmological models of dark energy, and finally show that Statefinder S{sub 2} is an excellent discriminant of ?CDM and modified gravity models.

  2. Entropy mode loops and cosmological correlations during perturbative reheating

    SciTech Connect

    Kaya, Ali; Kutluk, Emine Seyma E-mail: seymakutluk@gmail.com

    2015-01-01

    Recently, it has been shown that during preheating the entropy modes circulating in the loops, which correspond to the inflaton decay products, meaningfully modify the cosmological correlation functions at superhorizon scales. In this paper, we determine the significance of the same effect when reheating occurs in the perturbative regime. In a typical two scalar field model, the magnitude of the loop corrections are shown to depend on several parameters like the background inflaton amplitude in the beginning of reheating, the inflaton decay rate and the inflaton mass. Although the loop contributions turn out to be small as compared to the preheating case, they still come out larger than the loop effects during inflation.

  3. Can mirror matter solve the the cosmological lithium problem?

    SciTech Connect

    Coc, Alain [Centre de Sciences Nuclaires et de Sciences de la Matire (CSNSM), CNRS/IN2P3, Universit Paris Sud 11, UMR 8609, Btiment 104, 91405 Orsay Campus (France); Uzan, Jean-Philippe; Vangioni, Elisabeth [Institut d'Astrophysique de Paris, UMR-7095 du CNRS, Universit Pierre et Marie Curie, 98 bis bd Arago, 75014 Paris, France and Sorbonne Universits, Institut Lagrange de Paris, 98 bis bd Arago, 75014 Paris (France)

    2014-05-02

    The abundance of lithium-7 confronts cosmology with a long lasting inconsistency between the predictions of standard Big Bang Nucleosynthesis with the baryonic density determined from the Cosmic Microwave Background observations on the one hand, and the spectroscopic determination of the lithium-7 abundance on the other hand. We investigated the influence of the existence of a mirror world, focusing on models in which mirror neutrons can oscillate into ordinary neutrons. Such a mechanism allows for an effective late time neutron injection, which induces an increase of the destruction of beryllium-7and thus a lower final lithium-7 abundance.

  4. The mass spectra, hierarchy and cosmology of B-L MSSM heterotic compactifications

    SciTech Connect

    Ambroso, Michael; Ovrut, Burt A.

    2011-04-10

    The matter spectrum of the MSSM, including three right-handed neutrino supermultiplets and one pair of Higgs-Higgs conjugate superfields, can be obtained by compactifying the E? x E? heterotic string and M-theory on Calabi-Yau manifolds with specific SU(4) vector bundles. These theories have the standard model gauge group augmented by an additional gauged U(1)B-L. Their minimal content requires that the B-L gauge symmetry be spontaneously broken by a vacuum expectation value of at least one right-handed neutrino. In previous papers, we presented the results of a quasi-analytic renormalization group analysis showing that B-L gauge symmetry is indeed radiatively broken with an appropriate B-L/electroweak hierarchy. In this paper, we extend these results by 1) enlarging the initial parameter space and 2) explicitly calculating all renormalization group equations numerically. The regions of the initial parameter space leading to realistic vacua are presented and the B-L/electroweak hierarchy computed over these regimes. At representative points, the mass spectrum for all particles and Higgs fields is calculated and shown to be consistent with present experimental bounds. Some fundamental phenomenological signatures of a non-zero right-handed neutrino expectation value are discussed, particularly the cosmology and proton lifetime arising from induced lepton and baryon number violating interactions.

  5. The mass spectra, hierarchy and cosmology of B-L MSSM heterotic compactifications

    DOE PAGES [OSTI]

    Ambroso, Michael; Ovrut, Burt A.

    2011-04-10

    The matter spectrum of the MSSM, including three right-handed neutrino supermultiplets and one pair of Higgs-Higgs conjugate superfields, can be obtained by compactifying the E₈ x E₈ heterotic string and M-theory on Calabi-Yau manifolds with specific SU(4) vector bundles. These theories have the standard model gauge group augmented by an additional gauged U(1)B-L. Their minimal content requires that the B-L gauge symmetry be spontaneously broken by a vacuum expectation value of at least one right-handed neutrino. In previous papers, we presented the results of a quasi-analytic renormalization group analysis showing that B-L gauge symmetry is indeed radiatively broken with anmore » appropriate B-L/electroweak hierarchy. In this paper, we extend these results by 1) enlarging the initial parameter space and 2) explicitly calculating all renormalization group equations numerically. The regions of the initial parameter space leading to realistic vacua are presented and the B-L/electroweak hierarchy computed over these regimes. At representative points, the mass spectrum for all particles and Higgs fields is calculated and shown to be consistent with present experimental bounds. Some fundamental phenomenological signatures of a non-zero right-handed neutrino expectation value are discussed, particularly the cosmology and proton lifetime arising from induced lepton and baryon number violating interactions.« less

  6. The Geometrization of Matter Proposal in the Barrett-Crane Model and Resolution of Cosmological Problems

    SciTech Connect

    Alexander, Stephon

    2003-07-15

    We give an overview of the current issues in early universe cosmology and consider the potential resolution of these issues in an as yet nascent spin foam cosmology. The model is the Barrett-Crane Model for quantum gravity along with a generalization of manifold complexes to complexes including conical singularities.

  7. Some Cosmological Models for Poincare Gauge Gravity and Accelerated Expansion of the Universe

    SciTech Connect

    Mebarki, N.

    2010-10-31

    Two cosmological Models for the Poincare Gauge Gravity theory with a non vanishing torsion are proposed. It is shown that the torsion plays an important role in explaining the accelerated expansion of the universe. Some of the cosmological parameters are also expressed in terms of the redshift and the dark energy scenarios are discussed.

  8. The circular velocity function of group galaxies

    SciTech Connect

    Abramson, Louis E.; Williams, Rik J.; Benson, Andrew J.; Kollmeier, Juna A.; Mulchaey, John S.

    2014-09-20

    A robust prediction of ΛCDM cosmology is the halo circular velocity function (CVF), a dynamical cousin of the halo mass function. The correspondence between theoretical and observed CVFs is uncertain, however: cluster galaxies are reported to exhibit a power-law CVF consistent with N-body simulations, but that of the field is distinctly Schechter-like, flattened compared to ΛCDM expectations at circular velocities v {sub c} ≲ 200 km s{sup –1}. Groups offer a powerful probe of the role environment plays in this discrepancy as they bridge the field and clusters. Here, we construct the CVF for a large, mass- and multiplicity-complete sample of group galaxies from the Sloan Digital Sky Survey. Using independent photometric v {sub c} estimators, we find no transition from field to ΛCDM-shaped CVF above v {sub c} = 50 km s{sup –1} as a function of group halo mass. All groups with 12.4 ≲ log M {sub halo}/M {sub ☉} ≲ 15.1 (Local Group analogs to rich clusters) display similar Schechter-like CVFs marginally suppressed at low v {sub c} compared to that of the field. Conversely, some agreement with N-body results emerges for samples saturated with late-type galaxies, with isolated late-types displaying a CVF similar in shape to ΛCDM predictions. We conclude that the flattening of the low-v {sub c} slope in groups is due to their depressed late-type fractions—environment affecting the CVF only to the extent that it correlates with this quantity—and that previous cluster analyses may suffer from interloper contamination. These results serve as useful benchmarks for cosmological simulations of galaxy formation.

  9. Inverse Compton Emission from Galactic Supernova Remnants: Effect of the Interstellar Radiation Field

    SciTech Connect

    Porter, Troy A.; Moskalenko, Igor V.; Strong, Andrew W.; /Garching, Max Planck Inst., MPE

    2006-08-01

    The evidence for particle acceleration in supernova shells comes from electrons whose synchrotron emission is observed in radio and X-rays. Recent observations by the HESS instrument reveal that supernova remnants also emit TeV {gamma}-rays; long awaited experimental evidence that supernova remnants can accelerate cosmic rays up to the ''knee'' energies. Still, uncertainty exists whether these {gamma}-rays are produced by electrons via inverse Compton scattering or by protons via {pi}{sup 0}-decay. The multi-wavelength spectra of supernova remnants can be fitted with both mechanisms, although a preference is often given to {pi}{sup 0}-decay due to the spectral shape at very high energies. A recent study of the interstellar radiation field indicates that its energy density, especially in the inner Galaxy, is higher than previously thought. In this paper we evaluate the effect of the interstellar radiation field on the inverse Compton emission of electrons accelerated in a supernova remnant located at different distances from the Galactic Centre. We show that contribution of optical and infra-red photons to the inverse Compton emission may exceed the contribution of cosmic microwave background and in some cases broaden the resulted {gamma}-ray spectrum. Additionally, we show that if a supernova remnant is located close to the Galactic Centre its {gamma}-ray spectrum will exhibit a ''universal'' cutoff at very high energies due to the Klein-Nishina effect and not due to the cut-off of the electron spectrum. As an example, we apply our calculations to the supernova remnants RX J1713.7-3946 and G0.9+0.1 recently observed by HESS.

  10. The effective field theory of cosmological large scale structures

    SciTech Connect

    Carrasco, John Joseph M.; Hertzberg, Mark P.; Senatore, Leonardo

    2012-09-20

    Large scale structure surveys will likely become the next leading cosmological probe. In our universe, matter perturbations are large on short distances and small at long scales, i.e. strongly coupled in the UV and weakly coupled in the IR. To make precise analytical predictions on large scales, we develop an effective field theory formulated in terms of an IR effective fluid characterized by several parameters, such as speed of sound and viscosity. These parameters, determined by the UV physics described by the Boltzmann equation, are measured from N-body simulations. We find that the speed of sound of the effective fluid is c2s ? 106c2 and that the viscosity contributions are of the same order. The fluid describes all the relevant physics at long scales k and permits a manifestly convergent perturbative expansion in the size of the matter perturbations ?(k) for all the observables. As an example, we calculate the correction to the power spectrum at order ?(k)4. As a result, the predictions of the effective field theory are found to be in much better agreement with observation than standard cosmological perturbation theory, already reaching percent precision at this order up to a relatively short scale k ? 0.24h Mpc1.

  11. EINSTEIN'S SIGNATURE IN COSMOLOGICAL LARGE-SCALE STRUCTURE

    SciTech Connect

    Bruni, Marco; Hidalgo, Juan Carlos; Wands, David

    2014-10-10

    We show how the nonlinearity of general relativity generates a characteristic nonGaussian signal in cosmological large-scale structure that we calculate at all perturbative orders in a large-scale limit. Newtonian gravity and general relativity provide complementary theoretical frameworks for modeling large-scale structure in ?CDM cosmology; a relativistic approach is essential to determine initial conditions, which can then be used in Newtonian simulations studying the nonlinear evolution of the matter density. Most inflationary models in the very early universe predict an almost Gaussian distribution for the primordial metric perturbation, ?. However, we argue that it is the Ricci curvature of comoving-orthogonal spatial hypersurfaces, R, that drives structure formation at large scales. We show how the nonlinear relation between the spatial curvature, R, and the metric perturbation, ?, translates into a specific nonGaussian contribution to the initial comoving matter density that we calculate for the simple case of an initially Gaussian ?. Our analysis shows the nonlinear signature of Einstein's gravity in large-scale structure.

  12. Parameters of cosmological models and recent astronomical observations

    SciTech Connect

    Sharov, G.S.; Vorontsova, E.G., E-mail: german.sharov@mail.ru, E-mail: elenavor@inbox.ru [Tver state university, 170002, Sadovyj per. 35, Tver (Russian Federation)

    2014-10-01

    For different gravitational models we consider limitations on their parameters coming from recent observational data for type Ia supernovae, baryon acoustic oscillations, and from 34 data points for the Hubble parameter H(z) depending on redshift. We calculate parameters of 3 models describing accelerated expansion of the universe: the ?CDM model, the model with generalized Chaplygin gas (GCG) and the multidimensional model of I. Pahwa, D. Choudhury and T.R. Seshadri. In particular, for the ?CDM model 1? estimates of parameters are: H{sub 0}=70.2620.319 km {sup -1}Mp {sup -1}, ?{sub m}=0.276{sub -0.008}{sup +0.009}, ?{sub ?}=0.7690.029, ?{sub k}=-0.0450.032. The GCG model under restriction 0?? is reduced to the ?CDM model. Predictions of the multidimensional model essentially depend on 3 data points for H(z) with z?2.3.

  13. Exploiting the neutronization burst of a galactic supernova

    SciTech Connect

    Kachelriess, M.; Tomas, R.; Buras, R.; Janka, H.-Th.; Marek, A.; Rampp, M.

    2005-03-15

    One of the robust features found in simulations of core-collapse supernovae (SNe) is the prompt neutronization burst, i.e., the first {approx}25 milliseconds after bounce when the SN emits with very high luminosity mainly {nu}{sub e} neutrinos. We examine the dependence of this burst on variations in the input of current SN models and find that recent improvements of the electron capture rates as well as uncertainties in the nuclear equation of state or a variation of the progenitor mass have only little effect on the signature of the neutronization peak in a megaton water Cherenkov detector for different neutrino mixing schemes. We show that exploiting the time structure of the neutronization peak allows one to identify the case of a normal mass hierarchy and large 13-mixing angle {theta}{sub 13}, where the peak is absent. The robustness of the predicted total event number in the neutronization burst makes a measurement of the distance to the SN feasible with a precision of about 5%, even in the likely case that the SN is optically obscured.

  14. EFFECTS OF RESISTIVITY ON MAGNETIZED CORE-COLLAPSE SUPERNOVAE

    SciTech Connect

    Sawai, H.; Suzuki, H.; Yamada, S.; Kotake, K.

    2013-02-10

    We studied the role of turbulent resistivity in the core-collapse of a strongly magnetized massive star, carrying out two-dimensional resistive-MHD simulations. Three cases with different initial strengths of magnetic field and rotation are investigated: (1) a strongly magnetized rotating core, (2) a moderately magnetized rotating core, and (3) a very strongly magnetized non-rotating core. In each case, one ideal-MHD model and two resistive-MHD models are computed. As a result of these computations, each model shows an eruption of matter assisted by magnetic acceleration (and also by centrifugal acceleration in the rotating cases). We found that resistivity attenuates the explosion in cases 1 and 2, while it enhances the explosion in case 3. We also found that in the rotating cases, the main mechanisms for the amplification of a magnetic field in the post-bounce phase are an outward advection of the magnetic field and a twisting of poloidal magnetic field lines by differential rotation, which are somewhat dampened down with the presence of resistivity. Although magnetorotational instability seems to occur in the rotating models, it plays only a minor role in magnetic field amplification. Another impact of resistivity is that on the aspect ratio. In the rotating cases, a large aspect ratio of the ejected matter, >2.5, attained in an ideal-MHD model is reduced to some extent in a resistive model. These results indicate that resistivity possibly plays an important role in the dynamics of strongly magnetized supernovae.

  15. Low Mach Number Modeling of Type Ia Supernovae

    SciTech Connect

    Almgren, Ann S.; Bell, John B.; Rendleman, Charles A.; Zingale,Michael

    2005-08-05

    We introduce a low Mach number equation set for the large-scale numerical simulation of carbon-oxygen white dwarfs experiencing a thermonuclear deflagration. Since most of the interesting physics in a Type Ia supernova transpires at Mach numbers from 0.01 to 0.1, such an approach enables both a considerable increase in accuracy and savings in computer time compared with frequently used compressible codes. Our equation set is derived from the fully compressible equations using low Mach number asymptotics, but without any restriction on the size of perturbations in density or temperature. Comparisons with simulations that use the fully compressible equations validate the low Mach number model in regimes where both are applicable. Comparisons to simulations based on the more traditional an elastic approximation also demonstrate the agreement of these models in the regime for which the anelastic approximation is valid. For low Mach number flows with potentially finite amplitude variations in density and temperature, the low Mach number model overcomes the limitations of each of the more traditional models and can serve as the basis for an accurate and efficient simulation tool.

  16. Cosmic ray acceleration at perpendicular shocks in supernova remnants

    SciTech Connect

    Ferrand, Gilles; Danos, Rebecca J.; Shalchi, Andreas; Safi-Harb, Samar; Edmon, Paul; Mendygral, Peter

    2014-09-10

    Supernova remnants (SNRs) are believed to accelerate particles up to high energies through the mechanism of diffusive shock acceleration (DSA). Except for direct plasma simulations, all modeling efforts must rely on a given form of the diffusion coefficient, a key parameter that embodies the interactions of energetic charged particles with magnetic turbulence. The so-called Bohm limit is commonly employed. In this paper, we revisit the question of acceleration at perpendicular shocks, by employing a realistic model of perpendicular diffusion. Our coefficient reduces to a power law in momentum for low momenta (of index ?), but becomes independent of the particle momentum at high momenta (reaching a constant value ?{sub ?} above some characteristic momentum p {sub c}). We first provide simple analytical expressions of the maximum momentum that can be reached at a given time with this coefficient. Then we perform time-dependent numerical simulations to investigate the shape of the particle distribution that can be obtained when the particle pressure back-reacts on the flow. We observe that for a given index ? and injection level, the shock modifications are similar for different possible values of p {sub c}, whereas the particle spectra differ markedly. Of particular interest, low values of p {sub c} tend to remove the concavity once thought to be typical of non-linear DSA, and result in steep spectra, as required by recent high-energy observations of Galactic SNRs.

  17. Numeric spectral radiation hydrodynamic calculations of supernova shock breakouts

    SciTech Connect

    Sapir, Nir; Halbertal, Dorri

    2014-12-01

    We present here an efficient numerical scheme for solving the non-relativistic one-dimensional radiation-hydrodynamics equations including inelastic Compton scattering, which is not included in most codes and is crucial for solving problems such as shock breakout. The devised code is applied to the problems of a steady-state planar radiation mediated shock (RMS) and RMS breakout from a stellar envelope. The results are in agreement with those of a previous work on shock breakout, in which Compton equilibrium between matter and radiation was assumed and the 'effective photon' approximation was used to describe the radiation spectrum. In particular, we show that the luminosity and its temporal dependence, the peak temperature at breakout, and the universal shape of the spectral fluence derived in this earlier work are all accurate. Although there is a discrepancy between the spectral calculations and the effective photon approximation due to the inaccuracy of the effective photon approximation estimate of the effective photon production rate, which grows with lower densities and higher velocities, the difference in peak temperature reaches only 30% for the most discrepant cases of fast shocks in blue supergiants. The presented model is exemplified by calculations for supernova 1987A, showing the detailed evolution of the burst spectrum. The incompatibility of the stellar envelope shock breakout model results with observed properties of X-ray flashes (XRFs) and the discrepancy between the predicted and observed rates of XRFs remain unexplained.

  18. Off-center observers versus supernovae in inhomogeneous pressure universes

    SciTech Connect

    Balcerzak, Adam; Dabrowski, Mariusz P.; Denkiewicz, Tomasz [Institute of Physics, University of Szczecin, Wielkopolska 15, 70-451 Szczecin (Poland)

    2014-09-10

    Exact luminosity distance and apparent magnitude formulae are applied to the Union2 557 supernovae sample in order to constrain the possible position of an observer outside of the center of symmetry in spherically symmetric inhomogeneous pressure Stephani universes, which are complementary to inhomogeneous density Lematre-Tolman-Bondi (LTB) void models. Two specific models are investigated. The first allows a barotropic equation of state at the center of symmetry without the need to specify a scale factor function (model IIA). The second has no barotropic equation of state at the center, but has an explicit dust-like scale factor evolution (model IIB). It is shown that even at 3? CL, an off-center observer cannot be further than about 4.4 Gpc away from the center of symmetry, which is comparable to the reported size of a void in LTB models with the most likely value of the distance from the center at about 341 Mpc for model IIA and 68 Mpc for model IIB. The off-center observer cannot be farther away from the center than about 577 Mpc for model IIB at 3? CL. It is determined that the best-fit parameters which characterize inhomogeneity are ?{sub inh} = 0.77 (dimensionless: model IIA) and ? = 7.31 10{sup 9} (s km{sup 1}){sup 2/3} Mpc{sup 4/3} (model IIB).

  19. Gamma-ray burst supernovae as standardizable candles

    SciTech Connect

    Cano, Z., E-mail: zewcano@gmail.com [Centre for Astrophysics and Cosmology, Science Institute, University of Iceland, Reykjavik (Iceland)

    2014-10-20

    A long-duration gamma-ray burst (GRB) marks the violent end of a massive star. GRBs are rare in the universe, and their progenitor stars are thought to possess unique physical properties such as low metal content and rapid rotation, while the supernovae (SNe) that are associated with GRBs are expected to be highly aspherical. To date, it has been unclear whether GRB-SNe could be used as standardizable candles, with contrasting conclusions found by different teams. In this paper, I present evidence that GRB-SNe have the potential to be used as standardizable candles and show that a statistically significant relation exists between the brightness and width of their decomposed light curves relative to a template SN. Every single nearby spectroscopically identified GRB-SN for which the rest frame and host contributions have been accurately determined follows this relation. Additionally, it is shown that not only GRB-SNe, but perhaps all SNe whose explosions are powered by a central engine may eventually be used as a standardizable candle. Finally, I suggest that the use of GRB-SNe as standardizable candles likely arises from a combination of the viewing angle and similar explosion geometry in each event, the latter of which is influenced by the explosion mechanism of GRB-SNe.

  20. Two-dimensional simulations of pulsational pair-instability supernovae

    SciTech Connect

    Chen, Ke-Jung; Woosley, Stan [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Heger, Alexander [Monash Centre for Astrophysics, Monash University, Melbourne, Victoria 3800 (Australia); Almgren, Ann [Center for Computational Sciences and Engineering, Lawrence Berkeley National Lab, Berkeley, CA 94720 (United States); Whalen, Daniel J., E-mail: kchen@ucolick.org [T-2, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2014-09-01

    Massive stars that end their lives with helium cores in the range of 35-65 M {sub ?} are known to produce repeated thermonuclear outbursts due to a recurring pair-instability. In some of these events, solar masses of material are ejected in repeated outbursts of several 10{sup 50} erg each. Collisions between these shells can sometimes produce very luminous transients that are visible from the edge of the observable universe. Previous one-dimensional (1D) studies of these events produce thin, high-density shells as one ejection plows into another. Here, in the first multi-dimensional simulations of these collisions, we show that the development of a Rayleigh-Taylor instability truncates the growth of the high-density spike and drives mixing between the shells. The progenitor is a 110 M {sub ?} solar-metallicity star that was shown in earlier work to produce a superluminous supernova. The light curve of this more realistic model has a peak luminosity and duration that are similar to those of 1D models but a structure that is smoother.

  1. DISCOVERY OF AN APPARENT HIGH LATITUDE GALACTIC SUPERNOVA REMNANT

    SciTech Connect

    Fesen, Robert A.; Neustadt, Jack M. M.; Black, Christine S.; Koeppel, Ari H. D.

    2015-10-10

    Deep Hα images of a faint emission complex 4.°0 × 5.°5 in angular extent and located far off the Galactic plane at l = 70.°0, b = −21.°5 reveal numerous thin filaments suggestive of a supernova remnant’s (SNR’s) shock emission. Low dispersion optical spectra covering the wavelength range 4500–7500 Å show only Balmer line emissions for one filament while three others show a Balmer dominated spectrum along with weak [N i] 5198, 5200 Å, [O i] 6300, 6364 Å, [N ii] 6583 Å, [S ii] 6716, 6731 Å, and in one case [O iii] 5007 Å line emission. Many of the brighter Hα filaments are visible in near-UV GALEX images presumably due to C iii] 1909 Å line emission. ROSAT All Sky Survey images of this region show a faint crescent-shaped X-ray emission nebula coincident with the portion of the Hα nebulosity closest to the Galactic plane. The presence of long, thin Balmer dominated emission filaments with associated UV emission and coincident X-ray emission suggests this nebula is a high latitude Galactic SNR despite a lack of known associated nonthermal radio emission. Relative line intensities of the optical lines in some filaments differ from commonly observed [S ii]/Hα ≥ 0.4 radiative shocked filaments and typical Balmer filaments in SNRs. We discuss possible causes for the unusual optical SNR spectra.

  2. THE ANGULAR MOMENTA OF NEUTRON STARS AND BLACK HOLES AS A WINDOW ON SUPERNOVAE

    SciTech Connect

    Miller, J. M.; Miller, M. C.; Reynolds, C. S.

    2011-04-10

    It is now clear that a subset of supernovae displays evidence for jets and is observed as gamma-ray bursts (GRBs). The angular momentum distribution of massive stellar endpoints provides a rare means of constraining the nature of the central engine in core-collapse explosions. Unlike supermassive black holes, the spin of stellar-mass black holes in X-ray binary systems is little affected by accretion and accurately reflects the spin set at birth. A modest number of stellar-mass black hole angular momenta have now been measured using two independent X-ray spectroscopic techniques. In contrast, rotation-powered pulsars spin down over time, via magnetic braking, but a modest number of natal spin periods have now been estimated. For both canonical and extreme neutron star parameters, statistical tests strongly suggest that the angular momentum distributions of black holes and neutron stars are markedly different. Within the context of prevalent models for core-collapse supernovae, the angular momentum distributions are consistent with black holes typically being produced in GRB-like supernovae with jets and with neutron stars typically being produced in supernovae with too little angular momentum to produce jets via magnetohydrodynamic processes. It is possible that neutron stars are with high spin initially and rapidly spun down shortly after the supernova event, but the available mechanisms may be inconsistent with some observed pulsar properties.

  3. SPECTRAL IDENTIFICATION OF AN ANCIENT SUPERNOVA USING LIGHT ECHOES IN THE LMC

    SciTech Connect

    Rest, A; Matheson, T; Blondin, S; Bergmann, M; Welch, D L; Suntzeff, N B; Smith, R C; Olsen, K; Prieto, J L; Garg, A; Challis, P; Stubbs, C; Hicken, M; Modjaz, M; Wood-Vasey, W M; Zenteno, A; Damke, G; Newman, A; Huber, M; Cook, K H; Nikolaev, S; Becker, A C; Miceli, A; Covarrubias, R; Morelli, L; Pignata, G; Clocchiatti, A; Minniti, D; Foley, R J

    2008-02-07

    We report the successful identification of the type of the supernova responsible for the supernova remnant SNR 0509-675 in the Large Magellanic Cloud (LMC) using Gemini spectra of surrounding light echoes. The ability to classify outbursts associated with centuries-old remnants provides a new window into several aspects of supernova research and is likely to be successful in providing new constraints on additional LMC supernovae as well as their historical counterparts in the Milky Way Galaxy (MWG). The combined spectrum of echo light from SNR 0509-675 shows broad emission and absorption lines consistent with a supernova (SN) spectrum. We create a spectral library consisting of 26 SNe Ia and 6 SN Ib/c that are time-integrated, dust-scattered by LMC dust, and reddened by the LMC and MWG. We fit these SN templates to the observed light echo spectrum using {chi}{sup 2} minimization as well as correlation techniques, and we find that overluminous 91T-like SNe Ia with {Delta}m{sub 15} < 0.9 match the observed spectrum best.

  4. SLOW-SPEED SUPERNOVAE FROM THE PALOMAR TRANSIENT FACTORY: TWO CHANNELS

    SciTech Connect

    White, Christopher J.; Kasliwal, Mansi M.; Piro, Anthony L.; Nugent, Peter E.; Gal-Yam, Avishay; Ofek, Eran O.; Ben-Ami, Sagi; Howell, D. Andrew; Sullivan, Mark; Goobar, Ariel; Bloom, Joshua S.; Kulkarni, Shrinivas R.; Cao, Yi; Laher, Russ R.; Masci, Frank; Surace, Jason; Hook, Isobel M.; Jönsson, Jakob; Matheson, Thomas; and others

    2015-01-20

    Since the discovery of the unusual prototype SN 2002cx, the eponymous class of Type I (hydrogen-poor) supernovae with low ejecta speeds has grown to include approximately two dozen members identified from several heterogeneous surveys, in some cases ambiguously. Here we present the results of a systematic study of 1077 Type I supernovae discovered by the Palomar Transient Factory, leading to nine new members of this peculiar class. Moreover, we find there are two distinct subclasses based on their spectroscopic, photometric, and host galaxy properties: ''SN 2002cx-like'' supernovae tend to be in later-type or more irregular hosts, have more varied and generally dimmer luminosities, have longer rise times, and lack a Ti II trough when compared to ''SN 2002es-like'' supernovae. None of our objects show helium, and we counter a previous claim of two such events. We also find that the occurrence rate of these transients relative to Type Ia supernovae is 5.6{sub −3.8}{sup +22}% (90% confidence), lower compared to earlier estimates. Combining our objects with the literature sample, we propose that these subclasses have two distinct physical origins.

  5. H{sub ?} SPECTRAL DIVERSITY OF TYPE II SUPERNOVAE: CORRELATIONS WITH PHOTOMETRIC PROPERTIES

    SciTech Connect

    Gutirrez, Claudia P.; Hamuy, Mario; Gonzlez-Gaitn, Santiago [Millennium Institute of Astrophysics, Casilla 36-D, Santiago (Chile); Anderson, Joseph P. [Departamento de Astronoma, Universidad de Chile, Casilla 36-D, Santiago (Chile); Folatelli, Gastn [Institute for the Physics and Mathematics of the Universe (IPMU), University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8583 (Japan); Morrell, Nidia I.; Phillips, Mark M.; Thomas-Osip, Joanna [Carnegie Observatories, Las Campanas Observatory, Casilla 601, La Serena (Chile); Stritzinger, Maximilian D. [Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C (Denmark); McCarthy, Patrick [Observatories of the Carnegie Institution for Science, Pasadena, CA 91101 (United States); Suntzeff, Nicholas B., E-mail: cgutierr@das.uchile.cl [George P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy, Department of Physics and Astronomy, Texas A and M University, College Station, TX 77843 (United States)

    2014-05-10

    We present a spectroscopic analysis of the H{sub ?} profiles of hydrogen-rich Type II supernovae. A total of 52 Type II supernovae having well-sampled optical light curves and spectral sequences were analyzed. Concentrating on the H{sub ?} P-Cygni profile we measure its velocity from the FWHM of the emission and the ratio of absorption to emission (a/e) at a common epoch at the start of the recombination phase, and search for correlations between these spectral parameters and photometric properties of the V-band light curves. Testing the strength of various correlations we find that a/e appears to be the dominant spectral parameter in terms of describing the diversity in our measured supernova properties. It is found that supernovae with smaller a/e have higher H{sub ?} velocities, more rapidly declining light curves from maximum during the plateau and radioactive tail phase, are brighter at maximum light, and have shorter optically thick phase durations. We discuss possible explanations of these results in terms of physical properties of Type II supernovae, speculating that the most likely parameters that influence the morphologies of H{sub ?} profiles are the mass and density profile of the hydrogen envelope, together with additional emission components due to circumstellar interaction.

  6. Research Groups - Cyclotron Institute

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    Research Groups Research Group Homepages: Nuclear Theory Group Dr. Sherry Yennello's Research Group Dr. Dan Melconian's Research Group Dr. Cody Folden's Group...

  7. BULLET CLUSTER: A CHALLENGE TO {Lambda}CDM COSMOLOGY

    SciTech Connect

    Lee, Jounghun; Komatsu, Eiichiro

    2010-07-20

    To quantify how rare the bullet-cluster-like high-velocity merging systems are in the standard {Lambda} cold dark matter (CDM) cosmology, we use a large-volume (27 h {sup -3} Gpc{sup 3}) cosmological N-body MICE simulation to calculate the distribution of infall velocities of subclusters around massive main clusters. The infall velocity distribution is given at (1-3)R{sub 200} of the main cluster (where R{sub 200} is similar to the virial radius), and thus it gives the distribution of realistic initial velocities of subclusters just before collision. These velocities can be compared with the initial velocities used by the non-cosmological hydrodynamical simulations of 1E0657-56 in the literature. The latest parameter search carried out by Mastropietro and Burkert has shown that an initial velocity of 3000 km s{sup -1} at about 2R{sub 200} is required to explain the observed shock velocity, X-ray brightness ratio of the main and subcluster, X-ray morphology of the main cluster, and displacement of the X-ray peaks from the mass peaks. We show that such a high infall velocity at 2R{sub 200} is incompatible with the prediction of a {Lambda}CDM model: the probability of finding 3000 km s{sup -1} in (2-3)R{sub 200} is between 3.3 x 10{sup -11} and 3.6 x 10{sup -9}. A lower velocity, 2000 km s{sup -1} at 2R{sub 200}, is also rare, and moreover, Mastropietro and Burkert have shown that such a low initial velocity does not reproduce the X-ray brightness ratio of the main and subcluster or morphology of the main cluster. Therefore, we conclude that the existence of 1E0657-56 is incompatible with the prediction of a {Lambda}CDM model, unless a lower infall velocity solution for 1E0657-56 with {approx}<1800 km s{sup -1} at 2R{sub 200} is found.

  8. Spectroscopic Properties of Star-Forming Host Galaxies and Type Ia Supernova Hubble Residuals in a Nearly Unbiased Sample

    SciTech Connect

    D'Andrea, Chris B.; et al.

    2011-12-20

    We examine the correlation between supernova host galaxy properties and their residuals on the Hubble diagram. We use supernovae discovered during the Sloan Digital Sky Survey II - Supernova Survey, and focus on objects at a redshift of z < 0.15, where the selection effects of the survey are known to yield a complete Type Ia supernova sample. To minimize the bias in our analysis with respect to measured host-galaxy properties, spectra were obtained for nearly all hosts, spanning a range in magnitude of -23 < M_r < -17. In contrast to previous works that use photometric estimates of host mass as a proxy for global metallicity, we analyze host-galaxy spectra to obtain gas-phase metallicities and star-formation rates from host galaxies with active star formation. From a final sample of ~ 40 emission-line galaxies, we find that light-curve corrected Type Ia supernovae are ~ 0.1 magnitudes brighter in high-metallicity hosts than in low-metallicity hosts. We also find a significant (> 3{\\sigma}) correlation between the Hubble residuals of Type Ia supernovae and the specific star-formation rate of the host galaxy. We comment on the importance of supernova/host-galaxy correlations as a source of systematic bias in future deep supernova surveys.

  9. The Coyote Universe II: Cosmological Models and Precision Emulation of the Nonlinear Matter Power Spectrum

    SciTech Connect

    Heitmann, Katrin; Habib, Salman; Higdon, David; Williams, Brian J; White, Martin; Wagner, Christian

    2008-01-01

    The power spectrum of density fluctuations is a foundational source of cosmological information. Precision cosmological probes targeted primarily at investigations of dark energy require accurate theoretical determinations of the power spectrum in the nonlinear regime. To exploit the observational power of future cosmological surveys, accuracy demands on the theory are at the one percent level or better. Numerical simulations are currently the only way to produce sufficiently error-controlled predictions for the power spectrum. The very high computational cost of (precision) N-body simulations is a major obstacle to obtaining predictions in the nonlinear regime, while scanning over cosmological parameters. Near-future observations, however, are likely to provide a meaningful constraint only on constant dark energy equation of state 'wCDM' cosmologies. In this paper we demonstrate that a limited set of only 37 cosmological models -- the 'Coyote Universe' suite -- can be used to predict the nonlinear matter power spectrum at the required accuracy over a prior parameter range set by cosmic microwave background observations. This paper is the second in a series of three, with the final aim to provide a high-accuracy prediction scheme for the nonlinear matter power spectrum for wCDM cosmologies.

  10. Spallation Model for the Titanium-Rich Supernova Remnant Cassiopeia A

    SciTech Connect

    Ouyed, Rachid; Leahy, Denis; Ouyed, Amir; Jaikumar, Prashanth

    2011-10-07

    Titanium-rich subluminous supernovae are rare and challenge current SN nucleosynthesis models. We present a model in which ejecta from a standard supernova is impacted by a second explosion of the neutron star (a quark nova), resulting in spallation reactions that lead to {sup 56}Ni destruction and {sup 44}Ti creation under the right conditions. Basic calculations of the spallation products shows that a delay between the two explosions of {approx}5 days reproduces the observed abundance of {sup 44}Ti in Cas A and explains its low luminosity as a result of the destruction of {sup 56}Ni. Our results could have important implications for light curves of subluminous as well as superluminous supernovae.

  11. SUPERNOVA REMNANT KES 17: AN EFFICIENT COSMIC RAY ACCELERATOR INSIDE A MOLECULAR CLOUD

    SciTech Connect

    Gelfand, Joseph D.; Castro, Daniel; Slane, Patrick O.; Temim, Tea; Hughes, John P.; Rakowski, Cara E-mail: cara.rakowski@gmail.com

    2013-11-10

    The supernova remnant Kes 17 (SNR G304.6+0.1) is one of a few but growing number of remnants detected across the electromagnetic spectrum. In this paper, we analyze recent radio, X-ray, and γ-ray observations of this object, determining that efficient cosmic ray acceleration is required to explain its broadband non-thermal spectrum. These observations also suggest that Kes 17 is expanding inside a molecular cloud, though our determination of its age depends on whether thermal conduction or clump evaporation is primarily responsible for its center-filled thermal X-ray morphology. Evidence for efficient cosmic ray acceleration in Kes 17 supports recent theoretical work concluding that the strong magnetic field, turbulence, and clumpy nature of molecular clouds enhance cosmic ray production in supernova remnants. While additional observations are needed to confirm this interpretation, further study of Kes 17 is important for understanding how cosmic rays are accelerated in supernova remnants.

  12. Cosmological perturbations in non-local higher-derivative gravity

    SciTech Connect

    Craps, Ben; Jonckheere, Tim De; Koshelev, Alexey S. E-mail: Tim.De.Jonckheere@vub.ac.be

    2014-11-01

    We study cosmological perturbations in a non-local higher-derivative model of gravity introduced by Biswas, Mazumdar and Siegel. We extend previous work, which had focused on classical scalar perturbations around a cosine hyperbolic bounce solution, in three ways. First, we point out the existence of a Starobinsky solution in this model, which is more attractive from a phenomenological point of view (even though it has no bounce). Second, we study classical vector and tensor pertuxsxrbations. Third, we show how to quantize scalar and tensor perturbations in a de Sitter phase (for choices of parameters such that the model is ghost-free). Our results show that the model is well-behaved at this level, and are very similar to corresponding results in local f(R) models. In particular, for the Starobinsky solution of non-local higher-derivative gravity, we find the same tensor-to-scalar ratio as for the conventional Starobinsky model.

  13. Mapping the Heavens: Probing Cosmology with Large Surveys

    ScienceCinema

    Frieman, Joshua [Fermilab

    2016-07-12

    This talk will provide an overview of recent and on-going sky surveys, focusing on their implications for cosmology. I will place particular emphasis on the Sloan Digital Sky Survey, the most ambitious mapping of the Universe yet undertaken, showing a virtual fly-through of the survey that reveals the large-scale structure of the galaxy distribution. Recent measurements of this large-scale structure, in combination with observations of the cosmic microwave background, have provided independent evidence for a Universe dominated by dark matter and dark energy as well as insights into how galaxies and larger-scale structures formed. Future planned surveys will build on these foundations to probe the history of the cosmic expansion--and thereby the dark energy--with greater precision.

  14. The Atacama Cosmology Telescope: cross correlation with Planck maps

    SciTech Connect

    Louis, Thibaut; Calabrese, Erminia; Dunkley, Joanna; Næss, Sigurd; Addison, Graeme E.; Hincks, Adam D.; Hasselfield, Matthew; Hlozek, Renée; Bond, J. Richard; Hajian, Amir; Das, Sudeep; Devlin, Mark J.; Dünner, Rolando; Infante, Leopoldo; Gralla, Megan; Marriage, Tobias A.; Huffenberger, Kevin; Kosowsky, Arthur; Moodley, Kavilan; Niemack, Michael D.; and others

    2014-07-01

    We present the temperature power spectrum of the Cosmic Microwave Background obtained by cross-correlating maps from the Atacama Cosmology Telescope (ACT) at 148 and 218 GHz with maps from the Planck satellite at 143 and 217 GHz, in two overlapping regions covering 592 square degrees. We find excellent agreement between the two datasets at both frequencies, quantified using the variance of the residuals between the ACT power spectra and the ACT × Planck cross-spectra. We use these cross-correlations to measure the calibration of the ACT data at 148 and 218 GHz relative to Planck, to 0.7% and 2% precision respectively. We find no evidence for anisotropy in the calibration parameter. We compare the Planck 353 GHz power spectrum with the measured amplitudes of dust and cosmic infrared background (CIB) of ACT data at 148 and 218 GHz. We also compare planet and point source measurements from the two experiments.

  15. A caveat on building nonlocal models of cosmology

    SciTech Connect

    Tsamis, N.C.; Woodard, R.P. E-mail: woodard@phys.ufl.edu

    2014-09-01

    Nonlocal models of cosmology might derive from graviton loop corrections to the effective field equations from the epoch of primordial inflation. Although the Schwinger-Keldysh formalism would automatically produce causal and conserved effective field equations, the models so far proposed have been purely phenomenological. Two techniques have been employed to generate causal and conserved field equations: either varying an invariant nonlocal effective action and then enforcing causality by the ad hoc replacement of any advanced Green's function with its retarded counterpart, or else introducing causal nonlocality into a general ansatz for the field equations and then enforcing conservation. We point out here that the two techniques access very different classes of models, and that neither one of them may represent what would actually arise from fundamental theory.

  16. Galileons coupled to massive gravity: general analysis and cosmological solutions

    SciTech Connect

    Goon, Garrett; Trodden, Mark; Gümrükçüoğlu, A. Emir; Hinterbichler, Kurt; Mukohyama, Shinji E-mail: Emir.Gumrukcuoglu@nottingham.ac.uk E-mail: shinji.mukohyama@ipmu.jp

    2014-08-01

    We further develop the framework for coupling galileons and Dirac-Born-Infeld (DBI) scalar fields to a massive graviton while retaining both the non-linear symmetries of the scalars and ghost-freedom of the theory. The general construction is recast in terms of vielbeins which simplifies calculations and allows for compact expressions. Expressions for the general form of the action are derived, with special emphasis on those models which descend from maximally symmetric spaces. We demonstrate the existence of maximally symmetric solutions to the fully non-linear theory and analyze their spectrum of quadratic fluctuations. Finally, we consider self-accelerating cosmological solutions and study their perturbations, showing that the vector and scalar modes have vanishing kinetic terms.

  17. Predicting the cosmological constant from the causal entropic principle

    SciTech Connect

    Bousso, Raphael; Harnik, Roni; Kribs, Graham D.; Perez, Gilad

    2007-08-15

    We compute the expected value of the cosmological constant in our universe from the causal entropic principle. Since observers must obey the laws of thermodynamics and causality, the principle asserts that physical parameters are most likely to be found in the range of values for which the total entropy production within a causally connected region is maximized. Despite the absence of more explicit anthropic criteria, the resulting probability distribution turns out to be in excellent agreement with observation. In particular, we find that dust heated by stars dominates the entropy production, demonstrating the remarkable power of this thermodynamic selection criterion. The alternative approach - weighting by the number of 'observers per baryon' - is less well-defined, requires problematic assumptions about the nature of observers, and yet prefers values larger than present experimental bounds.

  18. Predicting the Cosmological Constant from the Causal Entropic Principle

    SciTech Connect

    Bousso, Raphael; Bousso, Raphael; Harnik, Roni; Kribs, Graham D.; Perez, Gilad

    2007-05-01

    We compute the expected value of the cosmological constant in our universe from the Causal Entropic Principle. Since observers must obey the laws of thermodynamics and causality, the principle asserts that physical parameters are most likely to be found in the range of values for which the total entropy production within a causally connected region is maximized. Despite the absence of more explicit anthropic criteria, the resulting probability distribution turns out to be in excellent agreement with observation. In particular, we find that dust heated by stars dominates the entropy production, demonstrating the remarkable power of this thermodynamic selection criterion. The alternative approach-weighting by the number of"observers per baryon" -- is less well-defined, requires problematic assumptions about the nature of observers, and yet prefers values larger than present experimental bounds.

  19. Predicting the Cosmological Constant from the CausalEntropic Principle

    SciTech Connect

    Bousso, Raphael; Harnik, Roni; Kribs, Graham D.; Perez, Gilad

    2007-02-20

    We compute the expected value of the cosmological constant in our universe from the Causal Entropic Principle. Since observers must obey the laws of thermodynamics and causality, it asserts that physical parameters are most likely to be found in the range of values for which the total entropy production within a causally connected region is maximized. Despite the absence of more explicit anthropic criteria, the resulting probability distribution turns out to be in excellent agreement with observation. In particular, we find that dust heated by stars dominates the entropy production, demonstrating the remarkable power of this thermodynamic selection criterion. The alternative approach--weighting by the number of ''observers per baryon''--is less well-defined, requires problematic assumptions about the nature of observers, and yet prefers values larger than present experimental bounds.

  20. Non-adiabatic perturbations in decaying vacuum cosmology

    SciTech Connect

    Zimdahl, W.; Fabris, J.C.; Borges, H.A.; Carneiro, S.; Hiplito-Ricaldi, W.S. E-mail: humberto@ufba.br E-mail: fabris@pq.cnpq.br

    2011-04-01

    We investigate a spatially flat Friedmann-Lematre-Robertson-Walker cosmology in which a decaying vacuum term causes matter production at late times. Assuming a decay proportional to the Hubble rate, the ratio of the background energy densities of dark matter and dark energy changes with the cosmic scale factor as a{sup ?3/2}. The intrinsically non-adiabatic two-component perturbation dynamics of this model is reduced to a single second-order equation. Perturbations of the vacuum term are shown to be negligible on scales that are relevant for structure formation. On larger scales, dark-energy perturbations give a somewhat higher contribution but remain always smaller than the dark-matter perturbations.

  1. On the non-linear scale of cosmological perturbation theory

    SciTech Connect

    Blas, Diego; Garny, Mathias; Konstandin, Thomas E-mail: mathias.garny@desy.de

    2013-09-01

    We discuss the convergence of cosmological perturbation theory. We prove that the polynomial enhancement of the non-linear corrections expected from the effects of soft modes is absent in equal-time correlators like the power or bispectrum. We first show this at leading order by resumming the most important corrections of soft modes to an arbitrary skeleton of hard fluctuations. We derive the same result in the eikonal approximation, which also allows us to show the absence of enhancement at any order. We complement the proof by an explicit calculation of the power spectrum at two-loop order, and by further numerical checks at higher orders. Using these insights, we argue that the modification of the power spectrum from soft modes corresponds at most to logarithmic corrections at any order in perturbation theory. Finally, we discuss the asymptotic behavior in the large and small momentum regimes and identify the expansion parameter pertinent to non-linear corrections.

  2. ORBITING CIRCUMGALACTIC GAS AS A SIGNATURE OF COSMOLOGICAL ACCRETION

    SciTech Connect

    Stewart, Kyle R.; Kaufmann, Tobias; Bullock, James S.; Barton, Elizabeth J.; Maller, Ariyeh H.; Diemand, Juerg; Wadsley, James

    2011-09-01

    We use cosmological smoothed particle hydrodynamic simulations to study the kinematic signatures of cool gas accretion onto a pair of well-resolved galaxy halos. We find that cold-flow streams and gas-rich mergers produce a circumgalactic component of cool gas that generally orbits with high angular momentum about the galaxy halo before falling in to build the disk. This signature of cosmological accretion should be observable using background-object absorption-line studies as features that are offset from the galaxy's systemic velocity by {approx}100 km s{sup -1}. In most cases, the accreted gas co-rotates with the central disk in the form of a warped, extended cold flow disk, such that the observed velocity offset will be in the same direction as galaxy rotation, appearing in sight lines that avoid the galactic poles. This prediction provides a means to observationally distinguish accreted gas from outflow gas: the accreted gas will show large one-sided velocity offsets in absorption-line studies while radial/bi-conical outflows will not (except possibly in special polar projections). Such a signature of rotation has already been seen in studies of intermediate-redshift galaxy-absorber pairs, and we suggest that these observations may be among the first to provide indirect observational evidence for cold accretion onto galactic halos. This cold-mode halo gas typically has {approx}3-5 times more specific angular momentum than the dark matter. The associated cold-mode disk configurations are likely related to extended H I/extended UV disks that are seen around galaxies in the local universe. The fraction of galaxies with extended cold flow disks and associated offset absorption-line gas should decrease around bright galaxies at low redshift as cold-mode accretion dies out.

  3. Cosmological simulations of isotropic conduction in galaxy clusters

    SciTech Connect

    Smith, Britton; O'Shea, Brian W.; Voit, G. Mark; Ventimiglia, David; Skillman, Samuel W.

    2013-12-01

    Simulations of galaxy clusters have a difficult time reproducing the radial gas-property gradients and red central galaxies observed to exist in the cores of galaxy clusters. Thermal conduction has been suggested as a mechanism that can help bring simulations of cluster cores into better alignment with observations by stabilizing the feedback processes that regulate gas cooling, but this idea has not yet been well tested with cosmological numerical simulations. Here we present cosmological simulations of 10 galaxy clusters performed with five different levels of isotropic Spitzer conduction, which alters both the cores and outskirts of clusters, though not dramatically. In the cores, conduction flattens central temperature gradients, making them nearly isothermal and slightly lowering the central density, but failing to prevent a cooling catastrophe there. Conduction has little effect on temperature gradients outside of cluster cores because outward conductive heat flow tends to inflate the outer parts of the intracluster medium (ICM), instead of raising its temperature. In general, conduction tends reduce temperature inhomogeneity in the ICM, but our simulations indicate that those homogenizing effects would be extremely difficult to observe in ?5 keV clusters. Outside the virial radius, our conduction implementation lowers the gas densities and temperatures because it reduces the Mach numbers of accretion shocks. We conclude that, despite the numerous small ways in which conduction alters the structure of galaxy clusters, none of these effects are significant enough to make the efficiency of conduction easily measurable, unless its effects are more pronounced in clusters hotter than those we have simulated.

  4. Bianchi type-I magnetized cosmological models for the Einstein-Boltzmann equation with the cosmological constant

    SciTech Connect

    Ayissi, Raoul Domingo Noutchegueme, Norbert

    2015-01-15

    Global solutions regular for the Einstein-Boltzmann equation on a magnetized Bianchi type-I cosmological model with the cosmological constant are investigated. We suppose that the metric is locally rotationally symmetric. The Einstein-Boltzmann equation has been already considered by some authors. But, in general Bancel and Choquet-Bruhat [Ann. Henri Poincaré XVIII(3), 263 (1973); Commun. Math. Phys. 33, 83 (1973)], they proved only the local existence, and in the case of the nonrelativistic Boltzmann equation. Mucha [Global existence of solutions of the Einstein-Boltzmann equation in the spatially homogeneous case. Evolution equation, existence, regularity and singularities (Banach Center Publications, Institute of Mathematics, Polish Academy of Science, 2000), Vol. 52] obtained a global existence result, for the relativistic Boltzmann equation coupled with the Einstein equations and using the Yosida operator, but confusing unfortunately with the nonrelativistic case. Noutchegueme and Dongho [Classical Quantum Gravity 23, 2979 (2006)] and Noutchegueme, Dongho, and Takou [Gen. Relativ. Gravitation 37, 2047 (2005)], have obtained a global solution in time, but still using the Yosida operator and considering only the uncharged case. Noutchegueme and Ayissi [Adv. Stud. Theor. Phys. 4, 855 (2010)] also proved a global existence of solutions to the Maxwell-Boltzmann system using the characteristic method. In this paper, we obtain using a method totally different from those used in the works of Noutchegueme and Dongho [Classical Quantum Gravity 23, 2979 (2006)], Noutchegueme, Dongho, and Takou [Gen. Relativ. Gravitation 37, 2047 (2005)], Noutchegueme and Ayissi [Adv. Stud. Theor. Phys. 4, 855 (2010)], and Mucha [Global existence of solutions of the Einstein-Boltzmann equation in the spatially homogeneous case. Evolution equation, existence, regularity and singularities (Banach Center Publications, Institute of Mathematics, Polish Academy of Science, 2000), Vol. 52] the

  5. Mapping luminosity-redshift relationship to Lemaitre-Tolman-Bondi cosmology

    SciTech Connect

    Chung, Daniel J. H.; Romano, Antonio Enea

    2006-11-15

    We derive a direct general map from the luminosity distance D{sub L}(z) to the inhomogeneous matter distribution M(r) in the Lemaitre-Tolman-Bondi (LTB) cosmology and compute several examples. One of our examples explicitly demonstrates that it is possible to tune the LTB cosmological solution to approximately reproduce the luminosity distance curve of a flat Friedmann-Robertson-Walker universe with a cosmological constant. We also discuss how smooth matter distributions can evolve into naked singularities due to shell crossing when the inhomogeneous 'curvature' E(r) is a function which changes sign.

  6. COLLOQUIUM: Small-scale CMB Cosmology: ACT, Planck and Beyond | Princeton

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    Plasma Physics Lab June 25, 2014, 4:00pm to 5:30pm Colloquia MBG Auditorium COLLOQUIUM: Small-scale CMB Cosmology: ACT, Planck and Beyond Dr. Renee Hlozek Princeton University Abstract: PDF icon COLL.06.25.14.pdf The Atacama Cosmology Telescope (ACT) has mapped the microwave sky to arcminute scales. We present constraints on parameters from the observations at 148 and 217 GHz respectively by ACT from three years of observations. We fit a model of primary cosmological and secondary foreground

  7. Interstellar and ejecta dust in the cas a supernova remnant

    SciTech Connect

    Arendt, Richard G.; Dwek, Eli; Kober, Gladys; Rho, Jeonghee; Hwang, Una

    2014-05-01

    Infrared continuum observations provide a means of investigating the physical composition of the dust in the ejecta and swept up medium of the Cas A supernova remnant (SNR). Using low-resolution Spitzer IRS spectra (5-35 μm), and broad-band Herschel PACS imaging (70, 100, and 160 μm), we identify characteristic dust spectra, associated with ejecta layers that underwent distinct nuclear burning histories. The most luminous spectrum exhibits strong emission features at ∼9 and 21 μm and is closely associated with ejecta knots with strong Ar emission lines. The dust features can be reproduced by magnesium silicate grains with relatively low Mg to Si ratios. Another dust spectrum is associated with ejecta having strong Ne emission lines. It has no indication of any silicate features and is best fit by Al{sub 2}O{sub 3} dust. A third characteristic dust spectrum shows features that are best matched by magnesium silicates with a relatively high Mg to Si ratio. This dust is primarily associated with the X-ray-emitting shocked ejecta, but it is also evident in regions where shocked interstellar or circumstellar material is expected. However, the identification of dust composition is not unique, and each spectrum includes an additional featureless dust component of unknown composition. Colder dust of indeterminate composition is associated with emission from the interior of the SNR, where the reverse shock has not yet swept up and heated the ejecta. Most of the dust mass in Cas A is associated with this unidentified cold component, which is ≲ 0.1 M {sub ☉}. The mass of warmer dust is only ∼0.04 M {sub ☉}.

  8. A SPITZER SURVEY FOR DUST IN TYPE IIn SUPERNOVAE

    SciTech Connect

    Fox, Ori D.; Chevalier, Roger A.; Skrutskie, Michael F.; Soderberg, Alicia M.; Filippenko, Alexei V.; Ganeshalingam, Mohan; Silverman, Jeffrey M.; Smith, Nathan; Steele, Thea N.

    2011-11-01

    Recent observations suggest that Type IIn supernovae (SNe IIn) may exhibit late-time (>100 days) infrared (IR) emission from warm dust more than other types of core-collapse SNe. Mid-IR observations, which span the peak of the thermal spectral energy distribution, provide useful constraints on the properties of the dust and, ultimately, the circumstellar environment, explosion mechanism, and progenitor system. Due to the low SN IIn rate (<10% of all core-collapse SNe), few IR observations exist for this subclass. The handful of isolated studies, however, show late-time IR emission from warm dust that, in some cases, extends for five or six years post-discovery. While previous Spitzer/IRAC surveys have searched for dust in SNe, none have targeted the Type IIn subclass. This paper presents results from a warm Spitzer/IRAC survey of the positions of all 68 known SNe IIn within a distance of 250 Mpc between 1999 and 2008 that have remained unobserved by Spitzer more than 100 days post-discovery. The detection of late-time emission from 10 targets ({approx}15%) nearly doubles the database of existing mid-IR observations of SNe IIn. Although optical spectra show evidence for new dust formation in some cases, the data show that in most cases the likely origin of the mid-IR emission is pre-existing dust, which is continuously heated by optical emission generated by ongoing circumstellar interaction between the forward shock and circumstellar medium. Furthermore, an emerging trend suggests that these SNe decline at {approx}1000-2000 days post-discovery once the forward shock overruns the dust shell. The mass-loss rates associated with these dust shells are consistent with luminous blue variable progenitors.

  9. Critical surface for explosions of rotational core-collapse supernovae

    SciTech Connect

    Iwakami, Wakana; Nagakura, Hiroki [Yukawa Institute for Theoretical Physics, Kyoto University, Oiwake-cho, Kitashirakawa, Sakyo-ku, Kyoto, 606-8502 (Japan); Yamada, Shoichi, E-mail: wakana@heap.phys.waseda.ac.jp [Advanced Research Institute for Science and Engineering, Waseda University, 3-4-1, Okubo, Shinjuku, Tokyo, 169-8555 (Japan)

    2014-09-20

    The effect of rotation on the explosion of core-collapse supernovae is investigated systematically in three-dimensional simulations. In order to obtain the critical conditions for explosion as a function of mass accretion rate, neutrino luminosity, and specific angular momentum, rigidly rotating matter was injected from the outer boundary with an angular momentum, which is increased every 500 ms. It is found that there is a critical value of the specific angular momentum, above which the standing shock wave revives, for a given combination of mass accretion rate and neutrino luminosity, i.e., an explosion can occur by rotation even if the neutrino luminosity is lower than the critical value for a given mass accretion rate in non-rotational models. The coupling of rotation and hydrodynamical instabilities plays an important role in characterizing the dynamics of shock revival for the range of specific angular momentum that are supposed to be realistic. Contrary to expectations from past studies, the most rapidly expanding direction of the shock wave is not aligned with the rotation axis. Being perpendicular to the rotation axis on average, it can be oriented in various directions. Its dispersion is small when the spiral mode of the standing accretion shock instability (SASI) governs the dynamics, while it is large when neutrino-driven convection is dominant. As a result of the comparison between two-dimensional and three-dimensional rotational models, it is found that m ? 0 modes of neutrino-driven convection or SASI are important for shock revival around the critical surface.

  10. PHYSICAL STRUCTURE AND NATURE OF SUPERNOVA REMNANTS IN M101

    SciTech Connect

    Franchetti, Nicholas A.; Gruendl, Robert A.; Chu, You-Hua; Dunne, Bryan C.; Pannuti, Thomas G.; Grimes, Caleb K.; Kuntz, Kip D.; Chen, C.-H. Rosie; Aldridge, Tabitha M. E-mail: gruendl@astro.illinois.edu E-mail: bdunne@astro.illinois.edu E-mail: ckgrim01@moreheadstate.edu E-mail: rchen@mpifr-bonn.mpg.de

    2012-04-15

    Supernova remnant (SNR) candidates in the giant spiral galaxy M101 have been previously identified from ground-based H{alpha} and [S II] images. We have used archival Hubble Space Telescope (HST) H{alpha} and broadband images as well as stellar photometry of 55 SNR candidates to examine their physical structure, interstellar environment, and underlying stellar population. We have also obtained high-dispersion echelle spectra to search for shocked high-velocity gas in 18 SNR candidates, and identified X-ray counterparts to SNR candidates using data from archival observations made by the Chandra X-Ray Observatory. Twenty-one of these 55 SNR candidates studied have X-ray counterparts, although one of them is a known ultraluminous X-ray source. The multi-wavelength information has been used to assess the nature of each SNR candidate. We find that within this limited sample, {approx}16% are likely remnants of Type Ia SNe and {approx}45% are remnants of core-collapse SNe. In addition, about {approx}36% are large candidates which we suggest are either superbubbles or OB/H II complexes. Existing radio observations are not sensitive enough to detect the non-thermal emission from these SNR candidates. Several radio sources are coincident with X-ray sources, but they are associated with either giant H II regions in M101 or background galaxies. The archival HST H{alpha} images do not cover the entire galaxy and thus prevents a complete study of M101. Furthermore, the lack of HST [S II] images precludes searches for small SNR candidates which could not be identified by ground-based observations. Such high-resolution images are needed in order to obtain a complete census of SNRs in M101 for a comprehensive investigation of the distribution, population, and rates of SNe in this galaxy.

  11. A Measurement of the Rate of Type Ia Supernovae in Galaxy Clusters from the SDSS-II Supernova Survey

    SciTech Connect

    Dilday, Benjamin; Bassett, Bruce; Becker, Andrew; Bender, Ralf; Castander, Francisco; Cinabro, David; Frieman, Joshua A.; Galbany, Lluis; Garnavich, Peter; Goobar, Ariel; Hopp, Ulrich; /Munich, Tech. U. /Munich U. Observ. /Tokyo U.

    2010-03-01

    We present measurements of the Type Ia supernova (SN) rate in galaxy clusters based on data from the Sloan Digital Sky Survey-II (SDSS-II) Supernova Survey. The cluster SN Ia rate is determined from 9 SN events in a set of 71 C4 clusters at z {le} 0.17 and 27 SN events in 492 maxBCG clusters at 0.1 {le} z {le} 0.3. We find values for the cluster SN Ia rate of (0.37{sub -0.12-0.01}{sup +0.17+0.01}) SNur h{sup 2} and (0.55{sub -0.11-0.01}{sup +0.13+0.02}) SNur h{sup 2} (SNux = 10{sup -12}L{sub x{circle_dot}}{sup -1} yr{sup -1}) in C4 and maxBCG clusters, respectively, where the quoted errors are statistical and systematic, respectively. The SN rate for early-type galaxies is found to be (0.31{sub -0.12-0.01}{sup +0.18+0.01}) SNur h{sup 2} and (0.49{sub -0.11-0.01}{sup +0.15+0.02}) SNur h{sup 2} in C4 and maxBCG clusters, respectively. The SN rate for the brightest cluster galaxies (BCG) is found to be (2.04{sub -1.11-0.04}{sup +1.99+0.07}) SNur h{sup 2} and (0.36{sub -0.30-0.01}{sup +0.84+0.01}) SNur h{sup 2} in C4 and maxBCG clusters, respectively. The ratio of the SN Ia rate in cluster early-type galaxies to that of the SN Ia rate in field early-type galaxies is 1.94{sub -0.91-0.015}{sup +1.31+0.043} and 3.02{sub -1.03-0.048}{sup +1.31+0.062}, for C4 and maxBCG clusters, respectively. The SN rate in galaxy clusters as a function of redshift, which probes the late time SN Ia delay distribution, shows only weak dependence on redshift. Combining our current measurements with previous measurements, we fit the cluster SN Ia rate data to a linear function of redshift, and find r{sub L} = [(0.49{sub -0.14}{sup +0.15}) + (0.91{sub -0.81}{sup +0.85}) x z] SNuB h{sup 2}. A comparison of the radial distribution of SNe in cluster to field early-type galaxies shows possible evidence for an enhancement of the SN rate in the cores of cluster early-type galaxies. With an observation of at most 3 hostless, intra-cluster SNe Ia, we estimate the fraction of cluster SNe that are

  12. Setting the stage for circumstellar interaction in core-collapse supernovae. II. Wave-driven mass loss in supernova progenitors

    SciTech Connect

    Shiode, Joshua H.; Quataert, Eliot E-mail: eliot@berkeley.edu

    2014-01-01

    Supernovae (SNe) powered by interaction with circumstellar material provide evidence for intense stellar mass loss during the final years before core collapse. We have argued that during and after core neon burning, internal gravity waves excited by core convection can tap into the core fusion power and transport a super-Eddington energy flux out to the stellar envelope, potentially unbinding ?1 solar mass of material. In this work, we explore the internal conditions of SN progenitors using the MESA one-dimensional stellar evolution code in search of those most susceptible to wave-driven mass loss. We focus on simple, order of magnitude considerations applicable to a wide range of progenitors. Wave-driven mass loss during core neon and oxygen fusion happens preferentially in either lower mass (?20 solar mass zero-age main sequence) stars or massive, sub-solar metallicity stars. Roughly 20% of the SN progenitors we survey can excite 10{sup 46-48} erg of energy in waves that can potentially drive mass loss within a few months to a decade of core collapse. This energy can generate circumstellar environments with 10{sup 3}-1 solar masses reaching 100 AU before explosion. We predict a correlation between the energy associated with pre-SN mass ejection and the time to core collapse, with the most intense mass loss preferentially occurring closer to core collapse. During silicon burning, wave energy may inflate 10{sup 3}-1 solar masses of the envelope to 10-100 s of solar radii. This suggests that some nominally compact SN progenitors (Type Ibc progenitors) will have a significantly different SN shock breakout signature than traditionally assumed.

  13. Making sense of the new cosmology (Conference) | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    The New Cosmology greatly extends the highly successful hot big-bang model. Now we have to make sense of all this: What is the dark matter particle? What is the nature of the dark ...

  14. TOWARD CHARACTERIZATION OF THE TYPEIIP SUPERNOVA PROGENITOR POPULATION: A STATISTICAL SAMPLE OF LIGHT CURVES FROM Pan-STARRS1

    SciTech Connect

    Sanders, N. E.; Soderberg, A. M.; Chornock, R.; Berger, E.; Challis, P.; Drout, M.; Kirshner, R. P.; Lunnan, R.; Marion, G. H.; Margutti, R.; McKinnon, R.; Milisavljevic, D.; Gezari, S.; Betancourt, M.; Foley, R. J.; Narayan, G.; Rest, A.; Kankare, E.; Mattila, S.; Smartt, S. J.; and others

    2015-02-01

    In recent years, wide-field sky surveys providing deep multiband imaging have presented a new path for indirectly characterizing the progenitor populations of core-collapse supernovae (SNe): systematic light-curve studies. We assemble a set of 76 grizy-band TypeIIP SN light curves from Pan-STARRS1, obtained over a constant survey program of 4yr and classified using both spectroscopy and machine-learning-based photometric techniques. We develop and apply a new Bayesian model for the full multiband evolution of each light curve in the sample. We find no evidence of a subpopulation of fast-declining explosions (historically referred to as ''TypeIIL'' SNe). However, we identify a highly significant relation between the plateau phase decay rate and peak luminosity among our SNeIIP. These results argue in favor of a single parameter, likely determined by initial stellar mass, predominantly controlling the explosions of red supergiants. This relation could also be applied for SN cosmology, offering a standardizable candle good to an intrinsic scatter of ? 0.2mag. We compare each light curve to physical models from hydrodynamic simulations to estimate progenitor initial masses and other properties of the Pan-STARRS1 TypeIIP SN sample. We show that correction of systematic discrepancies between modeled and observed SNIIP light-curve properties and an expanded grid of progenitor properties are needed to enable robust progenitor inferences from multiband light-curve samples of this kind. This work will serve as a pathfinder for photometric studies of core-collapse SNe to be conducted through future wide-field transient searches.

  15. Analysis of the Sultana-Dyer cosmological black hole solution of the Einstein equations

    SciTech Connect

    Faraoni, Valerio

    2009-08-15

    The Sultana-Dyer solution of general relativity representing a black hole embedded in a special cosmological background is analyzed. We find an expanding (weak) spacetime singularity instead of the reported conformal Killing horizon, which is covered by an expanding black hole apparent horizon (internal to a cosmological apparent horizon) for most of the history of the Universe. This singularity was naked early on. The global structure of the solution is studied as well.

  16. Weak Lensing by Galaxy Clusters: from Pixels to Cosmology

    SciTech Connect

    Gruen, Daniel

    2015-03-11

    The story of the origin and evolution of our Universe is told, equivalently, by space-time itself and by the structures that grow inside of it. Clusters of galaxies are the frontier of bottom-up structure formation. They are the most massive objects to have collapsed at the present epoch. By that virtue, their abundance and structural parameters are highly sensitive to the composition and evolution of the Universe. The most common probe of cluster cosmology, abundance, uses samples of clusters selected by some observable. Applying a mass-observable relation (MOR), cosmological parameters can be constrained by comparing the sample to predicted cluster abundances as a function of observable and redshift. Arguably, however, cluster probes have not yet entered the era of per cent level precision cosmology. The primary reason for this is our imperfect understanding of the MORs. The overall normalization, the slope of mass vs. observable, the redshift evolution, and the degree and correlation of intrinsic scatters of observables at fixed mass have to be constrained for interpreting abundances correctly. Mass measurement of clusters by means of the differential deflection of light from background sources in their gravitational field, i.e. weak lensing, is a powerful approach for achieving this. This thesis presents new methods for and scientific results of weak lensing measurements of clusters of galaxies. The former include, on the data reduction side, (i) the correction of CCD images for non-linear effects due to the electric fields of accumulated charges and (ii) a method for masking artifact features in sets of overlapping images of the sky by comparison to the median image. Also, (iii) I develop a method for the selection of background galaxy samples based on their color and apparent magnitude that includes a new correction for contamination with cluster member galaxies. The main scientific results are the following. (i) For the Hubble Frontier Field cluster RXC J

  17. Cosmological QCD phase transition in steady non-equilibrium dissipative Ho?avaLifshitz early universe

    SciTech Connect

    Khodadi, M. Sepangi, H.R.

    2014-07-15

    We study the phase transition from quarkgluon plasma to hadrons in the early universe in the context of non-equilibrium thermodynamics. According to the standard model of cosmology, a phase transition associated with chiral symmetry breaking after the electro-weak transition has occurred when the universe was about 110?s old. We focus attention on such a phase transition in the presence of a viscous relativistic cosmological background fluid in the framework of non-detailed balance Ho?avaLifshitz cosmology within an effective model of QCD. We consider a flat FriedmannRobertsonWalker universe filled with a non-causal and a causal bulk viscous cosmological fluid respectively and investigate the effects of the running coupling constants of Ho?avaLifshitz gravity, ?, on the evolution of the physical quantities relevant to a description of the early universe, namely, the temperature T, scale factor a, deceleration parameter q and dimensionless ratio of the bulk viscosity coefficient to entropy density (?)/s . We assume that the bulk viscosity cosmological background fluid obeys the evolution equation of the steady truncated (Eckart) and full version of the IsraelStewart fluid, respectively. -- Highlights: In this paper we have studied quarkhadron phase transition in the early universe in the context of the Ho?avaLifshitz model. We use a flat FRW universe with the bulk viscosity cosmological background fluid obeying the evolution equation of the steady truncated (Eckart) and full version of the IsraelStewart fluid, respectively.

  18. Mass calibration and cosmological analysis of the SPT-SZ galaxy cluster sample using velocity dispersion σ v and x-ray Y X measurements

    DOE PAGES [OSTI]

    Bocquet, S.; Saro, A.; Mohr, J. J.; Aird, K. A.; Ashby, M. L. N.; Bautz, M.; Bayliss, M.; Bazin, G.; Benson, B. A.; Bleem, L. E.; et al

    2015-01-30

    Here, we present a velocity-dispersion-based mass calibration of the South Pole Telescope Sunyaev-Zel'dovich effect survey (SPT-SZ) galaxy cluster sample. Using a homogeneously selected sample of 100 cluster candidates from 720 deg2 of the survey along with 63 velocity dispersion (σv) and 16 X-ray YX measurements of sample clusters, we simultaneously calibrate the mass-observable relation and constrain cosmological parameters. Our method accounts for cluster selection, cosmological sensitivity, and uncertainties in the mass calibrators. The calibrations using σv and YX are consistent at the 0.6σ level, with the σ v calibration preferring ~16% higher masses. We use the full SPTCL data setmore » (SZ clusters+σv+YX) to measure σ8(Ωm/0.27)0.3 = 0.809 ± 0.036 within a flat ΛCDM model. The SPT cluster abundance is lower than preferred by either the WMAP9 or Planck+WMAP9 polarization (WP) data, but assuming that the sum of the neutrino masses is mν = 0.06 eV, we find the data sets to be consistent at the 1.0σ level for WMAP9 and 1.5σ for Planck+WP. Allowing for larger Σmν further reconciles the results. When we combine the SPTCL and Planck+WP data sets with information from baryon acoustic oscillations and Type Ia supernovae, the preferred cluster masses are 1.9σ higher than the YX calibration and 0.8σ higher than the σ v calibration. Given the scale of these shifts (~44% and ~23% in mass, respectively), we execute a goodness-of-fit test; it reveals no tension, indicating that the best-fit model provides an adequate description of the data. Using the multi-probe data set, we measure Ωm = 0.299 ± 0.009 and σ8 = 0.829 ± 0.011. Within a νCDM model we find Σmν = 0.148 ± 0.081 eV. We present a consistency test of the cosmic growth rate using SPT clusters. Allowing both the growth index γ and the dark energy equation-of-state parameter w to vary, we find γ = 0.73 ± 0.28 and w = –1.007 ± 0.065, demonstrating that the eΣxpansion and the growth

  19. Affine group formulation of the Standard Model coupled to gravity

    SciTech Connect

    Chou, Ching-Yi; Ita, Eyo; Soo, Chopin

    2014-04-15

    In this work we apply the affine group formalism for four dimensional gravity of Lorentzian signature, which is based on Klauders affine algebraic program, to the formulation of the Hamiltonian constraint of the interaction of matter and all forces, including gravity with non-vanishing cosmological constant ?, as an affine Lie algebra. We use the hermitian action of fermions coupled to gravitation and YangMills theory to find the density weight one fermionic super-Hamiltonian constraint. This term, combined with the YangMills and Higgs energy densities, are composed with Yorks integrated time functional. The result, when combined with the imaginary part of the ChernSimons functional Q, forms the affine commutation relation with the volume element V(x). Affine algebraic quantization of gravitation and matter on equal footing implies a fundamental uncertainty relation which is predicated upon a non-vanishing cosmological constant. -- Highlights: WheelerDeWitt equation (WDW) quantized as affine algebra, realizing Klauders program. WDW formulated for interaction of matter and all forces, including gravity, as affine algebra. WDW features Hermitian generators in spite of fermionic content: Standard Model addressed. Constructed a family of physical states for the full, coupled theory via affine coherent states. Fundamental uncertainty relation, predicated on non-vanishing cosmological constant.

  20. SUPERNOVA 2008bk AND ITS RED SUPERGIANT PROGENITOR

    SciTech Connect

    Van Dyk, Schuyler D.; Elias-Rosa, Nancy [Spitzer Science Center/Caltech, Mailcode 220-6, Pasadena, CA 91125 (United States); Davidge, Tim J., E-mail: vandyk@ipac.caltech.edu, E-mail: tim.davidge@nrc.ca [Herzberg Institute of Astrophysics, National Research Council of Canada, Victoria, B.C., V9E 2E7 (Canada); and others

    2012-01-15

    We have obtained limited photometric and spectroscopic data for supernova (SN) 2008bk in NGC 7793, primarily at {approx}> 150 days after explosion. We find that it is a Type II-Plateau (II-P) SN that most closely resembles the low-luminosity SN 1999br in NGC 4900. Given the overall similarity between the observed light curves and colors of SNe 2008bk and 1999br, we infer that the total visual extinction to SN 2008bk (A{sub V} = 0.065 mag) must be almost entirely due to the Galactic foreground, similar to what has been assumed for SN 1999br. We confirm the identification of the putative red supergiant (RSG) progenitor star of the SN in high-quality g'r'i' images we had obtained in 2007 at the Gemini-South 8 m telescope. Little ambiguity exists in this progenitor identification, qualifying it as the best example to date, next to the identification of the star Sk -69 Degree-Sign 202 as the progenitor of SN 1987A. From a combination of photometry of the Gemini images with that of archival, pre-SN, Very Large Telescope JHK{sub s} images, we derive an accurate observed spectral energy distribution (SED) for the progenitor. We find from nebular strong-intensity emission-line indices for several H II regions near the SN that the metallicity in the environment is likely subsolar (Z Almost-Equal-To 0.6 Z{sub Sun }). The observed SED of the star agrees quite well with synthetic SEDs obtained from model RSG atmospheres with effective temperature T{sub eff} = 3600 {+-} 50 K. We find, therefore, that the star had a bolometric luminosity with respect to the Sun of log (L{sub bol}/L{sub Sun} ) = 4.57 {+-} 0.06 and radius R{sub *} = 496 {+-} 34 R{sub Sun} at {approx}6 months prior to explosion. Comparing the progenitor's properties with theoretical massive-star evolutionary models, we conclude that the RSG progenitor had an initial mass in the range of 8-8.5 M{sub Sun }. This mass is consistent with, albeit at the low end of, the inferred range of initial masses for SN II

  1. Scattered-Light Echoes from the Historical Galactic Supernovae Cassiopeia A and Tycho (SN 1572)

    SciTech Connect

    Rest, A; Welch, D L; Suntzeff, N B; Oaster, L; Lanning, H; Olsen, K; Smith, R C; Becker, A C; Bergmann, M; Challis, P; Clocchiatti, A; Cook, K H; Damke, G; Garg, A; Huber, M E; Matheson, T; Minniti, D; Prieto, J L; Wood-Vasey, W M

    2008-05-06

    We report the discovery of an extensive system of scattered light echo arclets associated with the recent supernovae in the local neighborhood of the Milky Way: Tycho (SN 1572) and Cassiopeia A. Existing work suggests that the Tycho SN was a thermonuclear explosion while the Cas A supernova was a core collapse explosion. Precise classifications according to modern nomenclature require spectra of the outburst light. In the case of ancient SNe, this can only be done with spectroscopy of their light echo, where the discovery of the light echoes from the outburst light is the first step. Adjacent light echo positions suggest that Cas A and Tycho may share common scattering dust structures. If so, it is possible to measure precise distances between historical Galactic supernovae. On-going surveys that alert on the development of bright scattered-light echo features have the potential to reveal detailed spectroscopic information for many recent Galactic supernovae, both directly visible and obscured by dust in the Galactic plane.

  2. Spectrum and light curve of a supernova shock breakout through a thick Wolf-Rayet wind

    SciTech Connect

    Svirski, Gilad; Nakar, Ehud

    2014-06-20

    Wolf-Rayet stars are known to eject winds. Thus, when a Wolf-Rayet star explodes as a supernova, a fast (≳ 40, 000 km s{sup –1}) shock is expected to be driven through a wind. We study the signal expected from a fast supernova shock propagating through an optically thick wind and find that the electrons behind the shock driven into the wind are efficiently cooled by inverse Compton over soft photons that were deposited by the radiation-mediated shock that crossed the star. Therefore, the bolometric luminosity is comparable to the kinetic energy flux through the shock, and the spectrum is found to be a power law, whose slope and frequency range depend on the number flux of soft photons available for cooling. Wolf-Rayet supernovae that explode through a thick wind have a high flux of soft photons, producing a flat spectrum, νF {sub ν} = Const, in the X-ray range of 0.1 ≲ T ≲ 50 keV. As the shock expands into an optically thin wind, the soft photons are no longer able to cool the shock that plows through the wind, and the bulk of the emission takes the form of a standard core-collapse supernova (without a wind). However, a small fraction of the soft photons is upscattered by the shocked wind and produces a transient unique X-ray signature.

  3. Constraining absolute neutrino masses via detection of galactic supernova neutrinos at JUNO

    SciTech Connect

    Lu, Jia-Shu; Cao, Jun; Li, Yu-Feng; Zhou, Shun

    2015-05-26

    A high-statistics measurement of the neutrinos from a galactic core-collapse supernova is extremely important for understanding the explosion mechanism, and studying the intrinsic properties of neutrinos themselves. In this paper, we explore the possibility to constrain the absolute scale of neutrino masses m{sub ν} via the detection of galactic supernova neutrinos at the Jiangmen Underground Neutrino Observatory (JUNO) with a 20 kiloton liquid-scintillator detector. In assumption of a nearly-degenerate neutrino mass spectrum and a normal mass ordering, the upper bound on the absolute neutrino mass is found to be m{sub ν}<(0.83±0.24) eV at the 95% confidence level for a typical galactic supernova at a distance of 10 kpc, where the mean value and standard deviation are shown to account for statistical fluctuations. For comparison, we find that the bound in the Super-Kamiokande experiment is m{sub ν}<(0.94±0.28) eV at the same confidence level. However, the upper bound will be relaxed when the model parameters characterizing the time structure of supernova neutrino fluxes are not exactly known, and when the neutrino mass ordering is inverted.

  4. Measurements of the Rate of Type Ia Supernovae at Redshift z < ~0.3 from the SDSS-II Supernova Survey

    SciTech Connect

    Dilday, Benjamin; Smith, Mathew; Bassett, Bruce; Becker, Andrew; Bender, Ralf; Castander, Francisco; Cinabro, David; Filippenko, Alexei V.; Frieman, Joshua A.; Galbany, Lluis; Garnavich, Peter M.; /Notre Dame U. /Stockholm U., OKC /Stockholm U.

    2010-01-01

    We present a measurement of the volumetric Type Ia supernova (SN Ia) rate based on data from the Sloan Digital Sky Survey II (SDSS-II) Supernova Survey. The adopted sample of supernovae (SNe) includes 516 SNe Ia at redshift z {approx}< 0.3, of which 270 (52%) are spectroscopically identified as SNe Ia. The remaining 246 SNe Ia were identified through their light curves; 113 of these objects have spectroscopic redshifts from spectra of their host galaxy, and 133 have photometric redshifts estimated from the SN light curves. Based on consideration of 87 spectroscopically confirmed non-Ia SNe discovered by the SDSS-II SN Survey, we estimate that 2.04{sub -0.95}{sup +1.61}% of the photometric SNe Ia may be misidentified. The sample of SNe Ia used in this measurement represents an order of magnitude increase in the statistics for SN Ia rate measurements in the redshift range covered by the SDSS-II Supernova Survey. If we assume a SN Ia rate that is constant at low redshift (z < 0.15), then the SN observations can be used to infer a value of the SN rate of r{sub V} = (2.69{sub -0.30-0.01}{sup +0.34+0.21}) x 10{sup -5} SNe yr{sup -1} Mpc{sup -3} (H{sub 0}/(70 km s{sup -1} Mpc{sup -1})){sup 3} at a mean redshift of {approx} 0.12, based on 79 SNe Ia of which 72 are spectroscopically confirmed. However, the large sample of SNe Ia included in this study allows us to place constraints on the redshift dependence of the SN Ia rate based on the SDSS-II Supernova Survey data alone. Fitting a power-law model of the SN rate evolution, r{sub V} (z) = A{sub p} x ((1+z)/(1+z{sub 0})){sup {nu}}, over the redshift range 0.0 < z < 0.3 with z{sub 0} = 0.21, results in A{sub p} = (3.43{sub -0.15}{sup +0.15}) x 10{sup -5} SNe yr{sup -1} Mpc{sup -3} (H{sub 0}/(70 km s{sup -1} Mpc{sup -1})){sup 3} and {nu} = 2.04{sub -0.89}{sup +0.90}.

  5. Radio observations reveal a smooth circumstellar environment around the extraordinary type Ib supernova 2012au

    SciTech Connect

    Kamble, Atish; Soderberg, Alicia M.; Margutti, Raffaella; Milisavljevic, Dan; Chakraborti, Sayan; Dittmann, Jason; Drout, Maria; Sanders, Nathan; Chomiuk, Laura; Medvedev, Mikhail; Chevalier, Roger; Chugai, Nikolai; Fransson, Claes; Nakar, Ehud

    2014-12-10

    We present extensive radio and X-ray observations of SN 2012au, an energetic, radio-luminous supernova of Type Ib that exhibits multi-wavelength properties bridging subsets of hydrogen-poor superluminous supernovae, hypernovae, and normal core-collapse supernovae. The observations closely follow models of synchrotron emission from a shock-heated circumburst medium that has a wind density profile (??r {sup 2}). We infer a sub-relativistic velocity for the shock wave v ? 0.2 c and a radius of r ? 1.4 10{sup 16}cm at 25 days after the estimated date of explosion. For a wind velocity of 1000 km s{sup 1}, we determine the mass-loss rate of the progenitor to be M-dot =3.610{sup ?6} M{sub ?} yr{sup ?1}, consistent with the estimates from X-ray observations. We estimate the total internal energy of the radio-emitting material to be E ? 10{sup 47} erg, which is intermediate to SN 1998bw and SN 2002ap. The evolution of the radio light curve of SN 2012au is in agreement with its interaction with a smoothly distributed circumburst medium and the absence of stellar shells ejected from previous outbursts out to r ? 10{sup 17} cm from the supernova site. We conclude that the bright radio emission from SN 2012au was not dissimilar from other core-collapse supernovae despite its extraordinary optical properties, and that the evolution of the SN 2012au progenitor star was relatively quiet, marked with a steady mass loss, during the final years preceding explosion.

  6. Characterizing the V-band light-curves of hydrogen-rich type II supernovae

    SciTech Connect

    Anderson, Joseph P.; González-Gaitán, Santiago; Hamuy, Mario; Gutiérrez, Claudia P.; Antezana, Roberto; De Jaeger, Thomas; Förster, Francisco; González, Luis; Stritzinger, Maximilian D.; Contreras, Carlos; Olivares E, Felipe; Phillips, Mark M.; Campillay, Abdo; Castellón, Sergio; Hsiao, Eric; Schulze, Steve; Bolt, Luis; Folatelli, Gastón; Freedman, Wendy L.; Krzemiński, Wojtek; and others

    2014-05-01

    We present an analysis of the diversity of V-band light-curves of hydrogen-rich type II supernovae. Analyzing a sample of 116 supernovae, several magnitude measurements are defined, together with decline rates at different epochs, and time durations of different phases. It is found that magnitudes measured at maximum light correlate more strongly with decline rates than those measured at other epochs: brighter supernovae at maximum generally have faster declining light-curves at all epochs. We find a relation between the decline rate during the 'plateau' phase and peak magnitudes, which has a dispersion of 0.56 mag, offering the prospect of using type II supernovae as purely photometric distance indicators. Our analysis suggests that the type II population spans a continuum from low-luminosity events which have flat light-curves during the 'plateau' stage, through to the brightest events which decline much faster. A large range in optically thick phase durations is observed, implying a range in progenitor envelope masses at the epoch of explosion. During the radioactive tails, we find many supernovae with faster declining light-curves than expected from full trapping of radioactive emission, implying low mass ejecta. It is suggested that the main driver of light-curve diversity is the extent of hydrogen envelopes retained before explosion. Finally, a new classification scheme is introduced where hydrogen-rich events are typed as simply 'SN II' with an 's {sub 2}' value giving the decline rate during the 'plateau' phase, indicating its morphological type.

  7. FAINT POPULATION III SUPERNOVAE AS THE ORIGIN OF THE MOST IRON-POOR STARS

    SciTech Connect

    Ishigaki, Miho N.; Tominaga, Nozomu; Kobayashi, Chiaki; Nomoto, Ken'ichi, E-mail: miho.ishigaki@ipmu.jp [Kavli Institute for the Physics and Mathematics of the Universe (WPI), The University of Tokyo, Kashiwa, Chiba 277-8583 (Japan)

    2014-09-10

    The most iron-poor stars in the Milky Way provide important observational clues to the astrophysical objects that enriched the primordial gas with heavy elements. Among them, the recently discovered iron-deficient star SMSS J031300.36670839.3 shows a remarkable chemical composition with a non-detection of iron ([Fe/H] <7.1) and large enhancement of carbon and magnesium relative to calcium. We investigate supernova yields of metal-free (Population III) stars to interpret the abundance pattern observed in this star. We report that the high [C/Ca] and [C/Mg] ratios and upper limits of other elemental abundances are well reproduced with the yields of core-collapse supernovae (which have normal kinetic energies of explosion E of E {sub 51} = E/10{sup 51}erg=1) and hypernovae (E {sub 51} ? 10) of Population III 25 M {sub ?} or 40 M {sub ?} stars. The best-fit models assume that the explosions undergo extensive matter mixing and fallback, leaving behind a black hole remnant. In these models, Ca is produced by static/explosive O burning and incomplete Si burning in the Population III supernova/hypernova, in contrast to the suggestion that Ca is originated from the hot-CNO cycle during pre-supernova evolution. Chemical abundances of four carbon-rich iron-poor stars with [Fe/H] <4.5, including SMSS J031300.36670839.3, are consistently explained by faint supernova models with ejected masses of {sup 56}Ni less than 10{sup 3} M {sub ?}.

  8. Ostrogradski approach for the Regge-Teitelboim type cosmology

    SciTech Connect

    Cordero, Ruben; Molgado, Alberto; Rojas, Efrain

    2009-01-15

    We present an alternative geometric inspired derivation of the quantum cosmology arising from a brane universe in the context of geodetic gravity. We set up the Regge-Teitelboim model to describe our universe, and we recover its original dynamics by thinking of such field theory as a second-order derivative theory. We refer to an Ostrogradski Hamiltonian formalism to prepare the system to its quantization. Our analysis highlights the second-order derivative nature of the RT model and the inherited geometrical aspect of the theory. A canonical transformation brings us to the internal physical geometry of the theory and induces its quantization straightforwardly. By using the Dirac canonical quantization method our approach comprises the management of both first- and second-class constraints where the counting of degrees of freedom follows accordingly. At the quantum level our Wheeler-De Witt equation agrees with previous results recently found. On these lines, we also comment upon the compatibility of our approach with the Hamiltonian approach proposed by Davidson and coworkers.

  9. Observational constraints on electromagnetic Born-Infeld cosmology

    SciTech Connect

    Bretón, Nora; Montiel, Ariadna; Lazkoz, Ruth E-mail: amontiel@fis.cinvestav.mx

    2012-10-01

    The cosmological model consisting of an electromagnetic Born-Infeld (BI) field coupled to a Robertson-Walker geometry is tested with the standard probes of SNIa, GRBs and direct Hubble parameter. The analysis shows that the inclusion of the nonlinear electromagnetic component does not contribute in a significative way to the observed expansion. The BI electromagnetic matter is considered with an abundance of Ω{sub BI}, that our best fit leads to Ω{sub BI} = 0.037 when tested with SNIa and the Hubble parameter data (0.1 < z < 1.75); while when tested with GRBs the result is of Ω{sub BI} = 0.304, which may indicate that this electrodynamics was important at epochs close to the appearance of large structure (z ≈ 7), although this late result has not as much reliability as that corresponding to the first two probes, since we know that the dispersion in GRBs data is still considerable. In view of these results we can rule out the electromagnetic Born-Infeld matter as the origin of the present accelerated expansion, this conclusion concerns exclusively the Born-Infeld theory.

  10. Accuracy of cosmological parameters using the baryon acoustic scale

    SciTech Connect

    Thepsuriya, Kiattisak; Lewis, Antony E-mail: antony@cosmologist.info

    2015-01-01

    Percent-level measurements of the comoving baryon acoustic scale standard ruler can be used to break degeneracies in parameter constraints from the CMB alone. The sound horizon at the epoch of baryon drag is often used as a proxy for the scale of the peak in the matter density correlation function, and can conveniently be calculated quickly for different cosmological models. However, the measurements are not directly constraining this scale, but rather a measurement of the full correlation function, which depends on the detailed evolution through decoupling. We assess the level of reliability of parameter constraints based on a simple approximation of the acoustic scale compared to a more direct determination from the full numerical two-point correlation function. Using a five-parameter fitting technique similar to recent BAO data analyses, we find that for standard ΛCDM models and extensions with massive neutrinos and additional relativistic degrees of freedom, the approximation is at better than 0.15% for most parameter combinations varying over reasonable ranges.

  11. Cosmological information in the intrinsic alignments of luminous red galaxies

    SciTech Connect

    Chisari, Nora Elisa; Dvorkin, Cora E-mail: cdvorkin@ias.edu

    2013-12-01

    The intrinsic alignments of galaxies are usually regarded as a contaminant to weak gravitational lensing observables. The alignment of Luminous Red Galaxies, detected unambiguously in observations from the Sloan Digital Sky Survey, can be reproduced by the linear tidal alignment model of Catelan, Kamionkowski and Blandford (2001) on large scales. In this work, we explore the cosmological information encoded in the intrinsic alignments of red galaxies. We make forecasts for the ability of current and future spectroscopic surveys to constrain local primordial non-Gaussianity and Baryon Acoustic Oscillations (BAO) in the cross-correlation function of intrinsic alignments and the galaxy density field. For the Baryon Oscillation Spectroscopic Survey, we find that the BAO signal in the intrinsic alignments is marginally significant with a signal-to-noise ratio of 1.8 and 2.2 with the current LOWZ and CMASS samples of galaxies, respectively, and increasing to 2.3 and 2.7 once the survey is completed. For the Dark Energy Spectroscopic Instrument and for a spectroscopic survey following the EUCLID redshift selection function, we find signal-to-noise ratios of 12 and 15, respectively. Local type primordial non-Gaussianity, parametrized by f{sub NL} = 10, is only marginally significant in the intrinsic alignments signal with signal-to-noise ratios < 2 for the three surveys considered.

  12. Cosmological perturbation in f(T) gravity revisited

    SciTech Connect

    Izumi, Keisuke; Ong, Yen Chin E-mail: ongyenchin@member.ams.org

    2013-06-01

    We perform detailed investigation of cosmological perturbations in f(T) theory of gravity coupled with scalar field. Our work emphasizes on the way to gauge fix the theory and we examine all possible modes of perturbations up to second order. The analysis includes pseudoscalar and pseudovector modes in addition to the usual scalar, vector, and tensor modes. We find no gravitational propagating degree of freedom in the scalar, pseudoscalar, vector, as well as pseudovector modes. In addition, we find that the scalar and tensor perturbations have exactly the same form as their counterparts in usual general relativity with scalar field, except that the factor of reduced Planck mass squared M{sub pl}{sup 2}?1/(8?G) that occurs in the latter has now been replaced by an effective time-dependent gravitational coupling ?2(df/dT)|{sub T=T{sub 0}}, with T{sub 0} being the background torsion scalar. The absence of extra degrees of freedom of f(T) gravity at second order linear perturbation indicates that f(T) gravity is highly nonlinear. Consequently one cannot conclusively analyze stability of the theory without performing nonlinear analysis that can reveal the propagation of the extra degrees of freedom.

  13. Halo model and halo properties in Galileon gravity cosmologies

    SciTech Connect

    Barreira, Alexandre; Li, Baojiu; Hellwing, Wojciech A.; Baugh, Carlton M.; Lombriser, Lucas; Pascoli, Silvia E-mail: baojiu.li@durham.ac.uk E-mail: llo@roe.ac.uk E-mail: silvia.pascoli@durham.ac.uk

    2014-04-01

    We investigate the performance of semi-analytical modelling of large-scale structure in Galileon gravity cosmologies using results from N-body simulations. We focus on the Cubic and Quartic Galileon models that provide a reasonable fit to CMB, SNIa and BAO data. We demonstrate that the Sheth-Tormen mass function and linear halo bias can be calibrated to provide a very good fit to our simulation results. We also find that the halo concentration-mass relation is well fitted by a power law. The nonlinear matter power spectrum computed in the halo model approach is found to be inaccurate in the mildly nonlinear regime, but captures reasonably well the effects of the Vainshtein screening mechanism on small scales. In the Cubic model, the screening mechanism hides essentially all of the effects of the fifth force inside haloes. In the case of the Quartic model, the screening mechanism leaves behind residual modifications to gravity, which make the effective gravitational strength time-varying and smaller than the standard value. Compared to normal gravity, this causes a deficiency of massive haloes and leads to a weaker matter clustering on small scales. For both models, we show that there are realistic halo occupation distributions of Luminous Red Galaxies that can match both the observed large-scale clustering amplitude and the number density of these galaxies.

  14. Dirac fields, torsion and Barbero-Immirzi parameter in cosmology

    SciTech Connect

    Berredo-Peixoto, G. de; Shapiro, I.L.; Souza, C.A. de; Freidel, L. E-mail: lfreidel@perimeterinstitute.ca E-mail: abrahaocleber@gmail.com

    2012-06-01

    We consider cosmological solution for Einstein gravity with massive fermions with a four-fermion coupling, which emerges from the Holst action and is related to the Barbero-Immirzi (BI) parameter. This gravitational action is an important object of investigation in a non-perturbative formalism of quantum gravity. We study the equation of motion for the Dirac field within the standard Friedman-Robertson-Walker (FRW) metric. Finally, we show the theory with BI parameter and minimally coupling Dirac field, in the zero mass limit, is equivalent to an additional term which looks like a perfect fluid with the equation of state p = wρ, with w = 1 which is independent of the BI parameter. The existence of mass imposes a variable w, which creates either an inflationary phase with w = −1, or assumes an ultra hard equation of states w = 1 for very early universe. Both phases relax to a pressure less fluid w = 0 for late universe (corresponding to the limit m → ∞)

  15. Sterile neutrinos with secret interactions — lasting friendship with cosmology

    SciTech Connect

    Chu, Xiaoyong; Dasgupta, Basudeb; Kopp, Joachim

    2015-10-06

    Sterile neutrinos with mass ≃1 eV and order 10% mixing with active neutrinos have been proposed as a solution to anomalies in neutrino oscillation data, but are tightly constrained by cosmological limits. It was recently shown that these constraints are avoided if sterile neutrinos couple to a new MeV-scale gauge boson A{sup ′}. However, even this scenario is restricted by structure formation constraints when A{sup ′}-mediated collisional processes lead to efficient active-to-sterile neutrino conversion after neutrinos have decoupled. In view of this, we reevaluate in this paper the viability of sterile neutrinos with such “secret” interactions. We carefully dissect their evolution in the early Universe, including the various production channels and the expected modifications to large scale structure formation. We argue that there are two regions in parameter space — one at very small A{sup ′} coupling, one at relatively large A{sup ′} coupling — where all constraints from big bang nucleosynthesis (BBN), cosmic microwave background (CMB), and large scale structure (LSS) data are satisfied. Interestingly, the large A{sup ′} coupling region is precisely the region that was previously shown to have potentially important consequences for the small scale structure of dark matter halos if the A{sup ′} boson couples also to the dark matter in the Universe.

  16. Search for: All records | SciTech Connect

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    and robust image subtraction to find supernovae automatically and in near real-time. Since making cosmological inferences with supernovae relies crucially on accurate...

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    PHYSICS; ACCURACY; COLOR; COSMOLOGICAL CONSTANT; LUMINOSITY; PHOTOMETRY; SHAPE; SUPERNOVAE Astrophysics,ASTRO",,"We combine the CfA3 supernovae Type Ia (SN Ia) sample with...

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    Systematic Effects in Type a Supernovae Surveys from Host Galaxy Spectra Strauss Michael A Princeton University ASTRONOMY AND ASTROPHYSICS Cosmology supernovae stellar populations...

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    Report: Discovering the Nature of Dark Energy: Towards Better Distances from Type Ia Supernovae Saurabh W. Jha 79 ASTRONOMY AND ASTROPHYSICS dark energy; supernovae; cosmology dark...

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    Report Discovering the Nature of Dark Energy Towards Better Distances from Type Ia Supernovae Saurabh W Jha ASTRONOMY AND ASTROPHYSICS dark energy supernovae cosmology dark...

  1. XMM-NEWTON OBSERVATIONS OF TWO CANDIDATE SUPERNOVA REMNANTS

    SciTech Connect

    Kargaltsev, O.; Schmitt, B. M.; Pavlov, G. G.; Misanovic, Z.

    2012-01-20

    Candidate supernova remnants (SNRs) G23.5+0.1 and G25.5+0.0 were observed by XMM-Newton in the course of a snapshot survey of plerionic and composite SNRs in the Galactic plane. In the field of G23.5+0.1, we detected an extended source, {approx}3' in diameter, which we tentatively interpret as a pulsar wind nebula (PWN) of the middle-aged radio pulsar B1830-08 (J1833-0827; P = 85.3 ms, {tau} = 147 kyr, E-dot = 5.8 Multiplication-Sign 10{sup 35} erg s{sup -1}, d = 5.7 kpc), with the PWN luminosity L{sub 0.2-10keV} Almost-Equal-To 5 Multiplication-Sign 10{sup 33} erg s{sup -1} Almost-Equal-To 8 Multiplication-Sign 10{sup -3} E-dot . The pulsar is not resolved in the EPIC images. Our analysis suggests an association between PSR B1830-08 and the surrounding diffuse radio emission. If the radio emission is due to the SNR, then the pulsar must be significantly younger than its characteristic age. Alternatively, the radio emission may come from a relic PWN. The field also contains SGR 1833-0832 and another middle-aged pulsar B1829-08 (J1832-0827; P = 647 ms, {tau} = 161 kyr, E-dot = 9.3 Multiplication-Sign 10{sup 33} erg s{sup -1}, d = 4.7 kpc), none of which are detected in our observation. In the field of G25.5+0.0, which contains the extended TeV source HESS J1837-069, we detected the recently discovered young high-energy pulsar J1838-0655 (P = 70.5 ms, {tau} = 23 kyr, E-dot = 5.5 Multiplication-Sign 10{sup 36} erg s{sup -1}) embedded in a PWN with extent of 1.'3. The unabsorbed pulsar + PWN luminosity is L{sub 2-11keV} Almost-Equal-To 2 Multiplication-Sign 10{sup 34} erg s{sup -1} Almost-Equal-To 4 Multiplication-Sign 10{sup -3} E-dot at an assumed distance of 7 kpc. We also detected another PWN candidate (AX J1837.3-0652) with an extent of 2' and unabsorbed luminosity L{sub 2-10keV} Almost-Equal-To 4 Multiplication-Sign 10{sup 33} erg s{sup -1} at d = 7 kpc. The third X-ray source, located within the extent of the HESS J1837-069, has a peculiar extended radio

  2. TEC Working Group Topic Groups Archives

    Energy.gov [DOE]

    The following Topic Groups are no longer active; however, related documents and notes for these archived Topic Groups are available through the following links:

  3. SWIFT/BAT DETECTION OF HARD X-RAYS FROM TYCHO'S SUPERNOVA REMNANT: EVIDENCE FOR TITANIUM-44

    SciTech Connect

    Troja, E.; Baumgartner, W.; Markwardt, C.; Barthelmy, S.; Gehrels, N.; Segreto, A.; La Parola, V.; Cusumano, G.; Hartmann, D.

    2014-12-10

    We report Swift/Burst Alert Telescope survey observations of the Tycho's supernova remnant, performed over a period of 104 months since the mission's launch. The remnant is detected with high significance (>10σ) below 50 keV. We detect significant hard X-ray emission in the 60-85 keV band, above the continuum level predicted by a simple synchrotron model. The location of the observed excess is consistent with line emission from radioactive titanium-44, so far reported only for Type II supernova explosions. We discuss the implications of these results in the context of the galactic supernova rate, and nucleosynthesis in Type Ia supernova.

  4. Luminosity distance in 'Swiss cheese' cosmology with randomized voids. I. Single void size

    SciTech Connect

    Vanderveld, R. Ali; Flanagan, Eanna E.; Wasserman, Ira

    2008-10-15

    Recently, there have been suggestions that the Type Ia supernova data can be explained using only general relativity and cold dark matter with no dark energy. In 'Swiss cheese' models of the Universe, the standard Friedmann-Robertson-Walker picture is modified by the introduction of mass-compensating spherical inhomogeneities, typically described by the Lemaitre-Tolman-Bondi metric. If these inhomogeneities correspond to underdense cores surrounded by mass-compensating overdense shells, then they can modify the luminosity distance-redshift relation in a way that can mimic accelerated expansion. It has been argued that this effect could be large enough to explain the supernova data without introducing dark energy or modified gravity. We show that the large apparent acceleration seen in some models can be explained in terms of standard weak field gravitational lensing together with insufficient randomization of void locations. The underdense regions focus the light less than the homogeneous background, thus dimming supernovae in a way that can mimic the effects of acceleration. With insufficient randomization of the spatial location of the voids and of the lines of sight, coherent defocusing can lead to anomalously large demagnification effects. We show that a proper randomization of the voids and lines of sight reduces the effect to the point that it can no longer explain the supernova data.

  5. Multi-Scale Initial Conditions For Cosmological Simulations

    SciTech Connect

    Hahn, Oliver; Abel, Tom; /KIPAC, Menlo Park /ZAH, Heidelberg /HITS, Heidelberg

    2011-11-04

    We discuss a new algorithm to generate multi-scale initial conditions with multiple levels of refinements for cosmological 'zoom-in' simulations. The method uses an adaptive convolution of Gaussian white noise with a real-space transfer function kernel together with an adaptive multi-grid Poisson solver to generate displacements and velocities following first- (1LPT) or second-order Lagrangian perturbation theory (2LPT). The new algorithm achieves rms relative errors of the order of 10{sup -4} for displacements and velocities in the refinement region and thus improves in terms of errors by about two orders of magnitude over previous approaches. In addition, errors are localized at coarse-fine boundaries and do not suffer from Fourier-space-induced interference ringing. An optional hybrid multi-grid and Fast Fourier Transform (FFT) based scheme is introduced which has identical Fourier-space behaviour as traditional approaches. Using a suite of re-simulations of a galaxy cluster halo our real-space-based approach is found to reproduce correlation functions, density profiles, key halo properties and subhalo abundances with per cent level accuracy. Finally, we generalize our approach for two-component baryon and dark-matter simulations and demonstrate that the power spectrum evolution is in excellent agreement with linear perturbation theory. For initial baryon density fields, it is suggested to use the local Lagrangian approximation in order to generate a density field for mesh-based codes that is consistent with the Lagrangian perturbation theory instead of the current practice of using the Eulerian linearly scaled densities.

  6. Toward the inflationary paradigm: Lectures on inflationary cosmology

    SciTech Connect

    Turner, M.S.

    1987-02-01

    Guth's inflationary Universe scenario has revolutionized our thinking about the very early Universe. The inflationary scenario offers the possibility of explaining a handful of very fundamental cosmological facts - the homogeneity, isotropy, and flatness of the Universe, the origin of density inhomogeneities and the origin of the baryon asymmetry, while at the same time avoiding the monopole problem. It is based upon microphysical events which occurred early (t less than or equal to 10/sup -34/ sec) in the history of the Universe, but well after the planck epoc (t greater than or equal to 10/sup -43/ sec). While Guth's original model was fundamentally flawed, the variant based on the slow-rollover transition proposed by Linde, and Albrecht and Steinhardt (dubbed 'new inflation') appears viable. Although old inflation and the earliest models of new inflation were based upon first order phase transitions associated with spontaneous-symmetry breaking (SSB), it now appears that the inflationary transition is a much more generic phenomenon, being associated with the evolution of a weakly-coupled scalar field which for some reason or other was initially displaced from the minimum of its potential. Models now exist which are based on a wide variety of microphysics: SSB, SUSY/SUGR, compactification of extra dimensions, R/sup 2/ gravity, induced gravity, and some random, weakly-coupled scalar field. While there are several models which successfully implement the inflation, none is particularly compelling and all seem somewhat ad hoc. The common distasteful feature of all the successful models is the necessity of a small dimensionless number in the model - usually in the form of a dimensionless coupling of order 10/sup -15/. All inflationary scenarios rely upon the assumption that vacuum energy was once dynamically very significant, whereas today there exists every evidence that it is not. 133 refs., 17 figs.

  7. Dark matter relic density in Gauss-Bonnet braneworld cosmology

    SciTech Connect

    Meehan, Michael T.; Whittingham, Ian B., E-mail: Michael.Meehan@my.jcu.edu.au, E-mail: Ian.Whittingham@jcu.edu.au [College of Science, Technology and Engineering, James Cook University, 1 James Cook Dr., Townsville 4811 (Australia)

    2014-12-01

    The relic density of symmetric and asymmetric dark matter in a Gauss-Bonnet (GB) modified Randall-Sundrum (RS) type II braneworld cosmology is investigated. The existing study of symmetric dark matter in a GB braneworld (Okada and Okada, 2009) found that the expansion rate was reduced compared to that in standard General Relativity (GR), thereby delaying particle freeze-out and resulting in relic abundances which are suppressed by up to O(10{sup ?2}). This is in direct contrast to the behaviour observed in RS braneworlds where the expansion rate is enhanced and the final relic abundance boosted. However, this finding that relic abundances are suppressed in a GB braneworld is based upon a highly contrived situation in which the GB era evolves directly into a standard GR era, rather than passing through a RS era as is the general situation. This collapse of the RS era requires equating the mass scale m{sub ?} of the GB modification and the mass scale m{sub ?} of the brane tension. However, if the GB contribution is to be considered as the lowest order correction from string theory to the RS action, we would expect m{sub ?} > m{sub ?}. We investigate the effect upon the relic abundance of choosing more realistic values for the ratio R{sub m} ? m{sub ?}/m{sub ?} and find that the relic abundance can be either enhanced or suppressed by more than two orders of magnitude. However, suppression only occurs for a small range of parameter choices and, overwhelmingly, the predominant situation is that of enhancement as we recover the usual Randall-Sundrum type behaviour in the limit R{sub m} >> 1. We use the latest observational bound ?{sub DM}h{sup 2}=0.11870.0017 to constrain the various model parameters and briefly discuss the implications for direct/indirect dark matter detection experiments as well as dark matter particle models.

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

    SciTech Connect

    More, Surhud

    2013-11-10

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

  9. LOW-RESOLUTION SPECTROSCOPY FOR THE GLOBULAR CLUSTERS WITH SIGNS OF SUPERNOVA ENRICHMENT: M22, NGC 1851, AND NGC 288

    SciTech Connect

    Lim, Dongwook; Han, Sang-Il; Lee, Young-Wook; Roh, Dong-Goo; Sohn, Young-Jong; Chun, Sang-Hyun; Lee, Jae-Woo; Johnson, Christian I.

    2015-01-01

    There is increasing evidence for the presence of multiple red giant branches (RGBs) in the color-magnitude diagrams of massive globular clusters (GCs). In order to investigate the origin of this split on the RGB, we have performed new narrow-band Ca photometry and low-resolution spectroscopy for M22, NGC 1851, and NGC 288. We find significant differences (more than 4σ) in calcium abundance from the spectroscopic HK' index for M22 and NGC 1851. We also find more than 8σ differences in CN-band strength between the Ca-strong and Ca-weak subpopulations for these GCs. For NGC 288, however, a large difference is detected only in the CN strength. The calcium abundances of RGB stars in this GC are identical to within the errors. This is consistent with the conclusion from our new Ca photometry where the RGB splits are confirmed in M22 and NGC 1851, but not in NGC 288. We also find interesting differences in the CN-CH correlations among these GCs. While CN and CH are anti-correlated in NGC 288, they show a positive correlation in M22. NGC 1851, however, shows no difference in CH between the two groups of stars with different CN strengths. We suggest that all of these systematic differences would be best explained by how strongly Type II supernovae enrichment has contributed to the chemical evolution of these GCs.

  10. Supernova constraints on neutrino oscillation and EoS for proto-neutron star

    SciTech Connect

    Kajino, T.; Aoki, W.; Cheoun, M.-K.; Hayakawa, T.; Hidaka, J.; Hirai, Y.; Shibagaki, S.; Mathews, G. J.; Nakamura, K.; Suzuki, T.

    2014-05-02

    Core-collapse supernovae eject huge amount of flux of energetic neutrinos which affect explosive nucleosynthesis of rare isotopes like {sup 7}Li, {sup 11}B, {sup 92}Nb, {sup 138}La and Ta and r-process elements. Several isotopes depend strongly on the neutrino flavor oscillation due to the Mikheyev-Smirnov-Wolfenstein (MSW) effect. We here discuss how to determine the neutrino temperatures and propose a method to determine still unknown neutrino oscillation parameters, mass hierarchy and ?{sub 13}, simultaneously. Combining the recent experimental constraints on ?{sub 13} with isotopic ratios of the light elements discovered in presolar grains from the Murchison meteorite, we show that our method suggests at a marginal preference for an inverted neutrino mass hierarchy. We also discuss supernova relic neutrinos that may indicate the softness of the equation of state (EoS) of nuclear matter as well as adiabatic conditions of the neutrino oscillation.

  11. A HIGH-RESOLUTION SPECTROSCOPIC SEARCH FOR THE REMAINING DONOR FOR TYCHO'S SUPERNOVA

    SciTech Connect

    Kerzendorf, Wolfgang E.; Yong, David; Schmidt, Brian P.; Murphy, Simon J.; Bessell, Michael S.; Simon, Joshua D.; Jeffery, C. Simon; Anderson, Jay; Podsiadlowski, Philipp; Gal-Yam, Avishay; Silverman, Jeffrey M.; Filippenko, Alexei V.; Nomoto, Ken'ichi; Venn, Kim A.; Foley, Ryan J.

    2013-09-10

    In this paper, we report on our analysis using Hubble Space Telescope astrometry and Keck-I HIRES spectroscopy of the central six stars of Tycho's supernova remnant (SN 1572). With these data, we measured the proper motions, radial velocities, rotational velocities, and chemical abundances of these objects. Regarding the chemical abundances, we do not confirm the unusually high [Ni/Fe] ratio previously reported for Tycho-G. Rather, we find that for all metrics in all stars, none exhibit the characteristics expected from traditional Type Ia supernova single-degenerate-scenario calculations. The only possible exception is Tycho-B, a rare, metal-poor A-type star; however, we are unable to find a suitable scenario for it. Thus, we suggest that SN 1572 cannot be explained by the standard single-degenerate model.

  12. Near-infrared line identification in type Ia supernovae during the transitional phase

    SciTech Connect

    Friesen, Brian; Baron, E.; Wisniewski, John P.; Miller, Timothy R.; Parrent, Jerod T.; Thomas, R. C.; Marion, G. H.

    2014-09-10

    We present near-infrared synthetic spectra of a delayed-detonation hydrodynamical model and compare them to observed spectra of four normal Type Ia supernovae ranging from day +56.5 to day +85. This is the epoch during which supernovae are believed to be undergoing the transition from the photospheric phase, where spectra are characterized by line scattering above an optically thick photosphere, to the nebular phase, where spectra consist of optically thin emission from forbidden lines. We find that most spectral features in the near-infrared can be accounted for by permitted lines of Fe II and Co II. In addition, we find that [Ni II] fits the emission feature near 1.98 μm, suggesting that a substantial mass of {sup 58}Ni exists near the center of the ejecta in these objects, arising from nuclear burning at high density.

  13. Supernovae, Dark Energy and the Accelerating Universe: How DOE Helped to Win (yet another) Nobel Prize

    SciTech Connect

    Perlmutter, Saul

    2012-01-13

    The Department of Energy (DOE) hosted an event Friday, January 13, with 2011 Physics Nobel Laureate Saul Perlmutter. Dr. Perlmutter, a physicist at the Departments Lawrence Berkeley National Laboratory and a professor of physics at the University of California at Berkeley, won the 2011 Nobel Prize in Physics for the discovery of the accelerating expansion of the Universe through observations of distant supernovae. DOEs Office of Science has supported Dr. Perlmutters research at Berkeley Lab since 1983. After the introduction from Secretary of Energy Steven Chu, Dr. Perlmutter delivered a presentation entitled "Supernovae, Dark Energy and the Accelerating Universe: How DOE Helped to Win (yet another) Nobel Prize." [Copied with editing from DOE Media Advisory issued January 10th, found at http://energy.gov/articles/energy-department-host-event-2011-physics-nobel-laureate-saul-perlmutter

  14. Supernovae, Dark Energy and the Accelerating Universe: How DOE Helped to Win (yet another) Nobel Prize

    ScienceCinema

    Perlmutter, Saul

    2012-01-13

    The Department of Energy (DOE) hosted an event Friday, January 13, with 2011 Physics Nobel Laureate Saul Perlmutter. Dr. Perlmutter, a physicist at the Department?s Lawrence Berkeley National Laboratory and a professor of physics at the University of California at Berkeley, won the 2011 Nobel Prize in Physics ?for the discovery of the accelerating expansion of the Universe through observations of distant supernovae.? DOE?s Office of Science has supported Dr. Perlmutter?s research at Berkeley Lab since 1983. After the introduction from Secretary of Energy Steven Chu, Dr. Perlmutter delivered a presentation entitled "Supernovae, Dark Energy and the Accelerating Universe: How DOE Helped to Win (yet another) Nobel Prize." [Copied with editing from DOE Media Advisory issued January 10th, found at http://energy.gov/articles/energy-department-host-event-2011-physics-nobel-laureate-saul-perlmutter

  15. Cosmological perturbations during the Bose-Einstein condensation of dark matter

    SciTech Connect

    Freitas, R.C.; Gonçalves, S.V.B. E-mail: sergio.vitorino@pq.cnpq.br

    2013-04-01

    In the present work, we analyze the evolution of the scalar and tensorial perturbations and the quantities relevant for the physical description of the Universe, as the density contrast of the scalar perturbations and the gravitational waves energy density during the Bose-Einstein condensation of dark matter. The behavior of these parameters during the Bose-Einstein phase transition of dark matter is analyzed in details. To study the cosmological dynamics and evolution of scalar and tensorial perturbations in a Universe with and without cosmological constant we use both analytical and numerical methods. The Bose-Einstein phase transition modifies the evolution of gravitational waves of cosmological origin, as well as the process of large-scale structure formation.

  16. Semiclassical states, effective dynamics, and classical emergence in loop quantum cosmology

    SciTech Connect

    Singh, Parampreet; Vandersloot, Kevin

    2005-10-15

    We construct physical semiclassical states annihilated by the Hamiltonian constraint operator in the framework of loop quantum cosmology as a method of systematically determining the regime and validity of the semiclassical limit of the quantum theory. Our results indicate that the evolution can be effectively described using continuous classical equations of motion with nonperturbative corrections down to near the Planck scale below which the Universe can only be described by the discrete quantum constraint. These results, for the first time, provide concrete evidence of the emergence of classicality in loop quantum cosmology and also clearly demarcate the domain of validity of different effective theories. We prove the validity of modified Friedmann dynamics incorporating discrete quantum geometry effects which can lead to various new phenomenological applications. Furthermore the understanding of semiclassical states allows for a framework for interpreting the quantum wave functions and understanding questions of a semiclassical nature within the quantum theory of loop quantum cosmology.

  17. Conversion of relic gravitational waves into photons in cosmological magnetic fields

    SciTech Connect

    Dolgov, Alexander D.; Ejlli, Damian E-mail: ejlli@fe.infn.it

    2012-12-01

    Conversion of gravitational waves into electromagnetic radiation is discussed. The probability of transformations of gravitons into photons in presence of cosmological background magnetic field is calculated at the recombination epoch and during subsequent cosmological stages. The produced electromagnetic radiation is concentrated in the X-ray part of the spectrum. It is shown that if the early Universe was dominated by primordial black holes (PBHs) prior to Big Bang Nucleosynthesis (BBN), the relic gravitons emitted by PBHs would transform to an almost isotropic background of electromagnetic radiation due to conversion of gravitons into photons in cosmological magnetic fields. Such extragalactic radiation could be noticeable or even dominant component of Cosmic X-ray Background.

  18. 2HOT: An Improved Parallel Hashed Oct-Tree N-Body Algorithm for Cosmological Simulation

    DOE PAGES [OSTI]

    Warren, Michael S.

    2014-01-01

    We report on improvements made over the past two decades to our adaptive treecode N-body method (HOT). A mathematical and computational approach to the cosmological N-body problem is described, with performance and scalability measured up to 256k (2 18 ) processors. We present error analysis and scientific application results from a series of more than ten 69 billion (4096 3 ) particle cosmological simulations, accounting for 4×10 20 floating point operations. These results include the first simulations using the new constraints on the standard model of cosmology from the Planck satellite. Our simulations set a new standard for accuracymore » and scientific throughput, while meeting or exceeding the computational efficiency of the latest generation of hybrid TreePM N-body methods.« less

  19. Constraining mass spectra with sterile neutrinos from neutrinoless double beta decay, tritium beta decay, and cosmology

    SciTech Connect

    Goswami, Srubabati [Harish-Chandra Research Institute, Chhatnag Road, Jhunsi, Allahabad 211 019 (India); Physik-Department, Technische Universitaet Muenchen, James-Franck-Strasse, D-85748 Garching (Germany); Rodejohann, Werner [Physik-Department, Technische Universitaet Muenchen, James-Franck-Strasse, D-85748 Garching (Germany)

    2006-06-01

    We analyze the constraints on neutrino mass spectra with extra sterile neutrinos as implied by the LSND experiment. The various mass related observables in neutrinoless double beta decay, tritium beta decay and cosmology are discussed. Both neutrino oscillation results as well as recent cosmological neutrino mass bounds are taken into account. We find that some of the allowed mass patterns are severely restricted by the current constraints, in particular, by the cosmological constraints on the total sum of neutrino masses and by the nonmaximality of the solar neutrino mixing angle. Furthermore, we estimate the form of the four neutrino mass matrices and also comment on the situation in scenarios with two additional sterile neutrinos.

  20. On the no-boundary proposal for ekpyrotic and cyclic cosmologies

    SciTech Connect

    Battarra, Lorenzo; Lehners, Jean-Luc, E-mail: lorenzo.battarra@aei.mpg.de, E-mail: jlehners@aei.mpg.de [Max-Planck-Institute for Gravitational Physics (Albert-Einstein-Institute), Am Muehlenberg 1, D-14476 Potsdam-Golm (Germany)

    2014-12-01

    The no-boundary proposal provides a compelling theory for the initial conditions of our universe. We study the implications of such initial conditions for ekpyrotic and cyclic cosmologies. These cosmologies allow for the existence of a new type of ''ekpyrotic instanton'', which describes the creation of a universe in the ekpyrotic contraction phase. Remarkably, we find that the ekpyrotic attractor can explain how the universe became classical. In a cyclic context, in addition to the ekpyrotic instantons there exist de Sitter-like instantons describing the emergence of the universe in the dark energy phase. Our results show that typically the ekpyrotic instantons yield a higher probability. In fact, in a potential energy landscape allowing both inflationary and cyclic cosmologies, the no-boundary proposal implies that the probability for ekpyrotic and cyclic initial conditions is vastly higher than that for inflationary ones.

  1. Critical study of type II supernovae: equations of state and general relativity

    SciTech Connect

    Kahana, S.

    1986-01-01

    The relevance of relativistic gravitation and of the properties of nuclear matter at high density to supernova explosions is examined in detail. The existing empirical knowledge on the nuclear equation of state at densities greater than saturation, extracted from analysis of heavy ion collisions and from the breathing mode in heavy nuclei, is also considered. Particulars of the prompt explosions recently obtained theoretically by Baron, Cooperstein, and Kahana are presented. 40 refs., 9 figs., 3 tabs.

  2. Multi-dimensional simulations of the expanding supernova remnant of SN 1987A

    SciTech Connect

    Potter, T. M.; Staveley-Smith, L. [International center for Radio Astronomy Research (ICRAR) M468, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009 (Australia); Reville, B. [Center for Plasma Physics, Queen's University Belfast, University Road, Belfast BT7 1NN (United Kingdom); Ng, C.-Y. [Department of Physics, The University of Hong Kong, Pokfulam Road (Hong Kong); Bicknell, G. V.; Sutherland, R. S. [Research School of Astronomy and Astrophysics, Australian National University, Canberra, ACT 0200 (Australia); Wagner, A. Y., E-mail: tobympotter@gmail.com [Center for Computational Sciences, Tsukuba University, Tsukuba, Ibaraki, 305-8577 (Japan)

    2014-10-20

    The expanding remnant from SN 1987A is an excellent laboratory for investigating the physics of supernovae explosions. There is still a large number of outstanding questions, such as the reason for the asymmetric radio morphology, the structure of the pre-supernova environment, and the efficiency of particle acceleration at the supernova shock. We explore these questions using three-dimensional simulations of the expanding remnant between days 820 and 10,000 after the supernova. We combine a hydrodynamical simulation with semi-analytic treatments of diffusive shock acceleration and magnetic field amplification to derive radio emission as part of an inverse problem. Simulations show that an asymmetric explosion, combined with magnetic field amplification at the expanding shock, is able to replicate the persistent one-sided radio morphology of the remnant. We use an asymmetric Truelove and McKee progenitor with an envelope mass of 10 M {sub ?} and an energy of 1.5 10{sup 44} J. A termination shock in the progenitor's stellar wind at a distance of 0.''43-0.''51 provides a good fit to the turn on of radio emission around day 1200. For the H II region, a minimum distance of 0.''63 0.''01 and maximum particle number density of (7.11 1.78) 10{sup 7} m{sup 3} produces a good fit to the evolving average radius and velocity of the expanding shocks from day 2000 to day 7000 after explosion. The model predicts a noticeable reduction, and possibly a temporary reversal, in the asymmetric radio morphology of the remnant after day 7000, when the forward shock left the eastern lobe of the equatorial ring.

  3. Research in nuclear astrophysics: Stellar collapse and supernovae. Performance reports, December 1, 1991--November 30, 1992

    SciTech Connect

    Lattimer, J.M.; Yahil, A.

    1992-07-01

    This progress report describes the nuclear astrophysics research activities in the Earth and Space Sciences Department at Stony Brook during the last year. Our research focused on three aspects of nuclear astrophysics: (1) the equation of state of hot, dense matter, (2) the origin of supernovae and neutron stars, (3) the early cooling epoch of neutron stars. The following contains detailed reports which summarize each completed project.

  4. I. Neutrino Oscillations with the MiniBooNE Experiment at FNAL...

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    Outline: Motivation: astrophysics and cosmology "Sterile" Neutrinos *Cosmology: o Dark matter o Baryogenisis o Dark energy *Core collapse supernova * Explosion processes * Heavy ...

  5. Abundances of presolar graphite and SiC from supernovae and AGB stars in the Murchison meteorite

    SciTech Connect

    Amari, Sachiko; Zinner, Ernst; Gallino, Roberto

    2014-05-02

    Pesolar graphite grains exhibit a range of densities (1.65 – 2.20 g/cm{sup 3}). We investigated abundances of presolar graphite grains formed in supernovae and in asymptotic giant branch (AGB) stars in the four density fractions KE3, KFA1, KFB1 and KFC1 extracted from the Murchison meteorite to probe dust productions in these stellar sources. Seventy-six and 50% of the grains in the low-density fractions KE3 and KFA1, respectively, are supernova grains, while only 7.2% and 0.9% of the grains in the high-density fractions KFB1 and KFC1 have a supernova origin. Grains of AGB star origin are concentrated in the high-density fractions KFB1 and KFC1. From the C isotopic distributions of these fractions and the presence of s-process Kr with {sup 86}Kr/{sup 82}Kr = 4.43±0.46 in KFC1, we estimate that 76% and 80% of the grains in KFB1 and KFC1, respectively, formed in AGB stars. From the abundance of graphite grains in the Murchison meteorite, 0.88 ppm, the abundances of graphite from supernovae and AGB stars are 0.24 ppm and 0.44 ppm, respectively: the abundances of graphite in supernovae and AGB stars are comparable. In contrast, it has been known that 1% of SiC grains formed in supernovae and 95% formed in AGB stars in meteorites. Since the abundance of SiC grains is 5.85 ppm in the Murchison meteorite, the abundances of SiC from supernovae and AGB stars are 0.063 ppm and 5.6 ppm, respectively: the dominant source of SiC grains is AGB stars. Since SiC grains are harder and likely to survive better in space than graphite grains, the abundance of supernova graphite grains, which is higher than that of supernova SiC grains, indicates that supernovae proficiently produce graphite grains. Graphite grains from AGB stars are, in contrast, less abundant that SiC grains from AGB stars (0.44 ppm vs. 5.6 ppm). It is difficult to derive firm conclusions for graphite and SiC formation in AGB stars due to the difference in susceptibility to grain destruction. Metallicity of

  6. The Sloan Digital Sky Survey-II Supernova Survey: Technical Summary

    SciTech Connect

    Frieman, Joshua A.; Bassett, Bruce; Becker, Andrew; Choi, Changsu; Cinabro, David; DeJongh, Don Frederic; Depoy, Darren L.; Doi, Mamoru; Garnavich, Peter M.; Hogan, Craig J.; Holtzman, Jon; Im, Myungshin; Jha, Saurabh; Konishi, Kohki; Lampeitl, Hubert; Marriner, John; Marshall, Jennifer L.; McGinnis, David; Miknaitis, Gajus; Nichol, Robert C.; Prieto, Jose Luis; /Ohio State U. /Rochester Inst. Tech. /Stanford U., Phys. Dept. /Pennsylvania U. /Penn State U., Astron. Astrophys. /Portsmouth U. /Tokyo U. /Tokyo U. /South African Astron. Observ. /Tokyo U. /Stanford U., Phys. Dept. /Fermilab /Fermilab /Ohio State U. /Stanford U., Phys. Dept. /Fermilab /Bristol U. /Apache Point Observ. /Liverpool John Moores U., ARI /Columbia U., CBA /Apache Point Observ. /Ohio State U. /Durham U. /Portsmouth U. /South African Astron. Observ. /Naval Academy, Annapolis /UC, Berkeley /UC, Berkeley /Ohio State U. /Stockholm U. /New Mexico State U. /Princeton U. Observ. /Tokyo U. /Washington U., Seattle, Astron. Dept. /Stanford U., Phys. Dept. /Jefferson Lab /Apache Point Observ. /Gottingen U. /Chicago U. /San Francisco State U. /DARK Cosmology Ctr. /Fermilab /Apache Point Observ. /Durham U. /Princeton U. Observ. /Apache Point Observ. /Apache Point Observ. /Apache Point Observ. /Barcelona U. /Stockholm U. /Apache Point Observ. /Lick Observ. /Sussex U. /Barcelona U. /Apache Point Observ. /Ohio State U. /Apache Point Observ. /Fermilab /DARK Cosmology Ctr. /Chicago U. /Fermilab /South African Astron. Observ. /Ohio State U. /Apache Point Observ. /Texas U., McDonald Observ. /Fermilab

    2007-09-14

    The Sloan Digital Sky Survey-II (SDSS-II) has embarked on a multi-year project to identify and measure light curves for intermediate-redshift (0.05 < z < 0.35) Type Ia supernovae (SNe Ia) using repeated five-band (ugriz) imaging over an area of 300 sq. deg. The survey region is a stripe 2.5 degrees wide centered on the celestial equator in the Southern Galactic Cap that has been imaged numerous times in earlier years, enabling construction of a deep reference image for discovery of new objects. Supernova imaging observations are being acquired between 1 September and 30 November of 2005-7. During the first two seasons, each region was imaged on average every five nights. Spectroscopic follow-up observations to determine supernova type and redshift are carried out on a large number of telescopes. In its first two three-month seasons, the survey has discovered and measured light curves for 327 spectroscopically confirmed SNe Ia, 30 probable SNe Ia, 14 confirmed SNe Ib/c, 32 confirmed SNe II, plus a large number of photometrically identified SNe Ia, 94 of which have host-galaxy spectra taken so far. This paper provides an overview of the project and briefly describes the observations completed during the first two seasons of operation.

  7. Testing neutrino spectra formation in collapsing stars with the diffuse supernova neutrino flux

    SciTech Connect

    Lunardini, Cecilia

    2007-04-01

    I address the question of what can be learned from the observation of the diffuse supernova neutrino flux in the precision phase, at next generation detectors of Megaton scale. An analytical study of the spectrum of the diffuse flux shows that, above realistic detection thresholds of 10 MeV or higher, the spectrum essentially reflects the exponential-times-polynomial structure of the original neutrino spectrum at the emission point. There is only a weak (tens of percent) dependence on the power {beta} describing the growth of the supernova rate with the redshift. Different original neutrino spectra correspond to large differences in the observed spectrum of events at a water Cherenkov detector: for typical supernova rates, the ratio of the numbers of events in the first and second energy bins (of 5 MeV width) varies in the interval 1.5-4.3 for pure water (energy threshold 18 MeV) and in the range 1-2.5 for water with gadolinium (10 MeV threshold). In the first case, discrimination would be difficult due to the large errors associated with background. With gadolinium, instead, the reduction of the total error down to the 10%-20% level would allow spectral sensitivity, with a dramatic improvement of precision with respect to the SN1987A data. Even in this latter case, for typical neutrino luminosity the dependence on {beta} is below sensitivity, so that it can be safely neglected in data analysis.

  8. A reconnaissance of the possible donor stars to the Kepler supernova

    SciTech Connect

    Kerzendorf, Wolfgang E.; Childress, Michael; Schmidt, Brian P.; Scharwächter, Julia; Do, Tuan

    2014-02-10

    The identity of Type Ia supernova progenitors remains a mystery, with various lines of evidence pointing toward either accretion from a nondegenerate companion or the rapid merger of two degenerate stars leading to the thermonuclear destruction of a white dwarf. In this paper, we spectroscopically scrutinize 24 of the brightest stars residing in the central 38'' × 38'' of the SN 1604 (Kepler) supernova remnant to search for a possible surviving companion star. We can rule out, with high certainty, a red giant companion star—a progenitor indicated by some models of the supernova remnant. Furthermore, we find no star that exhibits properties uniquely consistent with those expected of a donor star down to L > 10 L {sub ☉}. While the distribution of star properties toward the remnant are consistent with unrelated stars, we identify the most promising candidates for further astrometric and spectroscopic follow up. Such a program would either discover the donor star or place strong limits on progenitor systems to luminosities with L << L {sub ☉}.

  9. Weak decay processes in pre-supernova core evolution within the gross theory

    SciTech Connect

    Ferreira, R. C.; Dimarco, A. J.; Samana, A. R.; Barbero, C. A.

    2014-03-20

    The beta decay and electron capture rates are of fundamental importance in the evolution of massive stars in a pre-supernova core. The beta decay process gives its contribution by emitting electrons in the plasma of the stellar core, thereby increasing pressure, which in turn increases the temperature. From the other side, the electron capture removes free electrons from the plasma of the star core contributing to the reduction of pressure and temperature. In this work we calculate the beta decay and electron capture rates in stellar conditions for 63 nuclei of relevance in the pre-supernova stage, employing Gross Theory as the nuclear model. We use the abundances calculated with the Saha equations in the hypothesis of nuclear statistical equilibrium to evaluate the time derivative of the fraction of electrons. Our results are compared with other evaluations available in the literature. They have shown to be one order less or equal than the calculated within other models. Our results indicate that these differences may influence the evolution of the star in the later stages of pre-supernova.

  10. TEC Working Group Topic Groups Tribal

    Energy.gov [DOE]

    The Tribal Topic Group was established in January 1998 to address government-to-government consultation between DOE and Indian Tribes affected by its transportation activities. The group focuses on...

  11. Discovery of Dark Energy Ushered in a New Era in Computational Cosmology

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    Discovery of Dark Energy Ushered in a New Era in Computational Cosmology Discovery of Dark Energy Ushered in a New Era in Computational Cosmology October 4, 2011 John Hules, JAHules@lbl.gov, +1 510 486 6008 "If NERSC does not enable a major scientific discovery every few years, then we're not doing our job." That was the challenge issued by Bill McCurdy, then Lawrence Berkeley National Laboratory's Associate Laboratory Director for Computing Sciences, at the first all-hands meeting for

  12. Cosmological and wormhole solutions in low-energy effective string theory

    SciTech Connect

    Cadoni, M. INFN, Sezione di Cagliari, Via Ada Negri 18, I---09127 Cagliari ); Cavaglia, M. INFN, Sezione di Cagliari, Via Ada Negri 18, I-09127 Cagliari )

    1994-11-15

    We derive and study a class of cosmological and wormhole solutions of low-energy effective string field theory. We consider a general four-dimensional string effective action where moduli of the compactified manifold and the electromagnetic field are present. The cosmological solutions of the two-dimensional effective theory obtained by dimensional reduction of the former are discussed. In particular we demonstrate that the two-dimensional theory possesses a scale-factor duality invariance. Eucidean four-dimensional instantons describing the nucleation of the baby universes are found and the probability amplitude for the nucleation process given.

  13. Cosmological implications of the CMB large-scale structure

    SciTech Connect

    Melia, Fulvio

    2015-01-01

    The Wilkinson Microwave Anisotropy Probe (WMAP) and Planck may have uncovered several anomalies in the full cosmic microwave background (CMB) sky that could indicate possible new physics driving the growth of density fluctuations in the early universe. These include an unusually low power at the largest scales and an apparent alignment of the quadrupole and octopole moments. In a ?CDM model where the CMB is described by a Gaussian Random Field, the quadrupole and octopole moments should be statistically independent. The emergence of these low probability features may simply be due to posterior selections from many such possible effects, whose occurrence would therefore not be as unlikely as one might naively infer. If this is not the case, however, and if these features are not due to effects such as foreground contamination, their combined statistical significance would be equal to the product of their individual significances. In the absence of such extraneous factors, and ignoring the biasing due to posterior selection, the missing large-angle correlations would have a probability as low as ?0.1% and the low-l multipole alignment would be unlikely at the ?4.9% level; under the least favorable conditions, their simultaneous observation in the context of the standard model could then be likely at only the ?0.005% level. In this paper, we explore the possibility that these features are indeed anomalous, and show that the corresponding probability of CMB multipole alignment in the R{sub h}=ct universe would then be ?710%, depending on the number of large-scale SachsWolfe induced fluctuations. Since the low power at the largest spatial scales is reproduced in this cosmology without the need to invoke cosmic variance, the overall likelihood of observing both of these features in the CMB is ?7%, much more likely than in ?CDM, if the anomalies are real. The key physical ingredient responsible for this difference is the existence in the former of a maximum fluctuation

  14. Interagency mechanical operations group numerical systems group

    SciTech Connect

    1997-09-01

    This report consists of the minutes of the May 20-21, 1971 meeting of the Interagency Mechanical Operations Group (IMOG) Numerical Systems Group. This group looks at issues related to numerical control in the machining industry. Items discussed related to the use of CAD and CAM, EIA standards, data links, and numerical control.

  15. Cosmological constraints from the redshift dependence of the Alcock-Paczynski test: galaxy density gradient field

    SciTech Connect

    Li, Xiao-Dong; Park, Changbom; Forero-Romero, J. E.; Kim, Juhan E-mail: cbp@kias.re.kr E-mail: kjhan@kias.re.kr

    2014-12-01

    We propose a method based on the redshift dependence of the Alcock-Paczynski (AP) test to measure the expansion history of the universe. It uses the isotropy of the galaxy density gradient field to constrain cosmological parameters. If the density parameter ? {sub m} or the dark energy equation of state w are incorrectly chosen, the gradient field appears to be anisotropic with the degree of anisotropy varying with redshift. We use this effect to constrain the cosmological parameters governing the expansion history of the universe. Although redshift-space distortions (RSD) induced by galaxy peculiar velocities also produce anisotropies in the gradient field, these effects are close to uniform in magnitude over a large range of redshift. This makes the redshift variation of the gradient field anisotropy relatively insensitive to the RSD. By testing the method on mock surveys drawn from the Horizon Run 3 cosmological N-body simulations, we demonstrate that the cosmological parameters can be estimated without bias. Our method is complementary to the baryon acoustic oscillation or topology methods as it depends on D{sub AH} , the product of the angular diameter distance and the Hubble parameter.

  16. The cosmological constant: Plus CA change, plus C`est La Meme Chose

    SciTech Connect

    Frieman, J.A.

    1998-02-01

    Recent measurements of the cosmological parameters have renewed interest in the cosmological constant {Lambda}. I briefly review the current status of these measurements and the corresponding arguments for and against cosmological models with non-zero {Lambda}. I outline a scenario which attempts to incorporate non-zero vacuum energy into the framework of particle physics, based on an ultra-light pseudo-Nambu-Goldstone boson. With global spontaneous symmetry breaking scale f {approx_equal} 10{sup 18} GeV and explicit breaking scale comparable to MSW neutrino masses, M {approximately} 10{sup -3} eV, such a field, which acquires a mass M{sub {phi}} {approximately} M{sup 2}/f {approximately} H{sub 0}, would have become dynamical at recent epochs and currently dominate the energy density of the universe. The field acts as an effective cosmological constant for several expansion times and then relaxes into a condensate of coherent non-relativistic bosons. Such a model can reconcile dynamical estimates of the density parameter, {Omega}{sub m} {approximately} 0.2, with a spatially flat universe, and can yield an expansion age H{sub 0}t{sub 0} {approx_equal} 1 while remaining consistent with limits from gravitational lens statistics.

  17. Brane gravity, massless bulk scalar, and self-tuning of the cosmological constant

    SciTech Connect

    Kim, Jihn E.; Kyae, Bumseok; Shafi, Qaisar

    2004-09-15

    We show that a self-tuning mechanism of the cosmological constant could work in 5D noncompact space-time with a Z{sub 2} symmetry in the presence of a massless scalar field. The standard model matter fields live only on the 4D brane. The change of vacuum energy on the brane (brane cosmological constant) by, for instance, electroweak and QCD phase transitions, just gives rise to dynamical shifts of the profiles of the background metric and the scalar field in the extra dimension, keeping 4D space-time flat without any fine-tuning. To avoid naked singularities in the bulk, the brane cosmological constant should be negative. We introduce an additional brane-localized 4D Einstein-Hilbert term so as to provide the observed 4D gravity with the noncompact extra dimension. With a general form of the brane-localized gravity term allowed by the symmetries, the low energy Einstein gravity is successfully reproduced on the brane at long distances. We show this phenomenon explicitly for the case of vanishing bulk cosmological constant.

  18. Asymmetric dark matter annihilation as a test of non-standard cosmologies

    SciTech Connect

    Gelmini, Graciela B.; Huh, Ji-Haeng; Rehagen, Thomas E-mail: jhhuh@physics.ucla.edu

    2013-08-01

    We show that the relic abundance of the minority component of asymmetric dark matter can be very sensitive to the expansion rate of the Universe and the temperature of transition between a non-standard pre-Big Bang Nucleosynthesis cosmological phase and the standard radiation dominated phase, if chemical decoupling happens before this transition. In particular, because the annihilation cross section of asymmetric dark matter is typically larger than that of symmetric dark matter in the standard cosmology, the decrease in relic density of the minority component in non-standard cosmologies with respect to the majority component may be compensated by the increase in annihilation cross section, so that the annihilation rate at present of asymmetric dark matter, contrary to general belief, could be larger than that of symmetric dark matter in the standard cosmology. Thus, if the annihilation cross section of the asymmetric dark matter candidate is known, the annihilation rate at present, if detectable, could be used to test the Universe before Big Bang Nucleosynthesis, an epoch from which we do not yet have any data.

  19. Black hole solutions of dimensionally reduced Einstein-Gauss-Bonnet gravity with a cosmological constant

    SciTech Connect

    Melis, M.; Mignemi, S.

    2007-01-15

    We study the phase space of the spherically symmetric solutions of the system obtained from the dimensional reduction of the six-dimensional Einstein-Gauss-Bonnet action with a cosmological constant. We show that all the physical solutions have anti-de Sitter asymptotic behavior.

  20. Effective matter cosmologies of massive gravity I: non-physical fluids

    SciTech Connect

    Y?lmaz, Nejat Tevfik

    2014-08-01

    For the massive gravity, after decoupling from the metric equation we find a broad class of solutions of the Stckelberg sector by solving the background metric in the presence of a diagonal physical metric. We then construct the dynamics of the corresponding FLRW cosmologies which inherit effective matter contribution through the decoupling solution mechanism of the scalar sector.

  1. TEC Working Group Topic Groups Archives Communications

    Energy.gov [DOE]

    The Communications Topic Group was convened in April 1998 to improve internal and external strategic level communications regarding DOE shipments of radioactive and other hazardous materials.

  2. Luminosity distance for Born-Infeld electromagnetic waves propagating in a cosmological magnetic background

    SciTech Connect

    Aiello, Matias; Bengochea, Gabriel R; Ferraro, Rafael E-mail: gabriel@iafe.uba.ar; Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellon I, 1428 Buenos Aires

    2008-06-15

    Born-Infeld electromagnetic waves interacting with a static magnetic background in an expanding universe are studied. The non-linear character of Born-Infeld electrodynamics modifies the relation between the energy flux and the distance to the source, which gains a new dependence on the redshift that is governed by the background field. We compute the luminosity distance as a function of the redshift and compare with Maxwellian curves for supernovae type Ia.

  3. Cosmological and astrophysical parameter measurements with 21-cm anisotropies during the era of reionization

    SciTech Connect

    Santos, Mario G.; Cooray, Asantha

    2006-10-15

    We study the prospects for extracting cosmological and astrophysical parameters from the low radio frequency 21-cm background due to the spin-flip transition of neutral hydrogen during and prior to the reionization of the Universe. We make use of the angular power spectrum of 21-cm anisotropies, which exists due to inhomogeneities in the neutral hydrogen density field, the gas temperature field, the gas velocity field, and the spatial distribution of the Lyman-{alpha} intensity field associated with first luminous sources that emit UV photons. We extract parameters that describe both the underlying mass power spectrum and the global cosmology, as well as a set of simplified astrophysical parameters that connect fluctuations in the dark matter to those that govern 21-cm fluctuations. We also marginalize over a model for the foregrounds at low radio frequencies. In this general description, we find large degeneracies between cosmological parameters and the astrophysical parameters, though such degeneracies are reduced when strong assumptions are made with respect to the spin temperature relative to the cosmic microwave background (CMB) temperature or when complicated sources of anisotropy in the brightness temperature are ignored. Some of the degeneracies between cosmological and astrophysical parameters are broken when 21-cm anisotropy measurements are combined with information from the CMB, such as the temperature and the polarization measurements with Planck. While the overall improvement on the cosmological parameter estimates is not significant when measurements from first-generation interferometers are combined with Planck, such a combination can measure astrophysical parameters such as the ionization fraction in several redshift bins with reasonable accuracy.

  4. TEC Working Group Topic Groups Archives Protocols

    Energy.gov [DOE]

    The Transportation Protocols Topic Group serves as an important vehicle for DOE senior managers to assess and incorporate stakeholder input into the protocols process. The Topic Group was formed to review a series of transportation protocols developed in response to a request for DOE to be more consistent in its approach to transportation.

  5. JLF User Group

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    jlf user group JLF User Group 2015 NIF and JLF User Group Meeting Links: Send request to join the JLF User Group Join the NIF User Group Dr. Carolyn Kuranz - JLF User Group Dr. Carolyn Kuranz received her Ph.D. in Applied Physics from the University of Michigan in 2009. She is currently an Assistant Research Scientist at the Center for Laser Experimental Astrophysical Research and the Center for Radiative Shock Hydrodynamics at the University of Michigan. Her research involves hydrodynamic

  6. CAN STELLAR MIXING EXPLAIN THE LACK OF TYPE Ib SUPERNOVAE IN LONG-DURATION GAMMA-RAY BURSTS?

    SciTech Connect

    Frey, Lucille H. [HPC-3, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Fryer, Chris L. [CCS-2, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Young, Patrick A. [School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85276 (United States)

    2013-08-10

    The discovery of supernovae associated with long-duration gamma-ray burst observations is primary evidence that the progenitors of these outbursts are massive stars. One of the principle mysteries in understanding these progenitors has been the fact that all of these gamma-ray-burst-associated supernovae are Type Ic supernovae with no evidence of helium in the stellar atmosphere. Many studies have focused on whether or not this helium is simply hidden from spectral analyses. In this Letter, we show results from recent stellar models using new convection algorithms based on our current understanding of stellar mixing. We demonstrate that enhanced convection may lead to severe depletion of stellar helium layers, suggesting that the helium is not observed simply because it is not in the star. We also present light curves and spectra of these compact helium-depleted stars compared to models with more conventional helium layers.

  7. Neutrinos from type Ia supernovae: The deflagration-to-detonation transition scenario

    DOE PAGES [OSTI]

    Wright, Warren P.; Nagaraj, Gautam; Kneller, James P.; Scholberg, Kate; Seitenzahl, Ivo R.

    2016-07-19

    It has long been recognized that the neutrinos detected from the next core-collapse supernova in the Galaxy have the potential to reveal important information about the dynamics of the explosion and the nucleosynthesis conditions as well as allowing us to probe the properties of the neutrino itself. The neutrinos emitted from thermonuclear—type Ia—supernovae also possess the same potential, although these supernovae are dimmer neutrino sources. For the first time, we calculate the time, energy, line of sight, and neutrino-flavor-dependent features of the neutrino signal expected from a three-dimensional delayed-detonation explosion simulation, where a deflagration-to-detonation transition triggers the complete disruption ofmore » a near-Chandrasekhar mass carbon-oxygen white dwarf. We also calculate the neutrino flavor evolution along eight lines of sight through the simulation as a function of time and energy using an exact three-flavor transformation code. We identify a characteristic spectral peak at ˜10 MeV as a signature of electron captures on copper. This peak is a potentially distinguishing feature of explosion models since it reflects the nucleosynthesis conditions early in the explosion. We simulate the event rates in the Super-K, Hyper-K, JUNO, and DUNE neutrino detectors with the SNOwGLoBES event rate calculation software and also compute the IceCube signal. Hyper-K will be able to detect neutrinos from our model out to a distance of ˜10 kpc. Here, at 1 kpc, JUNO, Super-K, and DUNE would register a few events while IceCube and Hyper-K would register several tens of events.« less

  8. MULTI-DIMENSIONAL FEATURES OF NEUTRINO TRANSFER IN CORE-COLLAPSE SUPERNOVAE

    SciTech Connect

    Sumiyoshi, K. [Numazu College of Technology, Ooka 3600, Numazu, Shizuoka 410-8501 (Japan); Takiwaki, T. [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Matsufuru, H. [Computing Research Center, High Energy Accelerator Research Organization 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Yamada, S., E-mail: sumi@numazu-ct.ac.jp, E-mail: takiwaki.tomoya@nao.ac.jp, E-mail: hideo.matsufuru@kek.jp, E-mail: shoichi@heap.phys.waseda.ac.jp [Science and Engineering and Advanced Research Institute for Science and Engineering, Waseda University, Okubo, 3-4-1, Shinjuku, Tokyo 169-8555 (Japan)

    2015-01-01

    We study the multi-dimensional properties of neutrino transfer inside supernova cores by solving the Boltzmann equations for neutrino distribution functions in genuinely six-dimensional phase space. Adopting representative snapshots of the post-bounce core from other supernova simulations in three dimensions, we solve the temporal evolution to stationary states of neutrino distribution functions using our Boltzmann solver. Taking advantage of the multi-angle and multi-energy feature realized by the S {sub n} method in our code, we reveal the genuine characteristics of spatially three-dimensional neutrino transfer, such as nonradial fluxes and nondiagonal Eddington tensors. In addition, we assess the ray-by-ray approximation, turning off the lateral-transport terms in our code. We demonstrate that the ray-by-ray approximation tends to propagate fluctuations in thermodynamical states around the neutrino sphere along each radial ray and overestimate the variations between the neutrino distributions on different radial rays. We find that the difference in the densities and fluxes of neutrinos between the ray-by-ray approximation and the full Boltzmann transport becomes ?20%, which is also the case for the local heating rate, whereas the volume-integrated heating rate in the Boltzmann transport is found to be only slightly larger (?2%) than the counterpart in the ray-by-ray approximation due to cancellation among different rays. These results suggest that we should carefully assess the possible influences of various approximations in the neutrino transfer employed in current simulations of supernova dynamics. Detailed information on the angle and energy moments of neutrino distribution functions will be profitable for the future development of numerical methods in neutrino-radiation hydrodynamics.

  9. TEC Working Group Topic Groups Archives Consolidated Grant Topic Group

    Energy.gov [DOE]

    The Consolidated Grant Topic Group arose from recommendations provided by the TEC and other external parties to the DOE Senior Executive Transportation Forum in July 1998. It was proposed that the consolidation of multiple funding streams from numerous DOE sources into a single grant would provide a more equitable and efficient means of assistance to States and Tribes affected by DOE nuclear material shipments.

  10. MULTI-COLOR OPTICAL AND NEAR-INFRARED LIGHT CURVES OF 64 STRIPPED-ENVELOPE CORE-COLLAPSE SUPERNOVAE

    SciTech Connect

    Bianco, F. B.; Modjaz, M. [Center for Cosmology and Particle Physics, New York University, 4 Washington Place, New York, NY 10003 (United States); Hicken, M.; Friedman, A.; Kirshner, R. P.; Challis, P.; Marion, G. H. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Bloom, J. S. [Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States); Wood-Vasey, W. M. [PITT PACC, Department of Physics and Astronomy, 3941 O'Hara Street, University of Pittsburgh, Pittsburgh, PA 15260 (United States); Rest, A., E-mail: fb55@nyu.edu [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)

    2014-08-01

    We present a densely sampled, homogeneous set of light curves of 64 low-redshift (z ? 0.05) stripped-envelope supernovae (SNe of Type IIb, Ib, Ic, and Ic-BL). These data were obtained between 2001 and 2009 at the Fred L. Whipple Observatory (FLWO) on Mount Hopkins in Arizona, with the optical FLWO 1.2 m and the near-infrared (NIR) Peters Automated Infrared 1.3 m telescopes. Our data set consists of 4543 optical photometric measurements on 61 SNe, including a combination of U BV RI, U BV r{sup ?}i{sup ?}, and u{sup ?} BV r{sup ?}i{sup ?}, and 1919 JHK{sub s} NIR measurements on 25 SNe. This sample constitutes the most extensive multi-color data set of stripped-envelope SNe to date. Our photometry is based on template-subtracted images to eliminate any potential host-galaxy light contamination. This work presents these photometric data, compares them with data in the literature, and estimates basic statistical quantities: date of maximum, color, and photometric properties. We identify promising color trends that may permit the identification of stripped-envelope SN subtypes from their photometry alone. Many of these SNe were observed spectroscopically by the Harvard-Smithsonian Center for Astrophysics (CfA) SN group, and the spectra are presented in a companion paper. A thorough exploration that combines the CfA photometry and spectroscopy of stripped-envelope core-collapse SNe will be presented in a follow-up paper.

  11. SUPERNOVA SHOCK-WAVE-INDUCED CO-FORMATION OF GLASSY CARBON AND NANODIAMOND

    SciTech Connect

    Stroud, Rhonda; Chisholm, Matthew F; Heck, Phillipp; Alexander, Conel; Nittler, Larry

    2011-01-01

    Nanodiamond (ND) was the first extrasolar dust phase to be identified in meteorites. However, the 2 nm average size of the NDs precludes isotopic analysis of individual particles, and thus their origin(s) remains controversial. Using electron microscopy with subnanometer resolution, we show that ND separates from the Allende and Murchison meteorites are actually a two-phase mixture of ND and glassy carbon. This phase mixture is likely the product of supernova shock-wave transformation of pre-formed organics in the interstellar medium (ISM). The glassy carbon ND mixture is also a plausible contributor to the 2175 extinction feature in the diffuse ISM.

  12. RADIO OBSERVATIONS REVEAL UNUSUAL CIRCUMSTELLAR ENVIRONMENTS FOR SOME TYPE Ibc SUPERNOVA PROGENITORS

    SciTech Connect

    Wellons, Sarah; Soderberg, Alicia M.; Chevalier, Roger A.

    2012-06-10

    We present extensive radio observations of the nearby Type Ibc supernovae (SNe Ibc) 2004cc, 2004dk, and 2004gq spanning {Delta}t Almost-Equal-To 8-1900 days after explosion. Using a dynamical model developed for synchrotron emission from a slightly decelerated shock wave, we estimate the velocity and energy of the fastest ejecta and the density profile of the circumstellar medium. The shock waves of all three supernovae are characterized by non-relativistic velocities of v-bar approx. (0.1-25)c and associated energies of E Almost-Equal-To (2-10) Multiplication-Sign 10{sup 47} erg, in line with the expectations for a typical homologous explosion. Smooth circumstellar density profiles are indicated by the early radio data and we estimate the progenitor mass-loss rates to be M-dot approx. (0.6-13) x 10{sup -5} M{sub Sun} yr{sup -1} (wind velocity, v{sub w} = 10{sup 3} km s{sup -1}). These estimates approach the saturation limit ( M-dot {approx}10{sup -4} M{sub Sun} yr{sup -1}) for line-driven winds from Wolf-Rayet stars, the favored progenitors of SNe Ibc including those associated with long-duration gamma-ray bursts. Intriguingly, at later epochs all three supernovae show evidence for abrupt radio variability that we attribute to large density modulations (factor of {approx}3-6) at circumstellar radii of r Almost-Equal-To (1-50) Multiplication-Sign 10{sup 16} cm. If due to variable mass loss, these modulations are associated with progenitor activity on a timescale of {approx}10-100 years before explosion. We consider these results in the context of variable mass-loss mechanisms including wind clumping, metallicity-independent continuum-driven ejections, and binary-induced modulations. It may also be possible that the SN shock waves are dynamically interacting with wind termination shocks; however, this requires the environment to be highly pressurized and/or the progenitor to be rapidly rotating prior to explosion. The proximity of the density modulations to the

  13. TEC Working Group Topic Groups Routing

    Energy.gov [DOE]

    The Routing Topic Group has been established to examine topics of interest and relevance concerning routing of shipments of spent nuclear fuel (SNF) and high-level radioactive waste (HLW) to a...

  14. TEC Working Group Topic Groups Manual Review

    Energy.gov [DOE]

    This group is responsible for the update of DOE Manual 460.2-1, Radioactive Material Transportation Practices Manual.  This manual was issued on September 23, 2002, and establishes a set of...

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

    SciTech Connect

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

    2013-09-01

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

  16. JLab Users Group

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    JLab Users Group Please upgrade your browser. This site's design is only visible in a graphical browser that supports web standards, but its content is accessible to any browser. Concerns? JLab Users Group User Liaison Home Users Group Program Advisory Committee User/Researcher Information print version UG Resources Background & Purpose Users Group Wiki By Laws Board of Directors Board of Directors Minutes Directory of Members Events At-A-Glance Member Institutions News Users Group Mailing

  17. Improved limit on {theta}{sub 13} and implications for neutrino masses in neutrinoless double beta decay and cosmology

    SciTech Connect

    Lindner, Manfred; Merle, Alexander; Rodejohann, Werner [Physik-Department, Technische Universitaet Muenchen, James-Franck-Strasse, D-85748 Garching (Germany)

    2006-03-01

    We analyze the impact of a measurement, or of an improved bound, on {theta}{sub 13} for the determination of the effective neutrino mass in neutrinoless double beta decay and cosmology. In particular, we discuss how an improved limit on (or a specific value of) {theta}{sub 13} can influence the determination of the neutrino mass spectrum via neutrinoless double beta decay. We also discuss the interplay with improved cosmological neutrino mass searches.

  18. Moltech Power Systems Group MPS Group | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Moltech Power Systems Group MPS Group Jump to: navigation, search Name: Moltech Power Systems Group (MPS Group) Place: China Product: China-based subsidiary of Shanghai Huayi Group...

  19. Hanergy Holdings Group Company Ltd formerly Farsighted Group...

    OpenEI (Open Energy Information) [EERE & EIA]

    Hanergy Holdings Group Company Ltd formerly Farsighted Group aka Huarui Group Jump to: navigation, search Name: Hanergy Holdings Group Company Ltd (formerly Farsighted Group, aka...

  20. Isovector dipole resonances in {sup 4}He and neutrino-heating in supernova

    SciTech Connect

    Nakayama, S.; Matsumoto, E.; Fushimi, K.; Hayami, R.; Suzuki, T.; Yamagata, T.; Akimune, H.; Ikemizu, H.; Fujiwara, M.; Hashimoto, H.; Kawase, K.; Nakanishi, K.; Oota, T.; Yosoi, M.; Greenfield, M. B.; Kudoh, T.; Sagara, K.; Tanaka, M.

    2010-06-01

    We studied transition strengths to isovector dipole resonances (GDR-1-bar , SDR-1-bar , and SDR-2-bar ) in {sup 4}He by using the {sup 4}He({sup 7}Li,{sup 7}Begamma) reaction at 455 MeV and by comparing with shell-model calculations, in order to estimate cross sections of {sup 4}He for reactions induced by neutrinos emitting from a thermalized neutrino-sphere in the type-II supernova. Excitation of the SDR was dominant in the neutrino-heating of {sup 4}He. The {sup 4}He-excitation via neutral-current reactions of nu{sub m}u{sub ,t}au and nu-bar{sub m}u{sub ,t}au was found to be one order of magnitude stronger than that via charged-current reactions of nu{sub e} and nu-bar{sub e}. The total energy-weighted cross section {sub N} for neutrino-induced neutral-current reactions on {sup 4}He was found to amount to about 1.0x10{sup -40} MeVcentre dotcm{sup 2} which is comparable to those used in the previous simulations. The neutrino-heating effect of {sup 4}He is small in the type-II supernova explosion.

  1. HYDRODYNAMICS OF CORE-COLLAPSE SUPERNOVAE AT THE TRANSITION TO EXPLOSION. I. SPHERICAL SYMMETRY

    SciTech Connect

    Fernandez, Rodrigo [Institute for Advanced Study, Einstein Drive, Princeton, NJ 08540 (United States)

    2012-04-20

    We study the transition to runaway expansion of an initially stalled core-collapse supernova shock. The neutrino luminosity, mass accretion rate, and neutrinospheric radius are all treated as free parameters. In spherical symmetry, this transition is mediated by a global non-adiabatic instability that develops on the advection time and reaches nonlinear amplitude. Here, we perform high-resolution, time-dependent hydrodynamic simulations of stalled supernova shocks with realistic microphysics to analyze this transition. We find that radial instability is a sufficient condition for runaway expansion if the neutrinospheric parameters do not vary with time and if heating by the accretion luminosity is neglected. For a given unstable mode, transition to runaway occurs when fluid in the gain region reaches positive specific energy. We find approximate instability criteria that accurately describe the behavior of the system over a wide region of parameter space. The threshold neutrino luminosities are in general different than the limiting value for a steady-state solution. We hypothesize that multidimensional explosions arise from the excitation of unstable large-scale modes of the turbulent background flow, at threshold luminosities that are lower than in the laminar case.

  2. A STUBBORNLY LARGE MASS OF COLD DUST IN THE EJECTA OF SUPERNOVA 1987A

    SciTech Connect

    Matsuura, M.; Barlow, M. J.; Dwek, E.; Babler, B.; Baes, M.; Fritz, Jacopo; Meixner, M.; Cernicharo, José; Clayton, Geoff C.; Dunne, L.; Fransson, C.; Lundqvist, P.; Gear, Walter; Gomez, H. L.; Groenewegen, M. A. T.; Indebetouw, R.; Ivison, R. J.; Jerkstrand, A.; Lebouteiller, V.; and others

    2015-02-10

    We present new Herschel photometric and spectroscopic observations of Supernova 1987A, carried out in 2012. Our dedicated photometric measurements provide new 70 μm data and improved imaging quality at 100 and 160 μm compared to previous observations in 2010. Our Herschel spectra show only weak CO line emission, and provide an upper limit for the 63 μm [O I] line flux, eliminating the possibility that line contaminations distort the previously estimated dust mass. The far-infrared spectral energy distribution (SED) is well fitted by thermal emission from cold dust. The newly measured 70 μm flux constrains the dust temperature, limiting it to nearly a single temperature. The far-infrared emission can be fitted by 0.5 ± 0.1 M {sub ☉} of amorphous carbon, about a factor of two larger than the current nucleosynthetic mass prediction for carbon. The observation of SiO molecules at early and late phases suggests that silicates may also have formed and we could fit the SED with a combination of 0.3 M {sub ☉} of amorphous carbon and 0.5 M {sub ☉} of silicates, totalling 0.8 M {sub ☉} of dust. Our analysis thus supports the presence of a large dust reservoir in the ejecta of SN 1987A. The inferred dust mass suggests that supernovae can be an important source of dust in the interstellar medium, from local to high-redshift galaxies.

  3. LATE-TIME DUST EMISSION FROM THE TYPE IIn SUPERNOVA 1995N

    SciTech Connect

    Van Dyk, Schuyler D.

    2013-05-15

    Type IIn supernovae (SNe IIn) have been found to be associated with significant amounts of dust. These core-collapse events are generally expected to be the final stage in the evolution of highly massive stars, either while in an extreme red supergiant phase or during a luminous blue variable phase. Both evolutionary scenarios involve substantial pre-supernova mass loss. I have analyzed the SN IIn 1995N in MCG -02-38-017 (Arp 261), for which mid-infrared archival data obtained with the Spitzer Space Telescope in 2009 ({approx}14.7 yr after explosion) and with the Wide-field Infrared Survey Explorer in 2010 ({approx}15.6-16.0 yr after explosion) reveal a luminous ({approx}2 Multiplication-Sign 10{sup 7} L{sub Sun }) source detected from 3.4 to 24 {mu}m. These observations probe the circumstellar material, set up by pre-SN mass loss, around the progenitor star and indicate the presence of {approx}0.05-0.12 M{sub Sun} of pre-existing, cool dust at {approx}240 K. This is at least a factor {approx}10 lower than the dust mass required to be produced from SNe at high redshift, but the case of SN 1995N lends further evidence that highly massive stars could themselves be important sources of dust.

  4. PTF 12gzkA rapidly declining, high-velocity type Ic radio supernova

    SciTech Connect

    Horesh, Assaf; Kulkarni, Shrinivas R.; Corsi, Alessandra; Frail, Dale A.; Cenko, S. Bradley; Ben-Ami, Sagi; Gal-Yam, Avishay; Yaron, Ofer; Arcavi, Iair; Ofek, Eran O.; Kasliwal, Mansi M.

    2013-11-20

    Only a few cases of Type Ic supernovae (SNe) with high-velocity ejecta (?0.2 c) have been discovered and studied. Here, we present our analysis of radio and X-ray observations of the Type Ic SN PTF 12gzk. The radio emission declined less than 10 days after explosion, suggesting SN ejecta expanding at high velocity (?0.3 c). The radio data also indicate that the density of the circumstellar material (CSM) around the supernova is lower by a factor of ?10 than the CSM around normal Type Ic SNe. PTF 12gzk may therefore be an intermediate event between a 'normal' SN Ic and a gamma-ray-burst-SN-like event. Our observations of this rapidly declining radio SN at a distance of 58 Mpc demonstrates the potential to detect many additional radio SNe, given the new capabilities of the Very Large Array (improved sensitivity and dynamic scheduling), which are currently missed, leading to a biased view of radio SNe Ic. Early optical discovery followed by rapid radio observations would provide a full description of the ejecta velocity distribution and CSM densities around stripped massive star explosions as well as strong clues about the nature of their progenitor stars.

  5. Collective flavor oscillations of supernova neutrinos and r-process nucleosynthesis

    SciTech Connect

    Chakraborty, Sovan; Kar, Kamales; Goswami, Srubabati E-mail: sandhya@hri.res.in E-mail: kamales.kar@saha.ac.in

    2010-06-01

    Neutrino-neutrino interactions inside core-collapse supernovae may give rise to collective flavor oscillations resulting in swap between flavors. These oscillations depend on the initial energy spectra, and relative fluxes or relative luminosities of the neutrinos. It has been observed that departure from energy equipartition among different flavors can give rise to one or more sharp spectral swap over energy, termed as splits. We study the occurrence of splits in the neutrino and antineutrino spectra, varying the initial relative fluxes for different models of initial energy spectrum, in both normal and inverted hierarchy. These initial relative flux variations give rise to several possible split patterns whereas variation over different models of energy spectra give similar results. We explore the effect of these spectral splits on the electron fraction, Y{sub e}, that governs r-process nucleosynthesis inside supernovae. Since spectral splits modify the electron neutrino and antineutrino spectra in the region where r-process is postulated to happen, and since the pattern of spectral splits depends on the initial conditions of the spectra and the neutrino mass hierarchy, we show that the condition Y{sub e} < 0.5 required for successful r-process nucleosynthesis will lead to constraints on the initial spectral conditions, for a given neutrino mass hierarchy.

  6. A THEORETICAL COLOR-VELOCITY CORRELATION FOR SUPERNOVAE ASSOCIATED WITH GAMMA-RAY BURSTS

    SciTech Connect

    Rapoport, Sharon; Sim, Stuart A.; Schmidt, Brian P.; Maeda, Keiichi; Nomoto, Ken'ichi; Tanaka, Masaomi; Kromer, Markus

    2012-11-01

    We carry out the first multi-dimensional radiative transfer calculations to simultaneously compute synthetic spectra and light curves for models of supernovae driven by fast bipolar outflows. These allow us to make self-consistent predictions for the orientation dependence of both color evolution and spectral features. We compare models with different degrees of asphericity and metallicity and find significant observable consequences of both. In aspherical models, we find spectral and light curve features that vary systematically with observer orientation. In particular, we find that the early-phase light curves are brighter and bluer when viewed close to the polar axis but that the peak flux is highest for equatorial (off-axis) inclinations. Spectral line features also depend systematically on observer orientation, including the velocity of the Si II 6355 A line. Consequently, our models predict a correlation between line velocity and color that could assist the identification of supernovae associated with off-axis jet-driven explosions. The amplitude and range of this correlation depends on the degree of asphericity, the metallicity, and the epoch of observation but we find that it is always present and acts in the same direction.

  7. TYCHO SN 1572: A NAKED Ia SUPERNOVA REMNANT WITHOUT AN ASSOCIATED AMBIENT MOLECULAR CLOUD

    SciTech Connect

    Tian, W. W.; Leahy, D. A.

    2011-03-10

    The historical supernova remnant (SNR) Tycho SN 1572 originates from the explosion of a normal Type Ia supernova that is believed to have originated from a carbon-oxygen white dwarf in a binary system. We analyze the 21 cm continuum, H I, and {sup 12}CO-line data from the Canadian Galactic Plane Survey in the direction of SN 1572 and the surrounding region. We construct H I absorption spectra to SN 1572 and three nearby compact sources. We conclude that SN 1572 has no molecular cloud interaction, which argues against previous claims that a molecular cloud is interacting with the SNR. This new result does not support a recent claim that dust, newly detected by AKARI, originates from such an SNR-cloud interaction. We suggest that the SNR has a kinematic distance of 2.5-3.0 kpc based on a nonlinear rotational curve model. Very high energy {gamma}-ray emission from the remnant has been detected by the VERITAS telescope, so our result shows that its origin should not be an SNR-cloud interaction. Both radio and X-ray observations support that SN 1572 is an isolated Type Ia SNR.

  8. Shell effects in hot nuclei and their influence on nuclear composition in supernova matter

    SciTech Connect

    Nishimura, Suguru [Department of Pure and Applied Physics, Waseda University, 3-4-1 Okubo Shinjuku-ku, Tokyo 169-8555 (Japan); Takano, Masatoshi [Department of Pure and Applied Physics, Waseda University, 3-4-1 Okubo Shinjuku-ku, Tokyo 169-8555, Japan and Research Institute for Science and Engineering, Waseda University, 3-4-1 Okubo Shinjuku-ku, Tokyo 169-8555 (Japan)

    2014-05-02

    We calculate nuclear composition in supernova (SN) matter explicitly taking into account the temperature dependence of nuclear shell effects. The abundance of nuclei in SN matter is important in the dynamics of core-collapse supernovae and, in recently constructed equations of state (EOS) for SN matter, the composition of nuclei are calculated assuming nuclear statistical equilibrium wherein the nuclear internal free energies govern the composition. However, in these EOS, thermal effects on the shell energy are not explicitly taken into account. To address this shortfall, we calculate herein the shell energies of hot nuclei and examine their influence on the composition of SN matter. Following a simplified macroscopic-microscopic approach, we first calculate single-particle (SP) energies by using a spherical Woods-Saxon potential. Then we extract shell energies at finite temperatures using Strutinsky method with the Fermi distribution as the average occupation probability of the SP levels. The results show that at relatively low temperatures, shell effects are still important and magic nuclei are abundant. However, at temperatures above approximately 2 MeV, shell effects are almost negligible, and the mass fractions with shell energies including the thermal effect are close to those obtained from a simple liquid drop model at finite temperatures.

  9. The general relativistic instability supernova of a supermassive population III star

    SciTech Connect

    Chen, Ke-Jung; Woosley, Stan [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Heger, Alexander [Monash Centre for Astrophysics, Monash University, Victoria 3800 (Australia); Almgren, Ann [Center for Computational Sciences and Engineering, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Whalen, Daniel J. [T-2, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Johnson, Jarrett L., E-mail: kchen@ucolick.org [XTD-PRI, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2014-08-01

    The formation of supermassive Population III stars with masses ?10,000 M{sub ?} in primeval galaxies in strong ultraviolet backgrounds at z ? 15 may be the most viable pathway to the formation of supermassive black holes by z ? 7. Most of these stars are expected to live for short times and then directly collapse to black holes, with little or no mass loss over their lives. However, we have now discovered that non-rotating primordial stars with masses close to 55,000 M{sub ?} can instead die as highly energetic thermonuclear supernovae powered by explosive helium burning, releasing up to 10{sup 55} erg, or about 10,000 times the energy of a Type Ia supernova. The explosion is triggered by the general relativistic contribution of thermal photons to gravity in the core of the star, which causes the core to contract and explosively burn. The energy release completely unbinds the star, leaving no compact remnant, and about half of the mass of the star is ejected into the early cosmos in the form of heavy elements. The explosion would be visible in the near infrared at z ? 20 to Euclid and the Wide-Field Infrared Survey Telescope, perhaps signaling the birth of supermassive black hole seeds and the first quasars.

  10. THE MORPHOLOGY AND DYNAMICS OF JET-DRIVEN SUPERNOVA REMNANTS: THE CASE OF W49B

    SciTech Connect

    González-Casanova, Diego F.; De Colle, Fabio; Ramirez-Ruiz, Enrico; Lopez, Laura A.

    2014-02-01

    The circumstellar medium (CSM) of a massive star is modified by its winds before a supernova (SN) explosion occurs, and thus the evolution of the resulting supernova remnant (SNR) is influenced by both the geometry of the explosion as well as the complex structure of the CSM. Motivated by recent work suggesting the SNR W49B was a jet-driven SN expanding in a complex CSM, we explore how the dynamics and the metal distributions in a jet-driven explosion are modified by the interaction with the surrounding environment. In particular, we perform hydrodynamical calculations to study the dynamics and explosive nucleosynthesis of a jet-driven SN triggered by the collapse of a 25 M {sub ☉} Wolf-Rayet star and its subsequent interaction with the CSM up to several hundred years following the explosion. We find that although the CSM has small-scale effects on the structure of the SNR, the overall morphology and abundance patterns are reflective of the initial asymmetry of the SN explosion. Thus, we predict that jet-driven SNRs, such as W49B, should be identifiable based on morphology and abundance patterns at ages up to several hundred years, even if they expand into a complex CSM environment.

  11. Direct numerical simulations of type Ia supernovae flames I: The landau-darrieus instability

    SciTech Connect

    Bell, J.B.; Day, M.S.; Rendleman, C.A.; Woosley, S.E.; Zingale, M.

    2003-11-24

    Planar flames are intrinsically unstable in open domains due to the thermal expansion across the burning front--the Landau-Darrieus instability. This instability leads to wrinkling and growth of the flame surface, and corresponding acceleration of the flame, until it is stabilized by cusp formation. We look at the Landau-Darrieus in stability for C/O thermonuclear flames at conditions relevant to the late stages of a Type Ia supernova explosion. Two-dimensional direct numerical simulations of both single-mode and multi-mode perturbations using a low Mach number hydrodynamics code are presented. We show the effect of the instability on the flame speed as a function of both the density and domain size, demonstrate the existence of the small scale cutoff to the growth of the instability, and look for the proposed breakdown of the non-linear stabilization at low densities. The effects of curvature on the flame as quantified through measurements of the growth rate and computation of the corresponding Markstein number. While accelerations of a few percent are observed, they are too small to have any direct outcome on the supernova explosion.

  12. Randall-Sundrum cosmological model with nonminimal derivative coupling of scalar field

    SciTech Connect

    Widiyani, Agustina Suroso, Agus Zen, Freddy P.

    2015-04-16

    Nonminimal derivative coupling (NMDC) of scalar field in time-dependent Randall-Sundrum model is investigated. Firstly, we take a simple relation between the scale factor on the brane, a(t), and the scale factor of the extradimension, b(t), as b = a{sup γ} where γ is a constant. Then, we derive the Einstein equation and find its cosmological solution for a special case of static extra dimension, γ = 0. As the result, we find that de Sitter solution is a typical solution of our model. We also find that the brane tension which is related to cosmological constant on the brane is related to the coupling constant of the model.

  13. Cosmological bounces in spatially flat FRW spacetimes in metric f(R) gravity

    SciTech Connect

    Paul, Niladri; Chakrabarty, Saikat Nil; Bhattacharya, Kaushik E-mail: snilch@iitk.ac.in

    2014-10-01

    The present work analyzes the various conditions in which there can be a bouncing universe solution in f(R) gravity. In the article an interesting method, to analyze the bouncing FRW solutions in a spatially flat universe using f(R) gravity models using an effective Einstein frame description of the process, is presented. The analysis shows that a cosmological bounce in the f(R) theory need not be described by an equivalent bounce in the Einstein frame description of the process where actually there may be no bounce at all. Nevertheless the Einstein frame description of the bouncing phenomena turns out to be immensely important as the dynamics of the bounce becomes amenable to logic based on general relativistic intuition. The theory of scalar cosmological perturbations in the bouncing universe models in f(R) theories has also been worked out in the Einstein frame.

  14. Cosmological back-reaction in modified gravity and its implications for dark energy

    SciTech Connect

    Preston, Anthony W.H.; Morris, Tim R. E-mail: T.R.Morris@soton.ac.uk

    2014-09-01

    We study the effective stress-energy tensor induced by cosmological inhomogeneity in f(R)=R+c R{sup 2} and equivalent scalar-tensor theories, motivated both by models of early universe inflation and by phenomenological alternative cosmologies to the standard Λ-CDM. We use Green and Wald's framework for averaging over classical fluctuations of short-wavelength λ. By ensuring that the leading non-linear terms from the fluctuations of the Einstein terms and the corrections both contribute in the formal limit as λ→0, we derive a diffeomorphism invariant effective stress-energy tensor whose trace is non-vanishing and of the right sign to potentially account for the current acceleration of the universe. However a more phenomenologically acceptable dark energy model would be required if this effect were to fully account for the current acceleration.

  15. COSMOLOGICAL TIME DILATION IN DURATIONS OF SWIFT LONG GAMMA-RAY BURSTS

    SciTech Connect

    Zhang, Fu-Wen; Fan, Yi-Zhong; Wei, Da-Ming [Key Laboratory of Dark Matter and Space Astronomy, Purple Mountain ObservatoryChinese Academy of Sciences, Nanjing 210008 (China); Shao, Lang [Department of Space Science and AstronomyHebei Normal University, Shijiazhuang 050024 (China)

    2013-11-20

    Cosmological time dilation is a fundamental phenomenon in an expanding universe, which stresses that both the duration and wavelength of the emitted light from a distant object at the redshift z will be dilated by a factor of 1 + z at the observer. By using a sample of 139 Swift long gamma-ray bursts with known redshift (z ? 8.2), we measure the observed duration (T {sub 90}) in the observed energy range between 140/(1 + z)keV and 350/(1 + z)keV, corresponding to a fixed energy range of 140-350keV in the rest frame. We obtain a significant correlation between the duration and the factor 1 + z, i.e., T {sub 90} = 10.5(1 + z){sup 0.94} {sup } {sup 0.26}, which is consistent with that expected from the cosmological time dilation effect.

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

    SciTech Connect

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

    2010-02-01

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

  17. Q&A with Nobelist George Smoot - 2009 BCCP Cosmology Workshop

    ScienceCinema

    George Smoot

    2010-09-01

    July 2009: What happens when dark matter and anti-dark mattter collide? If you were in a gravity free environment, what would happen to time? At the annual Cosmology Workshop at Lawrence Berkeley Lab, Nobelist George Smoot answers these questions and more from high school students and teachers. Dr. Smoot was co-awarded the 2006 Nobel Prize in Physics for the discovery of the blackbody form and anisotropy of the cosmic microwave background radiation.

  18. Cosmology and astrophysics from relaxed galaxy clusters - IV: Robustly calibrating hydrostatic masses with weak lensing

    DOE PAGES [OSTI]

    Applegate, D. E; Mantz, A.; Allen, S. W.; von der Linden, A.; Morris, R. G.; Hilbert, S.; Kelly, P. L.; Burke, D. L.; Ebeling, H.; Rapetti, D. A.; et al

    2016-02-04

    This is the fourth in a series of papers studying the astrophysics and cosmology of massive, dynamically relaxed galaxy clusters. Here, we use measurements of weak gravitational lensing from the Weighing the Giants project to calibrate Chandra X-ray measurements of total mass that rely on the assumption of hydrostatic equilibrium. This comparison of X-ray and lensing masses measures the combined bias of X-ray hydrostatic masses from both astrophysical and instrumental sources. While we cannot disentangle the two sources of bias, only the combined bias is relevant for calibrating cosmological measurements using relaxed clusters. Assuming a fixed cosmology, and within amore » characteristic radius (r2500) determined from the X-ray data, we measure a lensing to X-ray mass ratio of 0.96 ± 9% (stat) ± 9% (sys). We find no significant trends of this ratio with mass, redshift or the morphological indicators used to select the sample. Our results imply that any departures from hydrostatic equilibrium at these radii are offset by calibration errors of comparable magnitude, with large departures of tens-of-percent unlikely. In addition, we find a mean concentration of the sample measured from lensing data of c200 = 3.0+4.4–1.8. In conclusion, anticipated short-term improvements in lensing systematics, and a modest expansion of the relaxed lensing sample, can easily increase the measurement precision by 30–50%, leading to similar improvements in cosmological constraints that employ X-ray hydrostatic mass estimates, such as on Ωm from the cluster gas mass fraction.« less

  19. A TEST OF COSMOLOGICAL MODELS USING HIGH-z MEASUREMENTS OF H(z)

    SciTech Connect

    Melia, Fulvio; McClintock, Thomas M. E-mail: tmcclintock89@gmail.com

    2015-10-15

    The recently constructed Hubble diagram using a combined sample of SNLS and SDSS-II SNe Ia, and an application of the Alcock–Paczyński (AP) test using model-independent Baryon Acoustic Oscillation (BAO) data, have suggested that the principal constraint underlying the cosmic expansion is the total equation-of-state of the cosmic fluid, rather than that of its dark energy. These studies have focused on the critical redshift range (0 ≲ z ≲ 2) within which the transition from decelerated to accelerated expansion is thought to have occurred, and they suggest that the cosmic fluid has zero active mass, consistent with a constant expansion rate. The evident impact of this conclusion on cosmological theory calls for an independent confirmation. In this paper, we carry out this crucial one-on-one comparison between the R{sub h} = ct universe (a Friedmann–Robertson–Walker cosmology with zero active mass) and wCDM/ΛCDM, using the latest high-z measurements of H(z). Whereas the SNe Ia yield the integrated luminosity distance, while the AP diagnostic tests the geometry of the universe, the Hubble parameter directly samples the expansion rate itself. We find that the model-independent cosmic chronometer data prefer R{sub h} = ct over wCDM/ΛCDM with a Bayes Information Criterion likelihood of ∼95% versus only ∼5%, in strong support of the earlier SNe Ia and AP results. This contrasts with a recent analysis of H(z) data based solely on BAO measurements which, however, strongly depend on the assumed cosmology. We discuss why the latter approach is inappropriate for model comparisons, and emphasize again the need for truly model-independent observations to be used in cosmological tests.

  20. Background cosmological dynamics in f(R) gravity and observational constraints

    SciTech Connect

    Ali, Amna; Sami, M.; Sen, Anjan A.; Gannouji, Radouane

    2010-05-15

    In this paper, we carry out a study of viable cosmological models in f(R) gravity at the background level. We use observable parameters like {Omega} and {gamma} to form an autonomous system of equations and show that the models under consideration exhibit two different regimes in their time evolution, namely, a phantom phase followed by a quintessencelike behavior. We employ state finder parameters to emphasize a characteristic discriminative signature of these models.

  1. Double beta decay versus cosmology: Majorana CP phases and nuclear matrix elements

    SciTech Connect

    Deppisch, Frank; Paes, Heinrich [Institut fuer Theoretische Physik und Astrophysik, Universitaet Wuerzburg, D-97074 Wuerzburg (Germany); Suhonen, Jouni [Department of Physics, University of Jyvaeskylae, P.O.B. 35, FIN-40014, Jyvaeskylae (Finland)

    2005-08-01

    We discuss the relation between the absolute neutrino mass scale, the effective mass measured in neutrinoless double beta decay, and the Majorana CP phases. Emphasis is placed on estimating the upper bound on the nuclear matrix element entering calculations of the double beta decay half-life. Combining the claimed evidence for neutrinoless double beta decay with the neutrino mass bound from cosmology, one of the Majorana CP phases can be constrained.

  2. MiniBooNE Pion Group

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    Pion Group

  3. Running Jobs by Group

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    Running Jobs by Group Running Jobs by Group Daily Graph: Weekly Graph: Monthly Graph: Yearly Graph: 2 Year Graph: Last edited: 2011-04-05 13:59:48...

  4. Pending Jobs by Group

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    Pending Jobs by Group Pending Jobs by Group Daily Graph: Weekly Graph: Monthly Graph: Yearly Graph: 2 Year Graph: Last edited: 2011-04-05 14:00:14...

  5. SUB ZERO GROUP, INC.

    Energy.gov [DOE] (indexed site)

    SUB ZERO GROUP, INC. 4717 Hammersley Road. Madison, WI 53711 P: 800.532.7820 P: ... SUBZERO WOLF SUB ZERO GROUP, INC. 4717 Hpmmersley Road, Madison, WI 53711 P: 800.5327820 ...

  6. UFD Working Group 2015

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    Working Group 2015 - Sandia Energy Energy Search Icon Sandia Home Locations Contact Us ... Twitter Google + Vimeo GovDelivery SlideShare UFD Working Group 2015 HomeStationary ...

  7. Running Jobs by Group

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    Running Jobs by Group Running Jobs by Group Daily Graph: Weekly Graph: Monthly Graph: Yearly Graph: 2 Year Graph: Last edited: 2016-04-29 11:34:43

  8. Pending Jobs by Group

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    Pending Jobs by Group Pending Jobs by Group Daily Graph: Weekly Graph: Monthly Graph: Yearly Graph: 2 Year Graph: Last edited: 2016-04-29 11:35:04

  9. A POSSIBLE EVOLUTIONARY SCENARIO OF HIGHLY MAGNETIZED SUPER-CHANDRASEKHAR WHITE DWARFS: PROGENITORS OF PECULIAR TYPE Ia SUPERNOVAE

    SciTech Connect

    Das, Upasana; Mukhopadhyay, Banibrata; Rao, A. R. E-mail: bm@physics.iisc.ernet.in

    2013-04-10

    Several recently discovered peculiar Type Ia supernovae seem to demand an altogether new formation theory that might help explain the puzzling dissimilarities between them and the standard Type Ia supernovae. The most striking aspect of the observational analysis is the necessity of invoking super-Chandrasekhar white dwarfs having masses {approx}2.1-2.8 M{sub Sun }, M{sub Sun} being the mass of Sun, as their most probable progenitors. Strongly magnetized white dwarfs having super-Chandrasekhar masses have already been established as potential candidates for the progenitors of peculiar Type Ia supernovae. Owing to the Landau quantization of the underlying electron degenerate gas, theoretical results yielded the observationally inferred mass range. Here, we sketch a possible evolutionary scenario by which super-Chandrasekhar white dwarfs could be formed by accretion on to a commonly observed magnetized white dwarf, invoking the phenomenon of flux freezing. This opens multiple possible evolution scenarios ending in supernova explosions of super-Chandrasekhar white dwarfs having masses within the range stated above. We point out that our proposal has observational support, such as the recent discovery of a large number of magnetized white dwarfs by the Sloan Digital Sky Survey.

  10. Where the world stands still: turnaround as a strong test of ?CDM cosmology

    SciTech Connect

    Pavlidou, V.; Tomaras, T.N. E-mail: tomaras@physics.uoc.gr

    2014-09-01

    Our intuitive understanding of cosmic structure formation works best in scales small enough so that isolated, bound, relaxed gravitating systems are no longer adjusting their radius; and large enough so that space and matter follow the average expansion of the Universe. Yet one of the most robust predictions of ?CDM cosmology concerns the scale that separates these limits: the turnaround radius, which is the non-expanding shell furthest away from the center of a bound structure. We show that the maximum possible value of the turnaround radius within the framework of the ?CDM model is, for a given mass M, equal to (3GM/?c{sup 2}){sup 1/3}, with G Newton's constant and c the speed of light, independently of cosmic epoch, exact nature of dark matter, or baryonic effects. We discuss the possible use of this prediction as an observational test for ?CDM cosmology. Current data appear to favor ?CDM over alternatives with local inhomogeneities and no ?. However there exist several local-universe structures that have, within errors, reached their limiting size. With improved determinations of their turnaround radii and the enclosed mass, these objects may challenge the limit and ?CDM cosmology.

  11. Neutrinos and dark energy after Planck and BICEP2: data consistency tests and cosmological parameter constraints

    SciTech Connect

    Zhang, Jing-Fei; Geng, Jia-Jia; Zhang, Xin E-mail: gengjiajia163@163.com

    2014-10-01

    The detection of the B-mode polarization of the cosmic microwave background (CMB) by the BICEP2 experiment implies that the tensor-to-scalar ratio r should be involved in the base standard cosmology. In this paper, we extend the ΛCDM r+neutrino/dark radiation models by replacing the cosmological constant with the dynamical dark energy with constant w. Four neutrino plus dark energy models are considered, i.e., the wCDM r ∑ m{sub ν}, wCDM r N{sub eff}, wCDM r ∑ m{sub ν} N{sub eff}, and wCDM r N{sub eff} m{sub ν,sterile}{sup eff} models. The current observational data considered in this paper include the Planck temperature data, the WMAP 9-year polarization data, the baryon acoustic oscillation data, the Hubble constant direct measurement data, the Planck Sunyaev-Zeldovich cluster counts data, the Planck CMB lensing data, the cosmic shear data, and the BICEP2 polarization data. We test the data consistency in the four cosmological models, and then combine the consistent data sets to perform joint constraints on the models. We focus on the constraints on the parameters w, ∑ m{sub ν}, N{sub eff}, and m{sub ν,sterile}{sup eff}.

  12. Chaos-order transition in Bianchi type I non-Abelian Born-Infeld cosmology

    SciTech Connect

    Dyadichev, Vladimir V.; Gal'tsov, Dmitri V.; Moniz, Paulo Vargas

    2005-10-15

    We investigate the Bianchi I cosmology with the homogeneous SU(2) Yang-Mills field governed by the non-Abelian Born-Infeld action. A similar system with the standard Einstein-Yang-Mills (EYM) action is known to exhibit chaotic behavior induced by the Yang-Mills field. When the action is replaced by the Born-Infeld-type non-Abelian action (NBI), the chaos-order transition is observed in the high-energy region. This is interpreted as a smothering effect due to (nonperturbative in {alpha}{sup '}) string corrections to the classical EYM action. We give numerical evidence for the chaos-order transition and present an analytical proof of regularity of color oscillations in the limit of strong Born-Infeld nonlinearity. We also perform a general analysis of the Bianchi I NBI cosmology and derive an exact solution in the case of only the U(1) component excited. Our new exact solution generalizes the Rosen solution of the Bianchi I Einstein-Maxwell cosmology to the U(1) Einstein-Born-Infeld theory.

  13. HoravaLifshitz cosmology, entropic interpretation and quarkhadron phase transition

    SciTech Connect

    Kheyri, F. Khodadi, M. Sepangi, Hamid Reza

    2013-05-15

    Based on the assumptions of the standard model of cosmology, a phase transition associated with chiral symmetry breaking after the electroweak transition has occurred at approximately 10 ?s after the Big Bang to convert a plasma of free quarks and gluons into hadrons. We consider such a phase transition in the context of a deformed HoravaLifshitz cosmology. The Friedmann equation for the deformed HoravaLifshitz universe is obtained using the entropic interpretation of gravity, proposed by Verlinde. We investigate the effects of the parameter ? appearing in the theory on the evolution of the physical quantities relevant to a description of the early universe, namely, the energy density and temperature before, during and after the phase transition. Finally, we study the cross-over phase transition in both high and low temperature regions in view of the recent lattice QCD simulations data. -- Highlights: ? We study the problem of the quarkhadron phase transition in the early universe, in the context of HoravaLifshitz cosmology. ? We conduct this study by including the recently introduced entropic principle. ? We study the behavior of thermodynamical parameters of the theory.

  14. Non-singular bounce scenarios in loop quantum cosmology and the effective field description

    SciTech Connect

    Cai, Yi-Fu; Wilson-Ewing, Edward E-mail: wilson-ewing@phys.lsu.edu

    2014-03-01

    A non-singular bouncing cosmology is generically obtained in loop quantum cosmology due to non-perturbative quantum gravity effects. A similar picture can be achieved in standard general relativity in the presence of a scalar field with a non-standard kinetic term such that at high energy densities the field evolves into a ghost condensate and causes a non-singular bounce. During the bouncing phase, the perturbations can be stabilized by introducing a Horndeski operator. Taking the matter content to be a dust field and an ekpyrotic scalar field, we compare the dynamics in loop quantum cosmology and in a non-singular bouncing effective field model with a non-standard kinetic term at both the background and perturbative levels. We find that these two settings share many important properties, including the result that they both generate scale-invariant scalar perturbations. This shows that some quantum gravity effects of the very early universe may be mimicked by effective field models.

  15. GERLUMPH DATA RELEASE 1: HIGH-RESOLUTION COSMOLOGICAL MICROLENSING MAGNIFICATION MAPS AND eResearch TOOLS

    SciTech Connect

    Vernardos, G.; Fluke, C. J.; Croton, D.; Bate, N. F.

    2014-03-01

    As synoptic all-sky surveys begin to discover new multiply lensed quasars, the flow of data will enable statistical cosmological microlensing studies of sufficient size to constrain quasar accretion disk and supermassive black hole properties. In preparation for this new era, we are undertaking the GPU-Enabled, High Resolution cosmological MicroLensing parameter survey (GERLUMPH). We present here the GERLUMPH Data Release 1, which consists of 12,342 high resolution cosmological microlensing magnification maps and provides the first uniform coverage of the convergence, shear, and smooth matter fraction parameter space. We use these maps to perform a comprehensive numerical investigation of the mass-sheet degeneracy, finding excellent agreement with its predictions. We study the effect of smooth matter on microlensing induced magnification fluctuations. In particular, in the minima and saddle-point regions, fluctuations are enhanced only along the critical line, while in the maxima region they are always enhanced for high smooth matter fractions (≈0.9). We describe our approach to data management, including the use of an SQL database with a Web interface for data access and online analysis, obviating the need for individuals to download large volumes of data. In combination with existing observational databases and online applications, the GERLUMPH archive represents a fundamental component of a new microlensing eResearch cloud. Our maps and tools are publicly available at http://gerlumph.swin.edu.au/.

  16. Modified Baryonic Dynamics: two-component cosmological simulations with light sterile neutrinos

    SciTech Connect

    Angus, G.W.; Gentile, G.; Diaferio, A.; Famaey, B.; Heyden, K.J. van der E-mail: diaferio@ph.unito.it E-mail: gianfranco.gentile@ugent.be

    2014-10-01

    In this article we continue to test cosmological models centred on Modified Newtonian Dynamics (MOND) with light sterile neutrinos, which could in principle be a way to solve the fine-tuning problems of the standard model on galaxy scales while preserving successful predictions on larger scales. Due to previous failures of the simple MOND cosmological model, here we test a speculative model where the modified gravitational field is produced only by the baryons and the sterile neutrinos produce a purely Newtonian field (hence Modified Baryonic Dynamics). We use two-component cosmological simulations to separate the baryonic N-body particles from the sterile neutrino ones. The premise is to attenuate the over-production of massive galaxy cluster halos which were prevalent in the original MOND plus light sterile neutrinos scenario. Theoretical issues with such a formulation notwithstanding, the Modified Baryonic Dynamics model fails to produce the correct amplitude for the galaxy cluster mass function for any reasonable value of the primordial power spectrum normalisation.

  17. HASQARD Focus Group

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    17, 2012 The meeting was called to order by Huei Meznarich, HASQARD Focus Group Chair at 2:05 PM on July 17, 2012 in Conference Room 308 at 2420 Stevens. Those attending were: Huei Meznarich (Focus Group Chair), Cliff Watkins (Focus Group Secretary), Glen Clark, Robert Elkins, Scot Fitzgerald, Larry Markel, Cindy Taylor, Sam Vega, Rich Weiss and Eric Wyse. I. Huei Meznarich requested comments on the minutes from the June 12, 2012 meeting. No HASQARD Focus Group members present stated any

  18. HASQARD Focus Group

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    8, 2013 The meeting was called to order by Huei Meznarich, HASQARD Focus Group Chair at 2:05 PM on June 18, 2013 in Conference Room 308 at 2420 Stevens. Those attending were: Huei Meznarich (Focus Group Chair), Cliff Watkins (Focus Group Secretary), Glen Clark, Scot Fitzgerald, Joan Kessner, Larry Markel, Karl Pool, Chris Sutton, Amanda Tuttle, Rich Weiss and Eric Wyse. I. Huei Meznarich requested comments on the minutes from the May 21, 2013 meeting. No HASQARD Focus Group members present

  19. TEC Communications Topic Group

    Office of Environmental Management (EM)

    procurement - Routing criteriaemergency preparedness Tribal Issues Topic Group * TEPP Navajo Nation (Tom Clawson) - 1404 - Needs Assessment * Identified strengths and...

  20. NIF User Group

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    group NIF User Group The National Ignition Facility User Group provides an organized framework and independent vehicle for interaction between the scientists who use NIF for "Science Use of NIF" experiments and NIF management. Responsibility for NIF and the research programs carried out at NIF resides with the NIF Director. The NIF User Group advises the NIF Director on matters of concern to users, as well as providing a channel for communication for NIF users with funding agencies and