National Library of Energy BETA

Sample records for group supernova cosmology

  1. Supernovae as cosmological probes

    E-Print Network [OSTI]

    Nielsen, Jeppe Trost

    2015-01-01

    The cosmological standard model at present is widely accepted as containing mainly things we do not understand. In particular the appearance of a Cosmological Constant, or dark energy, is puzzling. This was first inferred from the Hubble diagram of a low number of Type Ia supernovae, and later corroborated by complementary cosmological probes. Today, a much larger collection of supernovae is available, and here I perform a rigorous statistical analysis of this dataset. Taking into account how the supernovae are calibrated to be standard candles, we run into some subtleties in the analysis. To our surprise, this new dataset - about an order of bigger than the size of the original dataset - shows, under standard assumptions, only mild evidence of an accelerated universe.

  2. Cosmological and supernova neutrinos

    SciTech Connect (OSTI)

    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 GSÜ, 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.

  3. The cosmological parameters from supernovae

    E-Print Network [OSTI]

    P. Ruiz-Lapuente

    1997-10-02

    Supernovae are bright luminous stellar objects observable up to redshifts close to z~1. They are used to probe the geometry of the Universe and its expansion rate by applying different methods. In this article, I review various approaches used to measure the present expansion rate of the Universe, $H_{0}$, and the paths to determine its matter density $\\Omega_{M}$ and the possible contribution of a non-zero cosmological constant $\\Lambda$. An account is given of the numerical estimates of those cosmological parameters according to the present status of the research.

  4. Type IIP supernovae as cosmological probes: A SEAM distance to SN 1999em

    E-Print Network [OSTI]

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

    2004-01-01

    Type IIP Supernovae as Cosmological Probes: A SEAM Distanceintrinsic brightness, supernovae make excellent cosmologicalstars: atmospheres — supernovae: 1999em Distances from

  5. The supernova cosmology cookbook: Bayesian numerical recipes

    E-Print Network [OSTI]

    Karpenka, N V

    2015-01-01

    Theoretical and observational cosmology have enjoyed a number of significant successes over the last two decades. Cosmic microwave background measurements from the Wilkinson Microwave Anisotropy Probe and Planck, together with large-scale structure and supernova (SN) searches, have put very tight constraints on cosmological parameters. Type Ia supernovae (SNIa) played a central role in the discovery of the accelerated expansion of the Universe, recognised by the Nobel Prize in Physics in 2011. The last decade has seen an enormous increase in the amount of high quality SN observations, with SN catalogues now containing hundreds of objects. This number is expected to increase to thousands in the next few years, as data from next-generation missions, such as the Dark Energy Survey and Large Synoptic Survey Telescope become available. In order to exploit the vast amount of forthcoming high quality data, it is extremely important to develop robust and efficient statistical analysis methods to answer cosmological q...

  6. Four Papers by the Supernova Cosmology Project

    E-Print Network [OSTI]

    Perlmutter, S.; Deustua, S.; Gabi, S.; Goldhaber, G.

    2008-01-01

    K CORRECTIONS FOR TYPE IA SUPERNOVAE AND A TEST FOR SPATIALDILATION USING TYPE IA SUPERNOVAE AS CLOCKS The SupernovaInstitute Thermonuclear Supernovae Conference, Aiguablava,

  7. Four Papers by the Supernova Cosmology Project

    E-Print Network [OSTI]

    Perlmutter, S.; Deustua, S.; Gabi, S.; Goldhaber, G.

    2008-01-01

    Study Institute Thermonuclear Supernovae Conference,STUDY INSTITUTE THERMONUCLEAR SUPERNOVAE Aiguablava, SPAIN20-30, 1995 To appear-in Thermonuclear Supernovae (NATO ASI)

  8. Towards a Cosmological Hubble Diagram for Type II-P Supernovae

    E-Print Network [OSTI]

    2006-01-01

    Supernova 1987A and other supernovae, ed. I. J. Danziger &I.A.U. Colloquium 192: Supernovae (10 years of SN1993J), ed.A. V. 2005, in 1604-2004: Supernovae as Cosmological Light-

  9. Ideal bandpasses for type Ia supernova cosmology

    E-Print Network [OSTI]

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

    2005-01-01

    diversity of type Ia Supernovae, in preparation. Kim, A.error in measurements of supernovae depends on a periodicABSTRACT To use type Ia supernovae as standard candles for

  10. Improving Type Ia Supernova Standard Candle Cosmology Measurements Using Observations of Early-Type Host Galaxies

    E-Print Network [OSTI]

    Meyers, Joshua Evan

    2012-01-01

    Host Galaxies of Type Ia Supernovae Introduction SN Ia Hosts109 C HAPTER 1 Cosmology, Type Ia Supernovae and HostGalaxies Observations of supernovae have played a role in

  11. Alternative cosmology fits supernovae redshifts with no dark energyy

    E-Print Network [OSTI]

    Francis J. M. Farley

    2009-03-17

    Supernovae and radio galaxy redshift data are fitted in an alternative cosmology. The galaxies are assumed to recede with unchanging velocities in a static Robertson-Walker metric with a(t) = 1. An exact fit is obtained with no adjustable parameters. There is no indication that the recession velocities are changing with time, so no call for "dark energy".

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

    SciTech Connect (OSTI)

    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 ? = 0.18 mag. 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.

  13. Tachyon cosmology, supernovae data and the Big Brake singularity

    E-Print Network [OSTI]

    Z. Keresztes; L. Á. Gergely; V. Gorini; U. Moschella; A. Yu. Kamenshchik

    2009-04-21

    We compare the existing observational data on type Ia Supernovae with the evolutions of the universe predicted by a one-parameter family of tachyon models which we have introduced recently in paper \\cite{we-tach}. Among the set of the trajectories of the model which are compatible with the data there is a consistent subset for which the universe ends up in a new type of soft cosmological singularity dubbed Big Brake. This opens up yet another scenario for the future history of the universe besides the one predicted by the standard $\\Lambda$CDM model.

  14. Cosmology with Photometrically-Classified Type Ia Supernovae from the SDSS-II Supernova Survey

    E-Print Network [OSTI]

    Campbell, Heather; Nichol, Robert C; Sako, Masao; Smith, Mathew; Lampeitl, Hubert; Olmstead, Matthew D; Bassett, Bruce; Biswas, Rahul; Brown, Peter; Cinabro, David; Dawson, Kyle S; Dilday, Ben; Foley, Ryan J; Frieman, Joshua A; Garnavich, Peter; Hlozek, Renee; Jha, Saurabh W; Kuhlmann, Steve; Kunz, Martin; Marriner, John; Miquel, Ramon; Richmond, Michael; Riess, Adam; Schneider, Donald P; Sollerman, Jesper; Taylor, Matt; Zhao, Gong-Bo

    2012-01-01

    We present the cosmological analysis of 752 photometrically-classified Type Ia Supernovae (SNe Ia) obtained from the full Sloan Digital Sky Survey II (SDSS-II) Supernova (SN) Survey, supplemented with host-galaxy spectroscopy from the SDSS-III Baryon Oscillation Spectroscopic Survey (BOSS). Our photometric-classification method is based on the SN typing technique of Sako et al. (2011), aided by host galaxy redshifts (0.05cosmological constraints. We quantify and correct for our selection effects (e.g., Malmquist bias) using simulations. When fitting to a flat LambdaCDM cosmological model, we find that our photometric sample alone gives omega_m=0.24+0.07-0.05 (statistical errors only). If we relax the constraint on flatness, then our sample provides competitive joint stati...

  15. UNITY: Confronting Supernova Cosmology's Statistical and Systematic Uncertainties in a Unified Bayesian Framework

    E-Print Network [OSTI]

    Rubin, David; Barbary, Kyle; Boone, Kyle; Chappell, Greta; Currie, Miles; Deustua, Susana; Fagrelius, Parker; Fruchter, Andrew; Hayden, Brian; Lidman, Chris; Nordin, Jakob; Perlmutter, Saul; Saunders, Clare; Sofiatti, Caroline

    2015-01-01

    While recent supernova cosmology research has benefited from improved measurements, current analysis approaches are not statistically optimal and will prove insufficient for future surveys. This paper discusses the limitations of current supernova cosmological analyses in treating outliers, selection effects, shape- and color-standardization relations, intrinsic dispersion, and heterogeneous observations. We present a new Bayesian framework, called UNITY (Unified Nonlinear Inference for Type-Ia cosmologY), that incorporates significant improvements in our ability to confront these effects. We apply the framework to real supernova observations and demonstrate smaller statistical and systematic uncertainties. We verify earlier results that SNe Ia require nonlinear shape and color standardizations, but we now include these nonlinear relations in a statistically well-justified way. This analysis was blinded, in that the method was first validated on simulated data, and no analysis changes were made after transiti...

  16. Lightcurves of thermonuclear supernovae as a probe of the explosion mechanism and their use in cosmology

    E-Print Network [OSTI]

    S. Blinnikov; E. Sorokina

    2002-12-30

    Thermonuclear supernovae are valuable for cosmology but their physics is not yet fully understood. Modeling the development and propagation of nuclear flame is complicated by numerous instabilities. The predictions of supernova light curves still involve some simplifying assumptions, but one can use the comparison of the computed fluxes with observations to constrain the explosion mechanism. In spite of great progress in recent years, a number of issues remains unsolved both in flame physics and light curve modeling.

  17. Cosmological Constant Problems and Renormalization Group

    E-Print Network [OSTI]

    Ilya L. Shapiro; Joan Sola

    2007-01-05

    The Cosmological Constant Problem emerges when Quantum Field Theory is applied to the gravitational theory, due to the enormous magnitude of the induced energy of the vacuum. The unique known solution of this problem involves an extremely precise fine-tuning of the vacuum counterpart. We review a few of the existing approaches to this problem based on the account of the quantum (loop) effects and pay special attention to the ones involving the renormalization group.

  18. Supernovae

    E-Print Network [OSTI]

    Trimble, V; Trimble, V

    1981-01-01

    Young extragalactic supernovae have now been seen as radio,about 2 years, finding supernovae out to the Virgo clusterprobe nucleosynthesis by supernovae. E. Kibblewhite and M.

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

    SciTech Connect (OSTI)

    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.

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

    SciTech Connect (OSTI)

    Zitrin, Adi [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, MS 249-17, Pasadena, CA 91125 (United States); Redlich, Matthias [Universität Heidelberg, Zentrum für Astronomie, Institut für 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.

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

    SciTech Connect (OSTI)

    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 ?6355 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.

  2. A review of "1604-2004: Supernovae as Cosmological Lighthouses." by Massimo Turatto, Stefano Benetti, Luca Zampieri, William Shea, eds. 

    E-Print Network [OSTI]

    Giostra, Alessandro

    2006-01-01

    . Massimo Turatto, Stefano Benetti, Luca Zampieri, William Shea, eds. 1604- 2004: Supernovae as Cosmological Lighthouses. Astronomical Society of the Pacific Conference Series, Vol. 342. San Francisco: ASP, 2005. 512 pp. $77.00. Review by ALESSANDRO... GIOSTRA, ACCADEMIA GEORGICA, TREIA. REVIEWS 223 The proceedings of the international conference, which took place in Padua on 16-19 June 2004 to commemorate the 400 th anniversary of the appearance of Kepler?s Supernova, are collected in this publication...

  3. On silicon group elements ejected by supernovae type IA

    SciTech Connect (OSTI)

    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 Astronomía, 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.

  4. Discovery of a Supernova Explosion at Half the Age of the Universe and its Cosmological Implications

    E-Print Network [OSTI]

    Perlmutter, S.

    2010-01-01

    and Bounds on qo. in Thermonuclear Supernovae (eds P. Ruiz-novae as clocks. in Thermonuclear Supernovae (eds P. Ruiz-distance indicators. in Thermonuclear Supernovae (eds P.

  5. Type Ia Supernova Intrinsic Magnitude Dispersion and the Fitting of Cosmological Parameters

    E-Print Network [OSTI]

    Kim, Alex G

    2011-01-01

    Applied to Type Ia supernovae, my strategy provides adata sets. Subject headings: Supernovae: Data Analysis andhomogeneous nature of Type Ia supernovae (SNe Ia) makes them

  6. Verifying the Cosmological Utility of Type Ia Supernovae: Implications of a Dispersion in the Ultraviolet Spectra

    E-Print Network [OSTI]

    Ellis, R. S.

    2008-01-01

    Utility of Type Ia Supernovae: Implications of a Dispersionheadings: surveys – supernovae: general – cosmologicalparameters Introduction Supernovae of Type Ia (SNe Ia) are

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

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    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

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

    SciTech Connect (OSTI)

    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.

  9. Feasibility of Measuring the Cosmological Constant [LAMBDA] and Mass Density [Omega] using Type Ia Supernovae

    E-Print Network [OSTI]

    Goobar, A.

    2008-01-01

    at z = 1. uncertainty for supernovae at z = 1. mR Adding theMass Density .Q Using Type Ia Supernovae A. Goobar and S.Density Q Using Type Ia Supernovae Ariel Goobar l and Saul

  10. Discovery of a Supernova Explosion at Half the Age of the Universe and its Cosmological Implications

    E-Print Network [OSTI]

    Perlmutter, S.

    2010-01-01

    ULDA Access Guide No.6: Supernovae (eds Cappellaro, E. ,of light curves of supernovae type 1. Astra. Astrophys.magnitudes of Type la supernovae. Astrophys. J. 413, LI05-

  11. Optimal Extraction of Cosmological Information from Supernova Data in the Presence of Calibration Uncertainties

    E-Print Network [OSTI]

    Kim, Alex G.; Miquel, Ramon

    2005-01-01

    The study of type-la supernovae provided the firstResults from more recent supernovae surveys [5, 6] further8] techniques to turn type-la supernovae into standardized

  12. Supercal: Cross-Calibration of Multiple Photometric Systems to Improve Cosmological Measurements with Type Ia Supernovae

    E-Print Network [OSTI]

    Scolnic, D; Riess, A G; Rest, A; Schlafly, E; Foley, R J; Finkbeiner, D; Tang, C; Burgett, W S; Chambers, K C; Draper, P W; Hodapp, K W; Huber, M E; Kaiser, N; Kudritzki, R P; Magnier, E A; Metcalfe, N; Stubbs, C W

    2015-01-01

    Current cosmological analyses which use Type Ia supernova (SN Ia) observations combine SN samples to expand the redshift range beyond that of a single sample and increase the overall sample size. The inhomogeneous photometric calibration between different SN samples is one of the largest systematic uncertainties of the cosmological parameter estimation. To place these different samples on a single system, analyses currently use observations of a small sample of very bright flux standards on the $HST$ system. We propose a complementary method, called `Supercal', in which we use measurements of secondary standards in each system, compare these to measurements of the same stars in the Pan-STARRS1 (PS1) system, and determine offsets for each system relative to PS1, placing all SN observations on a single, consistent photometric system. PS1 has observed $3\\pi$ of the sky and has a relative calibration of better than 5 mmag (for $\\sim15

  13. Constraining Dark Energy and Cosmological Transition Redshift with Type Ia Supernovae

    E-Print Network [OSTI]

    F. Y. Wang; Z. G. Dai

    2007-08-30

    The property of dark energy and the physical reason for acceleration of the present universe are two of the most difficult problems in modern cosmology. The dark energy contributes about two-thirds of the critical density of the present universe from the observations of type-Ia supernova (SNe Ia) and anisotropy of cosmic microwave background (CMB).The SN Ia observations also suggest that the universe expanded from a deceleration to an acceleration phase at some redshift, implying the existence of a nearly uniform component of dark energy with negative pressure. We use the ``gold'' sample containing 157 SNe Ia and two recent well-measured additions, SNe Ia 1994ae and 1998aq to explore the properties of dark energy and the transition redshift. For a flat universe with the cosmological constant, we measure $\\Omega_{M}=0.28_{-0.05}^{+0.04}$, which is consistent with Riess et al. The transition redshift is $z_{T}=0.60_{-0.08}^{+0.06}$. We also discuss several dark energy models that define the $w(z)$ of the parameterized equation of state of dark energy including one parameter and two parameters ($w(z)$ being the ratio of the pressure to energy density). Our calculations show that the accurately calculated transition redshift varies from $z_{T}=0.29_{-0.06}^{+0.07}$ to $z_{T}=0.60_{-0.08}^{+0.06}$ across these models. We also calculate the minimum redshift $z_{c}$ at which the current observations need the universe to accelerate.

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

    SciTech Connect (OSTI)

    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, Université Pierre et Marie Curie Paris 6, Universié 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.

  15. Identifying cosmological perturbations in group field theory condensates

    E-Print Network [OSTI]

    Steffen Gielen

    2015-08-03

    One proposal for deriving effective cosmological models from theories of quantum gravity is to view the former as a mean-field (hydrodynamic) description of the latter, which describes a universe formed by a 'condensate' of quanta of geometry. This idea has been successfully applied within the setting of group field theory (GFT), a quantum field theory of 'atoms of space' which can form such a condensate. We further clarify the interpretation of this mean-field approximation, and show how it can be used to obtain a semiclassical description of the GFT, in which the mean field encodes a classical statistical distribution of geometric data. In this sense, GFT condensates are quantum homogeneous geometries that also contain statistical information about cosmological inhomogeneities. We show in the isotropic case how this information can be extracted from geometric GFT observables and mapped to quantities of observational interest. Basic uncertainty relations of (non-commutative) Fourier transforms imply that this statistical description can only be compatible with the observed near-homogeneity of the Universe if the typical length scale associated to the distribution is much larger than the fundamental 'Planck' scale. As an example of effective cosmological equations derived from the GFT dynamics, we then use a simple approximation in one class of GFT models to derive the 'improved dynamics' prescription of holonomy corrections in loop quantum cosmology.

  16. Cosmological-model-parameter determination from satellite-acquired type Ia and IIP Supernova Data

    E-Print Network [OSTI]

    Podariu, Silviu; Nugent, Peter; Ratra, Bharat

    2000-01-01

    Since the B i g B a n g : Supernovae a n d G a m m a - R a ythe universe—space vehicles—supernovae: general Introductionbased on T y p e l a supernovae (hereafter S N e la) have

  17. Identifying cosmological perturbations in group field theory condensates

    E-Print Network [OSTI]

    Gielen, Steffen

    2015-01-01

    One proposal for deriving effective cosmological models from theories of quantum gravity is to view the former as a mean-field (hydrodynamic) description of the latter, which describes a universe formed by a 'condensate' of quanta of geometry. This idea has been successfully applied within the setting of group field theory (GFT), a quantum field theory of 'atoms of space' which can form such a condensate. We further clarify the interpretation of this mean-field approximation, and show how it can be used to obtain a semiclassical description of the GFT, in which the mean field encodes a classical statistical distribution of geometric data. In this sense, GFT condensates are quantum homogeneous geometries that also contain statistical information about cosmological inhomogeneities. We show in the isotropic case how this information can be extracted from geometric GFT observables and mapped to quantities of observational interest. Basic uncertainty relations of (non-commutative) Fourier transforms imply that thi...

  18. Higgs boson, renormalization group, and naturalness in cosmology

    E-Print Network [OSTI]

    A. O. Barvinsky; A. Yu. Kamenshchik; C. Kiefer; A. A. Starobinsky; C. F. Steinwachs

    2012-11-05

    We consider the renormalization group improvement in the theory of the Standard Model (SM) Higgs boson playing the role of an inflaton with a strong non-minimal coupling to gravity. At the one-loop level with the running of constants taken into account, it leads to a range of the Higgs mass that is entirely determined by the lower WMAP bound on the cosmic microwave background (CMB) spectral index. We find that the SM phenomenology is sensitive to current cosmological data, which suggests to perform more precise CMB measurements as a SM test complementary to the LHC program. By using the concept of a field-dependent cutoff, we show the naturalness of the gradient and curvature expansion in this model within the conventional perturbation theory range of the SM. We also discuss the relation of these results to two-loop calculations and the limitations of the latter caused by parametrization and gauge dependence problems.

  19. Accelerated Cosmological Models in Modified Gravity tested by distant Supernovae SNIa data

    E-Print Network [OSTI]

    Andrzej Borowiec; Wlodzimierz Godlowski; Marek Szydlowski

    2006-08-03

    Recent supernovae of type Ia measurements and other astronomical observations suggest that our universe is in accelerating phase of evolution at the present epoch. While a dark energy of unknown form is usually proposed as the most feasible mechanism for the acceleration, there are appears some alternative conception that some effects arising from generalization of Einstein equation can mimic dark energy through a modified Friedmann equation. In this work we investigate some observational constraints on modified Friedmann equation obtained from generalized Lagrangian ${\\cal L} \\propto R^n$ in minimal coupling with matter in Palatini formalism. We mainly concentrate on the constraints of model parameters from distant supernovae but other constraint from baryon oscillation prior is also considered. We obtain the confidence levels on two additional model parameter ($n$,$\\Omega_{m,0}$). We conclude that the FRW model of First-Order Non-linear gravity survives several observational test like SNIa observation and baryon oscillation peaks. We find preferred value of $\\Omega_{m,0} \\simeq 0.3$ from combined analysis of supernovae data and baryon oscillation peak. For deeper statistical analysis we apply Akaike and Bayesian information criteria of model selection for comparison prediction of the model with prediction of concordance $\\Lambda$CDM model.

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

    SciTech Connect (OSTI)

    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.

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

    SciTech Connect (OSTI)

    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}.

  2. Snapping Supernovae at z>1.7

    E-Print Network [OSTI]

    Aldering, Greg

    2009-01-01

    LBNL-61879 Snapping Supernovae at z > 1.7 Greg Aldering,of California. Snapping Supernovae at z > 1.7 Greg Aldering,of very high redshift Type Ia supernovae for cosmology and

  3. Timescale stretch parameterization of Type Ia supernova B-band light curves

    E-Print Network [OSTI]

    2001-01-01

    the light curve of Type Ia supernovae discovered by theof the high-redshift supernovae. This work was supported inobjects. Subject headings: supernovae: general – cosmology:

  4. Aspherical supernovae

    SciTech Connect (OSTI)

    Kasen, Daniel Nathan

    2004-05-21

    Although we know that many supernovae are aspherical, the exact nature of their geometry is undetermined. Because all the supernovae we observe are too distant to be resolved, the ejecta structure can't be directly imaged, and asymmetry must be inferred from signatures in the spectral features and polarization of the supernova light. The empirical interpretation of this data, however, is rather limited--to learn more about the detailed supernova geometry, theoretical modeling must been undertaken. One expects the geometry to be closely tied to the explosion mechanism and the progenitor star system, both of which are still under debate. Studying the 3-dimensional structure of supernovae should therefore provide new break throughs in our understanding. The goal of this thesis is to advance new techniques for calculating radiative transfer in 3-dimensional expanding atmospheres, and use them to study the flux and polarization signatures of aspherical supernovae. We develop a 3-D Monte Carlo transfer code and use it to directly fit recent spectropolarimetric observations, as well as calculate the observable properties of detailed multi-dimensional hydrodynamical explosion simulations. While previous theoretical efforts have been restricted to ellipsoidal models, we study several more complicated configurations that are tied to specific physical scenarios. We explore clumpy and toroidal geometries in fitting the spectropolarimetry of the Type Ia supernova SN 2001el. We then calculate the observable consequences of a supernova that has been rendered asymmetric by crashing into a nearby companion star. Finally, we fit the spectrum of a peculiar and extraordinarily luminous Type Ic supernova. The results are brought to bear on three broader astrophysical questions: (1) What are the progenitors and the explosion processes of Type Ia supernovae? (2) What effect does asymmetry have on the observational diversity of Type Ia supernovae, and hence their use in cosmology? (3) And , what are some of the physical properties of Type Ic supernovae, believed to be associated with gamma-ray bursts?

  5. Rates and progenitors of type Ia supernovae

    SciTech Connect (OSTI)

    Wood-Vasey, William Michael

    2004-08-16

    The remarkable uniformity of Type Ia supernovae has allowed astronomers to use them as distance indicators to measure the properties and expansion history of the Universe. However, Type Ia supernovae exhibit intrinsic variation in both their spectra and observed brightness. The brightness variations have been approximately corrected by various methods, but there remain intrinsic variations that limit the statistical power of current and future observations of distant supernovae for cosmological purposes. There may be systematic effects in this residual variation that evolve with redshift and thus limit the cosmological power of SN Ia luminosity-distance experiments. To reduce these systematic uncertainties, we need a deeper understanding of the observed variations in Type Ia supernovae. Toward this end, the Nearby Supernova Factory has been designed to discover hundreds of Type Ia supernovae in a systematic and automated fashion and study them in detail. This project will observe these supernovae spectrophotometrically to provide the homogeneous high-quality data set necessary to improve the understanding and calibration of these vital cosmological yardsticks. From 1998 to 2003, in collaboration with the Near-Earth Asteroid Tracking group at the Jet Propulsion Laboratory, a systematic and automated searching program was conceived and executed using the computing facilities at Lawrence Berkeley National Laboratory and the National Energy Research Supercomputing Center. An automated search had never been attempted on this scale. A number of planned future large supernovae projects are predicated on the ability to find supernovae quickly, reliably, and efficiently in large datasets. A prototype run of the SNfactory search pipeline conducted from 2002 to 2003 discovered 83 SNe at a final rate of 12 SNe/month. A large, homogeneous search of this scale offers an excellent opportunity to measure the rate of Type Ia supernovae. This thesis presents a new method for analyzing the true sensitivity of a multi-epoch supernova search and finds a Type Ia supernova rate from z {approx} 0.01-0.1 of r{sub V} = 4.26{sub -1.93 -0.10}{sup +1.39 +0.10} h{sup 3} x 10{sup -4} SNe Ia/yr/Mpc{sup 3} from a preliminary analysis of a subsample of the SNfactory prototype search. Several unusual supernovae were found in the course of the SNfactory prototype search. One in particular, SN 2002ic, was the first SN Ia to exhibit convincing evidence for a circumstellar medium and offers valuable insight into the progenitors of Type Ia supernovae.

  6. The farthest known supernova: Support for an accelerating universe and a glimpse of the epoch of deceleration

    E-Print Network [OSTI]

    2001-01-01

    ULDA Access Guide No. 6: Supernovae (The Netherlands: ESA)Livio, M. 2000, in Type Ia Supernovae: Theory and Cosmology,T. 2000, in Type Ia Supernovae: Theory and Cosmology, eds.

  7. Cosmological-Billiards Groups and self-adjoint BKL Transfer Operators

    E-Print Network [OSTI]

    Orchidea Maria Lecian

    2015-07-25

    Cosmological billiards arise as a map of the solution of the Einstein equations, when the most general symmetry for the metric tensor is hypothesized, and points are considered as spatially decoupled in the asymptotic limit towards the cosmological singularity, according to the BKL (Belinski Khalatnikov Lifshitz) paradigm. In $4=3+1$ dimensions, two kinds of cosmological billiards are considered: the so-called 'big billiard' which accounts for pure gravity, and the 'small billiard', which is a symmetry-reduced version of the previous one, and is obtained when the 'symmetry walls' are considered. The solution of Einstein field equations is this way mapped to the (discrete) Poincar\\'e map of a billiard ball on the sides of a triangular billiard table, in the Upper Poincar\\'e Half Plane (UPHP). The billiard modular group is the scheme within which the dynamics of classical chaotic systems on surfaces of constant negative curvature is analyzed. The periodic orbits of the two kinds of billiards are classified, according to the different symmetry-quotienting mechanisms. The differences with the description implied by the billiard modular group are investigated and outlined. In the quantum regime, the eigenvalues (i.e. the sign that wavefunctions acquire according to quantum BKL maps) for periodic phenomena of the BKL maps on the Maass wavefunctions are classified. The complete spectrum of the semiclassical operators which act as BKL map for periodic orbits is obtained. Differently form the case of the modular group, here it is shown that the semiclassical transfer operator for Cosmological Billiards is not only the adjoint operator of the one acting on the Maass waveforms, but that the two operators are the same \\it{self-adjoint} operator, thus outlining a different approach to the Langlands Jaquet correspondence.

  8. 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...

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

    SciTech Connect (OSTI)

    Rest, A. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Scolnic, D.; Riess, A.; Rodney, S.; Brout, D. [Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (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); Huber, M. E.; Tonry, J. L. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Narayan, G. [Department of Physics, Harvard University, 17 Oxford Street, Cambridge, MA 02138 (United States); Smartt, S. J. [Astrophysics Research Centre, School of Mathematics and Physics, Queens University Belfast, Belfast BT71NN (United Kingdom); Schlafly, E. [Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg (Germany); Botticella, M. T. [INAF-Osservatorio Astronomico di Capodimonte, Salita Moiariello 16, I-80131 Napoli (Italy); 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 ?{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 2.3? 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 <2?. We cannot conclude whether the tension with flat ?CDM 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.

  10. The nearby supernova factory

    SciTech Connect (OSTI)

    Wood-Vasey, W.M.; Aldering, G.; Lee, B.C.; Loken, S.; Nugent, P.; Perlmutter, S.; Siegrist, J.; Wang, L.; Antilogus, P.; Astier, P.; Hardin, D.; Pain, R.; Copin, Y.; Smadja, G.; Gangler, E.; Castera, A.; Adam, G.; Bacon, R.; Lemonnier, J.-P.; Pecontal, A.; Pecontal, E.; Kessler, R.

    2004-01-23

    The Nearby Supernova Factory (SNfactory) is an ambitious project to find and study in detail approximately 300 nearby Type Ia supernovae (SNe Ia) at redshifts 0.03 < z < 0.08. This program will provide an exceptional data set of well-studied SNe in the nearby smooth Hubble flow that can be used as calibration for the current and future programs designed to use SNe to measure the cosmological parameters. The first key ingredient for this program is a reliable supply of Hubble-flow SNe systematically discovered in unprecedented numbers using the same techniques as those used in distant SNe searches. In 2002, 35 SNe were found using our test-bed pipeline for automated SN search and discovery. The pipeline uses images from the asteroid search conducted by the Near Earth Asteroid Tracking group at JPL. Improvements in our subtraction techniques and analysis have allowed us to increase our effective SN discovery rate to {approx}12 SNe/month in 2003.

  11. Thermonuclear Supernovae

    E-Print Network [OSTI]

    F. K. Roepke

    2008-04-14

    The application of Type Ia supernovae (SNe Ia) as distance indicators in cosmology calls for a sound understanding of these objects. Recent years have seen a brisk development of astrophysical models which explain SNe Ia as thermonuclear explosions of white dwarf stars. While the evolution of the progenitor is still uncertain, the explosion mechanism certainly involves the propagation of a thermonuclear flame through the white dwarf star. Three-dimensional hydrodynamical simulations allowed to study a wide variety of possibilities involving subsonic flame propagation (deflagrations), flames accelerated by turbulence, and supersonic detonations. These possibilities lead to a variety of scenarios. I review the currently discussed approaches and present some recent results from simulations of the turbulent deflagration model and the delayed detonation model.

  12. Kaisey Mandel Supernova Group

    E-Print Network [OSTI]

    Wolfe, Patrick J.

    to instability (single / double degenerate) · Thermonuclear Explosion: Deflagration/Detonation · Nickel to Cobalt

  13. Scaling Cosmology

    E-Print Network [OSTI]

    Winfried Zimdahl; Diego Pavón

    2002-10-22

    We show that with the help of a suitable coupling between dark energy and cold dark matter it is possible to reproduce any scaling solution $\\rho _{X}\\propto \\rho_{M}a^{\\xi}$, where $\\rho_{X}$ and $\\rho_{M}$ are the densities of dark energy and dark matter, respectively. We demonstrate how the case $\\xi = 1$ alleviates the coincidence problem. Future observations of supernovae at high redshift as well as quasar pairs which are planned to discriminate between different cosmological models will also provide direct constraints on the coupling between dark matter and dark energy.

  14. Aspherical supernovae

    E-Print Network [OSTI]

    Kasen, Daniel Nathan

    2004-01-01

    g h t : T h e Physics of Supernovae, ed. W . H i l l e b r ar a n c h , D . 1990, i n Supernovae, Jerusalem W i n t e ri o , M . 2000, i n T y p e Ia Supernovae, T h e o r y a n d

  15. Defining photometric peculiar type Ia supernovae

    SciTech Connect (OSTI)

    González-Gaitán, S.; Pignata, G.; Förster, F.; Gutiérrez, C. P.; Bufano, F.; Galbany, L.; Hamuy, M.; De Jaeger, T. [Millennium Institute of Astrophysics, Casilla 36-D, Santiago (Chile); Hsiao, E. Y.; Phillips, M. M. [Carnegie Observatories, Las Campanas Observatory, Casilla 601, La Serena (Chile); Folatelli, G. [Kavli Institute for the Physics and Mathematics of the Universe, the University of Tokyo, Kashiwa 277-8583 (Kavli IPMU, WPI) (Japan); Anderson, J. P., E-mail: sgonzale@das.uchile.cl [European Southern Observatory, Alonso de Córdova 3107, Casilla 19, Santiago (Chile)

    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.

  16. The distant type Ia supernova rate

    SciTech Connect (OSTI)

    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.

    2002-05-20

    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.

  17. Renormalization-group running of the cosmological constant and its implication for the Higgs boson mass in the Standard Model

    E-Print Network [OSTI]

    A. Babic; B. Guberina; R. Horvat; H. Stefancic

    2001-11-16

    The renormalization-group equation for the zero-point energies associated with vacuum fluctuations of massive fields from the Standard Model is examined. Our main observation is that at any scale the running is necessarily dominated by the heaviest degrees of freedom, in clear contradistinction with the Appelquist & Carazzone decoupling theorem. Such an enhanced running would represent a disaster for cosmology, unless a fine-tuned relation among the masses of heavy particles is imposed. In this way, we obtain $m_H \\simeq 550 GeV$ for the Higgs mass, a value safely within the unitarity bound, but far above the more stringent triviality bound for the case when the validity of the Standard Model is pushed up to the grand unification (or Planck) scale.

  18. The nearby supernova factory

    E-Print Network [OSTI]

    2004-01-01

    cadence gives fewer supernovae but better constraints on thein 2003. Key words: supernovae, galaxies Preprint submitted2004 Introduction Type Ia supernovae (SNe Ia) have proven

  19. Supernova bangs as a tool to study big bang

    SciTech Connect (OSTI)

    Blinnikov, S. I., E-mail: Sergei.Blinnikov@itep.ru [Institute for Theoretical and Experimental Physics (Russian Federation)

    2012-09-15

    Supernovae and gamma-ray bursts are the most powerful explosions in observed Universe. This educational review tells about supernovae and their applications in cosmology. It is explained how to understand the production of light in the most luminous events with minimum required energy of explosion. These most luminous phenomena can serve as primary cosmological distance indicators. Comparing the observed distance dependence on red shift with theoretical models one can extract information on evolution of the Universe from Big Bang until our epoch.

  20. Supernovae. Part II: The aftermath

    E-Print Network [OSTI]

    Trimble, V; Trimble, V

    1983-01-01

    R. Viswanathan, 1980, As- Supernovae. Part II ExperimentalSmith, 1982, Astrophys. Supernovae. Chevalier, R. A. , andC. B. , 1974, Ed. , Supernovae and Supernova Rem- nants,

  1. Evidence for cosmological particle creation?

    E-Print Network [OSTI]

    Pigozzo, C; Alcaniz, J S; Borges, H A; Fabris, J C

    2015-01-01

    A joint analysis of the linear matter power spectrum, distance measurements from type Ia supernovae and the position of the first peak in the anisotropy spectrum of the cosmic microwave background indicates a cosmological, late-time dark matter creation at 99% confidence level.

  2. Overview of the nearby supernova factory

    SciTech Connect (OSTI)

    Aldering, Greg; Adam, Gilles; Antilogus, Pierre; Astier, Pierre; Bacon, Roland; Bongard, S.; Bonnaud, C.; Copin, Yannick; Hardin, D.; Howell, D. Andy; Lemmonnier, Jean-Pierre; Levy, J.-M.; Loken, S.; Nugent, Peter; Pain, Reynald; Pecontal, Arlette; Pecontal, Emmanuel; Perlmutter, Saul; Quimby, Robert; Schahmaneche, Kyan; Smadja, Gerard; Wood-Vasey, W. Michael

    2002-07-29

    The Nearby Supernova Factory (SNfactory) is an international experiment designed to lay the foundation for the next generation of cosmology experiments (such as CFHTLS, wP, SNAP and LSST) which will measure the expansion history of the Universe using Type Ia supernovae. The SNfactory will discover and obtain frequent lightcurve spectrophotometry covering 3200-10000 {angstrom} for roughly 300 Type Ia supernovae at the low-redshift end of the smooth Hubble flow. The quantity, quality, breadth of galactic environments, and homogeneous nature of the SNfactory dataset will make it the premier source of calibration for the Type Ia supernova width-brightness relation and the intrinsic supernova colors used for K-correction and correction for extinction by host-galaxy dust. This dataset will also allow an extensive investigation of additional parameters which possibly influence the quality of Type Ia supernovae as cosmological probes. The SNfactory search capabilities and follow-up instrumentation include wide-field CCD imagers on two 1.2-m telescopes (via collaboration with the Near Earth Asteroid Tracking team at JPL and the QUEST team at Yale), and a two-channel integral-field-unit optical spectrograph/imager being fabricated for the University of Hawaii 2.2-m telescope. In addition to ground-based follow-up, UV spectra for a subsample of these supernovae will be obtained with HST. The pipeline to obtain, transfer via wireless and standard internet, and automatically process the search images is in operation. Software and hardware development is now underway to enable the execution of follow-up spectroscopy of supernova candidates at the Hawaii 2.2-m telescope via automated remote control of the telescope and the IFU spectrograph/imager.

  3. Type Ia Supernova Progenitors, Environmental Effects, and Cosmic Supernova Rates

    E-Print Network [OSTI]

    Ken'ichi Nomoto; Hideyuki Umeda; Izumi Hachisu; Mariko Kato; Chiaki Kobayashi; Takuji Tsujimoto

    1999-07-27

    Relatively uniform light curves and spectral evolution of Type Ia supernovae (SNe Ia) have led to the use of SNe Ia as a ``standard candle'' to determine cosmological parameters, such as the Hubble constant, the density parameter, and the cosmological constant. Whether a statistically significant value of the cosmological constant can be obtained depends on whether the peak luminosities of SNe Ia are sufficiently free from the effects of cosmic and galactic evolutions. Here we first review the single degenerate scenario for the Chandrasekhar mass white dwarf (WD) models of SNe Ia. We identify the progenitor's evolution and population with two channels: (1) the WD+RG (red-giant) and (2) the WD+MS (near main-sequence He-rich star) channels. In these channels, the strong wind from accreting white dwarfs plays a key role, which yields important age and metallicity effects on the evolution. We then address the questions whether the nature of SNe Ia depends systematically on environmental properties such as metallicity and age of the progenitor system and whether significant evolutionary effects exist. We suggest that the variation of the carbon mass fraction $X$(C) in the C+O WD (or the variation of the initial WD mass) causes the diversity of the brightness of SNe Ia. This model can explain the observed dependence of SNe Ia brighness on the galaxy types. Finally, applying the metallicity effect on the evolution of SN Ia progenitors, we make a prediction of the cosmic supernova rate history as a composite of the supernova rates in different types of galaxies.

  4. Supernova Hunting with Supercomputers

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

    Supercomputers Supernova Hunting with Supercomputers Berkeley researchers provide "roadmap" and tools for finding and studying Type Ia supernovae in their natural habitat May...

  5. THE TIP OF THE RED GIANT BRANCH DISTANCES TO TYPE Ia SUPERNOVA HOST GALAXIES. II. M66 AND M96 IN THE LEO I GROUP

    SciTech Connect (OSTI)

    Lee, Myung Gyoon; Jang, In Sung, E-mail: mglee@astro.snu.ac.kr, E-mail: isjang@astro.snu.ac.kr [Astronomy Program, Department of Physics and Astronomy, Seoul National University, Gwanak-gu, Seoul 151-742 (Korea, Republic of)

    2013-08-10

    M66 and M96 in the Leo I Group are nearby spiral galaxies hosting Type Ia supernovae (SNe Ia). We estimate the distances to these galaxies from the luminosity of the tip of the red giant branch (TRGB). We obtain VI photometry of resolved stars in these galaxies from F555W and F814W images in the Hubble Space Telescope archive. From the luminosity function of these red giants, we find the TRGB I-band magnitude to be I{sub TRGB} = 26.20 {+-} 0.03 for M66 and 26.21 {+-} 0.03 for M96. These values yield distance modulus (m - M){sub 0} = 30.12 {+-} 0.03(random) {+-} 0.12(systematic) for M66 and (m - M){sub 0} = 30.15 {+-} 0.03(random) {+-} 0.12(systematic) for M96. These results show that they are indeed the members of the same group. With these results we derive absolute maximum magnitudes of two SNe (SN 1989B in M66 and SN 1998bu in M96). V-band magnitudes of these SNe Ia are {approx}0.2 mag fainter than SN 2011fe in M101, one of the nearest recent SNe Ia. We also derive near-infrared magnitudes for SN 1998bu. Optical magnitudes of three SNe Ia (SN 1989B, SN 1998bu, and SN 2011fe) based on TRGB analysis yield a Hubble constant, H{sub 0} = 68.4 {+-} 2.6(random) {+-} 3.7(systematic) km s{sup -1} Mpc{sup -1}. This value is similar to the values derived from recent WMAP9 results, H{sub 0} = 69.32 {+-} 0.80 km s{sup -1} Mpc{sup -1}, and from Planck results, H{sub 0} = 67.3 {+-} 1.2 km s{sup -1} Mpc{sup -1}, but smaller than other recent determinations based on Cepheid calibration for SNe Ia luminosity, H{sub 0} = 74 {+-} 3 km s{sup -1} Mpc{sup -1}.

  6. Unparticle effects in Supernovae cooling

    E-Print Network [OSTI]

    Prasanta Kumar Das

    2007-11-08

    Recently H. Georgi suggested that a scale invariant unparticle ${\\mathcal{U}}$ sector with an infrared fixed point at high energy can couple with the SM matter via a higher-dimensional operator suppressed by a high cut-off scale. Intense phenomenological search of this unparticle sector in the collider and flavour physics context has already been made. Here we explore it's impact in cosmology, particularly it's possible role in the supernovae cooling. We found that the energy-loss rate (and thus the cooling) is strongly dependent on the effective scale \\LdaU and the anomalous dimension \\dU of this unparticle theory.

  7. Viable cosmological solutions in massive bimetric gravity

    SciTech Connect (OSTI)

    Koennig, Frank; Amendola, Luca [Institut für Theoretische Physik, Ruprecht-Karls-Universität Heidelberg, Philosophenweg 16, Heidelberg, 69120 (Germany); Patil, Aashay, E-mail: koennig@thphys.uni-heidelberg.de, E-mail: aashay@students.iiserpune.ac.in, E-mail: l.amendola@thphys.uni-heidelberg.de [Department of Physics, Indian Institute of Science Education and Research, Dr. Homi Bhabha Road, Pashan, Pune, 411008 (India)

    2014-03-01

    We find the general conditions for viable cosmological solution at the background level in bigravity models. Furthermore, we constrain the parameters by comparing to the Union 2.1 supernovae catalog and identify, in some cases analytically, the best fit parameter or the degeneracy curve among pairs of parameters. We point out that a bimetric model with a single free parameter predicts a simple relation between the equation of state and the density parameter, fits well the supernovae data and is a valid and testable alternative to ?CDM. Additionally, we identify the conditions for a phantom behavior and show that viable bimetric cosmologies cannot cross the phantom divide.

  8. Dust around Type Ia supernovae

    E-Print Network [OSTI]

    Wang, Lifan

    2005-01-01

    Dust around Type Ia supernovae Lifan Wang 1,2 LawrenceIa. Subject headings: Supernovae: General, Dust, Extinctionline) bands for Type Ia supernovae. (a), upper panel, shows

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

    Office of Scientific and Technical Information (OSTI)

    European Southern Observ. NOAO, Tucson Fermilab Cerro-Tololo InterAmerican Obs. Baltimore, Space Telescope Sci. Johns Hopkins U. Res. Sch. Astron. Astrophys., Weston Creek...

  10. Verifying the use of supernovae as probes of the cosmic expansion

    E-Print Network [OSTI]

    Ellis, R; Ellis, Richard; Sullivan, Mark

    2000-01-01

    We present preliminary results of a follow-up survey which aims to characterise in detail those galaxies which hosted Type Ia supernovae found by the Supernova Cosmology Project (SCP). Our survey has two components: Hubble Space Telescope imaging with STIS and Keck spectroscopy with ESI, the goal being to classify each host galaxy into one of three broad morphological/spectral classes and hence to investigate the dependence of supernovae properties on host galaxy type over a large range in redshift. Of particular interest is the supernova Hubble diagram characterised by host galaxy class which suggests that most of the scatter arises from those occurring in late-type irregulars. Supernovae hosted by (presumed dust-free) E/S0 galaxies closely follow the adopted SCP cosmological model. Although larger datasets are required, we cannot yet find any significant difference in the light curves of distant supernovae hosted in different galaxy types.

  11. iCosmo: an Interactive Cosmology Package

    E-Print Network [OSTI]

    Alexandre Refregier; Adam Amara; Thomas Kitching; Anais Rassat

    2011-04-28

    Aims: The interactive software package iCosmo, designed to perform cosmological calculations is described. Methods: iCosmo is a software package to perform interactive cosmological calculations for the low redshift universe. Computing distance measures, the matter power spectrum, and the growth factor is supported for any values of the cosmological parameters. It also computes derived observed quantities for several cosmological probes such as cosmic shear, baryon acoustic oscillations and type Ia supernovae. The associated errors for these observables can be derived for customised surveys, or for pre-set values corresponding to current or planned instruments. The code also allows for the calculation of cosmological forecasts with Fisher matrices which can be manipulated to combine different surveys and cosmological probes. The code is written in the IDL language and thus benefits from the convenient interactive features and scientific library available in this language. iCosmo can also be used as an engine to perform cosmological calculations in batch mode, and forms a convenient adaptive platform for the development of further cosmological modules. With its extensive documentation, it may also serve as a useful resource for teaching and for newcomers in the field of cosmology. Results: The iCosmo package is described with various examples and command sequences. The code is freely available with documentation at http://www.icosmo.org, along with an interactive web interface and is part of the Initiative for Cosmology, a common archive for cosmological resources.

  12. Thermonuclear Burning Regimes and the Use of SNe Ia in Cosmology

    E-Print Network [OSTI]

    E. I. Sorokina; S. I. Blinnikov; O. S. Bartunov

    1999-10-02

    The calculations of the light curves of thermonuclear supernovae are carried out by a method of multi-group radiation hydrodynamics. The effects of spectral lines and expansion opacity are taken into account. The predictions for UBVI fluxes are given. The values of rise time for B and V bands found in our calculations are in good agreement with the observed values. We explain why our results for the rise time have more solid physical justification than those obtained by other authors. It is shown that small variations in the chemical composition of the ejecta, produced in the explosions with different regimes of nuclear burning, can influence drastically the light curve decline in the B band and, to a lesser extent, in the V band. We argue that recent results on positive cosmological constant Lambda, found from the high redshift supernova observations, could be wrong in the case of possible variations of the preferred mode of nuclear burning in the earlier Universe.

  13. Relics of subluminous supernovae in metal-poor stars

    E-Print Network [OSTI]

    Takuji Tsujimoto; Toshikazu Shigeyama

    2003-01-14

    The unique elemental abundance pattern of the carbon-rich stars CS29498-043 and CS22949-037 is characterized by a large excess of magnesium and silicon in comparison with iron. This excess is investigated in the context of a supernova-induced star formation scenario, and it is concluded that these stars were born from the matter swept up by supernova remnants containing little iron and that such supernovae are similar to the least-luminous SNe ever observed, SNe 1997D and 1999br. Comparison of the observed abundance pattern in iron-group elements of subluminous supernovae with those of other supernovae leads to an intriguing implication for explosion, nucleosynthesis, and mixing in supernovae. The observed invariance of these ratios can not be accounted for by a spherically symmetric supernova model.

  14. Rates and progenitors of type Ia supernovae

    E-Print Network [OSTI]

    Wood-Vasey, William Michael

    2004-01-01

    Supernovae . . . . . . . . . . . . . . . . . . . .Supernovae Found 5.1 Introduction . . . . . . . . . . . .1.2 Non-Type Ia Supernovae . . . . . . . . . . . . . . . 1.3

  15. Light propagation in inhomogeneous and anisotropic cosmologies

    E-Print Network [OSTI]

    Fleury, Pierre

    2015-01-01

    The standard model of cosmology is based on the hypothesis that the Universe is spatially homogeneous and isotropic. When interpreting most observations, this cosmological principle is applied stricto sensu: the light emitted by distant sources is assumed to propagate through a Friedmann-Lema\\^itre spacetime. The main goal of the present thesis was to evaluate how reliable this assumption is, especially when small scales are at stake. After having reviewed the laws of geometric optics in curved spacetime, and the standard interpretation of cosmological observables, the dissertation reports a comprehensive analysis of light propagation in Swiss-cheese models, designed to capture the clumpy character of the Universe. The resulting impact on the interpretation of the Hubble diagram is quantified, and shown to be relatively small, thanks to the cosmological constant. When applied to current supernova data, the associated corrections tend however to improve the agreement between the cosmological parameters inferre...

  16. Strong Ultraviolet Pulse From a Newborn Type Ia Supernova

    E-Print Network [OSTI]

    Cao, Yi; Howell, D Andrew; Gal-Yam, Avishay; Kasliwal, Mansi M; Valenti, Stefano; Johansson, J; Amanullah, R; Goobar, A; Sollerman, J; Taddia, F; Horesh, Assaf; Sagiv, Ilan; Cenko, S Bradley; Nugent, Peter E; Arcavi, Iair; Surace, Jason; Wo?niak, P R; Moody, Daniela I; Rebbapragada, Umaa D; Bue, Brian D; Gehrels, Neil

    2015-01-01

    Type Ia supernovae are destructive explosions of carbon oxygen white dwarfs. Although they are used empirically to measure cosmological distances, the nature of their progenitors remains mysterious, One of the leading progenitor models, called the single degenerate channel, hypothesizes that a white dwarf accretes matter from a companion star and the resulting increase in its central pressure and temperature ignites thermonuclear explosion. Here we report observations of strong but declining ultraviolet emission from a Type Ia supernova within four days of its explosion. This emission is consistent with theoretical expectations of collision between material ejected by the supernova and a companion star, and therefore provides evidence that some Type Ia supernovae arise from the single degenerate channel.

  17. From SupernovaeFrom Supernovae to Inflationto Inflation

    E-Print Network [OSTI]

    Yamamoto, Hirosuke

    From SupernovaeFrom Supernovae to Inflationto Inflation Katsuhiko SatoKatsuhiko Sato 1)Department.4. NucleosynthesisNucleosynthesis in supernovaein supernovae II.II. ParticleParticle cosmologycosmology andand Early

  18. Neutrino flavor transformation in core-collapse supernovae

    E-Print Network [OSTI]

    Cherry, John F.; Cherry, John F.

    2012-01-01

    in Supernovae . . . . . . . . . . . . . . . . . . . . .Collapse Supernovae . . . . . . . . . . . . . . . . . . . .Mechanisms of Core-Collapse Supernovae: Simulation Results

  19. SUPERNOVAE - FEWER AND FURTHER BETWEEN

    E-Print Network [OSTI]

    TRIMBLE, V

    1988-01-01

    1987). 2. Tammann. G.A. in Supernovae: A Survey of CurremCalifornia 94720, USA. Supernovae Fewer and further betweenmatic searches for supernovae in bright southern galaxies by

  20. Supernovae. Part I: The events

    E-Print Network [OSTI]

    Trimble, V; Trimble, V

    1982-01-01

    Barkat, Z. , 1977, in Supernovae, edited by D. N. Schramm {Sci. Rev. 27, Canal, Supernovae. R. A. , 1981f, in NATO81.C. B. , Ed. , 1974, Supernovae and Their Remnants,

  1. THE BERKELEY AUTOMATED SUPERNOVA SEARCH

    E-Print Network [OSTI]

    Kare, J.T.

    2010-01-01

    Dordrecht L . Rosino, in Supernovae, ed. D . Schramm, p.Texas Workshop on Type I Supernovae, ed. J . C . Wheeler, p.Studies Institute on Supernovae, (Reidel, Dordrecht 1981),

  2. Impact of the local void on the cosmological parameters

    SciTech Connect (OSTI)

    Yu, Bo, E-mail: yubo@pmo.ac.cn [Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China)

    2013-03-01

    In this paper, I discuss the effects of a local void on the cosmological parameters. It is found that, if the supernova distance is absolutely calibrated, then the bias of all the cosmological parameters is always important, while if the supernova distance is relatively calibrated, the largest effects will appear in the dark energy equation of state. For a local void of size ? 100 Mpc, the bias effects mainly manifest in the low redshift range. Therefore, the piecewise dark energy equation of state, especially the one in the range of lowest redshift, will be more strongly affected than the constant equation of state. In order to reduce this bias in constraining the cosmological parameters, one could require the distance of all the adopted supernovas be greater than 1.2 ? 1.5 times of the radius of the local void. In this case, the residual bias can be safely ignored.

  3. A Novel Supernova Detector

    E-Print Network [OSTI]

    David B. Cline

    2000-01-13

    We discuss the prospects for detecting nu_{mu,tau} and nu_{tau}neutrinos from Type II supernovas using the novel detector at the Supernova Burst Observatory (SNBO) or OMNIS that is being designed for an underground laboratory in the USA. This detector would collect ~2000 flavor selected events from a Galactic supernova and could probe neutrino mass down to a few eV, as well as the dynamics of the supernova process. We believe this is essential to further our understanding of the neutrino section of elementary particle physics.

  4. Search for: supernovae | DOE PAGES

    Office of Scientific and Technical Information (OSTI)

    supernovae Find + Advanced Search Advanced Search All Fields: supernovae Title: Full Text: Bibliographic Data: Creator Author: Name Name ORCID Search Authors Type: All...

  5. Cepheid Variables and their Application to the Cosmological Distance Scale 

    E-Print Network [OSTI]

    Hoffmann, Samantha L

    2013-05-02

    . . . . . . . . . . . . . . . . . . . . . . . . . . 55 3. DIFFERENCE IMAGING ANALYSIS OF TYPE IA SUPERNOVA HOST NGC 5584 FOR CEPHEID VARIABLES . . . . . . . . . . . . . . . . . . 63 3.1 Motivation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 3.2 Observations and Data Reduction... and type Ia supernovae (SNe Ia). This cosmological distance scale started with a geometric distance measurement of Cepheids, such as parallaxes by [5]. The Cepheid Period-Luminosity relation was characterized by [79] for use as a primary distance...

  6. Cosmological backreaction

    E-Print Network [OSTI]

    Dominik J. Schwarz

    2010-03-15

    This work summarises some of the attempts to explain the phenomenon of dark energy as an effective description of complex gravitational physics and the proper interpretation of observations. Cosmological backreaction has been shown to be relevant for observational (precision) cosmology, nevertheless no convincing explanation of dark energy by means of backreaction has been given so far.

  7. Nucleosynthesis in Supernovae

    E-Print Network [OSTI]

    C. J. Horowitz; Gang Li

    1999-05-19

    Core collapse supernovae are dominated by energy transport from neutrinos. Therefore, some supernova properties could depend on symetries and features of the standard model weak interactions. The cross section for neutrino capture is larger than that for antineutrino capture by one term of order the neutrino energy over the nucleon mass. This reduces the ratio of neutrons to protons in the $\

  8. Constraints on supernovae dimming from photon-pseudo scalar coupling

    E-Print Network [OSTI]

    Yong-Seon Song; Wayne Hu

    2005-07-29

    An alternative mechanism that dims high redshift supernovae without cosmic acceleration utilizes an oscillation of photons into a pseudo-scalar particle during transit. Since angular diameter distance measures are immune to the loss of photons, this ambiguity in interpretation can be resolved by combining CMB acoustic peak measurements with the recent baryon oscillation detection in galaxy power spectra. This combination excludes a non-accelerating dark energy species at the 4sigma level regardless of the level of the pseudo-scalar coupling. While solutions still exist with substantial non-cosmological dimming of supernovae, they may be tested with future improvement in baryon oscillation experiments.

  9. Marginal evidence for cosmic acceleration from Type Ia supernovae

    E-Print Network [OSTI]

    Jeppe Trøst Nielsen; Alberto Guffanti; Subir Sarkar

    2015-06-09

    The "standard" model of cosmology is founded on the basis that the expansion rate of the universe is accelerating at present --- as was inferred originally from the Hubble diagram of Type Ia supernovae. There exists now a much bigger database of supernovae so we can perform rigorous statistical tests to check whether these "standardisable candles" indeed indicate cosmic acceleration. Taking account of the empirical procedure by which corrections are made to their absolute magnitudes to allow for the varying shape of the light curve and extinction by dust, we find, rather surprisingly, that the data are still quite consistent with a constant rate of expansion.

  10. Marginal evidence for cosmic acceleration from Type Ia supernovae

    E-Print Network [OSTI]

    Nielsen, Jeppe Trøst; Sarkar, Subir

    2015-01-01

    The `standard' model of cosmology is founded on the basis that the expansion rate of the universe is accelerating at present --- as was inferred originally from the Hubble diagram of Type Ia supernovae. There exists now a much bigger database of supernovae so we can perform rigorous statistical tests to check whether these `standardisable candles' indeed indicate cosmic acceleration. Taking account of the empirical procedure by which corrections are made to their absolute magnitudes to allow for the varying shape of the light curve and extinction by dust, we find, rather surprisingly, that the data are still quite consistent with a constant rate of expansion.

  11. Conformally Friedmann-Lemaitre-Robertson-Walker cosmologies

    E-Print Network [OSTI]

    Visser, Matt

    2015-01-01

    In a universe where, according to the standard cosmological models, some 97% of the total mass-energy is still "missing in action" it behooves us to spend at least a little effort critically assessing and exploring radical alternatives. Among possible, (dare we say plausible), nonstandard but superficially viable models, those spacetimes conformal to the standard Friedmann-Lemaitre-Robertson-Walker class of cosmological models play a very special role --- these models have the unique and important property of permitting large non-perturbative geometric deviations from Friedmann-Lemaitre-Robertson-Walker cosmology without unacceptably distorting the cosmic microwave background. Performing a "cosmographic" analysis, (that is, temporarily setting aside the Einstein equations, since the question of whether or not the Einstein equations are valid on galactic and cosmological scales is essentially the same question as whether or not dark matter/dark energy actually exist), and using both supernova data and informat...

  12. Neutrinos from Supernovas and Supernova Remnants

    E-Print Network [OSTI]

    Francesco Vissani; Maria Laura Costantini

    2005-08-05

    Supernovae (SN) and supernova remnants (SNR) have key roles in galaxies, but their physical descriptions is still incomplete. Thus, it is of interest to study neutrino radiation to understand SN and SNR better. We will discuss: (1) The ~10 MeV thermal neutrinos that arise from core collapse SN, that were observed for SN1987A, and can be seen with several existing or planned experiments. (2) The 10-100 TeV neutrinos expected from galactic SNR (in particular from RX J1713.7-3946) targets of future underwater neutrino telescopes.

  13. Cosmology with matter diffusion

    SciTech Connect (OSTI)

    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.

  14. New approaches for modeling type Ia supernovae

    E-Print Network [OSTI]

    Zingale, Michael; Almgren, Ann S.; Bell, John B.; Day, Marcus S.; Rendleman, Charles A.; Woosley, Stan

    2007-01-01

    runaway in Type Ia supernovae: How to run away? oIgnition in Type Ia Supernovae. II. A Three- dimensionalnumber modeling of type Ia supernovae. I. hydrodynamics.

  15. Supernovae: Little bear's mass loss rate

    E-Print Network [OSTI]

    Trimble, V; Trimble, V

    1985-01-01

    Williamson (Dalhousie Univ. ). Supernovae Little Bear’s massidentified and defined supernovae as a distinct astronomicalType II (hydrogen-rich) supernovae, on the other hand, end

  16. Supernova Recognition using Support Vector Machines

    E-Print Network [OSTI]

    Romano, Raquel A.; Aragon, Cecilia R.; Ding, Chris

    2006-01-01

    pected to contain real supernovae. Astrophysicists who inObservational Evi- dence from Supernovae for an Acceleratingi.e. to ?nd all potential supernovae, while reducing the

  17. Cosmological and Astrophysical Constraints on Tensor Unparticles

    E-Print Network [OSTI]

    Ian Lewis

    2007-10-23

    We calculate cosmological and astrophysical bounds on the couplings between standard model fields and tensor unparticles. The present day density of tensor unparticles from neutrino-neutrino and photon-photon annihilation is calculated. Also, the supernovae volume energy loss rates from electron-positron and photon-photon annihilation to tensor unparticles are calculated. The constraints from matter density and supernovae volume energy loss rates from photon-photon annihilation are on the same order of magnitude, while the bounds from supernovae volume energy loss rates from electron-positron annihilation are an order of magnitude lower. We find the couplings between standard model fields and tensor unparticles are at least an order of magnitude lower than those used for previous studies of tensor unparticle collider phenomenology.

  18. Automated search for supernovae

    SciTech Connect (OSTI)

    Kare, J.T.

    1984-11-15

    This thesis describes the design, development, and testing of a search system for supernovae, based on the use of current computer and detector technology. This search uses a computer-controlled telescope and charge coupled device (CCD) detector to collect images of hundreds of galaxies per night of observation, and a dedicated minicomputer to process these images in real time. The system is now collecting test images of up to several hundred fields per night, with a sensitivity corresponding to a limiting magnitude (visual) of 17. At full speed and sensitivity, the search will examine some 6000 galaxies every three nights, with a limiting magnitude of 18 or fainter, yielding roughly two supernovae per week (assuming one supernova per galaxy per 50 years) at 5 to 50 percent of maximum light. An additional 500 nearby galaxies will be searched every night, to locate about 10 supernovae per year at one or two percent of maximum light, within hours of the initial explosion.

  19. Nucleosynthesis in Thermonuclear Supernovae

    SciTech Connect (OSTI)

    Claudia, Travaglio [Istituto Nazionale di Astrofisica, Osservatorio Astronomico di Torino; Hix, William Raphael [ORNL

    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.

  20. "Cosmologists have used these supernovae very pro-

    E-Print Network [OSTI]

    Zhang, Yi

    --the type II supernovae--presents theorists with another set of challenges. A type II supernova pops off

  1. Workflow management for a cosmology collaboratory

    SciTech Connect (OSTI)

    Loken, Stewart C.; McParland, Charles

    2001-07-20

    The Nearby Supernova Factory Project will provide a unique opportunity to bring together simulation and observation to address crucial problems in particle and nuclear physics. Its goal is to significantly enhance our understanding of the nuclear processes in supernovae and to improve our ability to use both Type Ia and Type II supernovae as reference light sources (standard candles) in precision measurements of cosmological parameters. Over the past several years, astronomers and astrophysicists have been conducting in-depth sky searches with the goal of identifying supernovae in their earliest evolutionary stages and, during the 4 to 8 weeks of their most ''explosive'' activity, measure their changing magnitude and spectra. The search program currently under development at LBNL is an earth-based observation program utilizing observational instruments at Haleakala and Mauna Kea, Hawaii and Mt. Palomar, California. This new program provides a demanding testbed for the integration of computational, data management and collaboratory technologies. A critical element of this effort is the use of emerging workflow management tools to permit collaborating scientists to manage data processing and storage and to integrate advanced supernova simulation into the real-time control of the experiments. This paper describes the workflow management framework for the project, discusses security and resource allocation requirements and reviews emerging tools to support this important aspect of collaborative work.

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

    SciTech Connect (OSTI)

    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; Castellón, 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.

  3. Cosmic Supernova Rate History and Type Ia Supernova Progenitors

    E-Print Network [OSTI]

    Chiaki Kobayashi; Ken'ichi Nomoto; Takuji Tsujimoto

    2001-02-14

    Adopting a single degenerate scenario for Type Ia supernova progenitors with the metallicity effect, we make a prediction of the cosmic supernova rate history as a composite of the supernova rates in spiral and elliptical galaxies, and compare with the recent observational data up to z ~ 0.55.

  4. Cosmological constraints on superconducting dark energy models

    E-Print Network [OSTI]

    Keresztes, Zoltán; Harko, Tiberiu; Liang, Shi-Dong

    2015-01-01

    We consider cosmological tests of a scalar-vector-tensor gravitational model, in which the dark energy is included in the total action through a gauge invariant, electromagnetic type contribution. The ground state of dark energy, corresponding to a constant potential $V$ is a Bose-Einstein type condensate with spontaneously broken U(1) symmetry. In another words dark energy appears as a massive vector field emerging from a superposition of a massless vector and a scalar field, the latter corresponding to the Goldstone boson. Two particular cosmological models, corresponding to pure electric and pure magnetic type potentials, respectively are confronted with Type IA Supernovae and Hubble parameter data. In the electric case good fit is obtained along a narrow inclined stripe in the $\\Omega _{m}-\\Omega _{V}$ parameter plane, which includes the $\\Lambda $CDM limit. The other points on this admissible region represent superconducting dark energy as a sum of a cosmological constant and a time-evolving contribution...

  5. The ESO/VLT 3rd year Type Ia supernova data set from the Supernova Legacy Survey

    E-Print Network [OSTI]

    Balland, C; Basa, S; Mouchet, M; Howell, D A; Astier, P; Carlberg, R G; Conley, A; Fouchez, D; Guy, J; Hardin, D; Hook, I M; Pain, R; Perrett, K; Pritchet, C J; Regnault, N; Rich, J; Sullivan, M; Antilogus, P; Arsenijevic, V; Du, J Le; Fabbro, S; Lidman, C; Mourao, A; Palanque-Delabrouille, Nathalie; Pécontal, E; Ruhlmann-Kleider, V

    2009-01-01

    We present 139 spectra of 124 Type Ia supernovae (SNeIa) that were observed at the ESO/VLT during the first three years of the Canada-France-Hawai Telescope (CFHT) Supernova Legacy Survey (SNLS). This homogeneous data set is used to test for redshift evolution of SNeIa spectra, and will be used in the SNLS 3rd year cosmological analyses. Spectra have been reduced and extracted with a dedicated pipeline that uses photometric information from deep CFHT Legacy Survey (CFHT-LS) reference images to trace, at sub-pixel accuracy, the position of the supernova on the spectrogram as a function of wavelength. It also separates the supernova and its host light in 60% of cases. The identification of the supernova candidates is performed using a spectrophotometric SNIa model. A total of 124 SNeIa, roughly 50% of the overall SNLS spectroscopic sample, have been identified using the ESO/VLT during the first three years of the survey. Their redshifts range from z=0.149 to z=1.031. The average redshift of the sample is z=0.63...

  6. Cosmological Recombination

    E-Print Network [OSTI]

    Wan Yan Wong

    2008-11-18

    In this thesis we focus on studying the physics of cosmological recombination and how the details of recombination affect the Cosmic Microwave Background (CMB) anisotropies. We present a detailed calculation of the spectral line distortions on the CMB spectrum arising from the Lyman-alpha and the lowest two-photon transitions in the recombination of hydrogen (H), and the corresponding lines from helium (He). The peak of these distortions mainly comes from the Lyman-alpha transition and occurs at about 170 microns, which is the Wien part of the CMB. The major theoretical limitation for extracting cosmological parameters from the CMB sky lies in the precision with which we can calculate the cosmological recombination process. With this motivation, we perform a multi-level calculation of the recombination of H and He with the addition of the spin-forbidden transition for neutral helium (He I), plus the higher order two-photon transitions for H and among singlet states of He I. We find that the inclusion of the spin-forbidden transition results in more than a percent change in the ionization fraction, while the other transitions give much smaller effects. Last we modify RECFAST by introducing one more parameter to reproduce recent numerical results for the speed-up of helium recombination. Together with the existing hydrogen `fudge factor', we vary these two parameters to account for the remaining dominant uncertainties in cosmological recombination. By using a Markov Chain Monte Carlo method with Planck forecast data, we find that we need to determine the parameters to better than 10% for He I and 1% for H, in order to obtain negligible effects on the cosmological parameters.

  7. Type Ia Supernova Carbon Footprints

    E-Print Network [OSTI]

    Thomas, R C; Aragon, C; Antilogus, P; Bailey, S; Baltay, C; Bongard, S; Buton, C; Canto, A; Childress, M; Chotard, N; Copin, Y; Fakhouri, H K; Gangler, E; Hsiao, E Y; Kerschhaggl, M; Kowalski, M; Loken, S; Nugent, P; Paech, K; Pain, R; Pecontal, E; Pereira, R; Perlmutter, S; Rabinowitz, D; Rigault, M; Rubin, D; Runge, K; Scalzo, R; Smadja, G; Tao, C; Weaver, B A; Wu, C; Brown, P J; Milne, P A

    2011-01-01

    We present convincing evidence of unburned carbon at photospheric velocities in new observations of 5 Type Ia supernovae (SNe Ia) obtained by the Nearby Supernova Factory. These SNe are identified by examining 346 spectra from 124 SNe obtained before +2.5 d relative to maximum. Detections are based on the presence of relatively strong C II 6580 absorption "notches" in multiple spectra of each SN, aided by automated fitting with the SYNAPPS code. Four of the 5 SNe in question are otherwise spectroscopically unremarkable, with ions and ejection velocities typical of SNe Ia, but spectra of the fifth exhibits high-velocity (v > 20,000 km/s) Si II and Ca II features. On the other hand, the light curve properties are preferentially grouped, strongly suggesting a connection between carbon-positivity and broad band light curve/color behavior: Three of the 5 have relatively narrow light curves but also blue colors, and a fourth may be a dust-reddened member of this family. Accounting for signal-to-noise and phase, we ...

  8. Essential Ingredients in Core-collapse Supernovae

    SciTech Connect (OSTI)

    Hix, William Raphael [ORNL; Lentz, E. J. [University of Tennessee (UTK) and Oak Ridge National Laboratory (ORNL); Endeve, Eirik [ORNL; Baird, Mark L [ORNL; Chertkow, Merek A [ORNL; Harris, James A [ORNL; Messer, Bronson [ORNL; Mezzacappa, Anthony [ORNL; Bruenn, S. W. [Florida Atlantic University, Boca Raton; Blondin, J. M. [North Carolina State University

    2014-01-01

    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 10$^{44}$ 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.

  9. Essential ingredients in core-collapse supernovae

    SciTech Connect (OSTI)

    Hix, W. Raphael [Physics Division, Oak Ridge National Laboratory, Oak Ridge TN 37831-6354 (United States) [Physics Division, Oak Ridge National Laboratory, Oak Ridge TN 37831-6354 (United States); Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996-1200 (United States); Lentz, Eric J.; Chertkow, M. Austin; Harris, J. Austin [Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996-1200 (United States)] [Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996-1200 (United States); Endeve, Eirik [Computer Science and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge TN 37831-6008 (United States)] [Computer Science and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge TN 37831-6008 (United States); Baird, Mark [Reactor and Nuclear Systems Division, Oak Ridge National Laboratory, Oak Ridge TN 37831-6003 (United States)] [Reactor and Nuclear Systems Division, Oak Ridge National Laboratory, Oak Ridge TN 37831-6003 (United States); Messer, O. E. Bronson [Physics Division, Oak Ridge National Laboratory, Oak Ridge TN 37831-6354 (United States) [Physics Division, Oak Ridge National Laboratory, Oak Ridge TN 37831-6354 (United States); Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996-1200 (United States); Center for Computational Sciences, Oak Ridge National Laboratory, Oak Ridge TN 37831-6008 (United States); Mezzacappa, Anthony [Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996-1200 (United States) [Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996-1200 (United States); Joint Institute for Computational Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6173 (United States); Bruenn, Stephen [Department of Physics, Florida Atlantic University, 777 W Glades Road, Boca Raton, FL 33431-0991 (United States)] [Department of Physics, Florida Atlantic University, 777 W Glades Road, Boca Raton, FL 33431-0991 (United States); Blondin, John [Department of Physics, North Carolina State University, Raleigh, NC 27695-8202 (United States)] [Department of Physics, North Carolina State University, Raleigh, NC 27695-8202 (United States)

    2014-04-15

    Carrying 10{sup 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 our solar system and ourselves. Signaling the inevitable death of a massive star, and the birth of a neutron star or black hole, core-collapse supernovae combine physics over a wide range in spatial scales, from kilometer-sized hydrodynamic motions (eventually growing to gigameter scale) down to femtometer-scale nuclear reactions. 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. Multi-dimensional models with spectral neutrino transport from several research groups, which slowly develop successful explosions for a range of progenitors, have recently 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 the births of neutron stars and the supernovae that result. Recent progress on both the macroscopic and microscopic effects that affect core-collapse supernovae are discussed.

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

    SciTech Connect (OSTI)

    Kim, A. G.; Aldering, G.; Aragon, C.; Bailey, S.; Childress, M.; Fakhouri, H. K.; Nordin, J. [Physics Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States)] [Physics Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Thomas, R. C. [Computational Cosmology Center, Computational Research Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road MS 50B-4206, Berkeley, CA 94720 (United States)] [Computational Cosmology Center, Computational Research Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road MS 50B-4206, Berkeley, CA 94720 (United States); Antilogus, P.; Bongard, S.; Canto, A.; Cellier-Holzem, F.; Guy, J. [Laboratoire de Physique Nucleaire et des Hautes Energies, Universite Pierre et Marie Curie Paris 6, Universite Denis Diderot Paris 7, CNRS-IN2P3, 4 place Jussieu, F-75252 Paris Cedex 05 (France)] [Laboratoire de Physique Nucleaire et des Hautes Energies, Universite Pierre et Marie Curie Paris 6, Universite Denis Diderot Paris 7, CNRS-IN2P3, 4 place Jussieu, F-75252 Paris Cedex 05 (France); Baltay, C. [Department of Physics, Yale University, New Haven, CT 06250-8121 (United States)] [Department of Physics, Yale University, New Haven, CT 06250-8121 (United States); Buton, C.; Kerschhaggl, M.; Kowalski, M. [Physikalisches Institut, Universitaet Bonn, Nussallee 12, D-53115 Bonn (Germany)] [Physikalisches Institut, Universitaet Bonn, Nussallee 12, D-53115 Bonn (Germany); Chotard, N. [Tsinghua Center for Astrophysics, Tsinghua University, Beijing 100084 (China)] [Tsinghua Center for Astrophysics, Tsinghua University, Beijing 100084 (China); Copin, Y.; Gangler, E. [Universite de Lyon, F-69622 Lyon (France)] [Universite de Lyon, F-69622 Lyon (France); 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.

  11. Photo-heating and supernova feedback amplify each other's effect on the cosmic star formation rate

    E-Print Network [OSTI]

    Andreas H. Pawlik; Joop Schaye

    2009-03-17

    Photo-heating associated with reionisation and kinetic feedback from core-collapse supernovae have previously been shown to suppress the high-redshift cosmic star formation rate. Here we investigate the interplay between photo-heating and supernova feedback using a set of cosmological, smoothed particle hydrodynamics simulations. We show that photo-heating and supernova feedback mutually amplify each other's ability to suppress the star formation rate. Our results demonstrate the importance of the simultaneous, non-independent inclusion of these two processes in models of galaxy formation to estimate the strength of the total negative feedback they exert. They may therefore be of particular relevance to semi-analytic models in which the effects of photo-heating and supernova feedback are implicitly assumed to act independently of each other.

  12. Cosmological constraints on superconducting dark energy models

    E-Print Network [OSTI]

    Zoltán Keresztes; László Á. Gergely; Tiberiu Harko; Shi-Dong Liang

    2015-09-01

    We consider cosmological tests of a scalar-vector-tensor gravitational model, in which the dark energy is included in the total action through a gauge invariant, electromagnetic type contribution. The ground state of dark energy, corresponding to a constant potential $V$ is a Bose-Einstein type condensate with spontaneously broken U(1) symmetry. In another words dark energy appears as a massive vector field emerging from a superposition of a massless vector and a scalar field, the latter corresponding to the Goldstone boson. Two particular cosmological models, corresponding to pure electric and pure magnetic type potentials, respectively are confronted with Type IA Supernovae and Hubble parameter data. In the electric case good fit is obtained along a narrow inclined stripe in the $\\Omega _{m}-\\Omega _{V}$ parameter plane, which includes the $\\Lambda $CDM limit. The other points on this admissible region represent superconducting dark energy as a sum of a cosmological constant and a time-evolving contribution. In the magnetic case the cosmological test selects either i) parameter ranges of the superconducting dark energy allowing for the standard baryonic plus dark matter or ii) a unified superconducting dark matter and dark energy model, additionally including only the baryonic sector. The cosmological data is best matched when the matter decouples from both the scalar and vector sectors of dark energy, hence favoring matter conservation as opposed to particle creation in an irreversible process.

  13. Rastall cosmology

    E-Print Network [OSTI]

    J. C. Fabris; O. F. Piattella; D. C. Rodrigues; C. E. M. Batista; M. H. Daouda

    2012-05-06

    We review the difficulties of the generalized Chaplygin gas model to fit observational data, due to the tension between background and perturbative tests. We argue that such issues may be circumvented by means of a self-interacting scalar field representation of the model. However, this proposal seems to be successful only if the self-interacting scalar field has a non-canonical form. The latter can be implemented in Rastall's theory of gravity, which is based on a modification of the usual matter conservation law. We show that, besides its application to the generalized Chaplygin gas model, other cosmological models based on Rastall's theory have many interesting and unexpected new features.

  14. High Rate for Type IC Supernovae

    E-Print Network [OSTI]

    Muller, R.A.

    2008-01-01

    Wheeler, J. C. 1990, in Supernovae, ed. A. G. Petschek (New4959. Tamrnann, G. A. 1977, in Supernovae, ed. D. Schramm (Wheeler, J. C. 1990, in Supernovae, ed. J. C. Wheeler, T.

  15. Overview of the nearby supernova factory

    E-Print Network [OSTI]

    2002-01-01

    from 42 High-Redshift Supernovae,” Astrophys J. 517, pp.Observational Evidence from Supernovae for an AcceleratingCalan/Tololo Type Ia Supernovae,” Astron. J. 112, p. 2391,

  16. 1987A: The greatest supernova since Kepler

    E-Print Network [OSTI]

    Trimble, V; Trimble, V

    1988-01-01

    Woosley, S. E. , 1988b, in Supernovae 19873 in the LargeGalactic Nuclei, and Supernovae, edited by S. Hayakawa andGalactic nuclei, and Supernovae, edited by S. Hayakawa and

  17. Cosmology of Bifundamental Fields

    E-Print Network [OSTI]

    Tanmay Vachaspati

    2008-12-17

    If a field theory contains gauged, non-Abelian, bi-fundamental fields i.e. fields that are charged under two separate non-Abelian gauge groups, the transition from a deconfined phase to a hadronic phase may be frustrated. Similar frustration may occur in non-Abelian gauge models containing matter only in higher dimensional representations e.g. models with pure glue, or if ordinary quarks are confined by two flux tubes, as implied in the triangular configuration of baryons within QCD. In a cosmological setting, such models can lead to the formation of a web of confining electric flux tubes that can potentially have observational signatures.

  18. Supernovae and neutrinos

    SciTech Connect (OSTI)

    John F. Beacom

    2002-09-19

    A long-standing problem in supernova physics is how to measure the total energy and temperature of {nu}{sub {mu}}, {nu}{sub {tau}}, {bar {nu}}{sub {mu}}, and {bar {nu}}{sub {tau}}. While of the highest importance, this is very difficult because these flavors only have neutral-current detector interactions. We propose that neutrino-proton elastic scattering, {nu} + p {yields} {nu} + p, can be used for the detection of supernova neutrinos in scintillator detectors. It should be emphasized immediately that the dominant signal is on free protons. Though the proton recoil kinetic energy spectrum is soft, with T{sub p} {approx_equal} 2E{sub {nu}}{sup 2}/M{sub p}, and the scintillation light output from slow, heavily ionizing protons is quenched, the yield above a realistic threshold is nearly as large as that from {bar {nu}}{sub e} + p {yields} e{sup +} + n. In addition, the measured proton spectrum is related to the incident neutrino spectrum. The ability to detect this signal would give detectors like KamLAND and Borexino a crucial and unique role in the quest to detect supernova neutrinos.

  19. Snapping Supernovae at z>1.7

    E-Print Network [OSTI]

    Aldering, Greg

    2009-01-01

    redshift supernovae — both thermonuclear and core collapse —between core-collapse and thermonuclear supernovae (Iben &such SNe — both thermonuclear and core collapse — will be

  20. Pair-instability supernovae in the local universe

    SciTech Connect (OSTI)

    Whalen, Daniel J. [Zentrum für Astronomie, Institut für Theoretische Astrophysik, Universität 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 ?}.

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

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    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.

  2. EUNHA: a new cosmological hydro simulation code

    E-Print Network [OSTI]

    Shina, Jihye; Kim, Sungsoo S; Park, Changbom

    2014-01-01

    We have developed a parallel cosmological hydrodynamic simulation code designed for the study of formation and evolution of cosmological structures. The gravitational force is calculated using the TreePM method and the hydrodynamics is implemented based on the smoothed particle hydrodynamics. The initial displacement and velocity of simulation particles are calculated according to second-order linear perturbation theory using the power spectra of dark matter and baryonic matter. The initial background temperature is given by Recfast and the temperature uctuations at the initial particle position are determined by the adiabatic model. We use a time-limiter scheme over the individual time steps to capture shock-fronts and to ease the time-step tension between the shock and preshock particles. We also include the astrophysical gas processes of radiative heating/cooling, star formation, metal enrichment, and supernova feedback. We have tested the code in several standard cases such as one-dimensional Riemann prob...

  3. The Atacama Cosmology Telescope: Cosmology from Galaxy Clusters...

    Office of Scientific and Technical Information (OSTI)

    The Atacama Cosmology Telescope: Cosmology from Galaxy Clusters Detected via the Sunyaev-Zel'dovich Effect Citation Details In-Document Search Title: The Atacama Cosmology...

  4. Scrutinizing Exotic Cosmological Models Using ESSENCE Supernova Data

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTechtail. (Conference) | SciTechsaturated fracturedConnectSciTechCombined With Other

  5. Scrutinizing Exotic Cosmological Models Using ESSENCE Supernova Data

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTechtail. (Conference) | SciTechsaturated fracturedConnectSciTechCombined With

  6. Supernova Neutrinos Detection On Earth

    E-Print Network [OSTI]

    Xin-Heng Guo; Ming-Yang Huang; Bing-Lin Young

    2009-05-12

    In this paper, we first discuss the detection of supernova neutrino on Earth. Then we propose a possible method to acquire information about $\\theta_{13}$ smaller than $1.5^\\circ$ by detecting the ratio of the event numbers of different flavor supernova neutrinos. Such an sensitivity cannot yet be achieved by the Daya Bay reactor neutrino experiment.

  7. Collective neutrino oscillations in supernovae

    SciTech Connect (OSTI)

    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.

  8. Nucleosynthesis in Type II Supernovae

    E-Print Network [OSTI]

    K. Nomoto; M. Hashimoto; T. Tsujimoto; F. -K. Thielemann; N. Kishimoto; Y. Kubo

    1997-06-03

    Presupernova evolution and explosive nucleosynthesis in massive stars for main-sequence masses from 13 $M_\\odot$ to 70 $M_\\odot$ are calculated. We examine the dependence of the supernova yields on the stellar mass, $^{12}C(\\alpha, \\gamma) ^{16}O}$ rate, and explosion energy. The supernova yields integrated over the initial mass function are compared with the solar abundances.

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

    SciTech Connect (OSTI)

    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.

  10. Supernova Hunting with Supercomputers

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home RoomPreservationBio-Inspired Solar Fuel Production 1: Totalof EnergyWind EnergySupernova

  11. Type Ia Supernovae

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home RoomPreservationBio-Inspired SolarAbout /Two Electron Holes in HematiteType Ia Supernovae Type Ia

  12. Supernova constraints on Multi-coupled Dark Energy

    E-Print Network [OSTI]

    Arpine Piloyan; Valerio Marra; Marco Baldi; Luca Amendola

    2013-07-09

    The persisting consistency of ever more accurate observational data with the predictions of the standard LCDM cosmological model puts severe constraints on possible alternative scenarios, but still does not shed any light on the fundamental nature of the cosmic dark sector.As large deviations from a LCDM cosmology are ruled out by data, the path to detect possible features of alternative models goes necessarily through the definition of cosmological scenarios that leave almost unaffected the background and -- to a lesser extent -- the linear perturbations evolution of the universe. In this context,the Multi-coupled DE (McDE) model was proposed by Baldi 2012 as a particular realization of an interacting Dark Energy field characterized by an effective screening mechanism capable of suppressing the effects of the coupling at the background and linear perturbation level. In the present paper, for the first time, we challenge the McDE scenario through a direct comparison with real data, in particular with the luminosity distance of Type Ia supernovae. By studying the existence and stability conditions of the critical points of the associated background dynamical system, we select only the cosmologically consistent solutions, and confront their background expansion history with data. Confirming previous qualitative results, the McDE scenario appears to be fully consistent with the adopted sample of Type Ia supernovae, even for coupling values corresponding to an associated scalar fifth-force about four orders of magnitude stronger than standard gravity. Our analysis demonstrates the effectiveness of the McDE background screening, and shows some new non-trivial asymptotic solutions for the future evolution of the universe. Our results show how the background expansion history might be highly insensitive to the fundamental nature and to the internal complexity of the dark sector. [Abridged

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

    SciTech Connect (OSTI)

    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.

  14. Throat Cosmology

    E-Print Network [OSTI]

    Harling, B v

    2010-01-01

    In this thesis, we study throats in the early, hot universe. Throats are a common feature of the landscape of type IIB string theory. If a throat is heated during cosmological evolution, energy is subsequently transferred to other throats and to the standard model. We calculate the heat transfer rate and the decay rate of throat-localized Kaluza-Klein states in a ten-dimensional model. For the calculation, we employ the dual description of the throats in terms of gauge theories. We discuss modifications of the decay rate which arise in flux compactifications and for Klebanov-Strassler throats and emphasize the role of tachyonic scalars in such throats in mediating decays of Kaluza-Klein modes. Our results are also applicable to the energy transfer from the heated standard model to throats. We determine the resulting energy density in throats at our epoch in dependence of their infrared scales and of the reheating temperature. The Kaluza-Klein modes in the throats decay to other sectors with a highly suppresse...

  15. K-corrections and spectral templates of Type Ia supernovae

    E-Print Network [OSTI]

    Hsiao, E. Y.

    2008-01-01

    templates of Type Ia supernovae E. Y. Hsiao 1 , A. Conleyobservations of low-redshift supernovae are less a?ected byobservations, stars: supernovae Department of Physics and

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

    E-Print Network [OSTI]

    Kim, A. G.

    2014-01-01

    magnitudes of type Ia supernovae from multi-band lightsuch an analysis on the supernovae of the Nearby Supernovaheadings: distance scale, supernovae: general 1 Physics

  17. Prospective Type Ia supernova surveys from Dome A

    E-Print Network [OSTI]

    Kim, A.

    2010-01-01

    time series of ?1000 z supernovae. These can serve tocapable of discovering supernovae shortly after explosion§4. 2. Low-Redshift Supernovae A nearby sample is essential

  18. A Probabilistic Approach to Classifying Supernovae Using Photometric Information

    E-Print Network [OSTI]

    Kuznetsova, Natalia V.; Connolly, Brian M.

    2008-01-01

    ciency of selecting type Ia supernovae for p cut = 0.98 (weApproach to Classifying Supernovae Using Photometricstudies). Subject headings: supernovae: general Introduction

  19. A fast contour descriptor algorithm for supernova image classification

    E-Print Network [OSTI]

    Aragon, Cecilia R.; Aragon, David Bradburn

    2006-01-01

    from 42 High-Redshift Supernovae," Astrophysical JournalObservational Evidence from Supernovae for an Acceleratingand Progenitors of Type Ia Supernovae," PhD dissertation,

  20. Pineapples and crabs: When young supernova remnants were even younger

    E-Print Network [OSTI]

    Trimble, V

    2001-01-01

    1977. The Historical Supernovae, Oxford, Pergamon 7 Trimble,C.B. Cosmovici (Ed. ) Supernovae and their Remnants, Reidel,C.B. Cosmovici (ed. ) Supernovae and their Remnants, Reidel,

  1. Nearby Supernova Factory Observations of SN 2006D: On Sporadic Carbon Signatures in Early Type Ia Supernova Spectra

    E-Print Network [OSTI]

    2006-01-01

    with low volume-?lling factor. Subject headings: supernovae:general — supernovae: individual (SN 2006D)Introduction Type Ia supernovae (SNe Ia) make valuable

  2. Thermonuclear supernova models, and observations of Type Ia supernovae

    E-Print Network [OSTI]

    E. Bravo; C. Badenes; D. Garcia-Senz

    2004-12-07

    In this paper, we review the present state of theoretical models of thermonuclear supernovae, and compare their predicitions with the constraints derived from observations of Type Ia supernovae. The diversity of explosion mechanisms usually found in one-dimensional simulations is a direct consequence of the impossibility to resolve the flame structure under the assumption of spherical symmetry. Spherically symmetric models have been successful in explaining many of the observational features of Type Ia supernovae, but they rely on two kinds of empirical models: one that describes the behaviour of the flame on the scales unresolved by the code, and another that takes account of the evolution of the flame shape. In contrast, three-dimensional simulations are able to compute the flame shape in a self-consistent way, but they still need a model for the propagation of the flame in the scales unresolved by the code. Furthermore, in three dimensions the number of degrees of freedom of the initial configuration of the white dwarf at runaway is much larger than in one dimension. Recent simulations have shown that the sensitivity of the explosion output to the initial conditions can be extremely large. New paradigms of thermonuclear supernovae have emerged from this situation, as the Pulsating Reverse Detonation. The resolution of all these issues must rely on the predictions of observational properties of the models, and their comparison with current Type Ia supernova data, including X-ray spectra of Type Ia supernova remnants.

  3. Cosmological model-independent Gamma-ray bursts calibration and its cosmological constraint to dark energy

    SciTech Connect (OSTI)

    Xu, Lixin, E-mail: lxxu@dlut.edu.cn [Institute of Theoretical Physics, School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian, 116024 (China)

    2012-04-01

    As so far, the redshift of Gamma-ray bursts (GRBs) can extend to z ? 8 which makes it as a complementary probe of dark energy to supernova Ia (SN Ia). However, the calibration of GRBs is still a big challenge when they are used to constrain cosmological models. Though, the absolute magnitude of GRBs is still unknown, the slopes of GRBs correlations can be used as a useful constraint to dark energy in a completely cosmological model independent way. In this paper, we follow Wang's model-independent distance measurement method and calculate their values by using 109 GRBs events via the so-called Amati relation. Then, we use the obtained model-independent distances to constrain ?CDM model as an example.

  4. FINDING THE FIRST COSMIC EXPLOSIONS. I. PAIR-INSTABILITY SUPERNOVAE

    SciTech Connect (OSTI)

    Whalen, Daniel J.; Smidt, Joseph; Lovekin, C. C. [T-2, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Even, Wesley; Fryer, Chris L. [CCS-2, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Frey, Lucille H. [HPC-3, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Johnson, Jarrett L.; Hungerford, Aimee L. [XTD-6, 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); Holz, Daniel E. [Enrico Fermi Institute, Department of Physics, and Kavli Institute for Cosmological Physics, University of Chicago, Chicago, IL 60637 (United States); Heger, Alexander [Monash Centre for Astrophysics, Monash University, Victoria 3800 (Australia); Woosley, S. E. [Department of Astronomy and Astrophysics, UCSC, Santa Cruz, CA 95064 (United States)

    2013-11-10

    The first stars are the key to the formation of primitive galaxies, early cosmological reionization and chemical enrichment, and the origin of supermassive black holes. Unfortunately, in spite of their extreme luminosities, individual Population III (Pop III) stars will likely remain beyond the reach of direct observation for decades to come. However, their properties could be revealed by their supernova explosions, which may soon be detected by a new generation of near-IR (NIR) observatories such as JWST and WFIRST. We present light curves and spectra for Pop III pair-instability supernovae calculated with the Los Alamos radiation hydrodynamics code RAGE. Our numerical simulations account for the interaction of the blast with realistic circumstellar envelopes, the opacity of the envelope, and Lyman absorption by the neutral intergalactic medium at high redshift, all of which are crucial to computing the NIR signatures of the first cosmic explosions. We find that JWST will detect pair-instability supernovae out to z ?> 30, WFIRST will detect them in all-sky surveys out to z ? 15-20, and LSST and Pan-STARRS will find them at z ?< 7-8. The discovery of these ancient explosions will probe the first stellar populations and reveal the existence of primitive galaxies that might not otherwise have been detected.

  5. Neutrinos and Nucleosynthesis in Supernova

    E-Print Network [OSTI]

    U. Solis; J. C. D'Olivo; L. G. Cabral-Rosetti

    2005-11-12

    The type II supernova is considered as a candidate site for the production of heavy elements. The nucleosynthesis occurs in an intense neutrino flux, we calculate the electron fraction in this environment.

  6. Brane-world Cosmology

    SciTech Connect (OSTI)

    Wands, David [Institute of Cosmology and Gravitation, University of Portsmouth, Mercantile House, Portsmouth P01 2EG (United Kingdom)

    2006-06-19

    Brane-world models, where observers are restricted to a brane in a higher dimensional spacetime, offer a novel perspective on cosmology. I discuss some approaches to cosmology in extra dimensions and some interesting aspects of gravity and cosmology in brane-world models.

  7. Type Ia Supernovae: Progenitors and Evolution with Redshift

    E-Print Network [OSTI]

    Ken'ichi Nomoto; Hideyuki Umeda; Chiaki Kobayashi; Izumi Hachisu; Mariko Kato; Takuji Tsujimoto

    2000-03-09

    Relatively uniform light curves and spectral evolution of Type Ia supernovae (SNe Ia) have led to the use of SNe Ia as a ``standard candle'' to determine cosmological parameters. Whether a statistically significant value of the cosmological constant can be obtained depends on whether the peak luminosities of SNe Ia are sufficiently free from the effects of cosmic and galactic evolutions. Here we first review the single degenerate scenario for the Chandrasekhar mass white dwarf (WD) models of SNe Ia. We identify the progenitor's evolution and population with two channels: (1) the WD+RG (red-giant) and (2) the WD+MS (near main-sequence He-rich star) channels. In these channels, the strong wind from accreting WDs plays a key role, which yields important age and metallicity effects on the evolution. We then address the questions whether the nature of SNe Ia depends systematically on environmental properties such as metallicity and age of the progenitor system and whether significant evolutionary effects exist. We suggest that the variation of the carbon mass fraction $X$(C) in the C+O WD (or the variation of the initial WD mass) causes the diversity of the brightness of SNe Ia. This model can explain the observed dependences of SNe Ia brightness on the galaxy types and the distance from the galactic center. Finally, applying the metallicity effect on the evolution of SN Ia progenitors, we make a prediction of the cosmic supernova rate history as a composite of the supernova rates in different types of galaxies.

  8. Summary of JD 9 supernovae: Past, present, and future

    E-Print Network [OSTI]

    Trimble, VL

    2006-01-01

    Summary of JD 9 Supernovae: past, present, and futureZwicky (separately! ) that supernovae could serve as better

  9. Long Gamma-Ray Bursts Calibrated by Pade Method and Constraints on Cosmological Models

    E-Print Network [OSTI]

    Jing Liu; Hao Wei

    2014-10-15

    Gamma-ray bursts (GRBs) are among the most powerful sources in the universe. In the recent years, GRBs have been proposed as a complementary probe to type Ia supernovae (SNIa). However, as is well known, there is a circularity problem in the use of GRBs to study cosmology. In this work, based on the Pad\\'e approximant, we propose a new cosmology-independent method to calibrate GRBs. We consider a sample consisting 138 long GRBs and obtain 79 calibrated long GRBs at high redshift $z>1.4$ (named Mayflower sample) which can be used to constrain cosmological models without the circularity problem. Then, we consider the constraints on several cosmological models with these 79 calibrated GRBs and other observational data. We show that GRBs are competent to be a complementary probe to the other well-established cosmological observations.

  10. Light a Single Candle: Studying Supernovae

    E-Print Network [OSTI]

    O'Leary, Dianne P.

    Light a Single Candle: Studying Supernovae Dianne P. O'Leary Supernovae are exploding stars study, following a paper by Rust, O'Leary, and Mullen (2009), how well the acceleration hypothesis fits

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

    SciTech Connect (OSTI)

    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

    We report the independent discovery and follow-up observations of supernova 2005gj by the Nearby Supernova Factory. This is the second confirmed case of a ''hybrid'' Type Ia/IIn supernova, which like the prototype SN 2002ic, we interpret as the explosion of a white dwarf interacting with a circumstellar medium. Our early-phase photometry of SN 2005gj shows that the strength of the interaction between the supernova ejecta and circumstellar material is much stronger than for SN 2002ic. Our .rst spectrum shows a hot continuum with broad and narrow H{alpha} emission. Later spectra, spanning over 4 months from outburst, show clear Type Ia features combined with broad and narrow H{gamma}, H{beta},H{alpha} and He I {lambda}{lambda}5876,7065 in emission. At higher resolution, P Cygni profiles are apparent. Surprisingly, we also observe an inverted P Cygni profile for [O III] {lambda}5007. We find that the lightcurve and measured velocity of the unshocked circumstellar material imply mass loss as recently as 8 years ago. This is in contrast to SN 2002ic, for which an inner cavity in the circumstellar material was inferred. Within the context of the thin-shell approximation, the early lightcurve is well-described by a flat radial density profile for the circumstellar material. However, our decomposition of the spectra into Type Ia and shock emission components allows for little obscuration of the supernova, suggesting an aspherical or clumpy distribution for the circumstellar material. We suggest that the emission line velocity profiles arise from electron scattering rather than the kinematics of the shock. This is supported by the inferred high densities, and the lack of evidence for evolution in the line widths. Ground- and space-based photometry, and Keck spectroscopy, of the host galaxy are used to ascertain that the host galaxy has low metallicity (Z/Z{sub {circle_dot}} < 0.3; 95% confidence) and that this galaxy is undergoing a significant star formation event that began roughly 200 {+-} 70 Myr ago. We discuss the implications of these observations for progenitor models and cosmology using Type Ia supernovae.

  12. Supernova neutrinos and nucleosynthesis

    E-Print Network [OSTI]

    G. Martínez-Pinedo; T. Fischer; L. Huther

    2013-09-21

    Observations of metal-poor stars indicate that at least two different nucleosynthesis sites contribute to the production of r-process elements. One site is responsible for the production of light r-process elements Zwinds from core-collapse supernova are the main site for the production of these elements. We explore this possibility by performing nucleosynthesis calculations based on long term Boltzmann neutrino transport simulations. They are based on an Equation of State that reproduces recent constrains on the nuclear symmetry energy. We predict that the early ejecta is neutron-rich with Ye ~ 0.48, it becomes proton rich around 4 s and reaches Ye = 0.586 at 9 s when our simulation stops. The nucleosynthesis in this model produces elements between Zn and Mo, including 92Mo. The elemental abundances are consistent with the observations of the metal-poor star HD 12263. For the elements between Ge and Mo, we produce mainly the neutron-deficient isotopes. This prediction can be confirmed by observations of isotopic abundances in metal-poor stars. No elements heavier than Mo (Z=42) and no heavy r-process elements are produced in our calculations.

  13. A SEARCH FOR NEW CANDIDATE SUPER-CHANDRASEKHAR-MASS TYPE Ia SUPERNOVAE...

    Office of Scientific and Technical Information (OSTI)

    TYPE Ia SUPERNOVAE IN THE NEARBY SUPERNOVA FACTORY DATA SET We present optical photometry and spectroscopy of five Type Ia supernovae discovered by the Nearby Supernova...

  14. Type Ia Supernova Explosion Models

    E-Print Network [OSTI]

    W. Hillebrandt; J. C. Niemeyer

    2000-06-21

    Because calibrated light curves of Type Ia supernovae have become a major tool to determine the local expansion rate of the Universe and also its geometrical structure, considerable attention has been given to models of these events over the past couple of years. There are good reasons to believe that perhaps most Type Ia supernovae are the explosions of white dwarfs that have approached the Chandrasekhar mass, M_ch ~ 1.39 M_sun, and are disrupted by thermonuclear fusion of carbon and oxygen. However, the mechanism whereby such accreting carbon-oxygen white dwarfs explode continues to be uncertain. Recent progress in modeling Type Ia supernovae as well as several of the still open questions are addressed in this review. Although the main emphasis will be on studies of the explosion mechanism itself and on the related physical processes, including the physics of turbulent nuclear combustion in degenerate stars, we also discuss observational constraints.

  15. Thermonuclear supernova simulations with stochastic ignition

    E-Print Network [OSTI]

    W. Schmidt; J. C. Niemeyer

    2005-10-14

    We apply an ad hoc model for dynamical ignition in three-dimensional numerical simulations of thermonuclear supernovae assuming pure deflagrations. The model makes use of the statistical description of temperature fluctuations in the pre-supernova core proposed by Wunsch & Woosley (2004). Randomness in time is implemented by means of a Poisson process. We are able to vary the explosion energy and nucleosynthesis depending on the free parameter of the model which controls the rapidity of the ignition process. However, beyond a certain threshold, the strength of the explosion saturates and the outcome appears to be robust with respect to number of ignitions. In the most energetic explosions, we find about 0.75 solar masses of iron group elements. Other than in simulations with simultaneous multi-spot ignition, the amount of unburned carbon and oxygen at radial velocities of a few 1000 km/s tends to be reduced for an ever increasing number of ignition events and, accordingly, more pronounced layering results.

  16. The $m$-$z$ relation for Type Ia supernovae: safety in numbers or safely without worry?

    E-Print Network [OSTI]

    Helbig, Phillip

    2015-01-01

    The $m$-$z$ relation for Type Ia supernovae is compatible with the cosmological concordance model if one assumes that the Universe is homogeneous, at least with respect to light propagation. This could be due to the density along each line of sight being equal to the overall cosmological density, or to `safety in numbers', with variation in the density along all lines of sight averaging out if the sample is large enough. Statistical correlations (or lack thereof) between redshifts, residuals (differences between the observed distance moduli and those calculated from the best-fitting cosmological model), and observational uncertainties suggest that the former scenario is the better description, so that one can use the traditional formula for the luminosity distance safely without worry.

  17. Superbounce and Loop Quantum Cosmology Ekpyrosis from Modified Gravity

    E-Print Network [OSTI]

    V. K. Oikonomou

    2015-04-07

    As is known, in modified cosmological theories of gravity many of the cosmologies which could not be generated by standard Einstein gravity, can be consistently described by $F(R)$ theories. Using known reconstruction techniques, we investigate which $F(R)$ theories can lead to a Hubble parameter describing two types of cosmological bounces, the superbounce model, related to supergravity and non-supersymmetric models of contracting ekpyrosis and also the Loop Quantum Cosmology modified ekpyrotic model. Since our method is an approximate method, we investigate the problem at large and small curvatures. As we evince, both models yield power law reconstructed $F(R)$ gravities, with the most interesting new feature being that both lead to accelerating cosmologies, in the large curvature approximation. The mathematical properties of the some Friedmann-Robertson-Walker spacetimes $M$, that describe superbounce-like cosmologies are also pointed out, with regards to the group of curvature collineations $CC(M)$.

  18. BAHAMAS: new SNIa analysis reveals inconsistencies with standard cosmology

    E-Print Network [OSTI]

    Shariff, H; Trotta, R; van Dyk, D A

    2015-01-01

    We present results obtained by applying our BAyesian HierArchical Modeling for the Analysis of Supernova cosmology (BAHAMAS) software package to the 740 spectroscopically confirmed supernovae type Ia (SNIa) from the "Joint Light-curve Analysis" (JLA) dataset. We simultaneously determine cosmological parameters and standardization parameters, including host galaxy mass corrections, residual scatter and object-by-object intrinsic magnitudes. Combining JLA and Planck Cosmic Microwave Background data, we find significant discrepancies in cosmological parameter constraints with respect to the standard analysis: we find Omega_M = 0.399+/-0.027, 2.8\\sigma\\ higher than previously reported and w = -0.910+/-0.045, 1.6\\sigma\\ higher than the standard analysis. We determine the residual scatter to be sigma_res = 0.104+/-0.005. We confirm (at the 95% probability level) the existence of two sub-populations segregated by host galaxy mass, separated at log_{10}(M/M_solar) = 10, differing in mean intrinsic magnitude by 0.055+...

  19. Supernova neutrino detection at spallation neutron sources

    E-Print Network [OSTI]

    Huang, Ming-Yang; Young, Bing-Lin

    2015-01-01

    With considering the supernova shock effects, the Mikheyev-Smirnov-Wolfenstein effects, the neutrino collective effects, and the Earth matter effects, the detection of supernova neutrinos at China Spallation Neutron Sources is studied and the event numbers of different flavor supernova neutrinos observed through various reaction channels are calculated with the neutrino energy spectra described by the Fermi-Dirac distribution and "beta fit" distribution respectively. Furthermore, the numerical calculation method of supernova neutrino detection on the Earth is applied to some other spallation neutron sources, and the total event numbers of supernova neutrinos observed through different reactions channels are given.

  20. Spectropolarimetric diagnostics of thermonuclear supernova explosions

    E-Print Network [OSTI]

    Lifan Wang; Dietrich Baade; Ferdinando Patat

    2006-11-29

    Even at extragalactic distances, the shape of supernova ejecta can be effectively diagnosed by spectropolarimetry. We present here results for 17 Type Ia supernovae that allow a statistical study of the correlation among the geometric structures and other observable parameters of Type Ia supernovae. These observations suggest that their ejecta typically consist of a smooth, central iron rich core and an outer layer with chemical asymmetries. The degree of this peripheral asphericity is correlated with the light-curve decline rate of Type Ia supernovae. These observations lend strong support to delayed-detonation models of Type Ia supernovae.

  1. Supernova neutrinos and explosive nucleosynthesis

    SciTech Connect (OSTI)

    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.

  2. R-process Nucleosynthesis in Supernova Explosion

    SciTech Connect (OSTI)

    Saruwatari, M.; Hashimoto, M. [Department of Physics, School of Sciences, Kyushu University, Fukuoka 812-8581 (Japan); Kotake, K. [Division of Theoretical Astronomy, National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Yamada, S. [Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjyuku, Tokyo, 169-8555 (Japan)

    2011-10-28

    We investigate the possibility of the r-process during the magnetohydrodynamical (MHD) explosion of supernova in a massive star of 13 M{sub {center_dot}} with the effects of neutrinos included. Contrary to the case of the spherical explosion, jet-like explosion due to the combined effects of rotation and magnetic field lowers the electron fraction significantly inside the layers. We find that the ejected material of low electron fraction responsible for the r-process comes out from the inner deep region of the core that is made up of iron-group nuclei. This leads to the production of the second to third peak in the solar r-process elements. We suggest that there are some variations in the r-process nucleosynthesis according to the initial conditions of rotational and magnetic fields.

  3. A Taste of Cosmology

    E-Print Network [OSTI]

    L. Verde

    2015-04-22

    This is the summary of two lectures that aim to give an overview of cosmology. I will not try to be too rigorous in derivations, nor to give a full historical overview. The idea is to provide a "taste" of cosmology and some of the interesting topics it covers. The standard cosmological model is presented and I highlight the successes of cosmology over the past decade or so. Keys to the development of the standard cosmological model are observations of the cosmic microwave background and of large-scale structure, which are introduced. Inflation and dark energy and the outlook for the future are also discussed. Slides from the lectures are available from the school website: physicschool.web.cern.ch/PhysicSchool/CLASHEP/CLASHEP2011/.

  4. What We Know About Dark Energy From Supernovae

    ScienceCinema (OSTI)

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

    2010-01-08

    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.

  5. Lectures on Quantum Cosmology

    E-Print Network [OSTI]

    T. Christodoulakis

    2001-09-18

    The problems encountered in trying to quantize the various cosmological models, are brought forward by means of a concrete example. The Automorphism groups are revealed as the key element through which G.C.T.'s can be used for a general treatment of these problems. At the classical level, the time dependent automorphisms lead to significant simplifications of the line element for the generic spatially homogeneous geometry, without loss of generality. At the quantum level, the ''frozen'' automorphisms entail an important reduction of the configuration space --spanned by the 6 components of the scale factor matrix-- on which the Wheeler-DeWitt equation, is to be based. In this spirit the canonical quantization of the most general minisuperspace actions --i.e. with all six scale factor as well as the lapse function and the shift vector present-- describing the vacuum type II, I geometries, is considered. The reduction to the corresponding physical degrees of freedom is achieved through the usage of the linear constraints as well as the quantum version of the entire set of all classical integrals of motion.

  6. Workflow management for a cosmology collaboratory

    E-Print Network [OSTI]

    Loken, Stewart C.; McParland, Charles

    2001-01-01

    nuclear processes in supernovae and to improve our abilityType Ia and Type II supernovae as reference light sources (with the goal of identifying supernovae in their earliest

  7. Cosmological reconstruction and {\\it Om} diagnostic analysis of Einstein-Aether Theory

    E-Print Network [OSTI]

    Pasqua, Antonio; Momeni, Davood; Raza, Muhammad; Myrzakulov, Ratbay

    2015-01-01

    Cosmological reconstruction technique is applied to study the cosmology of the Einstein-Aether (EA) gravity. We reconstructed an analytical model of EA theory for a type of Hubble dependent dark energy density proposed by Granda and Oliveros. The reconstructed cosmological scale factors are comprised of power-law, future singular model, emergent scale factor, intermediate scale factor, a unified theory for matter and dark energy dominated phases and finally for a type of non-extensive exponential scale factor, the q-de Sitter scale factor. In each cosmological epoch, we reconstruct the Lagrangian of the vector part of theory $F(K)$. Furthermore, \\emph{Om} diagnostic analysis technique is applied to fit parameters using recent observational data, namely Type Ia Supernovae, BAO, and data of Hubble parameter.

  8. Observational Constraints on Cosmological Models with the Updated Long Gamma-Ray Bursts

    E-Print Network [OSTI]

    Hao Wei

    2010-08-16

    In the present work, by the help of the newly released Union2 compilation which consists of 557 Type Ia supernovae (SNIa), we calibrate 109 long Gamma-Ray Bursts (GRBs) with the well-known Amati relation, using the cosmology-independent calibration method proposed by Liang {\\it et al.}. We have obtained 59 calibrated high-redshift GRBs which can be used to constrain cosmological models without the circularity problem (we call them ``Hymnium'' GRBs sample for convenience). Then, we consider the joint constraints on 7 cosmological models from the latest observational data, namely, the combination of 557 Union2 SNIa dataset, 59 calibrated Hymnium GRBs dataset (obtained in this work), the shift parameter $R$ from the WMAP 7-year data, and the distance parameter $A$ of the measurement of the baryon acoustic oscillation (BAO) peak in the distribution of SDSS luminous red galaxies. We also briefly consider the comparison of these 7 cosmological models.

  9. Braneworld cosmology in $f(R,T)$ gravity

    E-Print Network [OSTI]

    P. H. R. S. Moraes

    2015-11-25

    Braneworld scenarios consider our observable universe as a brane embedded in a 5D space, named bulk. In this work, I derive the field equations of a braneworld model in a generalized theory of gravitation, namely $f(R,T)$ gravity, with $R$ and $T$, representing the Ricci scalar and the trace of the energy-momentum tensor, respectively. The cosmological parameters obtained from this approach are in agreement with recent constraints from Supernovae Ia data combined with baryon acoustic oscillations and cosmic microwave background observations, favouring such an alternative description of the universe dynamics.

  10. Braneworld cosmology in $f(R,T)$ gravity

    E-Print Network [OSTI]

    Moraes, P H R S

    2015-01-01

    Braneworld scenarios consider our observable universe as a brane embedded in a 5D space, named bulk. In this work, I derive the field equations of a braneworld model in a generalized theory of gravitation, namely $f(R,T)$ gravity, with $R$ and $T$, representing the Ricci scalar and the trace of the energy-momentum tensor, respectively. The cosmological parameters obtained from this approach are in agreement with recent constraints from Supernovae Ia data combined with baryon acoustic oscillations and cosmic microwave background observations, favouring such an alternative description of the universe dynamics.

  11. Cosmography: Extracting the Hubble series from the supernova data

    E-Print Network [OSTI]

    Celine Cattoen; Matt Visser

    2007-07-31

    We perform a number of inter-related cosmographic fits to the legacy05 and gold06 supernova datasets. We pay particular attention to the influence of both statistical and systematic uncertainties, and also to the extent to which the choice of distance scale and manner of representing the redshift scale affect the cosmological parameters. While the "preponderance of evidence" certainly suggests an accelerating universe, we would argue that (based on the supernova data) this conclusion is not currently supported "beyond reasonable doubt". As part of the analysis we develop two particularly transparent graphical representations of the redshift-distance relation -- representations in which acceleration versus deceleration reduces to the question of whether the graph slopes up or down. Turning to the details of the cosmographic fits, three issues in particular concern us: First, the fitted value for the deceleration parameter changes significantly depending on whether one performs a chi^2 fit to the luminosity distance, proper motion distance, angular diameter distance, or other suitable distance surrogate. Second, the fitted value for the deceleration parameter changes significantly depending on whether one uses the traditional redshift variable z, or what we shall argue is on theoretical grounds an improved parameterization y=z/(1+z). Third, the published estimates for systematic uncertainties are sufficiently large that they certainly impact on, and to a large extent undermine, the usual purely statistical tests of significance. We conclude that the case for an accelerating universe is considerably less watertight than commonly believed.

  12. Averaging Hypotheses in Newtonian Cosmology

    E-Print Network [OSTI]

    T. Buchert

    1995-12-20

    Average properties of general inhomogeneous cosmological models are discussed in the Newtonian framework. It is shown under which circumstances the average flow reduces to a member of the standard Friedmann--Lema\\^\\i tre cosmologies. Possible choices of global boundary conditions of inhomogeneous cosmologies as well as consequences for the interpretation of cosmological parameters are put into perspective.

  13. Transition redshift in $f(T)$ cosmology and observational constraints

    E-Print Network [OSTI]

    Salvatore Capozziello; Orlando Luongo; Emmanuel N. Saridakis

    2015-06-18

    We extract constraints on the transition redshift $z_{tr}$, determining the onset of cosmic acceleration, predicted by an effective cosmographic construction, in the framework of $f(T)$ gravity. In particular, employing cosmography we obtain bounds on the viable $f(T)$ forms and their derivatives. Since this procedure is model independent, as long as the scalar curvature is fixed, we are able to determine intervals for $z_{tr}$. In this way we guarantee that the Solar-System constraints are preserved and moreover we extract bounds on the transition time and the free parameters of the scenario. We find that the transition redshifts predicted by $f(T)$ cosmology, although compatible with the standard $\\Lambda$CDM predictions, are slightly smaller. Finally, in order to obtain observational constraints on $f(T)$ cosmology, we perform a Monte Carlo fitting using supernova data, involving the most recent union 2.1 data set.

  14. Comparison of cosmological models using standard rulers and candles

    E-Print Network [OSTI]

    Li, Xiaolei; Zheng, Xiaogang; Biesiada, Marek; Zhu, Zong-Hong

    2015-01-01

    In this paper, we used standard rulers and standard candles (separately and jointly) to explore five popular dark energy models under assumption of spatial flatness of the Universe. As standard rulers, we used a data set comprising 118 galactic-scale strong lensing systems (individual standard rulers if properly calibrated for the mass density profile) combined with BAO diagnostics (statistical standard ruler). Supernovae Ia served asstandard candles. Unlike in the most of previous statistical studies involving strong lensing systems, we relaxed the assumption of singular isothermal sphere (SIS) in favor of its generalization: the power-law mass density profile. Therefore, along with cosmological model parameters we fitted the power law index and its first derivative with respect to the redshift (thus allowing for mass density profile evolution). It turned out that the best fitted $\\gamma$ parameters are in agreement with each other irrespective of the cosmological model considered. This demonstrates that gal...

  15. Cosmology and New Physics

    E-Print Network [OSTI]

    A. D. Dolgov

    2006-06-21

    A comparison of the standard models in particle physics and in cosmology demonstrates that they are not compatible, though both are well established. Basics of modern cosmology are briefly reviewed. It is argued that the measurements of the main cosmological parameters are achieved through many independent physical phenomena and this minimizes possible interpretation errors. It is shown that astronomy demands new physics beyond the frameworks of the (minimal) standard model in particle physics. More revolutionary modifications of the basic principles of the theory are also discussed.

  16. Reducing Zero-point Systematics in Dark Energy Supernova Experiments

    E-Print Network [OSTI]

    Faccioli, Lorenzo

    2011-01-01

    Schmidt, B . P. 2003, i n Supernovae a n d G a m m a - R a ynumber of observed supernovae, m a x i m u m surveyObservations of type l a Supernovae (SNe la) have allowed

  17. Turbulence-Flame Interactions in Type Ia Supernovae

    E-Print Network [OSTI]

    Aspden, Andrew J; Lawrence Berkeley National Laboratory, 1 Cyclotron Road, MS 50A-1148, Berkeley, CA 94720 (Authors 1, 2 & 3); Department of Astronomy and Astrophysics, University of California at Santa Cruz, Santa Cruz, CA 95064 (Author 4); Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794 (Author 5)

    2008-01-01

    Interactions in Type Ia Supernovae A. J. Aspden 1 , J. B.involved in type Ia supernovae (SN Ia) requires the use of ?generated by RT in type Ia supernovae should obey Bolgiano-

  18. The Photometric Properties of Nearby Type Ia Supernovae

    E-Print Network [OSTI]

    Ganeshalingam, Mohan

    2012-01-01

    The Rise-Time Distribution of Nearby Type Ia Supernovae 3.1Highlight: The Physics of Supernovae, ed. W. Hillebrandt &1.1 Supernovae . . . . . . . . . . . . . . 1.1.1

  19. Signatures of the Late Time Core-Collapse Supernova Environment

    E-Print Network [OSTI]

    Roberts, Luke Forrest

    2012-01-01

    in K. Weiler (ed. ), Supernovae and Gamma-Ray Bursters, Vol.Recorded observations of supernovae go back almost twoModern observations of supernovae began in the late 1800s

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

    E-Print Network [OSTI]

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

    2004-01-01

    Highlight: The Physics of Supernovae. Pro- ceedings of the EThere Be A Hole In Type l a Supernovae? Daniel Kasen, Peterscenario, Type l a Supernovae (SNe la) arise from a white

  1. Environmental impact of Supernova Remnants

    E-Print Network [OSTI]

    Dubner, Gloria

    2015-01-01

    The explosion of a supernovae (SN) represents the sudden injection of about 10^51 ergs of thermal and mechanical energy in a small region of space, causing the formation of powerful shock waves that propagate through the interstellar medium at speeds of several thousands of km/s. These waves sweep, compress and heat the interstellar material that they encounter, forming the supernova remnants. Their evolution over thousands of years change forever, irreversibly, not only the physical but also the chemical properties of a vast region of space that can span hundreds of parsecs. This contribution briefly analyzes the impact of these explosions, discussing the relevance of some phenomena usually associated with SNe and their remnants in the light of recent theoretical and observational results.

  2. Type Ia Supernovae: Spectroscopic Surprises

    E-Print Network [OSTI]

    David Branch

    2003-10-23

    Recent observations have extended the range of diversity among spectra of Type Ia supernovae. I briefly discuss SN Ia explosion models in the spectroscopic context, the observed diversity, and some recent results from direct analysis with the Synow code for one normal and two peculiar SNe Ia. Relating the observational manifestations of diversity to their physical causes is looking like an ever more challenging problem.

  3. Turbulent Combustion in Type Ia Supernova Models

    E-Print Network [OSTI]

    F. K. Roepke; W. Hillebrandt

    2006-09-15

    We review the astrophysical modeling of type Ia supernova explosions and describe numerical methods to implement numerical simulations of these events. Some results of such simulations are discussed.

  4. The late emission of thermonuclear supernovae

    E-Print Network [OSTI]

    Pilar Ruiz-Lapuente

    1996-04-16

    The subject of late-time emission of Type Ia supernovae and its implications for the understanding of the explosions of C+O WDs is reviewed.

  5. Search for Relic Neutrinos and Supernova Bursts

    E-Print Network [OSTI]

    David B. Cline

    2000-01-14

    We describe the current situation concerning methods to search for relic neutrinos from the Big Bang and from all past supernovae (SNs). The most promising method for Big Bang neutrinos is by the interaction of ultra-high- energy (UHE) neutrinos. For supernova neutrinos, both Super Kamiokande- and ICARUS-type detectors will be important to study both nubar_{e} and nu_{e} fluxes. We also discuss a dedicated supernova burst observatory (OMNIS) being planned for three sites in the world. We also describe the possible analysis of the supernova type-II (SNII) neutrinos, including flavor mixing, that might be carried out in the future.

  6. Massive neutrinos and cosmology

    E-Print Network [OSTI]

    Julien Lesgourgues; Sergio Pastor

    2006-05-29

    The present experimental results on neutrino flavour oscillations provide evidence for non-zero neutrino masses, but give no hint on their absolute mass scale, which is the target of beta decay and neutrinoless double-beta decay experiments. Crucial complementary information on neutrino masses can be obtained from the analysis of data on cosmological observables, such as the anisotropies of the cosmic microwave background or the distribution of large-scale structure. In this review we describe in detail how free-streaming massive neutrinos affect the evolution of cosmological perturbations. We summarize the current bounds on the sum of neutrino masses that can be derived from various combinations of cosmological data, including the most recent analysis by the WMAP team. We also discuss how future cosmological experiments are expected to be sensitive to neutrino masses well into the sub-eV range.

  7. Cosmological Kinetic Mixing

    E-Print Network [OSTI]

    Das, Ashok; Pino, Miguel

    2015-01-01

    In this paper we generalize the kinetic mixing idea to time reparametrization invariant theories, namely, relativistic point particles and cosmology in order to obtain new insights for dark matter and energy. In the first example, two relativistic particles interact through an appropriately chosen coupling term. It is shown that the system can be diagonalized by means of a non-local field redefinition, and, as a result of this procedure, the mass of one the particles gets rescaled. In the second case, inspired by the previous example, two cosmological models (each with its own scale factor) are made to interact in a similar fashion. The equations of motion are solved numerically in different scenarios (dust, radiation or a cosmological constant coupled to each sector of the system). When a cosmological constant term is present, kinetic mixing rescales it to a lower value which may be more amenable to observations.

  8. Cosmological Kinetic Mixing

    E-Print Network [OSTI]

    Ashok Das; Jorge Gamboa; Miguel Pino

    2015-06-22

    In this paper we generalize the kinetic mixing idea to time reparametrization invariant theories, namely, relativistic point particles and cosmology in order to obtain new insights for dark matter and energy. In the first example, two relativistic particles interact through an appropriately chosen coupling term. It is shown that the system can be diagonalized by means of a non-local field redefinition, and, as a result of this procedure, the mass of one the particles gets rescaled. In the second case, inspired by the previous example, two cosmological models (each with its own scale factor) are made to interact in a similar fashion. The equations of motion are solved numerically in different scenarios (dust, radiation or a cosmological constant coupled to each sector of the system). When a cosmological constant term is present, kinetic mixing rescales it to a lower value which may be more amenable to observations.

  9. 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...

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

    Office of Scientific and Technical Information (OSTI)

    Conference: The Nearby Supernova Factory: Toward A High-Precision Spectro-Photometry Citation Details In-Document Search Title: The Nearby Supernova Factory: Toward A...

  11. 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...

  12. 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...

  13. Dark gravity and cosmology

    E-Print Network [OSTI]

    F. Henry-Couannier; A. Tilquin; C. Tao; A. Ealet

    2007-10-24

    The previous version of this article was a first attempt to confront the Dark Gravity theory to cosmological data. However, more recent developments lead to the conclusion that the cosmological principle is probably not valid in Dark Gravity so that this kind of analysis is at best very premature. A more recent and living review of the Dark Gravity theory can be found in gr-qc/0610079

  14. A LUMINOUS AND FAST-EXPANDING TYPE Ib SUPERNOVA SN 2012au

    SciTech Connect (OSTI)

    Takaki, Katsutoshi; Fukazawa, Yasushi; Itoh, Ryosuke; Ueno, Issei; Ui, Takahiro; Urano, Takeshi [Department of Physical Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Kawabata, Koji S.; Akitaya, Hiroshi; Moritani, Yuki; Ohsugi, Takashi; Uemura, Makoto; Yoshida, Michitoshi [Hiroshima Astrophysical Science Center, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Yamanaka, Masayuki [Kwasan Observatory, Kyoto University, Ohmine-cho Kita Kazan, Yamashina-ku, Kyoto 607-8471 (Japan); Maeda, Keiichi; Nomoto, Ken'ichi [Kavli Institute for the Physics and Mathematics of the Universe (WPI), Todai Institutes for Advanced Study, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8583 (Japan); Tanaka, Masaomi [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Kinugasa, Kenzo [Nobeyama Radio Observatory, National Astronomical Observatory of Japan, 462-2 Nobeyama, Minamimaki, Nagano 384-1305 (Japan); Sasada, Mahito, E-mail: takaki@hep01.hepl.hiroshima-u.ac.jp [Department of Astronomy, Kyoto University, Kitashirakawa-Oiwake-cho, Sakyo-ku, Kyoto 606-8502 (Japan)

    2013-08-01

    We present a set of photometric and spectroscopic observations of a bright Type Ib supernova SN 2012au from -6 days until {approx} + 150 days after maximum. The shape of its early R-band light curve is similar to that of an average Type Ib/c supernova. The peak absolute magnitude is M{sub R} = -18.7 {+-} 0.2 mag, which suggests that this supernova belongs to a very luminous group among Type Ib supernovae. The line velocity of He I {lambda}5876 is about 15,000 km s{sup -1} around maximum, which is much faster than that in a typical Type Ib supernova. From the quasi-bolometric peak luminosity of (6.7 {+-} 1.3) Multiplication-Sign 10{sup 42} erg s{sup -1}, we estimate the {sup 56}Ni mass produced during the explosion as {approx}0.30 M{sub Sun }. We also give a rough constraint to the ejecta mass 5-7 M{sub Sun} and the kinetic energy (7-18) Multiplication-Sign 10{sup 51} erg. We find a weak correlation between the peak absolute magnitude and He I velocity among Type Ib SNe. The similarities to SN 1998bw in the density structure inferred from the light-curve model as well as the large peak bolometric luminosity suggest that SN 2012au had properties similar to energetic Type Ic supernovae.

  15. Emergent cosmology revisited

    SciTech Connect (OSTI)

    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.

  16. Dark Matter Triggers of Supernovae

    E-Print Network [OSTI]

    Peter W. Graham; Surjeet Rajendran; Jaime Varela

    2015-05-17

    The transit of primordial black holes through a white dwarf causes localized heating around the trajectory of the black hole through dynamical friction. For sufficiently massive black holes, this heat can initiate runaway thermonuclear fusion causing the white dwarf to explode as a supernova. The shape of the observed distribution of white dwarfs with masses up to $1.25 M_{\\odot}$ rules out primordial black holes with masses $\\sim 10^{19}$ gm - $10^{20}$ gm as a dominant constituent of the local dark matter density. Black holes with masses as large as $10^{24}$ gm will be excluded if recent observations by the NuStar collaboration of a population of white dwarfs near the galactic center are confirmed. Black holes in the mass range $10^{20}$ gm - $10^{22}$ gm are also constrained by the observed supernova rate, though these bounds are subject to astrophysical uncertainties. These bounds can be further strengthened through measurements of white dwarf binaries in gravitational wave observatories. The mechanism proposed in this paper can constrain a variety of other dark matter scenarios such as Q balls, annihilation/collision of large composite states of dark matter and models of dark matter where the accretion of dark matter leads to the formation of compact cores within the star. White dwarfs, with their astronomical lifetimes and sizes, can thus act as large space-time volume detectors enabling a unique probe of the properties of dark matter, especially of dark matter candidates that have low number density. This mechanism also raises the intriguing possibility that a class of supernova may be triggered through rare events induced by dark matter rather than the conventional mechanism of accreting white dwarfs that explode upon reaching the Chandrasekhar mass.

  17. RESCEU Symposium, University of Tokyo, November 2008John Beacom, The Ohio State University The Diffuse Supernova Neutrino BackgroundThe Diffuse Supernova Neutrino Background

    E-Print Network [OSTI]

    Yamamoto, Hirosuke

    State University Products of Stars and SupernovaeProducts of Stars and Supernovae QuickTimeTM and a TIFF

  18. The strained state cosmology

    E-Print Network [OSTI]

    Tartaglia, Angelo

    2015-01-01

    Starting from some relevant facts concerning the behaviour of the universe over large scale and time span, the analogy between the geometric approach of General Relativ- ity and the classical description of an elastic strained material continuum is discussed. Extending the elastic deformation approach to four dimensions it is shown that the accelerated expansion of the universe is recovered. The strain field of space-time repro- duces properties similar to the ones ascribed to the dark energy currently called in to explain the accelerated expansion. The strain field in the primordial universe behaves as radiation, but asymptotically it reproduces the cosmological constant. Subjecting the theory to a number of cosmological tests confirms the soundness of the approach and gives an optimal value for the one parameter of the model, i.e. the bulk modulus of the space-time continuum. Finally various aspects of the Strained State Cosmology (SSC) are discussed and contrasted with some non-linear massive gravity theor...

  19. Nuclear & Particle Physics, Astrophysics, Cosmology

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

    Nuclear & Particle Physics science-innovationassetsimagesicon-science.jpg Nuclear & Particle Physics, Astrophysics, Cosmology National security depends on science and...

  20. Modular Quantum Cosmology

    E-Print Network [OSTI]

    Orfeu Bertolami; Ricardo Schiappa

    1999-04-30

    We study solutions of the Wheeler-DeWitt equation corresponding to an S-modular invariant N=1 supergravity model and a closed homogeneous and isotropic Friedmann-Robertson-Walker spacetime. The issues of inflation and of the cosmological constant problem are addressed with the help of the relevant wave functions. We find that topological type inflation is consistent from the quantum mechanical point of view and that a solution for the cosmological constant problem along the lines of the strong CP problem naturally arises.

  1. Higgs boson cosmology

    E-Print Network [OSTI]

    Ian G. Moss

    2015-07-21

    The discovery of the Standard Model Higgs boson opens up a range of speculative cosmological scenarios, from the formation of structure in the early universe immediately after the big bang, to relics from the electroweak phase transition one nanosecond after the big bang, on to the end of the present-day universe through vacuum decay. Higgs physics is wide-ranging, and gives an impetus to go beyond the Standard Models of particle physics and cosmology to explore the physics of ultra-high energies and quantum gravity.

  2. Higgs boson cosmology

    E-Print Network [OSTI]

    Moss, Ian G

    2015-01-01

    The discovery of the Standard Model Higgs boson opens up a range of speculative cosmological scenarios, from the formation of structure in the early universe immediately after the big bang, to relics from the electroweak phase transition one nanosecond after the big bang, on to the end of the present-day universe through vacuum decay. Higgs physics is wide-ranging, and gives an impetus to go beyond the Standard Models of particle physics and cosmology to explore the physics of ultra-high energies and quantum gravity.

  3. Dark Matter Triggers of Supernovae

    E-Print Network [OSTI]

    Graham, Peter W; Varela, Jaime

    2015-01-01

    The transit of primordial black holes through a white dwarf causes localized heating around the trajectory of the black hole through dynamical friction. For sufficiently massive black holes, this heat can initiate runaway thermonuclear fusion causing the white dwarf to explode as a supernova. The shape of the observed distribution of white dwarfs with masses up to $1.25 M_{\\odot}$ rules out primordial black holes with masses $\\sim 10^{19}$ gm - $10^{20}$ gm as a dominant constituent of the local dark matter density. Black holes with masses as large as $10^{24}$ gm will be excluded if recent observations by the NuStar collaboration of a population of white dwarfs near the galactic center are confirmed. Black holes in the mass range $10^{20}$ gm - $10^{22}$ gm are also constrained by the observed supernova rate, though these bounds are subject to astrophysical uncertainties. These bounds can be further strengthened through measurements of white dwarf binaries in gravitational wave observatories. The mechanism p...

  4. Detonating Failed Deflagration Model of Thermonuclear Supernovae I. Explosion Dynamics

    E-Print Network [OSTI]

    Tomasz Plewa

    2006-11-24

    We present a detonating failed deflagration model of Type Ia supernovae. In this model, the thermonuclear explosion of a massive white dwarf follows an off-center deflagration. We conduct a survey of asymmetric ignition configurations initiated at various distances from the stellar center. In all cases studied, we find that only a small amount of stellar fuel is consumed during deflagration phase, no explosion is obtained, and the released energy is mostly wasted on expanding the progenitor. Products of the failed deflagration quickly reach the stellar surface, polluting and strongly disturbing it. These disturbances eventually evolve into small and isolated shock-dominated regions which are rich in fuel. We consider these regions as seeds capable of forming self-sustained detonations that, ultimately, result in the thermonuclear supernova explosion. Preliminary nucleosynthesis results indicate the model supernova ejecta are typically composed of about 0.1-0.25 Msun of silicon group elements, 0.9-1.2 Msun of iron group elements, and are essentially carbon-free. The ejecta have a composite morphology, are chemically stratified, and display a modest amount of intrinsic asymmetry. The innermost layers are slightly egg-shaped with the axis ratio ~1.2-1.3 and dominated by the products of silicon burning. This central region is surrounded by a shell of silicon-group elements. The outermost layers of ejecta are highly inhomogeneous and contain products of incomplete oxygen burning with only small admixture of unburned stellar material. The explosion energies are ~1.3-1.5 10^51 erg.

  5. Progress Report on the Berkeley/Anglo-Australian Observatory High-Redshift Supernova Search

    E-Print Network [OSTI]

    Goldhaber, G.

    2008-01-01

    photometry curve for type Ia supernovae and the redshift vsdistributions for observed supernovae. Figure 5 from Millermain efforts related to supernovae in progress at Berkeley.

  6. How to Find More Supernovae with Less Work: Object Classification Techniques for Difference Imaging

    E-Print Network [OSTI]

    Bailey, Stephen; Aragon, Cecilia; Romano, Raquel; Thomas, Rollin C.; Weaver, Benjamin A.; Wong, Daniel

    2007-01-01

    How to Find More Supernovae with Less Work: Object Classi?methods: statistical — supernovae: general — techniques:for objects such as supernovae, active galactic nuclei,

  7. Long gamma-ray bursts and core-collapse supernovae have different environments

    E-Print Network [OSTI]

    2006-01-01

    and core-collapse supernovae have dif- ferent environmentsObservational Evidence from Supernovae for an Acceleratingfrom 42 High-Redshift Supernovae. Astrophys. J. 517, 565–

  8. High-Redshift Type Ia Supernova Rates in Galaxy Cluster and Field Environments

    E-Print Network [OSTI]

    Barbary, Kyle Harris

    2011-01-01

    29 Candidates classified as supernovae . . . . . . . .1.1 Type Ia Supernovae as Standard Candles . . . . . . . .4.2.3 Supernovae . . . . . . . . . . . . . . . . 4.2.4

  9. Direct numerical simulations of type Ia supernovae flames II: The rayleigh-taylor instability

    E-Print Network [OSTI]

    Bell, J.B.; Day, M.S.; Rendleman, C.A.; Woosley, S.E.; Zingale, M.

    2004-01-01

    Weaver, T. A. 1994, in Supernovae, Les Houches, Session LIV,Simulations of Type Ia Supernovae Flames II: The Rayleigh-Subject headings: supernovae: general — white dwarfs —

  10. Direct numerical simulations of type Ia supernovae flames I: The landau-darrieus instability

    E-Print Network [OSTI]

    Bell, J.B.; Day, M.S.; Rendleman, C.A.; Woosley, S.E.; Zingale, M.

    2003-01-01

    Simulations of Type Ia Supernovae Flames I: The Landau-Subject headings: supernovae: general — white dwarfs —could occur in Type Ia supernovae (Niemeyer & Woosley 1997),

  11. Low Mach Number Modeling of Type Ia Supernovae. II. Energy Evolution

    E-Print Network [OSTI]

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

    2006-01-01

    Number Modeling of Type Ia Supernovae. II. Energy EvolutionIa. Subject headings: supernovae: general — white dwarfs —the ignition of Type Ia supernovae (SNe Ia) is critical to

  12. Spectral Observations and Analyses of Low-Redshift Type Ia Supernovae

    E-Print Network [OSTI]

    Silverman, Jeffrey Michael

    2011-01-01

    1.2 Why Study Supernovae? . . . . . . . . . . . . .1.3 What are Supernovae? . . . . . . . .Core-Collapse Supernovae . . . . . . . . 1.3.2 Thermonuclear

  13. A complete analytic inversion of supernova lines in the Sobolev approximation

    E-Print Network [OSTI]

    Kasen, Daniel; Branch, David; Baron, E.; Jeffery, David

    2001-01-01

    D . & Branch, D . 1990, in Supernovae, ed. J . C . Wheeler &radia­ tive transfer — supernovae Lawrence Berkeley Nationalgradients, such as supernovae. The Sobolev approximation has

  14. Cosmic-ray acceleration in supernova shocks

    E-Print Network [OSTI]

    Vincent Tatischeff

    2008-07-25

    Galactic cosmic rays are widely believed to be accelerated in expanding shock waves initiated by supernova explosions. The theory of diffusive shock acceleration of cosmic rays is now well established, but two fundamental questions remain partly unanswered: what is the acceleration efficiency, i.e. the fraction of the total supernova energy converted to cosmic-ray energy, and what is the maximum kinetic energy achieved by particles accelerated in supernova explosions? Recent observations of supernova remnants, in X-rays with the Chandra and XMM-Newton satellites and in very-high-energy gamma rays with several ground-based atmospheric Cerenkov telescopes, have provided new pieces of information concerning these two questions. After a review of these observations and their current interpretations, I show that complementary information on the diffusive shock acceleration process can be obtained by studying the radio emission from extragalactic supernovae. As an illustration, a nonlinear model of diffusive shock acceleration is applied to the radio light curves of the supernova SN 1993J, which exploded in the nearby galaxy M81. The results of the model suggest that most of the Galactic cosmic rays may be accelerated during the early phase of interaction between the supernova ejecta and the wind lost from the progenitor star.

  15. Cosmology with Coupled Gravity and Dark Energy

    E-Print Network [OSTI]

    Ti-Pei Li

    2015-01-13

    Dark energy is a fundamental constituent of our universe, its status in the cosmological field equation should be equivalent to that of gravity. Here we construct a dark energy and matter gravity coupling (DEMC) model of cosmology in a way that dark energy and gravity are introduced into the cosmological field equation in parallel with each other from the beginning. The DEMC universe possesses a composite symmetry from global Galileo invariance and local Lorentz invariance. The observed evolution of the universe expansion rate at redshift z>1 is in tension with the standard LCDM model, but can be well predicted by the DEMC model from measurements of only nearby epochs. The so far most precise measured expansion rate at high z is quite a bit slower than the expectations from LCDM, but remarkably consistent with that from DEMC. It is hoped that the DEMC scenario can also help to solve other existing challenges to cosmology: large scale anomalies in CMB maps and large structures up to about 10^3 Mpc of a quasar group. The DEMC universe is a well defined mechanical system. From measurements we can quantitatively evaluate its total rest energy, present absolute radius and expanding speed.

  16. SPECTROSCOPY OF TYPE Ia SUPERNOVAE BY THE CARNEGIE SUPERNOVA PROJECT

    SciTech Connect (OSTI)

    Folatelli, Gaston [Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU, WPI), Todai Institutes for Advanced Study, the University of Tokyo, 277-8583 Kashiwa (Japan); Morrell, Nidia; Phillips, Mark M.; Hsiao, Eric; Campillay, Abdo; Contreras, Carlos; Castellon, Sergio; Roth, Miguel [Las Campanas Observatory, Carnegie Observatories, Casilla 601, La Serena (Chile); Hamuy, Mario; Anderson, Joseph P. [Departamento de Astronomia, Universidad de Chile, Casilla 36-D, Santiago (Chile); Krzeminski, Wojtek [N. Copernicus Astronomical Center, ul. Bartycka 18, 00-716 Warszawa (Poland); Stritzinger, Maximilian [Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C (Denmark); Burns, Christopher R.; Freedman, Wendy L.; Madore, Barry F.; Murphy, David; Persson, S. E. [Observatories of the Carnegie Institution of Washington, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Prieto, Jose L. [Department of Astrophysical Sciences, Princeton University, 4 Ivy Ln., Princeton, NJ 08544 (United States); Suntzeff, Nicholas B.; Krisciunas, Kevin, E-mail: gaston.folatelli@ipmu.jp [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); and others

    2013-08-10

    This is the first release of optical spectroscopic data of low-redshift Type Ia supernovae (SNe Ia) by the Carnegie Supernova Project including 604 previously unpublished spectra of 93 SNe Ia. The observations cover a range of phases from 12 days before to over 150 days after the time of B-band maximum light. With the addition of 228 near-maximum spectra from the literature, we study the diversity among SNe Ia in a quantitative manner. For that purpose, spectroscopic parameters are employed such as expansion velocities from spectral line blueshifts and pseudo-equivalent widths (pW). The values of those parameters at maximum light are obtained for 78 objects, thus providing a characterization of SNe Ia that may help to improve our understanding of the properties of the exploding systems and the thermonuclear flame propagation. Two objects, namely, SNe 2005M and 2006is, stand out from the sample by showing peculiar Si II and S II velocities but otherwise standard velocities for the rest of the ions. We further study the correlations between spectroscopic and photometric parameters such as light-curve decline rate and color. In agreement with previous studies, we find that the pW of Si II absorption features are very good indicators of light-curve decline rate. Furthermore, we demonstrate that parameters such as pW2 (Si II 4130) and pW6 (Si II 5972) provide precise calibrations of the peak B-band luminosity with dispersions of Almost-Equal-To 0.15 mag. In the search for a secondary parameter in the calibration of peak luminosity for SNe Ia, we find a Almost-Equal-To 2{sigma}-3{sigma} correlation between B-band Hubble residuals and the velocity at maximum light of S II and Si II lines.

  17. Scalar Field Inhomogeneous Cosmologies

    E-Print Network [OSTI]

    A. Feinstein; J. Ibáñez; P. Labraga

    1995-11-24

    Some exact solutions for the Einstein field equations corresponding to inhomogeneous $G_2$ cosmologies with an exponential-potential scalar field which generalize solutions obtained previously are considered. Several particular cases are studied and the properties related to generalized inflation and asymptotic behaviour of the models are discussed.

  18. Nuclear physics and cosmology

    SciTech Connect (OSTI)

    Coc, Alain [Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), CNRS/IN2P3, Université Paris Sud 11, UMR 8609, Bâtiment 104, F-91405 Orsay Campus (France)

    2014-05-09

    There are important aspects of Cosmology, the scientific study of the large scale properties of the universe as a whole, for which nuclear physics can provide insights. Here, we will focus on Standard Big-Bang Nucleosynthesis and we refer to the previous edition of the School [1] for the aspects concerning the variations of constants in nuclear cosmo-physics.

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

    SciTech Connect (OSTI)

    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 temperature and constrain SN models. We also consider supernova ?-process nucleosynthesis to deduce constraints on the temperature of the various neutrino flavors. We study the effects of neutrino oscillations on the detected neutrino energy spectrum and also show that one might distinguish the equation of state (EoS) as well as the cause of the possible missing luminous supernovae from the detection of supernova relic neutrinos. We also analyze a possible enhanced contribution from failed supernovae leading to a black hole remnant as a solution to the supernova rate problem. We conclude that indeed it might be possible (though difficult) to measure the neutrino temperature, neutrino oscillations, and the EoS and confirm this source of missing luminous supernovae by the detection of the spectrum of relic neutrinos.

  20. Observing the next galactic supernova

    SciTech Connect (OSTI)

    Adams, Scott M.; Kochanek, C. S.; Beacom, John F.; Stanek, K. Z. [Department of Astronomy, The Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Vagins, Mark R. [Kavli Institute for the Physics and Mathematics of the Universe (WPI), Todai Institutes for Advanced Study, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8583 (Japan)

    2013-12-01

    No supernova (SN) in the Milky Way has been observed since the invention of the optical telescope, instruments for other wavelengths, neutrino detectors, or gravitational wave observatories. It would be a tragedy to miss the opportunity to fully characterize the next one. To aid preparations for its observations, we model the distance, extinction, and magnitude probability distributions of a successful Galactic core-collapse supernova (ccSN), its shock breakout radiation, and its massive star progenitor. We find, at very high probability (? 100%), that the next Galactic SN will easily be detectable in the near-IR and that near-IR photometry of the progenitor star very likely (? 92%) already exists in the Two Micron All Sky Survey. Most ccSNe (98%) will be easily observed in the optical, but a significant fraction (43%) will lack observations of the progenitor due to a combination of survey sensitivity and confusion. If neutrino detection experiments can quickly disseminate a likely position (?3°), we show that a modestly priced IR camera system can probably detect the shock breakout radiation pulse even in daytime (64% for the cheapest design). Neutrino experiments should seriously consider adding such systems, both for their scientific return and as an added and internal layer of protection against false triggers. We find that shock breakouts from failed ccSNe of red supergiants may be more observable than those of successful SNe due to their lower radiation temperatures. We review the process by which neutrinos from a Galactic ccSN would be detected and announced. We provide new information on the EGADS system and its potential for providing instant neutrino alerts. We also discuss the distance, extinction, and magnitude probability distributions for the next Galactic Type Ia supernova (SN Ia). Based on our modeled observability, we find a Galactic ccSN rate of 3.2{sub ?2.6}{sup +7.3} per century and a Galactic SN Ia rate of 1.4{sub ?0.8}{sup +1.4} per century for a total Galactic SN rate of 4.6{sub ?2.7}{sup +7.4} per century is needed to account for the SNe observed over the last millennium, which implies a Galactic star formation rate of 3.6{sub ?3.0}{sup +8.3} M {sub ?} yr{sup –1}.

  1. Fluid Mechanics Explains Cosmology, Dark Matter, Dark Energy, and Life

    E-Print Network [OSTI]

    Carl H. Gibson

    2012-11-02

    Observations of the interstellar medium by the Herschel, Planck etc. infrared satellites throw doubt on standard {\\Lambda}CDMHC cosmological processes to form gravitational structures. According to the Hydro-Gravitational-Dynamics (HGD) cosmology of Gibson (1996), and the quasar microlensing observations of Schild (1996), the dark matter of galaxies consists of Proto-Globular-star-Cluster (PGC) clumps of Earth-mass primordial gas planets in metastable equilibrium since PGCs began star production at 0.3 Myr by planet mergers. Dark energy and the accelerating expansion of the universe inferred from SuperNovae Ia are systematic dimming errors produced as frozen gas dark matter planets evaporate to form stars. Collisionless cold dark matter that clumps and hierarchically clusters does not exist. Clumps of PGCs began diffusion from the Milky Way Proto-Galaxy upon freezing at 14 Myr to give the Magellanic Clouds and the faint dwarf galaxies of the 10^22 m diameter baryonic dark matter Galaxy halo. The first stars persist as old globular star clusters (OGCs). Water oceans and the biological big bang occurred at 2-8 Myr. Life inevitably formed and evolved in the cosmological primordial organic soup provided by 10^80 big bang planets and their hot oceans as they gently merged to form larger binary planets and small binary stars.

  2. CfAIR2: Near Infrared Light Curves of 94 Type Ia Supernovae

    E-Print Network [OSTI]

    Friedman, Andrew S; Marion, G H; Challis, Peter; Mandel, Kaisey S; Bloom, Joshua S; Modjaz, Maryam; Narayan, Gautham; Hicken, Malcolm; Foley, Ryan; Klein, Christopher R; Starr, Dan L; Morgan, Adam; Rest, Armin; Blake, Cullen H; Miller, Adam A; Falco, Emilio E; Wyatt, William F; Mink, Jessica; Skrutskie, Michael F; Kirshner, Robert P

    2014-01-01

    CfAIR2 is a large homogeneously reduced set of near-infrared (NIR) light curves for Type Ia supernovae (SN Ia) obtained with the 1.3m PAIRITEL (Peters Automated InfraRed Imaging TELescope). This data set includes 4607 measurements of 94 SN Ia and 4 additional SN Iax observed from 2005-2011 at the Fred Lawrence Whipple Observatory on Mount Hopkins, Arizona. CfAIR2 includes JHKs photometric measurements for 88 normal and 6 spectroscopically peculiar SN Ia in the nearby universe, with a median redshift of z~0.021 for the normal SN Ia. CfAIR2 data span the range from -13 days to +127 days from maximum in the B-band. More than half of the light curves begin before the time of maximum and the coverage typically contains ~13-18 epochs of observation, depending on the filter. We present extensive tests that verify the fidelity of the CfAIR2 data pipeline, including comparison to the excellent data of the Carnegie Supernova Project. CfAIR2 contributes to a firm local anchor for supernova cosmology studies in the NIR. ...

  3. Hydrogen in Type Ic Supernovae?

    E-Print Network [OSTI]

    David Branch; David J. Jeffery; Timothy R. Young; E. Baron

    2006-05-09

    By definition, a Type Ic supernova (SN Ic) does not have conspicuous lines of hydrogen or helium in its optical spectrum. SNe Ic usually are modelled in terms of the gravitational collapse of bare carbon-oxygen cores. We consider the possibility that the spectra of ordinary (SN 1994I-like) SNe Ic have been misinterpreted, and that SNe Ic eject hydrogen. An absorption feature usually attributed to a blend of Si II 6355 and C II 6580 may be produced by H-alpha. If SN 1994I-like SNe Ic eject hydrogen, the possibility that hypernova (SN 1998bw-like) SNe Ic, some of which are associated with gamma-ray bursts, also eject hydrogen should be considered. The implications of hydrogen for SN Ic progenitors and explosion models are briefly discussed.

  4. The supernova that destroyed a galaxy

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

    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...

  5. Supercomputing and the search for supernovae

    ScienceCinema (OSTI)

    Nugent, Peter

    2014-06-23

    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.

  6. The ESSENCE Supernova Survey: Survey Optimization, Observations...

    Office of Scientific and Technical Information (OSTI)

    (z approx 0.5 +- 0.2) is optimal for determining w. We describe the data analysis pipeline based on using reliable and robust image subtraction to find supernovae automatically...

  7. Supercomputing and the search for supernovae

    SciTech Connect (OSTI)

    Nugent, Peter

    2013-10-31

    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.

  8. How to See a Recently Discovered Supernova

    ScienceCinema (OSTI)

    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/

  9. UV Light Curves of Thermonuclear Supernovae

    E-Print Network [OSTI]

    S. I. Blinnikov; E. I. Sorokina

    2000-03-17

    Ultraviolet light curves are calculated for several thermonuclear supernova models using a multifrequency radiation hydrodynamic code. It is found that Chandrasekhar-mass models produce very similar light curves both for detonation and deflagration. Sub-Chandrasekhar-mass models essentially differ from ``normal'' Chandrasekhar ones regarding behaviour of their UV fluxes. Differences in absolute brightness and in shape of light curves of thermonuclear supernovae could be detectable up to 300 Mpc with modern UV space telescopes.

  10. Cosmological constraints on extended Galileon models

    SciTech Connect (OSTI)

    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.

  11. Baryonic matter perturbations in decaying vacuum cosmology

    SciTech Connect (OSTI)

    Marttens, R.F. vom; Zimdahl, W.; Hipólito-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.

  12. Early universe cosmology and tests of fundamental physics

    SciTech Connect (OSTI)

    Andreas Albrecht, Joshua A. Frieman and Mark Trodden

    2002-03-04

    This is the report of the Working Group on Early Universe Cosmology and tests of Fundamental Physics, group P4.8 of the of the Snowmass 2001 conference. Here we summarize the impressive array of advances that have taken place in this field, and identify opportunities for even greater progress in the future. Topics include Dark Energy, Cosmic Acceleration, Inflation, Phase Transitions, Baryogenesis, and String/M-theory Cosmology. The introductory section gives an executive summary with six key open questions on which we can expect to make significant progress.

  13. Holography from quantum cosmology

    E-Print Network [OSTI]

    M. Rashki; S. Jalalzadeh

    2014-12-12

    The Weyl-Wigner-Groenewold-Moyal formalism of deformation quantization is applied to the closed Friedmann-Lema\\^itre-Robertson-Walker (FLRW) cosmological model. We show that the phase space average for the surface of the apparent horizon is quantized in units of the Planck's surface, and that the total entropy of the universe is also quantized. Taking into account these two concepts, it is shown that 't Hooft conjecture on the cosmological holographic principle (CHP) in radiation and dust dominated quantum universes is satisfied as a manifestation of quantization. This suggests that the entire universe (not only inside the apparent horizon) can be seen as a two-dimensional information structure encoded on the apparent horizon.

  14. Quantum cosmology: a review

    E-Print Network [OSTI]

    Martin Bojowald

    2015-01-20

    In quantum cosmology, one applies quantum physics to the whole universe. While no unique version and no completely well-defined theory is available yet, the framework gives rise to interesting conceptual, mathematical and physical questions. This review presents quantum cosmology in a new picture that tries to incorporate the importance of inhomogeneity: De-emphasizing the traditional minisuperspace view, the dynamics is rather formulated in terms of the interplay of many interacting "microscopic" degrees of freedom that describe the space-time geometry. There is thus a close relationship with more-established systems in condensed-matter and particle physics even while the large set of space-time symmetries (general covariance) requires some adaptations and new developments. These extensions of standard methods are needed both at the fundamental level and at the stage of evaluating the theory by effective descriptions.

  15. White dwarf mergers,White dwarf mergers, thermonuclear supernovae,thermonuclear supernovae,

    E-Print Network [OSTI]

    Hinton, Jim

    White dwarf mergers,White dwarf mergers, thermonuclear supernovae,thermonuclear supernovae fusion is ignited. Degenerate, hence runaway. #12;CO white dwarf accretes, either from companion, or from disk after merger. As it approaches maximum mass, C fusion is ignited. Degenerate, hence runaway. SN Ia

  16. Cosmology of Vacuum

    E-Print Network [OSTI]

    V. Burdyuzha; G. Vereshkov

    2007-12-29

    Shortly the vacuum component of the Universe from the geometry point of view and from the point of view of the standard model of physics of elementary particles is discussed. Some arguments are given to the calculated value of the cosmological constant (Zeldovich approximation). A new component of space vacuum (the gravitational vacuum condensate) is involved the production of which has fixed time in our Universe. Also the phenomenon of vacuum selforganization must be included in physical consideration of the Universe evolution.

  17. Particle Physics and Cosmology

    E-Print Network [OSTI]

    P. Pralavorio

    2014-12-04

    Today, both particle physics and cosmology are described by few parameter Standard Models, i.e. it is possible to deduce consequence of particle physics in cosmology and vice verse. The former is examined in this lecture, in light of the recent systematic exploration of the electroweak scale by the LHC experiments. The two main results of the first phase of the LHC, the discovery of a Higgs-like particle and the absence so far of new particles predicted by "natural" theories beyond the Standard Model (supersymmetry, extra-dimension and composite Higgs) are put in a historical context to enlighten their importance and then presented extensively. To be complete, a short review from the neutrino physics, which can not be probed at LHC, is also given. The ability of all these results to resolve the 3 fundamental questions of cosmology about the nature of dark energy and dark matter as well as the origin of matter-antimatter asymmetry is discussed in each case.

  18. Signatures of a companion star in type Ia supernovae

    SciTech Connect (OSTI)

    Maeda, Keiichi [Department of Astronomy, Kyoto University, Kitashirakawa-Oiwake-cho, Sakyo-ku, Kyoto 606-8502 (Japan); Kutsuna, Masamichi; Shigeyama, Toshikazu, E-mail: keiichi.maeda@kusastro.kyoto-u.ac.jp [Research Center for the Early Universe, School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)

    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 H? is extremely difficult to identify. Alternatively, we find that P{sub ?} in postmaximum near-infrared spectra can potentially provide a powerful diagnostic.

  19. 3D Simulations of Thermonuclear Supernovae From Very Massive Stars

    E-Print Network [OSTI]

    Crowther, Paul

    3D Simulations of Thermonuclear Supernovae From Very Massive Stars Ke-Jung (Ken) Chen Johnston #12;3D Simulations of Thermonuclear Supernovae From Very Massive Stars Ke-Jung (Ken) Chen Johnston

  20. Nucleosynthesis in Type Ia Supernovae

    E-Print Network [OSTI]

    K. Nomoto; K. Iwamoto; N. Nakasato; F. -K. Thielemann; F. Brachwitz; T. Tsujimoto; Y. Kubo; N. Kishimoto

    1997-06-03

    Among the major uncertainties involved in the Chandrasekhar mass models for Type Ia supernovae are the companion star of the accreting white dwarf (or the accretion rate that determines the carbon ignition density) and the flame speed after ignition. We present nucleosynthesis results from relatively slow deflagration (1.5 - 3 % of the sound speed) to constrain the rate of accretion from the companion star. Because of electron capture, a significant amount of neutron-rich species such as ^{54}Cr, ^{50}Ti, ^{58}Fe, ^{62}Ni, etc. are synthesized in the central region. To avoid the too large ratios of ^{54}Cr/^{56}Fe and ^{50}Ti/^{56}Fe, the central density of the white dwarf at thermonuclear runaway must be as low as \\ltsim 2 \\e9 \\gmc. Such a low central density can be realized by the accretion as fast as $\\dot M \\gtsim 1 \\times 10^{-7} M_\\odot yr^{-1}$. These rapidly accreting white dwarfs might correspond to the super-soft X-ray sources.

  1. Dark Matter Balls Help Supernovae to Explode

    E-Print Network [OSTI]

    Colin D. Froggatt; Holger B. Nielsen

    2015-03-03

    As a solution to the well-known problem that the shock wave potentially responsible for the explosion of a supernova actually tends to stall, we propose a new energy source arising from our model for dark matter. Our earlier model proposed that dark matter should consist of cm-large white dwarf-like objects kept together by a skin separating two different sorts of vacua. These dark matter balls or pearls will collect in the middle of any star throughout its lifetime. At some stage during the development of a supernova the balls will begin to take in neutrons and then other surrounding material. By passing into a ball nucleons fall through a potential of order 10 MeV, causing a severe production of heat - of order 10 foe for a solar mass of material eaten by the balls. The temperature in the iron core will thereby be raised, splitting up the iron into smaller nuclei. This provides a mechanism for reviving the shock wave when it arrives and making the supernova explosion really occur. The onset of the heating due to the dark matter balls would at first stop the collapse of the supernova progenitor. This opens up the possibility of there being {\\em two} collapses giving two neutrino outbursts, as apparently seen in the supernova SN1987A - one in Mont Blanc, and one 4 hours 43 minutes later in both IMB and Kamiokande.

  2. Nucleosynthesis Basics and Applications to Supernovae

    E-Print Network [OSTI]

    F. -K. Thielemann; T. Rauscher; C. Freiburghaus; K. Nomoto; M. Hashimoto; B. Pfeiffer; K. -L. Kratz

    1998-02-06

    This review concentrates on nucleosynthesis processes in general and their applications to massive stars and supernovae. A brief initial introduction is given to the physics in astrophysical plasmas which governs composition changes. We present the basic equations for thermonuclear reaction rates and nuclear reaction networks. The required nuclear physics input for reaction rates is discussed, i.e. cross sections for nuclear reactions, photodisintegrations, electron and positron captures, neutrino captures, inelastic neutrino scattering, and beta-decay half-lives. We examine especially the present state of uncertainties in predicting thermonuclear reaction rates, while the status of experiments is discussed by others in this volume (see M. Wiescher). It follows a brief review of hydrostatic burning stages in stellar evolution before discussing the fate of massive stars, i.e. the nucleosynthesis in type II supernova explosions (SNe II). Except for SNe Ia, which are explained by exploding white dwarfs in binary stellar systems (which will not be discussed here), all other supernova types seem to be linked to the gravitational collapse of massive stars (M$>$8M$_\\odot$) at the end of their hydrostatic evolution. SN1987A, the first type II supernova for which the progenitor star was known, is used as an example for nucleosynthesis calculations. Finally, we discuss the production of heavy elements in the r-process up to Th and U and its possible connection to supernovae.

  3. Cosmic Rays from Supernovae Proven to Hit Earth

    Office of Energy Efficiency and Renewable Energy (EERE)

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

  4. Investigations of supernovae and supernova remnants in the era of SKA

    E-Print Network [OSTI]

    Wang, Lingzhi; Zhu, Hui; Tian, Wenwu; Wang, Xiaofeng

    2015-01-01

    Two main physical mechanisms are used to explain supernova explosions: thermonuclear explosion of a white dwarf(Type Ia) and core collapse of a massive star (Type II and Type Ib/Ic). Type Ia supernovae serve as distance indicators that led to the discovery of the accelerating expansion of the Universe. The exact nature of their progenitor systems however remain unclear. Radio emission from the interaction between the explosion shock front and its surrounding CSM or ISM provides an important probe into the progenitor star's last evolutionary stage. No radio emission has yet been detected from Type Ia supernovae by current telescopes. The SKA will hopefully detect radio emission from Type Ia supernovae due to its much better sensitivity and resolution. There is a 'supernovae rate problem' for the core collapse supernovae because the optically dim ones are missed due to being intrinsically faint and/or due to dust obscuration. A number of dust-enshrouded optically hidden supernovae should be discovered via SKA1-...

  5. Radioactive Probes of the Supernova-Contaminated Solar Nebula: Evidence that the Sun was Born in a Cluster

    E-Print Network [OSTI]

    Leslie W. Looney; John J. Tobin; Brian D. Fields

    2006-08-19

    We construct a simple model for radioisotopic enrichment of the protosolar nebula by injection from a nearby supernova, based on the inverse square law for ejecta dispersion. We find that the presolar radioisotopes abundances (i.e., in solar masses) demand a nearby supernova: its distance can be no larger than 66 times the size of the protosolar nebula, at a 90% confidence level, assuming 1 solar mass of protosolar material. The relevant size of the nebula depends on its state of evolution at the time of radioactivity injection. In one scenario, a collection of low-mass stars, including our sun, formed in a group or cluster with an intermediate- to high-mass star that ended its life as a supernova while our sun was still a protostar, a starless core, or perhaps a diffuse cloud. Using recent observations of protostars to estimate the size of the protosolar nebula constrains the distance of the supernova at 0.02 to 1.6 pc. The supernova distance limit is consistent with the scales of low-mass stars formation around one or more massive stars, but it is closer than expected were the sun formed in an isolated, solitary state. Consequently, if any presolar radioactivities originated via supernova injection, we must conclude that our sun was a member of such a group or cluster that has since dispersed, and thus that solar system formation should be understood in this context. In addition, we show that the timescale from explosion to the creation of small bodies was on the order of 1.8 Myr (formal 90% confidence range of 0 to 2.2 Myr), and thus the temporal choreography from supernova ejecta to meteorites is important. Finally, we can not distinguish between progenitor masses from 15 to 25 solar masses in the nucleosynthesis models; however, the 20 solar mass model is somewhat preferred.

  6. Sunyaev-Zeldovich Contributions from Early Supernova Winds

    E-Print Network [OSTI]

    California at Los Angles, University of

    Sunyaev-Zeldovich Contributions from Early Supernova Winds Sarah Benjamin Mentor: Steven Furlanetto was to determine the contributions to the Sunyaev-Zeldovich effect from supernova winds at high redshift. In order, especially at asymptotic bounds. Finally, the Compton y-parameter of the supernova winds can be found using

  7. Cosmology with Mimetic Matter

    SciTech Connect (OSTI)

    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.

  8. Cosmological principle and honeycombs

    E-Print Network [OSTI]

    C. Criado; N. Alamo

    2004-04-12

    We present the possibility that the gravitational growth of primordial density fluctuations leads to what can be considered a week version of the cosmological principle. The large scale mass distribution associated with this principle must have the geometrical structures known as a regular honeycombs. We give the most important parameters that characterize the honeycombs associated with the closed, open, and flat FLRW models. These parameters can be used to determine by means of observations which is the appropriate honeycomb. For each of these honeycombs, and for a nearly flat universe, we have calculated the probability that a randomly placed observer could detect the honeycomb as a function of the density parameters.

  9. Astrophysics & Cosmology

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTechtail.Theory of raregovAboutRecovery ActTools to someoneAstrophysics & Cosmology

  10. Scalar field potentials for cosmology

    E-Print Network [OSTI]

    Victor H. Cardenas; Sergio del Campo

    2004-01-05

    We discuss different aspects of modern cosmology through a scalar field potential construction method. We discuss the case of negative potential cosmologies and its relation with oscillatory cosmic evolution, models with a explicit interaction between dark energy and dark matter which address the coincidence problem and also the case of non-zero curvature space.

  11. Supernova Neutrinos: Production, Oscillations and Detection

    E-Print Network [OSTI]

    Mirizzi, Alessandro; Janka, Hans-Thomas; Saviano, Ninetta; Scholberg, Kate; Bollig, Robert; Hudepohl, Lorenz; Chakraborty, Sovan

    2015-01-01

    Neutrinos play a crucial role in the collapse and explosion of massive stars, governing the infall dynamics of the stellar core, triggering and fueling the explosion and driving the cooling and deleptonization of the newly formed neutron star. Due to their role neutrinos carry information from the heart of the explosion and, due to their weakly interacting nature, offer the only direct probe of the dynamics and thermodynamics at the center of a supernova. In this paper, we review the present status of modelling the neutrino physics and signal formation in collapsing and exploding stars. We assess the capability of current and planned large underground neutrino detectors to yield faithful information of the time and flavor dependent neutrino signal from a future Galactic supernova. We show how the observable neutrino burst would provide a benchmark for fundamental supernova physics with unprecedented richness of detail. Exploiting the treasure of the measured neutrino events requires a careful discrimination o...

  12. Jet Induced Supernovae-Hydrodynamics and Observational Consequences

    E-Print Network [OSTI]

    A. Khokhlov; Peter Hoeflich

    2000-11-01

    Core collapse supernovae (SN) are the final stages of stellar evolution in massive stars during which the central region collapses, forms a neutron star (NS), and the outer layers are ejected. Recent explosion scenarios assumed that the ejection is due to energy deposition by neutrinos into the envelope but detailed models do not produce powerful explosions. There is mounting evidence for an asphericity in the SN which is difficult to explain within this picture. This evidence includes the observed high polarization, pulsar kicks, high velocity iron-group and intermediate-mass elements material observed in remnants, etc. The discovery of highly magnetars revived the idea that the basic mechanism for the ejection of the envelope is related to a highly focused MHD-jet formed at the NS. Our 3-D hydro simulations of the jet propagation through the star confirmed that the mechanism can explain the asphericities. In this paper, detailed 3-D models for jet induced explosions of "classical" core collapse supernovae are presented. We demonstrate the influence of the jet properties and of the underlaying progenitor structure on the final density and chemical structure. Finally, we discuss the observational consequences, predictions and tests of this scenario.

  13. Properties of optically selected supernova remnant candidates in M33

    SciTech Connect (OSTI)

    Lee, Jong Hwan; Lee, Myung Gyoon, E-mail: leejh@astro.snu.ac.kr, E-mail: mglee@astro.snu.ac.kr [Astronomy Program, Department of Physics and Astronomy, Seoul National University, Seoul 151-747 (Korea, Republic of)

    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]/H? and round morphology in the continuum-subtracted H? 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, ? = 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]/H?) of the remnants has two concentrations at [S II]/H? ? 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.

  14. Tidally-induced thermonuclear Supernovae

    E-Print Network [OSTI]

    S. Rosswog; E. Ramirez-Ruiz; W. R. Hix

    2008-11-13

    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 $2\\times 10^5$ M$_\\odot$ swallow a typical 0.6 M$_\\odot$ dwarf before their tidal forces can overwhelm the star's self-gravity. 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 X-ray flare close to the Eddington limit of $L_{\\rm Edd} \\simeq 10^{41} {\\rm erg/s} M_{\\rm bh}/1000 M$_\\odot$), 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.

  15. Time in Cosmology

    E-Print Network [OSTI]

    R. Brout; R. Parentani

    1999-02-05

    The notion of time in cosmology is revealed through an examination of transition matrix elements of radiative processes occurring in the cosmos. To begin with, the very concept of time is delineated in classical physics in terms of correlations between the succession of configurations which describe a process and a standard trajectory called the clock. The total is an isolated system of fixed energy. This is relevant for cosmology in that the universe is an isolated system which we take to be homogeneous and isotropic. Furthermore, in virtue of the constraint which arises from reparametrization invariance of time, it has total energy zero. Therefore the momentum of the scale factor is determined from the energy of matter. In the quantum theory this is exploited through use of the WKB approximation for the wave function of the scale factor, justified for a large universe. The formalism then gives rise to matrix elements describing matter processes. These are shown to take on the form of usual time dependent quantum amplitudes wherein the temporal dependence is given by a background which is once more fixed by the total energy of matter.

  16. CONDITIONS FOR SUPERNOVAE-DRIVEN GALACTIC WINDS

    SciTech Connect (OSTI)

    Nath, Biman B. [Raman Research Institute, Sadashiva Nagar, Bangalore 560080 (India)] [Raman Research Institute, Sadashiva Nagar, Bangalore 560080 (India); Shchekinov, Yuri, E-mail: biman@rri.res.in, E-mail: yus@sfedu.ru [Department of Physics, Southern Federal University, Rostov on Don, 344090 (Russian Federation)] [Department of Physics, Southern Federal University, Rostov on Don, 344090 (Russian Federation)

    2013-11-01

    We point out that the commonly assumed condition for galactic outflows, that supernovae (SNe) heating is efficient in the central regions of starburst galaxies, suffers from invalid assumptions. We show that a large filling factor of hot (?10{sup 6} K) gas is difficult to achieve through SNe heating, irrespective of the SN's initial gas temperature and density, its uniformity, or its clumpiness. We instead suggest that correlated supernovae from OB associations in molecular clouds in the central region can drive powerful outflows if the molecular surface density is >10{sup 3} M {sub ?} pc{sup –2}.

  17. Hydrogen issue in Core Collapse Supernovae

    E-Print Network [OSTI]

    A. Elmhamdi; I. J. Danziger; D. Branch; B. Leibundgut

    2006-11-06

    We discuss results of analyzing a time series of selected photospheric-optical spectra of core collapse supernovae (CCSNe). This is accomplished by means of the parameterized supernovae synthetic spectrum (SSp) code ``SYNOW''. Special attention is addressed to traces of hydrogen at early phases, especially for the stripped-envelope SNe (i.e. SNe Ib-c). A thin low mass hydrogen layer extending to very high ejection velocities above the helium shell, is found to be the most likely scenario for Type Ib SNe.

  18. Deflagrations and Detonations in Thermonuclear Supernovae

    E-Print Network [OSTI]

    Vadim N. Gamezo; Alexei M. Khokhlov; Elaine S. Oran

    2004-06-03

    We study a type Ia supernova explosion using three-dimensional numerical simulations based on reactive fluid dynamics. We consider a delayed-detonation model that assumes a deflagration-to-detonation transition. In contrast to the pure deflagration model, the delayed-detonation model releases enough energy to account for a healthy explosion, and does not leave carbon, oxygen, and intermediate-mass elements in central parts of a white dwarf. This removes the key disagreement between simulations and observations, and makes a delayed detonation the mostly likely mechanism for type Ia supernovae.

  19. SALT2: using distant supernovae to improve the use of Type Ia supernovae as distance indicators

    E-Print Network [OSTI]

    J. Guy; P. Astier; S. Baumont; D. Hardin; R. Pain; N. Regnault; S. Basa; R. G. Carlberg; A. Conley; S. Fabbro; D. Fouchez; I. M. Hook; D. A. Howell; K. Perrett; C. J. Pritchet; J. Rich; M. Sullivan; P. Antilogus; E. Aubourg; G. Bazin; J. Bronder; M. Filiol; N. Palanque-Delabrouille; P. Ripoche; V. Ruhlmann-Kleider

    2007-01-29

    We present an empirical model of Type Ia supernovae spectro-photometric evolution with time. The model is built using a large data set including light-curves and spectra of both nearby and distant supernovae, the latter being observed by the SNLS collaboration. We derive the average spectral sequence of Type Ia supernovae and their main variability components including a color variation law. The model allows us to measure distance moduli in the spectral range 2500-8000 A with calculable uncertainties, including those arising from variability of spectral features. Thanks to the use of high-redshift SNe to model the rest-frame UV spectral energy distribution, we are able to derive improved distance estimates for SNe Ia in the redshift range 0.8supernovae.

  20. The supernova/gamma-ray burst/jet connection

    E-Print Network [OSTI]

    Hjorth, Jens

    2013-01-01

    The observed association between supernovae and gamma-ray bursts represents a cornerstone in our understanding of the nature of gamma-ray bursts. The collapsar model provides a theoretical framework for this connection. A key element is the launch of a bi-polar jet (seen as a gamma-ray burst). The resulting hot cocoon disrupts the star while the 56Ni produced gives rise to radioactive heating of the ejecta, seen as a supernova. In this discussion paper I summarise the observational status of the supernova/gamma-ray burst connection in the context of the 'engine' picture of jet-driven supernovae and highlight SN 2012bz/GRB 120422A -- with its luminous supernova but intermediate high-energy luminosity -- as a possible transition object between low-luminosity and jet gamma-ray bursts. The jet channel for supernova explosions may provide new insight into supernova explosions in general.

  1. The type Ia supernova SNLS-03D3bb from a super-Chandrasekhar-mass white dwarf star

    E-Print Network [OSTI]

    2008-01-01

    magnitudes of Type IA supernovae. Astrophys. J. Lett. 413,from 42 High-Redshift Supernovae. Astrophys. J. 517, 565–Observational Evidence from Supernovae for an Accelerating

  2. A New Determination of the High Redshift Type Ia Supernova Rates with the Hubble Space Telescope Advanced Camera for Surveys

    E-Print Network [OSTI]

    2008-01-01

    Schmidt, B. P. , 2003, in Supernovae and Gamma Ray Bursts,for identifying Type Ia supernovae (although spectroscopicfor future high-statistics supernovae searches in which

  3. COSMOLOGICAL FAST RADIO BURSTS FROM BINARY WHITE DWARF MERGERS

    SciTech Connect (OSTI)

    Kashiyama, Kazumi; Mészáros, Peter [Department of Astronomy and Astrophysics, Department of Physics, Center for Particle and Gravitational Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States)] [Department of Astronomy and Astrophysics, Department of Physics, Center for Particle and Gravitational Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States); Ioka, Kunihito, E-mail: kzk15@psu.edu, E-mail: nnp@psu.edu, E-mail: kunihito.ioka@kek.jp [Theory Center, Institute of Particle and Nuclear Studies, KEK, Department of Particle and Nuclear Physics, the Graduate University for Advanced Studies (Sokendai), Tsukuba 305-0801 (Japan)] [Theory Center, Institute of Particle and Nuclear Studies, KEK, Department of Particle and Nuclear Physics, the Graduate University for Advanced Studies (Sokendai), Tsukuba 305-0801 (Japan)

    2013-10-20

    Recently, Thornton et al. reported the detection of four fast radio bursts (FRBs). The dispersion measures indicate that the sources of these FRBs are at cosmological distance. Given the large full sky event rate ?10{sup 4} sky{sup –1} day{sup –1}, the FRBs are a promising target for multi-messenger astronomy. Here we propose double degenerate, binary white-dwarf (WD) mergers as the source of FRBs, which are produced by coherent emission from the polar region of a rapidly rotating, magnetized massive WD formed after the merger. The basic characteristics of the FRBs, such as the energetics, emission duration and event rate, can be consistently explained in this scenario. As a result, we predict that some FRBs can accompany type Ia supernovae (SNe Ia) or X-ray debris disks. Simultaneous detection could test our scenario and probe the progenitors of SNe Ia, and moreover would provide a novel constraint on the cosmological parameters. We strongly encourage future SN and X-ray surveys that follow up FRBs.

  4. Supernova 1987A: a Template to Link Supernovae to their Remnants

    E-Print Network [OSTI]

    Orlando, S; Pumo, M L; Bocchino, F

    2015-01-01

    The emission of supernova remnants reflects the properties of both the progenitor supernovae and the surrounding environment. The complex morphology of the remnants, however, hampers the disentanglement of the two contributions. Here we aim at identifying the imprint of SN 1987A on the X-ray emission of its remnant and at constraining the structure of the environment surrounding the supernova. We performed high-resolution hydrodynamic simulations describing SN 1987A soon after the core-collapse and the following three-dimensional expansion of its remnant between days 1 and 15000 after the supernova. We demonstrated that the physical model reproducing the main observables of SN 1987A during the first 250 days of evolution reproduces also the X-ray emission of the subsequent expanding remnant, thus bridging the gap between supernovae and supernova remnants. By comparing model results with observations, we constrained the explosion energy in the range $1.2-1.4\\times 10^{51}$~erg and the envelope mass in the rang...

  5. Multipole expansion method for supernova neutrino oscillations

    SciTech Connect (OSTI)

    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.

  6. Resonant conversion of massless neutrinos in supernovae

    E-Print Network [OSTI]

    Nunokawa, H; Rossi, A; Valle, José W F

    1996-01-01

    It has been noted for a long time that, in some circumstances, {\\sl massless} neutrinos may be {\\sl mixed} in the leptonic charged current. Conventional neutrino oscillation searches in vacuum are insensitive to this mixing. We discuss the effects of resonant massless-neutrino conversions in the dense medium of a supernova. In particular, we show how the detected \\bar\

  7. Protein folding and cosmology

    E-Print Network [OSTI]

    P. F. Gonzalez-Diaz; C. L. Siguenza

    1997-06-04

    Protein denaturing induced by supercooling is interpreted as a process where some or all internal symmetries of the native protein are spontaneously broken. Hence, the free-energy potential corresponding to a folding-funnel landscape becomes temperature-dependent and describes a phase transition. The idea that deformed vortices could be produced in the transition induced by temperature quenching, from native proteins to unfolded conformations is discussed in terms of the Zurek mechanism that implements the analogy between vortices, created in the laboratory at low energy, and the cosmic strings which are thought to have been left after symmetry breaking phase transitions in the early universe. An experiment is proposed to test the above idea which generalizes the cosmological analogy to also encompass biological systems and push a step ahead the view that protein folding is a biological equivalent of the big bang.

  8. Probing thermonuclear supernova explosions with neutrinos

    E-Print Network [OSTI]

    A. Odrzywolek; T. Plewa

    2011-03-27

    Aims: We present neutrino light curves and energy spectra for two representative type Ia supernova explosion models: a pure deflagration and a delayed detonation. Methods: We calculate the neutrino flux from $\\beta$ processes using nuclear statistical equilibrium abundances convoluted with approximate neutrino spectra of the individual nuclei and the thermal neutrino spectrum (pair+plasma). Results: Although the two considered thermonuclear supernova explosion scenarios are expected to produce almost identical electromagnetic output, their neutrino signatures appear vastly different, which allow an unambiguous identification of the explosion mechanism: a pure deflagration produces a single peak in the neutrino light curve, while the addition of the second maximum characterizes a delayed-detonation. We identified the following main contributors to the neutrino signal: (1) weak electron neutrino emission from electron captures (in particular on the protons Co55 and Ni56) and numerous beta-active nuclei produced by the thermonuclear flame and/or detonation front, (2) electron antineutrinos from positron captures on neutrons, and (3) the thermal emission from pair annihilation. We estimate that a pure deflagration supernova explosion at a distance of 1 kpc would trigger about 14 events in the future 50 kt liquid scintillator detector and some 19 events in a 0.5 Mt water Cherenkov-type detector. Conclusions: While in contrast to core-collapse supernovae neutrinos carry only a very small fraction of the energy produced in the thermonuclear supernova explosion, the SN Ia neutrino signal provides information that allows us to unambiguously distinguish between different possible explosion scenarios. These studies will become feasible with the next generation of proposed neutrino observatories.

  9. Dynamical 3-Space: Supernovae and the Hubble Expansion - Older Universe and End of Dark Energy

    E-Print Network [OSTI]

    Reginald T Cahill

    2007-06-05

    We apply the new dynamics of 3-space to cosmology by deriving a Hubble expansion solution. This dynamics involves two constants; G and alpha - the fine structure constant. This solution gives an excellent parameter-free fit to the recent supernova and gamma-ray burst data without the need for `dark energy' or `dark matter'. The data and theory together imply an older age for the universe of some 14.7Gyrs. Various problems such as fine tuning, the event horizon problem etc are now resolved. A brief review discusses the origin of the 3-space dynamics and how that dynamics explained the bore hole anomaly, spiral galaxy flat rotation speeds, the masses of black holes in spherical galaxies, gravitational light bending and lensing, all without invoking `dark matter' or `dark energy'. These developments imply that a new understanding of the universe is now available.

  10. Cosmological implications of baryon acoustic oscillation (BAO) measurements

    E-Print Network [OSTI]

    Éric Aubourg; Stephen Bailey; Julian E. Bautista; Florian Beutler; Vaishali Bhardwaj; Dmitry Bizyaev; Michael Blanton; Michael Blomqvist; Adam S. Bolton; Jo Bovy; Howard Brewington; J. Brinkmann; Joel R. Brownstein; Angela Burden; Nicolás G. Busca; William Carithers; Chia-Hsun Chuang; Johan Comparat; Antonio J. Cuesta; Kyle S. Dawson; Timothée Delubac; Daniel J. Eisenstein; Andreu Font-Ribera; Jian Ge; J. -M. Le Goff; Satya Gontcho A Gontcho; J. Richard Gott III; James E. Gunn; Hong Guo; Julien Guy; Jean-Christophe Hamilton; Shirley Ho; Klaus Honscheid; Cullan Howlett; David Kirkby; Francisco S. Kitaura; Jean-Paul Kneib; Khee-Gan Lee; Dan Long; Robert H. Lupton; Mariana Vargas Magaña; Viktor Malanushenko; Elena Malanushenko; Marc Manera; Claudia Maraston; Daniel Margala; Cameron K. McBride; Jordi Miralda-Escudé; Adam D. Myers; Robert C. Nichol; Pasquier Noterdaeme; Sebastián E. Nuza; Matthew D. Olmstead; Daniel Oravetz; Isabelle Pâris; Nikhil Padmanabhan; Nathalie Palanque-Delabrouille; Kaike Pan; Marcos Pellejero-Ibanez; Will J. Percival; Patrick Petitjean; Matthew M. Pieri; Francisco Prada; Beth Reid; Natalie A. Roe; Ashley J. Ross; Nicholas P. Ross; Graziano Rossi; Jose Alberto Rubiño-Martín; Ariel G. Sánchez; Lado Samushia; Ricardo Tanausú Génova Santos; Claudia G. Scóccola; David J. Schlegel; Donald P. Schneider; Hee-Jong Seo; Erin Sheldon; Audrey Simmons; Ramin A. Skibba; Anže Slosar; Michael A. Strauss; Daniel Thomas; Jeremy L. Tinker; Rita Tojeiro; Jose Alberto Vazquez; Matteo Viel; David A. Wake; Benjamin A. Weaver; David H. Weinberg; W. M. Wood-Vasey; Christophe Yèche; Idit Zehavi; Gong-Bo Zhao

    2015-10-09

    We derive constraints on cosmological parameters and tests of dark energy models from the combination of baryon acoustic oscillation (BAO) measurements with cosmic microwave background (CMB) and Type Ia supernova (SN) data. We take advantage of high-precision BAO measurements from galaxy clustering and the Ly-alpha forest (LyaF) in the BOSS survey of SDSS-III. BAO data alone yield a high confidence detection of dark energy, and in combination with the CMB angular acoustic scale they further imply a nearly flat universe. Combining BAO and SN data into an "inverse distance ladder" yields a 1.7% measurement of $H_0=67.3 \\pm1.1$ km/s/Mpc. This measurement assumes standard pre-recombination physics but is insensitive to assumptions about dark energy or space curvature, so agreement with CMB-based estimates that assume a flat LCDM cosmology is an important corroboration of this minimal cosmological model. For open LCDM, our BAO+SN+CMB combination yields $\\Omega_m=0.301 \\pm 0.008$ and curvature $\\Omega_k=-0.003 \\pm 0.003$. When we allow more general forms of evolving dark energy, the BAO+SN+CMB parameter constraints remain consistent with flat LCDM. While the overall $\\chi^2$ of model fits is satisfactory, the LyaF BAO measurements are in moderate (2-2.5 sigma) tension with model predictions. Models with early dark energy that tracks the dominant energy component at high redshifts remain consistent with our constraints. Expansion history alone yields an upper limit of 0.56 eV on the summed mass of neutrino species, improving to 0.26 eV if we include Planck CMB lensing. Standard dark energy models constrained by our data predict a level of matter clustering that is high compared to most, but not all, observational estimates. (Abridged)

  11. Thermodynamics in Loop Quantum Cosmology

    E-Print Network [OSTI]

    Li-Fang Li; Jian-Yang Zhu

    2008-12-18

    Loop quantum cosmology (LQC) is very powerful to deal with the behavior of early universe. And the effective loop quantum cosmology gives a successful description of the universe in the semiclassical region. We consider the apparent horizon of the Friedmann-Robertson-Walker universe as a thermodynamical system and investigate the thermodynamics of LQC in the semiclassical region. The effective density and effective pressure in the modified Friedmann equation from LQC not only determine the evolution of the universe in LQC scenario but are actually also found to be the thermodynamic quantities. This result comes from the energy definition in cosmology (the Misner-Sharp gravitational energy) and is consistent with thermodynamic laws. We prove that within the framework of loop quantum cosmology, the elementary equation of equilibrium thermodynamics is still valid.

  12. Radioactive Probes of the Supernova-Contaminated Solar Nebula: Evidence that the Sun was Born in a Cluster

    E-Print Network [OSTI]

    Looney, L W; Fields, B D; Looney, Leslie W.; Tobin, John J.; Fields, Brian D.

    2006-01-01

    We construct a simple model for radioisotopic enrichment of the protosolar nebula by injection from a nearby supernova, based on the inverse square law for ejecta dispersion. We find that the presolar radioisotopes abundances (i.e., in solar masses) demand a nearby supernova: its distance can be no larger than 66 times the size of the protosolar nebula, at a 90% confidence level, assuming 1 solar mass of protosolar material. The relevant size of the nebula depends on its state of evolution at the time of radioactivity injection. In one scenario, a collection of low-mass stars, including our sun, formed in a group or cluster with an intermediate- to high-mass star that ended its life as a supernova while our sun was still a protostar, a starless core, or perhaps a diffuse cloud. Using recent observations of protostars to estimate the size of the protosolar nebula constrains the distance of the supernova at 0.02 to 1.6 pc. The supernova distance limit is consistent with the scales of low-mass stars formation ar...

  13. Constraints on Off-Axis GRB Jets in Type Ibc Supernovae From Late-Time Radio Observations

    E-Print Network [OSTI]

    A. M. Soderberg; D. A. Frail; M. H. Wieringa

    2005-12-06

    It has been suggested that the peculiar properties of the luminous Type Ic supernova SN 1998bw and its low-energy gamma-ray burst GRB 980425 may be understood if they originated in a standard gamma-ray burst explosion viewed far from the axis of the relativistic jet. In this scenario, strong radio emission is predicted from the jet on a timescale 1 to 10 years after the explosion as it decelerates and spreads into our line of sight. To test this hypothesis we have carried out late-time radio observations of SN 1998bw at $t=5.6$ years, yielding upper limits which are consistent with the continued fading of the supernova. We find these limits to be consistent with an off-axis jet only if the progenitor mass loss rate is $\\dot{M}\\lesssim 4 \\times 10^{-7}$ M$_\\odot$ yr$^{-1}$ (for a wind velocity $v_w=1000$ km s$^{-1}$) or the fraction of the shock energy in magnetic fields is $\\epsilon_B \\lesssim 10^{-3}$. These values are low relative to those inferred for cosmological GRBs. We combine the SN 1998bw measurements with existing observations for a sample of 15 local Type Ibc supernovae to estimate that at most 6% produce collimated, relativistic outflows.

  14. PECULIAR OPTICAL AND IR BEHAVIOUR IN TYPE I SUPERNOVAE, AND THE ORIGIN OF THE 1.2 ABSORPTION

    E-Print Network [OSTI]

    Graham, J.R.

    2011-01-01

    Wheeler, le. , 1984. In "Supernovae as distance indicators",lR. , 1985. In "Dust in supernovae and supernova remnants",and IR behaviour in type I supernovae, and the origin of the

  15. A theoretician's analysis of the supernova data and the limitations in determining the nature of dark energy

    E-Print Network [OSTI]

    T. Padmanabhan; T. Roy Choudhury

    2003-06-18

    Current cosmological observations show a strong signature of the existence of a dark energy component with negative pressure. The most obvious candidate for this dark energy is the cosmological constant (with the equation of state w_X=p/\\rho=-1), which, however, raises several theoretical difficulties. This has led to models for dark energy component which evolves with time. We discuss certain questions related to the determination of the nature of dark energy component from observations of high redshift supernova. The main results of our analysis are: (i) Even if the precise value of w_X is known from observations, it is not possible to determine the nature of the unknown dark energy source using only kinematical and geometrical measurements. We have given explicit examples to show that different types of sources can give rise to a given w_X. (ii) Although the full data set of supernova observations (which are currently available) strongly rule out models without dark energy, the high (z>0.25) and low (z<0.25) redshift data sets, individually, admit decelerating models with zero dark energy. Any possible evolution in the absolute magnitude of the supernovae, if detected, might allow the decelerating models to be consistent with the data. (iii) We have introduced two parameters, which can be obtained entirely from theory, to study the sensitivity of the luminosity distance on w_X. Using these two parameters, we have argued that although one can determine the present value of w_X accurately from the data, one cannot constrain the evolution of w_X.

  16. Photometric selection of Type Ia supernovae in the Supernova Legacy Survey

    E-Print Network [OSTI]

    Bazin, G; Palanque-Delabrouille, N; Rich, J; Aubourg, E; Astier, P; Balland, C; Basa, S; Carlberg, R G; Conley, A; Fouchez, D; Guy, J; Hardin, D; Hook, I M; Howell, D A; Pain, R; Perrett, K; Pritchet, C J; Regnault, N; Sullivan, M; Fourmanoit, N; Gonzalez-Gaitan, S; Lidman, C; Perlmutter, S; Ripoche, P; Walker, E S

    2011-01-01

    We present a sample of 485 photometrically identified Type Ia supernova candidates mined from the first three years of data of the CFHT SuperNova Legacy Survey (SNLS). The images were submitted to a deferred processing independent of the SNLS real-time detection pipeline. Light curves of all transient events were reconstructed in the g_M, r_M, i_M and z_M filters and submitted to automated sequential cuts in order to identify possible supernovae. Pure noise and long-term variable events were rejected by light curve shape criteria. Type Ia supernova identification relied on event characteristics fitted to their light curves assuming the events to be normal SNe Ia. The light curve fitter SALT2 was used for this purpose, assigning host galaxy photometric redshifts to the tested events. The selected sample of 485 candidates is one magnitude deeper than that allowed by the SNLS spectroscopic identification. The contamination by supernovae of other types is estimated to be 4%. Testing Hubble diagram residuals with ...

  17. Type Ia supernova rate at a redshift of ~;0.1

    E-Print Network [OSTI]

    2004-01-01

    since the Big Bang: Supernovae and Gamma-Ray Bursts, held 3-rst the EROS search for supernovae is reviewed in Sect. 2.2. The EROS search for supernovae The EROS experiment used a

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

    E-Print Network [OSTI]

    2004-01-01

    high-velocity Type Ib/c supernovae such as SN 1998bw. Otherwith the luminous Type Ic supernovae 1998bw (Galama et al.a link between GRBs and supernovae. However GRB 980425 was a

  19. Three-dimensional numerical simulations of Rayleigh-Taylor unstable flames in type Ia supernovae

    E-Print Network [OSTI]

    Zingale, M.; Woosley, S.E.; Rendleman, C.A.; Day, M.S.; Bell, J.B.

    2005-01-01

    Unstable Flames in Type Ia Supernovae M. Zingale 1 , S. E.Subject headings: supernovae: general — white dwarfs —ame in Type Ia supernovae (SNe Ia) is well recognized (M¨

  20. A Progress Report on the Berkeley Search for Distant Supernovae to Measure {Omega}

    E-Print Network [OSTI]

    Pennypacker, Carl R.

    2008-01-01

    Search for Distant Supernovae to Measure Q C. Pennypacker,Search for Distant Supernovae to Measure n C. Pennypacker,Search for Distant Supernovae to Measure Q Carl Pennypacker,

  1. Quantitative comparison between Type Ia supernova spectra at low and high redshifts: A case study

    E-Print Network [OSTI]

    Garavini, G.; Supernova Cosmology Project

    2008-01-01

    Highlight - The Physics of Supernovae, ESO/MPA/MPE Workshop,Evolution in high-redshift supernovae Fig. 8 “Ca ii H&K”SN 1991T/SN 1999aa-like supernovae. 1. Introduction Type Ia

  2. Discovery of the Most Distant Supernovae and the Quest for Omega

    E-Print Network [OSTI]

    Goldhaber, G.

    2008-01-01

    of the Most Distant Supernovae and the Quest for .Q G.Discovery of the Most Distant Supernovae and the Quest for QOF THE MOST DISTANT SUPERNOVAE AND THE QUEST FOR fl* GERSON

  3. UV Spectroscopy of Type Ia Supernovae at Low- and High-Redshift

    E-Print Network [OSTI]

    Nugent, Peter

    2005-01-01

    Spectroscopy of Type Ia Supernovae at Low- and High-RedshiftUV properties of Type Ia Supernovae. The low-redshift studyULDA Access Guide No. 6: Supernovae, The Netherlands: ESA

  4. Measuring Type Ia Supernova Distances and Redshifts From Their Multi-band Light Curves

    E-Print Network [OSTI]

    Kim, Alex G.; Miquel, Ramon

    2007-01-01

    curve, http://supernovae.in2p3.fr/ ? guy/salt/index.htmlfor large numbers of supernovae; so many that it would becosmology:distance scale, supernovae:general Introduction

  5. PROGENITORS AND BIRTH-RATES OF CATACLYSMIC VARIABLES AND TYPE-I SUPER-NOVAE

    E-Print Network [OSTI]

    TRIMBLE, V

    1982-01-01

    1981. (I2) G. Tammann, in Supernovae, edited by M. J. Rees4) J. C. Wheeler, Type I Supernovae (University of Texas,production of Type I supernovae from the ancestral systems,

  6. Improving Type Ia Supernova Standard Candle Cosmology Measurements Using Observations of Early-Type Host Galaxies

    E-Print Network [OSTI]

    Meyers, Joshua Evan

    2012-01-01

    G. S. et al. 1998, in VIII Canary Islands Winter School ofA. Herrerro, & F. Sanchez, Canary Islands Winter School ofof La Palma in the Canary Islands. On the night of the first

  7. Discovery of a Supernova Explosion at Half the Age of the Universe and its Cosmological Implications

    E-Print Network [OSTI]

    Perlmutter, S.

    2010-01-01

    at Half the Age of the Universe and its Cosmologicalleft corner) a "bouncing" universe with no big bang 27 ,or (lower right corner) a universe younger than the oldest

  8. Absolute-magnitude distributions of supernovae

    SciTech Connect (OSTI)

    Richardson, Dean; Wright, John [Department of Physics, Xavier University of Louisiana, New Orleans, LA 70125 (United States); Jenkins III, Robert L. [Applied Physics Department, Richard Stockton College, Galloway, NJ 08205 (United States); Maddox, Larry, E-mail: drichar7@xula.edu [Department of Chemistry and Physics, Southeastern Louisiana University, Hammond, LA 70402 (United States)

    2014-05-01

    The absolute-magnitude distributions of seven supernova (SN) types are presented. The data used here were primarily taken from the Asiago Supernova Catalogue, but were supplemented with additional data. We accounted for both foreground and host-galaxy extinction. A bootstrap method is used to correct the samples for Malmquist bias. Separately, we generate volume-limited samples, restricted to events within 100 Mpc. We find that the superluminous events (M{sub B} < –21) make up only about 0.1% of all SNe in the bias-corrected sample. The subluminous events (M{sub B} > –15) make up about 3%. The normal Ia distribution was the brightest with a mean absolute blue magnitude of –19.25. The IIP distribution was the dimmest at –16.75.

  9. Merging White Dwarfs and Thermonuclear Supernovae

    E-Print Network [OSTI]

    van Kerkwijk, Marten H

    2012-01-01

    Thermonuclear supernovae result when interaction with a companion reignites nuclear fusion in a carbon-oxygen white dwarf, causing a thermonuclear runaway, a catastrophic gain in pressure, and the disintegration of the whole white dwarf. It is usually thought that fusion is reignited in near-pycnonuclear conditions when the white dwarf approaches the Chandrasekhar mass. I briefly describe two long-standing problems faced by this scenario, and our suggestion that these supernovae instead result from mergers of carbon-oxygen white dwarfs, including those that produce sub-Chandrasekhar mass remnants. I then turn to possible observational tests, in particular those that test the absence or presence of electron captures during the burning.

  10. Nuclear quests for supernova dynamics and nucleosynthesis

    SciTech Connect (OSTI)

    Langanke, K. [GSI Helmholtzzentrum fuer Schwerionenstreuung, Darmstadt, Germany, Institute fuer Kernphysik, Technical University of Darmstadt, Germany and Frankfurt Institute for Advanced Studies, Frankfurt (Germany); Martinez-Pinedo, G. [GSI Helmholtzzentrum fuer Schwerionenstreuung, Darmstadt (Germany)

    2011-10-28

    Nuclear physics plays a crucial role in various aspects of core collapse supernovae. The collapse dynamics is strongly influenced by electron captures. Using modern many-body theory improved capture rates have been derived recently with the important result that the process is dominated by capture on nuclei until neutrino trapping is achieved. Following the core bounce the ejected matter is the site of interesting nucleosynthesis. The early ejecta are proton-rich and give rise to the recently discovered {nu}p-process. Later ejecta might be neutron-rich and can be one site of the r-process. The manuscript discusses recent progress in describing nuclear input relevant for the supernova dynamics and nucleosynthesis.

  11. Cosmographic Hubble fits to the supernova data

    E-Print Network [OSTI]

    Cattoen, Celine

    2008-01-01

    The Hubble relation between distance and redshift is a purely cosmographic relation that depends only on the symmetries of a FLRW spacetime, but does not intrinsically make any dynamical assumptions. This suggests that it should be possible to estimate the parameters defining the Hubble relation without making any dynamical assumptions. To test this idea, we perform a number of inter-related cosmographic fits to the legacy05 and gold06 supernova datasets. Based on this supernova data, the "preponderance of evidence" certainly suggests an accelerating universe. However we would argue that (unless one uses additional dynamical and observational information) this conclusion is not currently supported "beyond reasonable doubt". As part of the analysis we develop two particularly transparent graphical representations of the redshift-distance relation -- representations in which acceleration versus deceleration reduces to the question of whether the relevant graph slopes up or down. Turning to the details of the co...

  12. Multimessengers from 3D Core-Collapse Supernovae

    E-Print Network [OSTI]

    Yakunin, Konstantin N; Mezzacappa, Anthony; Messer, O E Bronson; Lentz, Eric J; Bruenn, Stephen W; Hix, W Rafael; Harris, J Austin

    2015-01-01

    We present gravitational wave and neutrino signatures obtained in our first principle 3D core-collapse supernova simulation of 15M non-rotating progenitor with Chimera code. Observations of neutrinos emitted by the forming neutron star, and gravitational waves, which are produced by hydrodynamic instabilities is the only way to get direct information about the supernova engine. Both GW and neutrino signals show different phases of supernova evolution.

  13. The Physics of Core-Collapse Supernovae

    E-Print Network [OSTI]

    S. Woosley; H. -T. Janka

    2006-01-12

    Supernovae are nature's grandest explosions and an astrophysical laboratory in which unique conditions exist that are not achievable on Earth. They are also the furnaces in which most of the elements heavier than carbon have been forged. Scientists have argued for decades about the physical mechanism responsible for these explosions. It is clear that the ultimate energy source is gravity, but the relative roles of neutrinos, fluid instabilities, rotation and magnetic fields continue to be debated.

  14. X-rays from Supernova Remnants

    E-Print Network [OSTI]

    B. Aschenbach

    2002-08-28

    A summary of X-ray observations of supernova remnants is presented including the explosion fragment A of the Vela SNR, Tycho, N132D, RX J0852-4622, the Crab Nebula and the 'bulls eye', and SN 1987A, high-lighting the progress made with Chandra and XMM-Newton and touching upon the questions which arise from these observations and which might inspire future research.

  15. Type Ia Supernovae: Toward the Standard Model?

    E-Print Network [OSTI]

    David Branch

    2000-12-13

    In this short review I suggest that recent developments support the conjecture that Type Ia supernovae (SNe Ia) are the complete disruptions of Chandrasekhar-mass carbon-oxygen white dwarfs in single-degenerate binary systems. The causes of the observational diversity of SNe Ia within the context of this standard model, and the implications of the model for young remnants of SNe Ia, are briefly discussed.

  16. Nucleosynthesis in O-Ne-Mg Supernovae

    E-Print Network [OSTI]

    R. D. Hoffman; B. Muller; H. -T. Janka

    2007-12-27

    We have studied detailed nucleosynthesis in the shocked surface layers of an Oxygen-Neon-Magnesium core collapse supernova with an eye to determining if the conditions are suitable for r process nucleosynthesis. We find no such conditions in an unmodified model, but do find overproduction of N=50 nuclei (previously seen in early neutron-rich neutrino winds) in amounts that, if ejected, would pose serious problems for galactic chemical evolution.

  17. Nucleosynthesis in O-Ne-Mg Supernovae

    SciTech Connect (OSTI)

    Hoffman, R D; Janka, H; Muller, B

    2007-12-18

    We have studied detailed nucleosynthesis in the shocked surface layers of an oxygen-neon-magnesium core collapse supernova with an eye to determining whether the conditions are suitable for r-process nucleosynthesis. We find no such conditions in an unmodified model, but do find overproduction of N=50 nuclei (previously seen in early neutron-rich neutrino winds) in amounts that, if ejected, would pose serious problems for Galactic chemical evolution.

  18. 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,...

  19. Type Ia Supernovae M100 in Early 2006

    E-Print Network [OSTI]

    Crenshaw, Michael

    ://rsdwww.nrl.navy.mil/7212/montes/snetax.html 2.) http://www.lbl.gov/ScienceArticles/Archive/sabl/2005/October/04supernovae.html

  20. Earth Matter Effects in Detection of Supernova Neutrinos

    E-Print Network [OSTI]

    X. -H. Guo; Bing-Lin Young

    2006-05-11

    We calculated the matter effect, including both the Earth and supernova, on the detection of neutrinos from type II supernovae at the proposed Daya Bay reactor neutrino experiment. It is found that apart from the dependence on the flip probability P_H inside the supernova and the mass hierarchy of neutrinos, the amount of the Earth matter effect depends on the direction of the incoming supernova neutrinos, and reaches the biggest value when the incident angle of neutrinos is around 93^\\circ. In the reaction channel \\bar{\

  1. Pair instability supernovae of very massive population III stars...

    Office of Scientific and Technical Information (OSTI)

    In red supergiant progenitors, the amplitudes of these instabilities are sufficient to mix the supernova ejecta. less Authors: Chen, Ke-Jung ; Woosley, Stan 1 ; Heger,...

  2. Supernova Hydrodynamics on the Omega Laser

    SciTech Connect (OSTI)

    R. Paul Drake

    2004-01-16

    (B204)The fundamental motivation for our work is that supernovae are not well understood. Recent observations have clarified the depth of our ignorance, by producing observed phenomena that current theory and computer simulations cannot reproduce. Such theories and simulations involve, however, a number of physical mechanisms that have never been studied in isolation. We perform experiments, in compressible hydrodynamics and radiation hydrodynamics, relevant to supernovae and supernova remnants. These experiments produce phenomena in the laboratory that are believed, based on simulations, to be important to astrophysics but that have not been directly observed in either the laboratory or in an astrophysical system. During the period of this grant, we have focused on the scaling of an astrophysically relevant, radiative-precursor shock, on preliminary studies of collapsing radiative shocks, and on the multimode behavior and the three-dimensional, deeply nonlinear evolution of the Rayleigh-Taylor (RT) instability at a decelerating, embedded interface. These experiments required strong compression and decompression, strong shocks (Mach {approx}10 or greater), flexible geometries, and very smooth laser beams, which means that the 60-beam Omega laser is the only facility capable of carrying out this program.

  3. Neutrino-induced nucleosynthesis in supernovae

    SciTech Connect (OSTI)

    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.

  4. Can pair-instability supernova models match the observations of superluminous supernovae?

    E-Print Network [OSTI]

    Kozyreva, Alexandra

    2015-01-01

    An increasing number of so-called superluminous supernovae (SLSNe) are discovered. It is believed that at least some of them with slowly fading light curves originate in stellar explosions induced by the pair instability mechanism. Recent stellar evolution models naturally predict pair instability supernovae (PISNe) from very massive stars at wide range of metallicities (up to Z=0.006, Yusof et al. 2013). In the scope of this study we analyse whether PISN models can match the observational properties of SLSNe with various light curve shapes. Specifically, we explore the influence of different degrees of macroscopic chemical mixing in PISN explosive products on the resulting observational properties. We artificially apply mixing to the 250 Msun PISN evolutionary model from Kozyreva et al. (2014) and explore its supernova evolution with the one-dimensional radiation hydrodynamics code STELLA. The greatest success in matching SLSN observations is achieved in the case of an extreme macroscopic mixing, where all r...

  5. Physical Dust Models for the Extinction toward Supernova 2014J in M82

    E-Print Network [OSTI]

    Gao, Jian; Li, Aigen; Li, Jun; Wang, Xiaofeng

    2015-01-01

    Type Ia supernovae (SNe Ia) are powerful cosmological "standardizable candles" and the most precise distance indicators. However, a limiting factor in their use for precision cosmology rests on our ability to correct for the dust extinction toward them. SN 2014J in the starburst galaxy M82, the closest detected SN~Ia in three decades, provides unparalleled opportunities to study the dust extinction toward an SN Ia. In order to derive the extinction as a function of wavelength, we model the color excesses toward SN 2014J, which are observationally derived over a wide wavelength range in terms of dust models consisting of a mixture of silicate and graphite. The resulting extinction laws steeply rise toward the far ultraviolet, even steeper than that of the Small Magellanic Cloud (SMC). We infer a visual extinction of $A_V \\approx 1.9~\\rm mag$, a reddening of $E(B-V)\\approx1.1~ \\rm mag$, and a total-to-selective extinction ratio of $R_V \\approx 1.7$, consistent with that previously derived from photometric, spec...

  6. 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...

  7. Constraints on cosmology from the cosmic microwave background...

    Office of Scientific and Technical Information (OSTI)

    79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABUNDANCE; BACKGROUND RADIATION; COSMOLOGY; DETECTION; EV RANGE; FLUCTUATIONS; GALAXY CLUSTERS; HELIUM; INDEXES; LIMITING VALUES;...

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

    SciTech Connect (OSTI)

    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.

  9. Cosmology and the S-matrix

    E-Print Network [OSTI]

    Bousso, Raphael

    2009-01-01

    56710 Cosmology and the S-matrix Raphael Bousso Center for04/36 Cosmology and the S-matrix Raphael Bousso ? Center forassociated with an S-matrix. arXiv:hep-th/0412197v2 25 Jan

  10. Simulating Reionization in Numerical Cosmology

    E-Print Network [OSTI]

    Aaron Sokasian; Tom Abel; Lars E. Hernquist

    2001-05-10

    The incorporation of radiative transfer effects into cosmological hydrodynamical simulations is essential for understanding how the intergalactic medium (IGM) makes the transition from a neutral medium to one that is almost fully ionized. Here, we present an approximate numerical method designed to study in a statistical sense how a cosmological density field is ionized by a set of discrete point sources. A diffuse background radiation field is also computed self-consistently in our procedure. The method requires relatively few time steps and can be employed with simulations having high resolution. We describe the details of the algorithm and provide a description of how the method can be applied to the output from a pre-existing cosmological simulation to study the systematic reionization of a particular ionic species. As a first application, we compute the reionization of He II by quasars in the redshift range 3 to 6.

  11. The Cosmology - Particle Physics Connection

    E-Print Network [OSTI]

    Mark Trodden

    2006-05-26

    Modern cosmology poses deep and unavoidable questions for fundamental physics. In this plenary talk, delivered in slightly different forms at the {\\it Particles and Nuclei International Conference} (PANIC05) in Santa Fe, in October 2005, and at the {\\it CMB and Physics of the Early Universe International Conference}, on the island of Ischia, Italy, in April 2006, I discuss the broad connections between cosmology and particle physics, focusing on physics at the TeV scale, accessible at the next and future generations of colliders

  12. Diversity of Type Ia Supernovae Imprinted in Chemical Abundances

    E-Print Network [OSTI]

    Tsujimoto, Takuji

    2012-01-01

    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 a SN Ia-like elemental feature including a very low [Mg/Fe] (~-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 gives 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 nice...

  13. The Nuclear Equation of State and Supernovae James M. Lattimer

    E-Print Network [OSTI]

    Lattimer, James M.

    type of supernova is powered by thermonuclear energy. This type of event involves the end product elements. Iron­peak elements, lying at the maximum of the nuclear binding energy curve, are the final will be devoted to them. We will point out, however, that because thermonuclear supernovae occur from a quite

  14. Synthetic Spectrum Methods for Three-Dimensional Supernova Models

    E-Print Network [OSTI]

    R. C. Thomas

    2003-10-21

    Current observations stimulate the production of fully three-dimensional explosion models, which in turn motivates three-dimensional spectrum synthesis for supernova atmospheres. We briefly discuss techniques adapted to address the latter problem, and consider some fundamentals of line formation in supernovae without recourse to spherical symmetry. Direct and detailed extensions of the technique are discussed, and future work is outlined.

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

    Office of Scientific and Technical Information (OSTI)

    of the Supernova Remnant G8.7-0.1 We present a detailed analysis of the GeV gamma-ray emission toward the supernova remnant (SNR) G8.7-0.1 with the Large Area Telescope (LAT) on...

  16. The Nuclear Physics of Solar and Supernova Neutrino Detection

    E-Print Network [OSTI]

    W. C. Haxton

    1999-01-15

    This talk provides a basic introduction for students interested in the responses of detectors to solar, supernova, and other low-energy neutrino sources. Some of the nuclear physics is then applied in a discussion of nucleosynthesis within a Type II supernova, including the r-process and the neutrino process.

  17. An HST Search for Supernovae Accompanying X-ray Flashes

    E-Print Network [OSTI]

    A. M. Soderberg; S. R. Kulkarni; D. B. Fox; E. Berger; P. A. Price; S. B. Cenko; D. A. Howell; A. Gal-Yam; D. C. Leonard; D. A. Frail; D. Moon; R. A. Chevalier; M. Hamuy; K. C. Hurley; D. Kelson; K. Koviak; W. Krzeminski; P. Kumar; A. MacFadyen; P. J. McCarthy; H. S. Park; B. A. Peterson; M. M. Phillips; M. Rauch; M. Roth; B. P. Schmidt; S. Shectman

    2005-02-25

    We present the results from an Hubble Space Telescope/ACS search for supernovae associated with X-ray flashes 020903, 040701, 040812 and 040916. We find strong evidence that XRF 020903 (z=0.25) was associated with a SN 1998bw-like supernova and confirm this using optical spectroscopy at t ~ 25 days. We find no evidence, however, for SN 1998bw-like supernovae associated with the other three events. In the case of XRF 040701 (z=0.21), we rule out even a faint supernova similar to SN 2002ap, using template light-curves for several local Type Ic supernovae. For the two cases in which the redshift is not known, XRFs 040812 and 040916, we derive robust redshift limits assuming they were accompanied by supernovae similar to SN 1998bw and compare these limits with photometric redshift constraints provided by their host galaxies. We supplement this analysis with results for three additional events (XRFs 011030, 020427 and 030723) and discuss the observed diversity of supernovae associated with X-ray flashes and gamma-ray bursts. We conclude that XRF-SNe exist, but can be significantly fainter than SN 1998bw, possibly consistent with the observed spread in local Type Ibc supernovae.

  18. No evidence for bulk velocity from type Ia supernovae

    E-Print Network [OSTI]

    Huterer, Dragan; Schmidt, Fabian

    2015-01-01

    We revisit the effect of peculiar velocities on low-redshift type Ia supernovae. Velocities introduce an additional guaranteed source of correlations between supernova magnitudes that should be considered in all analyses of nearby supernova samples but has largely been neglected in the past. Applying a likelihood analysis to the latest compilation of nearby supernovae, we find no evidence for the presence of these correlations, although, given the significant noise, the data is also consistent with the correlations predicted for the standard LCDM model. We then consider the dipolar component of the velocity correlations - the frequently studied "bulk velocity" - and explicitly demonstrate that including the velocity correlations in the data covariance matrix is crucial for drawing correct and unambiguous conclusions about the bulk flow. In particular, current supernova data is consistent with no excess bulk flow on top of what is expected in LCDM and effectively captured by the covariance. We further clarify ...

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

    E-Print Network [OSTI]

    Abbar, Sajad

    2015-01-01

    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 paper we analyze the neutrino flavor instabilities in a time-dependent supernova model. Our results show that collective 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 t...

  20. Features of the Acoustic Mechanism of Core-Collapse Supernova Explosions

    E-Print Network [OSTI]

    A. Burrows; E. Livne; L. Dessart; C. D. Ott; J. Murphy

    2006-10-05

    In the context of 2D, axisymmetric, multi-group, radiation/hydrodynamic simulations of core-collapse supernovae over the full 180$^{\\circ}$ domain, we present an exploration of the progenitor dependence of the acoustic mechanism of explosion. All progenitor models we have tested with our Newtonian code explode. We investigate the roles of the Standing-Accretion-Shock-Instability (SASI), the excitation of core g-modes, the generation of core acoustic power, the ejection of matter with r-process potential, the wind-like character of the explosion, and the fundamental anisotropy of the blasts. We find that the breaking of spherical symmetry is central to the supernova phenomenon and the blasts, when top-bottom asymmetric, are self-collimating. We see indications that the initial explosion energies are larger for the more massive progenitors, and smaller for the less massive progenitors, and that the neutrino contribution to the explosion energy may be an increasing function of progenitor mass. The degree of explosion asymmetry we obtain is completely consistent with that inferred from the polarization measurements of Type Ic supernovae. Furthermore, we calculate for the first time the magnitude and sign of the net impulse on the core due to anisotropic neutrino emission and suggest that hydrodynamic and neutrino recoils in the context of our asymmetric explosions afford a natural mechanism for observed pulsar proper motions. [abridged

  1. Cosmological two-fluid thermodynamics

    E-Print Network [OSTI]

    Winfried Zimdahl; Diego Pavón

    2000-05-17

    We reveal unifying thermodynamic aspects of so different phenomena as the cosmological electron-positron annihilation, the evaporation of primordial black holes with a narrow mass range, and the ``deflationary'' transition from an initial de Sitter phase to a subsequent standard Friedmann-Lema\\^{\\i}tre-Robertson-Walker begin (FLRW) behavior.

  2. Summary & Outlook: Particles and Cosmology

    E-Print Network [OSTI]

    Wilfried Buchmuller

    2010-03-05

    We review new results on strong and electroweak interactions, flavour physics, cosmic rays and cosmology, which were presented at this conference, focussing on physics beyond the Standard Models. Special emphasis is given to the Higgs sector of the Standard Model of Particle Physics and recent results on high-energy cosmic rays and their implications for dark matter.

  3. Holographic Complexity And Cosmological Singularities

    E-Print Network [OSTI]

    Barbon, Jose L F

    2015-01-01

    We study the evolution of holographic complexity in various AdS/CFT models containing cosmological crunch singularities. We find that a notion of complexity measured by extremal bulk volumes tends to decrease as the singularity is approached in CFT time, suggesting that the corresponding quantum states have simpler entanglement structure at the singularity.

  4. Cosmographic Hubble fits to the supernova data

    E-Print Network [OSTI]

    Celine Cattoen; Matt Visser

    2008-09-03

    The Hubble relation between distance and redshift is a purely cosmographic relation that depends only on the symmetries of a FLRW spacetime, but does not intrinsically make any dynamical assumptions. This suggests that it should be possible to estimate the parameters defining the Hubble relation without making any dynamical assumptions. To test this idea, we perform a number of inter-related cosmographic fits to the legacy05 and gold06 supernova datasets. Based on this supernova data, the "preponderance of evidence" certainly suggests an accelerating universe. However we would argue that (unless one uses additional dynamical and observational information) this conclusion is not currently supported "beyond reasonable doubt". As part of the analysis we develop two particularly transparent graphical representations of the redshift-distance relation -- representations in which acceleration versus deceleration reduces to the question of whether the relevant graph slopes up or down. Turning to the details of the cosmographic fits, three issues in particular concern us: First, the fitted value for the deceleration parameter changes significantly depending on whether one performs a chi^2 fit to the luminosity distance, proper motion distance or other suitable distance surrogate. Second, the fitted value for the deceleration parameter changes significantly depending on whether one uses the traditional redshift variable z, or what we shall argue is on theoretical grounds an improved parameterization y=z/(1+z). Third, the published estimates for systematic uncertainties are sufficiently large that they certainly impact on, and to a large extent undermine, the usual purely statistical tests of significance. We conclude that the supernova data should be treated with some caution.

  5. Detecting the cosmological recombination signal from space

    E-Print Network [OSTI]

    Desjacques, Vincent; Silk, Joseph; de Bernardis, Francesco; Doré, Olivier

    2015-01-01

    Spectral distortions of the CMB have recently experienced an increased interest. One of the inevitable distortion signals of our cosmological concordance model is created by the cosmological recombination process, just a little before photons last scatter at redshift $z\\simeq 1100$. These cosmological recombination lines, emitted by the hydrogen and helium plasma, should still be observable as tiny deviation from the CMB blackbody spectrum in the cm--dm spectral bands. In this paper, we present a forecast for the detectability of the recombination signal with future satellite experiments. We argue that serious consideration for future CMB experiments in space should be given to probing spectral distortions and, in particular, the recombination line signals. The cosmological recombination radiation not only allows determination of standard cosmological parameters, but also provides a direct observational confirmation for one of the key ingredients of our cosmological model: the cosmological recombination histo...

  6. From Convection to Explosion: End-to-End Simulation of Type Ia Supernovae

    E-Print Network [OSTI]

    Bell, John B.

    Ia supernova is the thermonuclear runaway and subsequent explosion of a white dwarf that is accreting

  7. Three-dimensional Numerical Simulations of Rayleigh-Taylor Unstable Flames in Type Ia Supernovae

    E-Print Network [OSTI]

    Bell, John B.

    ) instability and turbulence in accelerating a thermonuclear flame in Type Ia supernovae (SNe Ia) is well

  8. How frequently will a Supernova dangerous to life on Earth explode in our galaxy? Michael Richmond

    E-Print Network [OSTI]

    Richmond, Michael W.

    How frequently will a Supernova dangerous to life on Earth explode in our galaxy? Michael Richmond of the disk ... How frequently do ``dangerous'' Type II supernovae occur? 3. Type Ia Supernovae in the halo concentrated in the spheroid ... How frequently do ``dangerous'' Type Ia supernovae occur? 4. Conclusion 1

  9. Nuclear physics with spherically symmetric supernova models

    E-Print Network [OSTI]

    M. Liebendoerfer; T. Fischer; C. Fröhlich; F. -K. Thielemann; S. Whitehouse

    2007-08-31

    Few years ago, Boltzmann neutrino transport led to a new and reliable generation of spherically symmetric models of stellar core collapse and postbounce evolution. After the failure to prove the principles of the supernova explosion mechanism, these sophisticated models continue to illuminate the close interaction between high-density matter under extreme conditions and the transport of leptons and energy in general relativistically curved space-time. We emphasize that very different input physics is likely to be relevant for the different evolutionary phases, e.g. nuclear structure for weak rates in collapse, the equation of state of bulk nuclear matter during bounce, multidimensional plasma dynamics in the postbounce evolution, and neutrino cross sections in the explosive nucleosynthesis. We illustrate the complexity of the dynamics using preliminary 3D MHD high-resolution simulations based on parameterized deleptonization. With established spherically symmetric models we show that typical features of the different phases are reflected in the predicted neutrino signal and that a consistent neutrino flux leads to electron fractions larger than 0.5 in neutrino-driven supernova ejecta.

  10. The Physics Of Supernova Neutrino Oscillations

    E-Print Network [OSTI]

    Kneller, James P

    2015-01-01

    On February 23, 1987 we collected 24 neutrinos from the explosion of a blue super-giant star in the Large Magellanic Cloud confirming the basic paradigm of core-collapse supernova. During the many years we have been waiting for a repeat of that momentous day, the number and size of neutrino detectors around the world has grown considerably. If the neutrinos from the next supernova in our Galaxy arrive tomorrow we shall collect upwards of tens of thousands of events and next generation detectors will increase the amount of data we collect by more than an order of magnitude. But it is also now apparent that the message is much more complex than previously thought because many time, energy and neutrino flavor dependent features are imprinted upon the signal either at emission or by the passage through the outer layers of the star. These features arise due to the explosion dynamics, the physics of nuclei at high temperatures and densities, and the properties of neutrinos. In this proceedings I will present some a...

  11. Nebular spectra of pair-instability supernovae

    E-Print Network [OSTI]

    Jerkstrand, A; Heger, A

    2015-01-01

    If very massive stars (M >~ 100 Msun) can form and avoid too strong mass loss during their evolution, they are predicted to explode as pair-instability supernovae (PISNe). One critical test for candidate events is whether their nucleosynthesis yields and internal ejecta structure, being revealed through nebular-phase spectra at t >~ 1 yr, match those of model predictions. Here we compute theoretical spectra based on model PISN ejecta at 1-3 years post-explosion to allow quantitative comparison with observations. The high column densities of PISNe lead to complete gamma-ray trapping for t >~ 2 years which, combined with fulfilled conditions of steady state, leads to bolometric supernova luminosities matching the 56Co decay. Most of the gamma-rays are absorbed by the deep-lying iron and silicon/sulphur layers. The ionization balance shows a predominantly neutral gas state, which leads to emission lines of Fe I, Si I, and S I. For low-mass PISNe the metal core expands slowly enough to produce a forest of distinc...

  12. Measurement of Omega_m, Omega_Lambda from a blind analysis of Type Ia supernovae with CMAGIC: Using color information to verify the acceleration of the Universe

    E-Print Network [OSTI]

    2006-01-01

    analysis of Type Ia supernovae with CMAGIC: Using colorof 21 high redshift supernovae using a new technique (lightcurves of Type Ia supernovae, ?rst introduced in Wang

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

    SciTech Connect (OSTI)

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

    2014-08-01

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

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

    SciTech Connect (OSTI)

    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.

  15. Cosmological implications of two types of baryon acoustic oscillation data

    E-Print Network [OSTI]

    Hu, Yazhou; Li, Nan; Wang, Shuang

    2015-01-01

    Aims: We explore the cosmological implications of two types of baryon acoustic oscillation (BAO) data that are extracted by using the spherically averaged one-dimensional galaxy clustering (GC) statistics (hereafter BAO1) and the anisotropic two-dimensional GC statistics (hereafter BAO2), respectively. Methods: Firstly, making use of the BAO1 and the BAO2 data, as well as the SNLS3 type Ia supernovae sample and the Planck distance priors data, we constrain the parameter spaces of the $\\Lambda$CDM, the $w$CDM, and the Chevallier-Polarski-Linder (CPL) model. Then, we discuss the impacts of different BAO data on parameter estimation, equation of state $w$, figure of merit and deceleration-acceleration transition redshift. At last, we use various dark energy diagnosis, including Hubble diagram $H(z)$, deceleration diagram $q(z)$, statefinder hierarchy $\\{S^{(1)}_3, S^{(1)}_4\\}$, composite null diagnosic (CND) $\\{S^{(1)}_3, \\epsilon(z)\\}$ and $\\{S^{(1)}_4, \\epsilon(z)\\}$, to distinguish the differences between the...

  16. Cosmological parameters from lensing power spectrum and bispectrum tomography

    E-Print Network [OSTI]

    Masahiro Takada; Bhuvnesh Jain

    2005-07-20

    We examine how lensing tomography with the bispectrum and power spectrum can constrain cosmological parameters and the equation of state of dark energy. Our analysis uses the full information at the two- and three-point level from angular scales of a few degrees to 5 arcminutes (50 < l < 3000), which will be probed by lensing surveys. We use all triangle configurations, cross-power spectra and bispectra constructed from up to three redshift bins with photometric redshifts, and relevant covariances in our analysis. We find that the parameter constraints from bispectrum tomography are comparable to those from power spectrum tomography. Combining the two improves parameter accuracies by a factor of three due to their complementarity. For the dark energy parameterization w(a) = w0 + wa(1-a), the marginalized errors from lensing alone are sigma(w0) = 0.03 fsky^{-1/2} and sigma(wa) = 0.1 fsky^{-1/2}. We show that these constraints can be further improved when combined with measurements of the cosmic microwave background or Type Ia supernovae. The amplitude and shape of the mass power spectrum are also shown to be precisely constrained. We use hyper-extended perturbation theory to compute the nonlinear lensing bispectrum for dark energy models. Accurate model predictions of the bispectrum in the moderately nonlinear regime, calibrated with numerical simulations, will be needed to realize the parameter accuracy we have estimated. Finally, we estimate how well the lensing bispectrum can constrain a model with primordial non-Gaussianity.

  17. EVOLUTION OF THE MASS-METALLICITY RELATIONS IN PASSIVE AND STAR-FORMING GALAXIES FROM SPH-COSMOLOGICAL SIMULATIONS

    SciTech Connect (OSTI)

    Romeo Velona, A. D.; Gavignaud, I.; Meza, A. [Departamento de Ciencias Fisicas, Universidad Andres Bello, Av. Republica 220, Santiago (Chile); Sommer-Larsen, J. [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Mariesvej 30, DK-2100 Copenhagen (Denmark); Napolitano, N. R. [INAF-Osservatorio Astronomico di Capodimonte, Salita Moiariello 16, I-80131 Napoli (Italy); Antonuccio-Delogu, V. [INAF-Osservatorio Astrofisico di Catania, v. S. Sofia 78, I-95123 Catania (Italy); Cielo, S., E-mail: aro@oact.inaf.it [Max-Planck-Institut fuer Astronomie, Koenigstuhl 17, D-69117 Heidelberg (Germany)

    2013-06-20

    We present results from SPH-cosmological simulations, including self-consistent modeling of supernova feedback and chemical evolution, of galaxies belonging to two clusters and 12 groups. We reproduce the mass-metallicity (ZM) relation of galaxies classified in two samples according to their star-forming (SF) activity, as parameterized by their specific star formation rate (sSFR), across a redshift range up to z = 2. The overall ZM relation for the composite population evolves according to a redshift-dependent quadratic functional form that is consistent with other empirical estimates, provided that the highest mass bin of the brightest central galaxies is excluded. Its slope shows irrelevant evolution in the passive sample, being steeper in groups than in clusters. However, the subsample of high-mass passive galaxies only is characterized by a steep increase of the slope with redshift, from which it can be inferred that the bulk of the slope evolution of the ZM relation is driven by the more massive passive objects. The scatter of the passive sample is dominated by low-mass galaxies at all redshifts and keeps constant over cosmic times. The mean metallicity is highest in cluster cores and lowest in normal groups, following the same environmental sequence as that previously found in the red sequence building. The ZM relation for the SF sample reveals an increasing scatter with redshift, indicating that it is still being built at early epochs. The SF galaxies make up a tight sequence in the SFR-M{sub *} plane at high redshift, whose scatter increases with time alongside the consolidation of the passive sequence. We also confirm the anti-correlation between sSFR and stellar mass, pointing at a key role of the former in determining the galaxy downsizing, as the most significant means of diagnostics of the star formation efficiency. Likewise, an anti-correlation between sSFR and metallicity can be established for the SF galaxies, while on the contrary more active galaxies in terms of simple SFR are also metal-richer. Finally, the [O/Fe] abundance ratio is presented too: we report a strong increasing evolution with redshift at given mass, especially at z {approx}> 1. The expected increasing trend with mass is recovered when only considering the more massive galaxies. We discuss these results in terms of the mechanisms driving the evolution within the high- and low-mass regimes at different epochs: mergers, feedback-driven outflows, and the intrinsic variation of the star formation efficiency.

  18. Cosmological perturbations in unimodular gravity

    SciTech Connect (OSTI)

    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.

  19. Quantum coherent states in cosmology

    E-Print Network [OSTI]

    Houri Ziaeepour

    2015-02-15

    Coherent states consist of superposition of infinite number of particles and do not have a classical analogue. We study their evolution in a FLRW cosmology and show that only when full quantum corrections are considered, they may survive the expansion of the Universe and form a global condensate. This state of matter can be the origin of accelerating expansion of the Universe, generally called dark energy, and inflation in the early universe. Additionally, such a quantum pool may be the ultimate environment for decoherence at shorter distances. If dark energy is a quantum coherent state, its dominant contribution to the total energy of the Universe at present provides a low entropy state which may be necessary as an initial condition for a new Big Bang in the framework of bouncing cosmology models.

  20. Thermonuclear supernova explosions and their remnants: the case of Tycho

    E-Print Network [OSTI]

    Carles Badenes; Eduardo Bravo; Kazimierz J. Borkowski

    2003-09-03

    We propose to use the thermal X-ray emission from young supernova remnants (SNRs) originated in Type Ia supernovae (SNe) to extract relevant information concerning the explosion mechanism. We focus on the differences between numerical 1D and 3D explosion calculations, and the impact that these differences could have on young SNRs. We use the remnant of the Tycho supernova (SN 1572) as a test case to compare with our predictions, discussing the observational features that allow to accept or discard a given model.

  1. Incompatibility of a comoving Ly-alpha forest with supernova-Ia luminosity distances

    E-Print Network [OSTI]

    Jens Thomas; Hartmut Schulz

    2001-03-18

    Recently Perlmutter et al. suggested a positive value of Einstein's cosmological constant Lambda on the basis of luminosity distances from type-Ia supernovae. However, Lambda world models had earlier been proposed by Hoell & Priester and Liebscher et al. on the basis of quasar absorption-line data. Employing more general repulsive fluids ("dark energy") encompassing the Lambda component we quantitatively compare both approaches with each other. Fitting the SN-data by a minimum-component model consisting of dark energy + dust yields a closed universe with a large amount of dust exceeding the baryonic content constrained by big-bang nucleosynthesis. The nature of the dark energy is hardly constrained. Only when enforcing a flat universe there is a clear tendency to a dark-energy Lambda fluid and the `canonical' value Omega_M = 0.3 for dust. Conversely, fitting the quasar-data by a minimum-component model yields a sharply defined, slightly closed model with a low dust density ruling out significant pressureless dark matter. The dark-energy component obtains an equation-of-state P = -0.96 epsilon close to that of a Lambda-fluid. Omega_M = 0.3 or a precisely flat spatial geometry are inconsistent with minimum-component models. It is found that quasar and supernova data sets cannot be reconciled with each other via (repulsive ideal fluid+dust+radiation)-world models. Compatibility could be reached by drastic expansion of the parameter space with at least two exotic fluids added to dust and radiation as world constituents. If considering such solutions as far-fetched one has to conclude that the quasar absorption line and the SN-Ia constraints are incompatible.

  2. THE ULTRAVIOLET BRIGHTEST TYPE Ia SUPERNOVA 2011de

    SciTech Connect (OSTI)

    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 Type Ia supernova (SN Ia) 2011de from the Swift Ultraviolet/Optical Telescope. We find it to be the UV brightest SN Ia yet observed—more 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.

  3. CARBON DEFLAGRATION IN TYPE Ia SUPERNOVA. I. CENTRALLY IGNITED MODELS

    SciTech Connect (OSTI)

    Ma, H.; Woosley, S. E.; Malone, C. M. [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Almgren, A.; Bell, J. [Center for Computational Sciences and Engineering, Lawrence Berkeley National Lab, Berkeley, CA 94720 (United States)

    2013-07-01

    A leading model for Type Ia supernovae (SNe Ia) begins with a white dwarf near the Chandrasekhar mass that ignites a degenerate thermonuclear runaway close to its center and explodes. In a series of papers, we shall explore the consequences of ignition at several locations within such dwarfs. Here we assume central ignition, which has been explored before, but is worth revisiting, if only to validate those previous studies and to further elucidate the relevant physics for future work. A perturbed sphere of hot iron ash with a radius of {approx}100 km is initialized at the middle of the star. The subsequent explosion is followed in several simulations using a thickened flame model in which the flame speed is either fixed-within the range expected from turbulent combustion-or based on the local turbulent intensity. Global results, including the explosion energy and bulk nucleosynthesis (e.g., {sup 56}Ni of 0.48-0.56 M{sub Sun }) turn out to be insensitive to this speed. In all completed runs, the energy released by the nuclear burning is adequate to unbind the star, but not enough to give the energy and brightness of typical SNe Ia. As found previously, the chemical stratification observed in typical events is not reproduced. These models produce a large amount of unburned carbon and oxygen in central low velocity regions, which is inconsistent with spectroscopic observations, and the intermediate mass elements and iron group elements are strongly mixed during the explosion.

  4. Casting Loop Quantum Cosmology in the Spin Foam Paradigm

    E-Print Network [OSTI]

    Abhay Ashtekar; Miguel Campiglia; Adam Henderson

    2010-04-03

    The goal of spin foam models is to provide a viable path integral formulation of quantum gravity. Because of background independence, their underlying framework has certain novel features that are not shared by path integral formulations of familiar field theories in Minkowski space. As a simple viability test, these features were recently examined through the lens of loop quantum cosmology (LQC). Results of that analysis, reported in a brief communication [1], turned out to provide concrete arguments in support of the spin foam paradigm. We now present detailed proofs of those results. Since the quantum theory of LQC models is well understood, this analysis also serves to shed new light on some long standing issues in the spin foam and group field theory literature. In particular, it suggests an intriguing possibility for addressing the question of why the cosmological constant is positive and small.

  5. Cosmology, Thermodynamics and Matter Creation

    E-Print Network [OSTI]

    J. A. S. Lima; M. O. Calvao; I. Waga

    2007-08-24

    Several approaches to the matter creation problem in the context of cosmological models are summarily reviewed. A covariant formulation of the general relativistic imperfect simple fluid endowed with a process of matter creation is presented. By considering the standard big bang model, it is shown how the recent results of Prigogine et alii \\cite{1} can be recovered and, at the same time their limits of validity are explicited.

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

    SciTech Connect (OSTI)

    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.

  7. Are Models for Core-Collapse Supernova Progenitors Consistent with the Properties of Supernova Remnants?

    E-Print Network [OSTI]

    Patnaude, Daniel J; Slane, Patrick O; Badenes, Carles; Heger, Alexander; Ellison, Donald C; Nagataki, Shigehiro

    2015-01-01

    The recent discovery that the Fe-K line luminosities and energy centroids observed in nearby SNRs are a strong discriminant of both progenitor type and circumstellar environment has implications for our understanding of supernova progenitor evolution. Using models for the chemical composition of core-collapse supernova ejecta, we model the dynamics and thermal X-ray emission from shocked ejecta and circumstellar material, modeled as an $r^{-2}$ wind, to ages of 3000 years. We compare the X-ray spectra expected from these models to observations made with the Suzaku satellite. We also model the dynamics and X-ray emission from Type Ia progenitor models. We find a clear distinction in Fe-K line energy centroid between core-collapse and Type Ia models. The core-collapse supernova models predict higher Fe-K line centroid energies than the Type Ia models, in agreement with observations. We argue that the higher line centroids are a consequence of the increased densities found in the circumstellar environment create...

  8. Emergent cosmological constant from colliding electromagnetic waves

    SciTech Connect (OSTI)

    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.

  9. String Gas Cosmology and Non-Gaussianities

    E-Print Network [OSTI]

    Bin Chen; Yi Wang; Wei Xue; Robert Brandenberger

    2008-03-05

    Recently it has been shown that string gas cosmology, an alternative model of the very early universe which does not involve a period of cosmological inflation, can give rise to an almost scale invariant spectrum of metric perturbations. Here we calculate the non-Gaussianities of the spectrum of cosmological fluctuations in string gas cosmology, and find that these non-Gaussianities depend linearly on the wave number and that their amplitude depends sensitively on the string scale. If the string scale is at the TeV scale, string gas cosmology could lead to observable non-Gaussianities, if it is close to the Planck scale, then the non-Gaussianities on current cosmological scales are negligible.

  10. Cosmological Time Dilation in Gamma Ray Bursts?

    E-Print Network [OSTI]

    David Band

    1994-07-01

    Norris et al. (1994) report that the temporal structure of faint gamma ray bursts is longer than that of bright bursts, as expected for time dilation in the cosmological models of burst origin. I show that the observed trends can easily be produced by a burst luminosity function and thus may not result from cosmological effects. A cosmological signature may be present, but the tests Norris et al. present are not powerful enough to detect these signatures.

  11. Group X

    SciTech Connect (OSTI)

    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.

  12. Progenitors of ultra-stripped supernovae

    E-Print Network [OSTI]

    Tauris, Thomas; Podsiadlowski, Philipp

    2015-01-01

    The explosion of ultra-stripped stars in close binaries may explain new discoveries of weak and fast optical transients. We have demonstrated that helium star companions to neutron stars (NSs) may evolve into naked metal cores as low as ~1.5 Msun, barely above the Chandrasekhar mass limit, by the time they explode. Here we present a new systematic investigation of the progenitor evolution leading to such ultra-stripped supernovae (SNe), in some cases yielding pre-SN envelopes of less than 0.01 Msun. We discuss the nature of these SNe (electron-capture vs iron core-collapse) and their observational light-curve properties. Ultra-stripped SNe are highly relevant for binary pulsars, as well as gravitational wave detection of merging NSs by LIGO/VIRGO, since these events are expected to produce mainly low-kick NSs in the mass range 1.10-1.80 Msun.

  13. Neutrino Nucleosynthesis of radioactive nuclei in supernovae

    E-Print Network [OSTI]

    A. Sieverding; L. Huther; K. Langanke; G. Martínez-Pinedo; A. Heger

    2015-05-05

    We study the neutrino-induced production of nuclides in explosive supernova nucleosynthesis for progenitor stars with solar metallicity and initial main sequence masses between 15 M$_\\odot$ and 40 M$_\\odot$. We improve previous investigations i) by using a global set of partial differential cross sections for neutrino-induced charged- and neutral-current reactions on nuclei with charge numbers $Z nuclides $^{22}$Na and $^{26}$Al. Both nuclei are prime candidates for gamma-ray astronomy. Other prime targets, $^{44}$Ti and $^{60}$Fe, however, are insignificantly produced by neutrino-induced reactions. We also find a large increase in the production of the long-lived nuclei $^{92}$Nb and $^{98}$Tc due to charged-current neutrino capture.

  14. Neutrino Nucleosynthesis of radioactive nuclei in supernovae

    E-Print Network [OSTI]

    Sieverding, A; Langanke, K; Martínez-Pinedo, G; Heger, A

    2015-01-01

    We study the neutrino-induced production of nuclides in explosive supernova nucleosynthesis for progenitor stars with solar metallicity and initial main sequence masses between 15 M$_\\odot$ and 40 M$_\\odot$. We improve previous investigations i) by using a global set of partial differential cross sections for neutrino-induced charged- and neutral-current reactions on nuclei with charge numbers $Z nucleosynthesis studies. We confirm the production of $^7$Li, $^{11}$B, $^{138}$La, and $^{180}$Ta by neutrino nucleosynthesis, albeit at slightly smaller abundances due to the changed neutrino spectra. We find that for stars with a mass smaller than 20 M$_\\odot$, $^{19}$F is produced mainly by explosive nucleosynthesis while for higher mass stars it is produced by the $\

  15. Classifying supernovae using only galaxy data

    SciTech Connect (OSTI)

    Foley, Ryan J. [Astronomy Department, University of Illinois at Urbana-Champaign, 1002 West Green Street, Urbana, IL 61801 (United States); Mandel, Kaisey [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

    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.

  16. Asymmetric Supernovae from Magneto-Centrifugal Jets

    E-Print Network [OSTI]

    J. Craig Wheeler; David L. Meier; James R. Wilson

    2001-12-02

    Strong toroidal magnetic fields generated in stellar collapse can generate magneto-centrifugal jets in analogy to those found in simulations of black hole accretion and explain why all core collapse supernovae are found to be substantially asymmetric and predominantly bi-polar. We describe two phases: the initial LeBlanc-Wilson jet and a subsequent protopulsar or toroidal jet that propagates at about the core escape velocity. The jets will produce bow shocks that tend to expel matter, including iron and silicon, into equatorial tori, accounting for observations of the element distribution in Cas A. A magnetic ``switch'' mechanism may apply in instances of low density and large magnetic field with subsequent increase in the speed and collimation of the toroidal jet, depositing relatively little momentum. The result could be enough infall to form a black hole with a third, highly relativistic jet that could catch up to the protopulsar jet after it has emerged from the star. The interaction of these two jets could generate internal shocks and explain the presence of iron lines in the afterglow. Recent estimates that typical gamma-ray burst energy is about 3x10^50 erg imply either a very low efficiency for conversion of rotation into jets, or a rather rapid turnoff of the jet process even though the black hole still rotates rapidly. Magnetars and ``hypernovae'' might arise in an intermediate parameter regime of energetic jets that yield larger magnetic fields and provide more energy than the routine case, but that are not so tightly collimated that they yield failed supernova. (slightly abridged)

  17. Sweetspot: Near-infrared observations of 13 type Ia supernovae...

    Office of Scientific and Technical Information (OSTI)

    of 13 type Ia supernovae from a new NOAO survey probing the nearby smooth Hubble flow Citation Details In-Document Search Title: Sweetspot: Near-infrared observations of 13...

  18. Evolution of the Crab nebula in a low energy supernova

    E-Print Network [OSTI]

    Yang, Haifeng

    2015-01-01

    The nature of the supernova leading to the Crab Nebula has long been controversial because of the low energy that is present in the observed nebula. One possibility is that there is significant energy in extended fast material around the Crab but searches for such material have not led to detections. An electron capture supernova model can plausibly account for the low energy and the observed abundances in the Crab. Here, we examine the evolution of the Crab pulsar wind nebula inside a freely expanding supernova and find that the observed properties are most consistent with a low energy event. Both the velocity and radius of the shell material, and the amount of gas swept up by the pulsar wind point to a low explosion energy ($\\sim 10^{50}$ ergs). We do not favor a model in which circumstellar interaction powers the supernova luminosity near maximum light because the required mass would limit the freely expanding ejecta.

  19. A Critique of Core--Collapse Supernova Theory Circa 1997

    E-Print Network [OSTI]

    Adam Burrows

    1997-03-02

    There has been a new infusion of ideas in the study of the mechanism and early character of core--collapse supernovae. However, despite recent conceptual and computational progress, fundamental questions remain. Some are summarize herein.

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

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

    in a violent explosion known as a Type IIb supernova. Using the iPTF pipeline, researchers at Israel's Weizmann Institute of Science led by Avishay Gal-Yam caught...

  1. Clocking the Rise and Fall of Core-Collapse Supernovae

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

    For several weeks, the brightness of that single event can rival that of an entire galaxy. As a result, supernovae of various types are often used as "standard candles" in...

  2. DIVERSITY OF TYPE Ia SUPERNOVAE IMPRINTED IN CHEMICAL ABUNDANCES

    SciTech Connect (OSTI)

    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.

  3. Stripped-envelope supernova rates and host-galaxy properties

    E-Print Network [OSTI]

    Graur, Or; Modjaz, Maryam; Maoz, Dan; Shivvers, Isaac; Filippenko, Alexei V; Li, Weidong

    2015-01-01

    The progenitors of stripped-envelope supernovae (SNe Ibc) remain to be conclsuively identified, but correlations between SN rates and host-galaxy properties can constrain progenitor models. Here, we present one result from a re-analysis of the rates from the Lick Observatory Supernova Search. Galaxies with stellar masses less than $\\sim 10^{10}~{\\rm M_\\odot}$ are less efficient at producing SNe Ibc than more massive galaxies. Any progenitor scenario must seek to explain this new observation.

  4. Observational constrains on cosmological models with Chaplygin gas and quadratic equation of state

    E-Print Network [OSTI]

    Sharov, G S

    2015-01-01

    Observational manifestations of accelerated expansion of the universe, in particular, recent data for Type Ia supernovae, baryon acoustic oscillations and for the Hubble parameter $H(z)$ are described with different cosmological models. We compare the $\\Lambda$CDM, the models with generalized and modified Chaplygin gas and the model with quadratic equation of state. For these models we estimate optimal model parameters and their permissible errors, in particular, for all 4 mentioned models the Hubble parameter and the curvature fraction are $H_0=70.1\\pm0.45$ km\\,c${}^{-1}$Mpc${}^{-1}$ and $-0.13\\le\\Omega_k\\le0.025$. The model with quadratic equation of state yields the minimal value of $\\chi^2$, but this model has 2 additional parameters in comparison with the $\\Lambda$CDM.

  5. Distance-Redshift in Inhomogeneous $Omega_0=1$ Friedmann-Lemaitre-Robertson-Walker Cosmology

    E-Print Network [OSTI]

    R. Kantowski; R. C. Thomas

    2001-06-18

    Distance--redshift relations are given in terms of associated Legendre functions for partially filled beam observations inspatially flat Friedmann-Lemaitre-Robertson-Walker (FLRW) cosmologies. These models are dynamically pressure-free, flat FLRW on large scales but, due to mass inhomogeneities, differ in their optical properties. The partially filled beam area-redshift equation is a Lame$^{\\prime}$ equation for arbitrary FLRW and is shown to simplify to the associated Legendre equation for the spatially flat, i.e. $\\Omega_0=1$ case. We fit these new analytic Hubble curves to recent supernovae (SNe) data in an attempt to determine both the mass parameter $\\Omega_m$ and the beam filling parameter $\

  6. Spatially adaptive radiation-hydrodynamical simulations of galaxy formation during cosmological reionization

    E-Print Network [OSTI]

    Pawlik, Andreas H; Vecchia, Claudio Dalla

    2015-01-01

    We present a suite of cosmological radiation-hydrodynamical simulations of the assembly of galaxies driving the reionization of the intergalactic medium (IGM) at z >~ 6. The simulations account for the hydrodynamical feedback from photoionization heating and the explosion of massive stars as supernovae (SNe). Our reference simulation, which was carried out in a box of size 25 comoving Mpc/h using 2 x 512^3 particles, produces a reasonable reionization history and matches the observed UV luminosity function of galaxies. Simulations with different box sizes and resolutions are used to investigate numerical convergence, and simulations in which either SNe or photoionization heating or both are turned off, are used to investigate the role of feedback from star formation. Ionizing radiation is treated using accurate radiative transfer at the high spatially adaptive resolution at which the hydrodynamics is carried out. SN feedback strongly reduces the star formation rates (SFRs) over nearly the full mass range of s...

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

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    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).

  8. Dynamics of a Supernova Envelope in a Cloudy Interstellar Medium

    E-Print Network [OSTI]

    Korolev, V V; Kovalenko, I G; Shchekinov, Yu A

    2015-01-01

    The evolution of a supernova remnant in a cloudy medium as a function of the volume filling factor of the clouds is studied in a three-dimensional axially symmetrical model. The model includes the mixing of heavy elements (metals) ejected by the supernova and their contribution to radiative losses. The interaction of the supernova envelope with the cloudy phase of the interstellar medium leads to nonsimultaneous, and on average earlier, onsets of the radiative phase in different parts of the supernova envelope. Growth in the volume filling factor $f$ leads to a decrease in the time for the transition of the envelope to the radiative phase and a decrease in the envelope's mean radius, due to the increased energy losses by the envelope in the cloudy medium. When the development of hydrodynamical instabilities in the supernova envelope is efficient, the thermal energy falls as $E_t\\sim t^{-2.3}$, for the propagation of the supernova remnant through either a homogeneous or a cloudy medium. When the volume filling...

  9. Restframe I-band Hubble diagram for type Ia supernovae up to redshift z ~; 0.5

    E-Print Network [OSTI]

    2005-01-01

    in STScI Symposium Ser. 13, Supernovae and gamma-ray bursts:Highlight: The Physics of Supernovae, ed. W. Hillebrandt &diagram for type Ia supernovae up to redshift z ? 0.5 ? S.

  10. 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...

  11. 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 ...

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

    SciTech Connect (OSTI)

    Côté, Benoit; Martel, Hugo; Drissen, Laurent [Département de physique, de Génie Physique et d'Optique, Université Laval, Québec, QC G1V 0A6 (Canada)

    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.

  13. Modified Entropic Gravity and Cosmology

    E-Print Network [OSTI]

    Miguel Zumalacarregui

    2012-02-06

    It has been recently proposed that gravity might be an entropic force. Although a well defined fundamental description for such a mechanism is still lacking, it is still possible to address the viability of phenomenological models of entropic-inspired modified gravities. I will summarize some recent work directed to using cosmology as a tool to constraint scenarios in which the modifications are aimed to explain the physics behind dark energy and inflation. A phenomenological modification is able to explain cosmic acceleration at the background level and fit observations, but simple inflation models with higher curvature corrections are in conflict with late time matter domination.

  14. Cosmological Perturbations of Ultrarelativistic Plasmas

    E-Print Network [OSTI]

    Dominik J. Schwarz

    1996-07-31

    Scalar cosmological perturbations of a weakly self-interacting plasma mixed with a perfect radiation fluid are investigated. Effects of this plasma are considered through order $\\lambda^{3/2}$ of perturbative thermal-field-theory in the radiation dominated universe. The breakdown of thermal perturbation theory at vastly subhorizon scales is circumvented by a Pad\\'e approximant solution. Compared to collisionless plasmas the phase speed and subhorizon damping of the plasma density perturbations are changed. An example for a self-interacting thermal field is provided by the neutrinos with effective 4-fermion interactions.

  15. Nucleosynthesis in slowly evolving Cosmologies

    E-Print Network [OSTI]

    Pranav Kumar; Daksh Lohiya

    2008-02-08

    We explore aspects of Cosmological Nucleosynthesis in an FRW universe in which the scale factor evolves linearly with time: $a(t) \\sim t$. A high Lepton number density during the period when significant nucleosynthesis takes place would lead to a dominant screening of the Coulomb potential of colliding nucleii. This would lead to a significant enhancement of nucleosynthesis rates. We demonstrate how adequate amount of $^4He$ and a collataral metallicity, close to the lowest metallicity observed in metal poor Pop II stars and clouds, can be produced with such an evolution.

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

    SciTech Connect (OSTI)

    Franca, Fabio La; Bianchi, Stefano; Branchini, Enzo; Matt, Giorgio [Dipartimento di Matematica e Fisica, Università Roma Tre, Via della Vasca Navale 84, I-00146, Roma (Italy); Ponti, Gabriele, E-mail: lafranca@fis.uniroma3.it [Max-Planck-Institut für Extraterrestrische Physik, Giessenbachstrasse 1, D-85748 Garching bei München (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 ?0.6 dex. 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 0.1 mag 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.

  17. Reduction of Cosmological Data for the Detection of Time-varying Dark Energy Density

    E-Print Network [OSTI]

    Jason Dick; Lloyd Knox; Mike Chu

    2006-07-10

    We present a method for reducing cosmological data to constraints on the amplitudes of modes of the dark energy density as a function of redshift. The modes are chosen so that (1) one of them has constant density and (2) the others are non-zero only if there is time-variation in the dark energy density and (3) the amplitude errors for the time-varying modes are uncorrelated with each other. We apply our method to various combinations of three-year WMAP data, baryon acoustic oscillation data, the 'Gold' supernova data set, and the Supernova Legacy Survey data set. We find no significant evidence for a time-varying dark energy density or for non-zero mean curvature. Although by some measure the limits on four of the time-varying mode amplitudes are quite tight, they are consistent with the expectation that the dark energy density does not vary on timescales shorter than a Hubble time. Since we do not expect detectable time variation in these modes, our results should be viewed as a systematic error test which the data have passed. We discuss a procedure to identify modes with maximal signal-to-noise ratio.

  18. Applications of Nash's Theorem to Cosmology

    E-Print Network [OSTI]

    M. D. Maia

    2008-11-24

    The cosmological constant problem is seen as a symptom of the ambiguity of the Riemann curvature in general relativity. The solution of that ambiguity provided by Nash's theorem on gravitational perturbations along extra dimensions eliminate the direct comparison between the vacuum energy density and Einstein's cosmological constant, besides being compatible with the formation of structures and the accelerated expansion of the universe.

  19. Vacuum Fluctuations and the Cosmological Constant

    E-Print Network [OSTI]

    Shi Qi

    2006-04-29

    The hypothesis is proposed that under the approximation that the quantum equations of motion reduce to the classical ones, the quantum vacuum also reduces to the classical vacuum--the empty space. The vacuum energy of QED is studied under this hypothesis. A possible solution to the cosmological constant problem is provided and a kind of parameterization of the cosmological "constant" is derived.

  20. Cosmological birefringence induced by neutrino current

    E-Print Network [OSTI]

    C. Q. Geng; S. H. Ho; J. N. Ng

    2007-11-29

    We review our recent work on the cosmological birefringence. We propose a new type of effective interactions in terms of the $CPT$-even dimension-six Chern-Simons-like term to generate the cosmological birefringence. We use the neutrino number asymmetry to induce a non-zero rotation polarization angle in the data of the cosmic microwave background radiation polarization.

  1. Cosmological electromagnetic fields and dark energy

    E-Print Network [OSTI]

    Jose Beltran Jimenez; Antonio L. Maroto

    2009-02-18

    We show that the presence of a temporal electromagnetic field on cosmological scales generates an effective cosmological constant which can account for the accelerated expansion of the universe. Primordial electromagnetic quantum fluctuations produced during electroweak scale inflation could naturally explain the presence of this field and also the measured value of the dark energy density. The behavior of the electromagnetic field on cosmological scales is found to differ from the well studied short-distance behavior and, in fact, the presence of a non-vanishing cosmological constant could be signalling the breakdown of gauge invariance on cosmological scales. The theory is compatible with all the local gravity tests, and is free from classical or quantum instabilities. Thus we see that, not only the true nature of dark energy can be established without resorting to new physics, but also the value of the cosmological constant finds a natural explanation in the context of standard inflationary cosmology. This mechanism could be discriminated from a true cosmological constant by upcoming observations of CMB anisotropies and large scale structure.

  2. An Alternative String Landscape Cosmology: Eliminating Bizarreness

    E-Print Network [OSTI]

    Clavelli, Louis J.

    An Alternative String Landscape Cosmology: Eliminating Bizarreness L. Clavelli and Gary R landscape models or whether there are scenarios in which it is avoided. If a viable alternative cosmology in mind that the alternative is not ruled out. In addition to being consistent with current observations

  3. Multi-Color Light Curves of Type Ia Supernovae on the Color-Magnitude Diagram: a Novel Step Toward More Precise Distance and Extinction Estimates

    E-Print Network [OSTI]

    Lifan Wang; Gerson Goldhaber; Greg Aldering; Saul Perlmutter

    2003-02-17

    We show empirically that fits to the color-magnitude relation of Type Ia supernovae after optical maximum can provide accurate relative extragalactic distances. We report the discovery of an empirical color relation for Type Ia light curves: During much of the first month past maximum, the magnitudes of Type Ia supernovae defined at a given value of color index have a very small magnitude dispersion; moreover, during this period the relation between $B$ magnitude and $B-V$ color (or $B-R$ or $B-I$ color) is strikingly linear, to the accuracy of existing well-measured data. These linear relations can provide robust distance estimates, in particular, by using the magnitudes when the supernova reaches a given color. After correction for light curve strech factor or decline rate, the dispersion of the magnitudes taken at the intercept of the linear color-magnitude relation are found to be around 0$^m$.08 for the sub-sample of supernovae with \\BVm $\\le 0^m.05$, and around 0$^m$.11 for the sub-sample with \\BVm $\\le 0^m.2$. This small dispersion is consistent with being mostly due to observational errors. The method presented here and the conventional light curve fitting methods can be combined to further improve statistical dispersions of distance estimates. It can be combined with the magnitude at maximum to deduce dust extinction. The slopes of the color-magnitude relation may also be used to identify intrinsically different SN Ia systems. The method provides a tool that is fundamental to using SN Ia to estimate cosmological parameters such as the Hubble constant and the mass and dark energy content of the universe.

  4. Color dispersion and Milky-Way-like reddening among type Ia supernovae

    SciTech Connect (OSTI)

    Scolnic, Daniel M.; Riess, Adam G.; Rodney, Steven A.; Brout, Dillon J.; Jones, David O. [Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States); Foley, Ryan J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Rest, Armin [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)

    2014-01-01

    Past analyses of Type Ia supernovae have identified an irreducible scatter of 5%-10% in distance, widely attributed to an intrinsic dispersion in luminosity. Another equally valid source of this scatter is intrinsic dispersion in color. Misidentification of the true source of this scatter can bias both the retrieved color-luminosity relation and cosmological parameter measurements. The size of this bias depends on the magnitude of the intrinsic color dispersion relative to the distribution of colors that correlate with distance. We produce a realistic simulation of a misattribution of intrinsic scatter and find a negative bias in the recovered color-luminosity relation, ?, of ?? ? –1.0 (?33%) and a positive bias in the equation of state parameter, w, of ?w ? +0.04 (?4%). We re-analyze current published datasets with the assumption that the distance scatter is predominantly the result of color. Unlike previous analyses, we find that the data are consistent with a Milky-Way-like reddening law (R{sub V} = 3.1) and that a Milky-Way dust model better predicts the asymmetric color-luminosity trends than the conventional luminosity scatter hypothesis. We also determine that accounting for color variation reduces the correlation between various host galaxy properties and Hubble residuals by ?20%.

  5. Supermassive population III supernovae and the birth of the first quasars

    SciTech Connect (OSTI)

    Whalen, Daniel J.; Smidt, Joseph [T-2, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Even, Wesley; Fryer, Chris L. [CCS-2, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Heger, Alexander [Monash Centre for Astrophysics, Monash University, Victoria 3800 (Australia); Chen, K.-J. [School of Physics and Astronomy, University of Minnesota, Twin Cities, Minneapolis, MN 55455 (United States); Stiavelli, Massimo [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Xu, Hao [Center for Astrophysics and Space Sciences, UC San Diego, La Jolla, CA 92093 (United States); Joggerst, Candace C. [XTD-3, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2013-11-20

    The existence of supermassive black holes as early as z ? 7 is one of the great, unsolved problems in cosmological structure formation. One leading theory argues that they are born during catastrophic baryon collapse in z ? 15 protogalaxies that form in strong Lyman-Werner UV backgrounds. Atomic line cooling in such galaxies fragments baryons into massive clumps that are thought to directly collapse to 10{sup 4}-10{sup 5} M {sub ?} black holes. We have now discovered that some of these fragments can instead become supermassive stars that eventually explode as thermonuclear supernovae (SNe) with energies of ?10{sup 55} erg, the most energetic explosions in the universe. We have calculated light curves and spectra for supermassive Pop III SNe with the Los Alamos RAGE and SPECTRUM codes. We find that they will be visible in near-infrared all-sky surveys by Euclid out to z ? 10-15 and by WFIRST and WISH out to z ? 15-20, perhaps revealing the birthplaces of the first quasars.

  6. COMPARING THE LIGHT CURVES OF SIMULATED TYPE Ia SUPERNOVAE WITH OBSERVATIONS USING DATA-DRIVEN MODELS

    SciTech Connect (OSTI)

    Diemer, Benedikt; Kessler, Richard; Graziani, Carlo; Jordan, George C. IV; Lamb, Donald Q.; Long, Min; Van Rossum, Daniel R., E-mail: bdiemer@oddjob.uchicago.edu [Flash Center for Computational Science, University of Chicago, Chicago, IL 60637 (United States)

    2013-08-20

    We propose a robust, quantitative method to compare the synthetic light curves of a Type Ia supernova (SN Ia) explosion model with a large set of observed SNe Ia, and derive a figure of merit for the explosion model's agreement with observations. The synthetic light curves are fit with the data-driven model SALT2 which returns values for stretch, color, and magnitude at peak brightness, as well as a goodness-of-fit parameter. Each fit is performed multiple times with different choices of filter bands and epoch range in order to quantify the systematic uncertainty on the fitted parameters. We use a parametric population model for the distribution of observed SN Ia parameters from large surveys, and extend it to represent red, dim, and bright outliers found in a low-redshift SN Ia data set. We discuss the potential uncertainties of this population model and find it to be reliable given the current uncertainties on cosmological parameters. Using our population model, we assign each set of fitted parameters a likelihood of being observed in nature, and a figure of merit based on this likelihood. We define a second figure of merit based on the quality of the light curve fit, and combine the two measures into an overall figure of merit for each explosion model. We compute figures of merit for a variety of one-, two-, and three-dimensional explosion models and show that our evaluation method allows meaningful inferences across a wide range of light curve quality and fitted parameters.

  7. Recovery from population III supernova explosions and the onset of second generation star formation

    E-Print Network [OSTI]

    Jeon, Myoungwon; Bromm, Volker; Milosavljevic, Milos

    2014-01-01

    We use cosmological simulations to assess how the explosion of the first stars in supernovae (SNe) influences early cosmic history. Specifically, we investigate the impact by SNe on the host systems for Population III (Pop III) star formation and explore its dependence on halo environment and Pop III progenitor mass. We then trace the evolution of the enriched gas until conditions are met to trigger second-generation star formation. To this extent, we quantify the recovery timescale, which measures the time delay between a Pop III SN explosion and the appearance of cold, dense gas, out of which second-generation stars can form. We find that this timescale is highly sensitive to the Pop III progenitor mass, and less so to the halo environment. For Pop III progenitor masses M recovery is prompt, ~ 10 Myr. For more massive progenitors, including those exploding in pair instability SNe, second-generation star formation is delayed significantly, for up to a Hubble time. The dependence of the re...

  8. Low-Metallicity Inhibition of Type Ia Supernovae and Galactic and Cosmic Chemical Evolution

    E-Print Network [OSTI]

    Chiaki Kobayashi; Takuji Tsujimoto; Ken'ich Nomoto; Izumi Hachisu; Mariko Kato

    1998-06-25

    We introduce a metallicity dependence of Type Ia supernova (SN Ia) rate into the Galactic and cosmic chemical evolution models. In our SN Ia progenitor scenario, the accreting white dwarf (WD) blows a strong wind to reach the Chandrasekhar mass limit. If the iron abundance of the progenitors is as low as [Fe/H] 1-2, SNe Ia can be found only in the environments where the timescale of metal enrichment is sufficiently short as in starburst galaxies and ellipticals. The low-metallicity inhibition of SNe Ia can shed new light on the following issues: 1) The limited metallicity range of the SN Ia progenitors would imply that ``evolution effects'' are relatively small for the use of high redshift SNe Ia to determine the cosmological parameters. 2) WDs of halo populations are poor producers of SNe Ia, so that the WD contribution to the halo mass is not constrained from the iron abundance in the halo. 3) The abundance patterns of globular clusters and field stars in the Galactic halo lack of SN Ia signatures in spite of their age difference of several Gyrs, which can be explained by the low-metallicity inhibition of SNe Ia. 4) It could also explain why the SN Ia contamination is not seen in the damped Ly\\alpha systems for over a wide range of redshift.

  9. Probing the isotropy of cosmic acceleration traced by Type Ia supernovae

    E-Print Network [OSTI]

    Javanmardi, Behnam; Kroupa, Pavel; Pflamm-Altenburg, Jan

    2015-01-01

    We present a method to test the isotropy of the magnitude-redshift relation of Type Ia Supernovae (SNe Ia) and single out the most discrepant direction (in terms of the signal-to-noise ratio) with respect to the all-sky data. Our technique accounts for possible directional variations of the corrections for SNe Ia and yields all-sky maps of the best-fit cosmological parameters with arbitrary angular resolution. To show its potential, we apply our method to the recent Union2.1 compilation, building maps with three different angular resolutions. We use a Monte Carlo method to estimate the statistical significance with which we could reject the null hypothesis that the magnitude-redshift relation is isotropic based on the properties of the observed most discrepant directions. We find that, based on pure signal-to-noise arguments, the null hypothesis cannot be rejected at any meaningful confidence level. However, if we also consider that the strongest deviations in the Union2.1 sample closely align with the dipole...

  10. Cosmological Hints of Modified Gravity ?

    E-Print Network [OSTI]

    Eleonora Di Valentino; Alessandro Melchiorri; Joseph Silk

    2015-09-24

    The recent measurements of Cosmic Microwave Background temperature and polarization anisotropies made by the Planck satellite have provided impressive confirmation of the $\\Lambda$CDM cosmological model. However interesting hints of slight deviations from $\\Lambda$CDM have been found, including a $95 \\%$ c.l. preference for a "modified gravity" structure formation scenario. In this paper we confirm the preference for a modified gravity scenario from Planck 2015 data, find that modified gravity solves the so-called $A_{lens}$ anomaly in the CMB angular spectrum, and constrains the amplitude of matter density fluctuations to $\\sigma_8=0.815_{-0.048}^{+0.032}$, in better agreement with weak lensing constraints. Moreover, we find a lower value for the reionization optical depth of $\\tau=0.059\\pm0.020$ (to be compared with the value of $\\tau= 0.079 \\pm 0.017$ obtained in the standard scenario), more consistent with recent optical and UV data. We check the stability of this result by considering possible degeneracies with other parameters, including the neutrino effective number, the running of the spectral index and the amount of primordial helium. The indication for modified gravity is still present at about $95\\%$ c.l., and could become more significant if lower values of $\\tau$ were to be further confirmed by future cosmological and astrophysical data.

  11. Statistical Mechanics and Quantum Cosmology

    E-Print Network [OSTI]

    B. L. Hu

    1995-11-29

    Statistical mechanical concepts and processes such as decoherence, correlation, and dissipation can prove to be of basic importance to understanding some fundamental issues of quantum cosmology and theoretical physics such as the choice of initial states, quantum to classical transition and the emergence of time. Here we summarize our effort in 1) constructing a unified theoretical framework using techniques in interacting quantum field theory such as influence functional and coarse-grained effective action to discuss the interplay of noise, fluctuation, dissipation and decoherence; and 2) illustrating how these concepts when applied to quantum cosmology can alter the conventional views on some basic issues. Two questions we address are 1) the validity of minisuperspace truncation, which is usually assumed without proof in most discussions, and 2) the relevance of specific initial conditions, which is the prevailing view of the past decade. We also mention how some current ideas in chaotic dynamics, dissipative collective dynamics and complexity can alter our view of the quantum nature of the universe.

  12. Cosmological Surveys at Submillimetre Wavelengths

    E-Print Network [OSTI]

    David H. Hughes

    2000-03-28

    One of the major goals of observational cosmology is to acquire empirical data that has the diagnostic power to develop the theoretical modelling of the high-redshift universe, ultimately leading to an accurate understanding of the processes by which galaxies and clusters form and subsequently evolve. New bolometer arrays operating on the world's largest submillimetre telescopes now offer a unique view of the high-redshift universe through unbiassed surveys with unprecedented sensitivity. For brevity, except when there is a need to be more specific, the FIR to millimetre wavelength regime (100um 1, and determine their contribution to the submm extragalactic background. The field of observational cosmology will be revolutionized during the course of the next 10 years due to the variety of powerful new ground-based, airborne and satellite facilities, particularly those operating at FIR to millimetre wavelengths. This review summarises the results from the recent blank-field submm surveys, and describes the future observations that will provide accurate source-counts over wider ranges of wavelength and flux-density, constrain the spectral energy distributions of the submm-selected galaxies and accurately constrain the redshift distribution and submm luminosity function by removing the current ambiguities in the optical, IR and radio counterparts.

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

    SciTech Connect (OSTI)

    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.

  14. Sensitivity study of explosive nucleosynthesis in Type Ia supernovae: I. Modification of individual thermonuclear reaction rates

    E-Print Network [OSTI]

    Eduardo Bravo; Gabriel Martínez-Pinedo

    2012-04-09

    We explore the sensitivity of the nucleosynthesis due to type Ia supernovae with respect to uncertainties in nuclear reaction rates. We have adopted a standard one-dimensional delayed detonation model of the explosion of a Chandrasekhar-mass white dwarf, and have post-processed the thermodynamic trajectories of every mass-shell with a nucleosynthetic code, with increases (decreases) by a factor of ten on the rates of 1196 nuclear reactions. We have computed as well hydrodynamic models for different rates of the fusion reactions of 12C and of 16O. For selected reactions, we have recomputed the nucleosynthesis with alternative prescriptions for their rates taken from the JINA REACLIB database, and have analyzed the temperature ranges where modifications of their rates have the strongest effect on nucleosynthesis. The nucleosynthesis resulting from the Type Ia supernova models is quite robust with respect to variations of nuclear reaction rates, with the exception of the reaction of fusion of 12C nuclei. The energy of the explosion changes by less than \\sim4%. The changes in the nucleosynthesis due to the modification of the rates of fusion reactions are as well quite modest, for instance no species with a mass fraction larger than 0.02 experiences a variation of its yield larger than a factor of two. We provide the sensitivity of the yields of the most abundant species with respect to the rates of the most intense reactions with protons, neutrons, and alphas. In general, the yields of Fe-group nuclei are more robust than the yields of intermediate-mass elements. Among the charged particle reactions, the most influential on supernova nucleosynthesis are 30Si + p \\rightleftarrows 31P + {\\gamma}, 20Ne + {\\alpha} \\rightleftarrows 24Mg + {\\gamma}, and 24Mg + {\\alpha} \\rightleftarrows 27Al + p. The temperatures at which a modification of their rate has a larger impact are in the range 2 < T < 4 GK. (abridged)

  15. Type IIb supernova SN 2011dh: Spectra and photometry from the...

    Office of Scientific and Technical Information (OSTI)

    IIb supernova SN 2011dh: Spectra and photometry from the ultraviolet to the near-infrared Citation Details In-Document Search Title: Type IIb supernova SN 2011dh: Spectra and...

  16. NEAR-ULTRAVIOLET PROPERTIES OF A LARGE SAMPLE OF TYPE Ia SUPERNOVAE...

    Office of Scientific and Technical Information (OSTI)

    SUPERNOVAE AS OBSERVED WITH THE Swift UVOT We present ultraviolet (UV) and optical photometry of 26 Type Ia supernovae (SNe Ia) observed from 2005 March to 2008 March with the...

  17. The Diversity of Variations in the Spectra of Type Ia Supernovae 

    E-Print Network [OSTI]

    Wagers, Andrew James

    2012-10-19

    Type Ia supernovae (SNe Ia) are currently the best probe of the expansion history of the universe. Their usefulness is due chiefly to their uniformity between supernovae (SNe). However, there are some slight variations amongst SNe that have yet...

  18. THE YOUNGEST KNOWN X-RAY BINARY: CIRCINUS X-1 AND ITS NATAL SUPERNOVA REMNANT

    E-Print Network [OSTI]

    Heinz, S.

    Because supernova remnants are short-lived, studies of neutron star X-ray binaries within supernova remnants probe the earliest stages in the life of accreting neutron stars. However, such objects are exceedingly rare: ...

  19. Oxygen emission in remnants of thermonuclear supernovae as a probe for their progenitor system

    E-Print Network [OSTI]

    Kosenko, D; Kromer, M; Blinnikov, S I; Pakmor, R; Kaastra, J S

    2014-01-01

    Recent progress in numerical simulations of thermonuclear supernova explosions brings up a unique opportunity in studying the progenitors of Type Ia supernovae. Coupling state-of-the-art explosion models with detailed hydrodynamical simulations of the supernova remnant evolution and the most up-to-date atomic data for X-ray emission calculations makes it possible to create realistic synthetic X-ray spectra for the supernova remnant phase. Comparing such spectra with high quality observations of supernova remnants could allow to constrain the explosion mechanism and the progenitor of the supernova. The present study focuses in particular on the oxygen emission line properties in young supernova remnants, since different explosion scenarios predict a different amount and distribution of this element. Analysis of the soft X-ray spectra from supernova remnants in the Large Magellanic Cloud and confrontation with remnant models for different explosion scenarios suggests that SNR 0509-67.5 could originate from a de...

  20. THE MORPHOLOGY AND DYNAMICS OF JET-DRIVEN SUPERNOVA REMNANTS: THE CASE OF W49B

    E-Print Network [OSTI]

    González-Casanova, Diego F.

    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 ...

  1. 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 Citation Details In-Document Search Title: Systematic Effects in Type-1a Supernovae Surveys from Host...

  2. Stellar feedback efficiencies: supernovae versus stellar winds

    E-Print Network [OSTI]

    Fierlinger, Katharina M; Ntormousi, Evangelia; Fierlinger, Peter; Schartmann, Marc; Ballone, Alessandro; Krause, Martin G H; Diehl, Roland

    2015-01-01

    Stellar winds and supernova (SN) explosions of massive stars ("stellar feedback") create bubbles in the interstellar medium (ISM) and insert newly produced heavy elements and kinetic energy into their surroundings, possibly driving turbulence. Most of this energy is thermalized and immediately removed from the ISM by radiative cooling. The rest is available for driving ISM dynamics. In this work we estimate the amount of feedback energy retained as kinetic energy when the bubble walls have decelerated to the sound speed of the ambient medium. We show that the feedback of the most massive star outweighs the feedback from less massive stars. For a giant molecular cloud (GMC) mass of 1e5 solar masses (as e.g. found in the Orion GMCs) and a star formation efficiency of 8% the initial mass function predicts a most massive star of approximately 60 solar masses. For this stellar evolution model we test the dependence of the retained kinetic energy of the cold GMC gas on the inclusion of stellar winds. In our model w...

  3. Dark Matter Admixed Type Ia Supernovae

    E-Print Network [OSTI]

    Leung, S -C; Lin, L -M

    2015-01-01

    We perform two-dimensional hydrodynamic simulations for the thermonuclear explosion of Chandrasekhar-mass white dwarfs with dark matter (DM) cores in Newtonian gravity. We include a 19-isotope nuclear reaction network and make use of the pure turbulent deflagration model as the explosion mechanism in our simulations. Our numerical results show that the general properties of the explosion depend quite sensitively on the mass of the DM core M$_{{\\rm DM}}$: a larger M$_{{\\rm DM}}$ generally leads to a weaker explosion and a lower mass of synthesized iron-peaked elements. In particular, the total mass of $^{56}$Ni produced can drop from about 0.3 to 0.03 $M_{\\odot}$ as M$_{{\\rm DM}}$ increases from 0.01 to 0.03 $M_{\\odot}$. We have also constructed the bolometric light curves obtained from our simulations and found that our results match well with the observational data of sub-luminous Type-Ia supernovae.

  4. TRANSPARENT HELIUM IN STRIPPED ENVELOPE SUPERNOVAE

    SciTech Connect (OSTI)

    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.

  5. AN ECHO OF SUPERNOVA 2008bk

    SciTech Connect (OSTI)

    Van Dyk, Schuyler D., E-mail: vandyk@ipac.caltech.edu [Spitzer Science Center/Caltech, Mailcode 220-6, Pasadena, CA 91125 (United States)

    2013-08-01

    I have discovered a prominent light echo around the low-luminosity Type II-plateau supernova (SN) 2008bk in NGC 7793, seen in archival images obtained with the Wide Field Channel of the Advanced Camera for Surveys on board the Hubble Space Telescope (HST). The echo is a partial ring, brighter to the north and east than to the south and west. The analysis of the echo I present suggests that it is due to the SN light pulse scattered by a sheet, or sheets, of dust located Almost-Equal-To 15 pc from the SN. The composition of the dust is assumed to be of standard Galactic diffuse interstellar grains. The visual extinction of the dust responsible for the echo is A{sub V} Almost-Equal-To 0.05 mag in addition to the extinction due to the Galactic foreground toward the host galaxy. That the SN experienced much less overall extinction implies that it is seen through a less dense portion of the interstellar medium in its environment. The late-time HST photometry of SN 2008bk also clearly demonstrates that the progenitor star has vanished.

  6. Neutronization During Type Ia Supernova Simmering

    E-Print Network [OSTI]

    Piro, Anthony L

    2007-01-01

    Prior to the incineration of a white dwarf (WD) that makes a Type Ia supernova (SN Ia), the star "simmers" for ~1000 years in a convecting, carbon burning region. We have found that weak interactions during this time increase the neutron excess by an amount that depends on the total quantity of carbon burned prior to the explosion. This contribution is in addition to the metallicity (Z) dependent neutronization through the 22Ne abundance (as studied by Timmes, Brown, & Truran). The main consequence is that we expect a floor to the level of neutronization that dominates over the metallicity contribution when Z/Z_\\odot<2/3, and it can be important for even larger metallicities if substantial energy is lost to neutrinos via the convective Urca process. This would mask any correlations between SN Ia properties and galactic environments at low metallicities. In addition, we show that recent observations of the dependences of SNe Ia on galactic environments make it clear that metallicity alone cannot provide...

  7. Neutronization During Type Ia Supernova Simmering

    E-Print Network [OSTI]

    Anthony L. Piro; Lars Bildsten

    2007-10-08

    Prior to the incineration of a white dwarf (WD) that makes a Type Ia supernova (SN Ia), the star "simmers" for ~1000 years in a convecting, carbon burning region. We have found that weak interactions during this time increase the neutron excess by an amount that depends on the total quantity of carbon burned prior to the explosion. This contribution is in addition to the metallicity (Z) dependent neutronization through the 22Ne abundance (as studied by Timmes, Brown, & Truran). The main consequence is that we expect a floor to the level of neutronization that dominates over the metallicity contribution when Z/Z_\\odot<2/3, and it can be important for even larger metallicities if substantial energy is lost to neutrinos via the convective Urca process. This would mask any correlations between SN Ia properties and galactic environments at low metallicities. In addition, we show that recent observations of the dependences of SNe Ia on galactic environments make it clear that metallicity alone cannot provide for the full observed diversity of events.

  8. Dark matter ignition of type Ia supernovae

    E-Print Network [OSTI]

    Bramante, Joseph

    2015-01-01

    Recent studies of low redshift type Ia supernovae (SNIa) indicate that half explode from less than Chandrasekhar mass white dwarfs, implying ignition must proceed from something besides the canonical criticality of Chandrasekhar mass SNIa progenitors. We show that $0.1-10$ PeV mass asymmetric dark matter, with imminently detectable nucleon scattering interactions, can accumulate to the point of self-gravitation in a white dwarf and collapse, shedding gravitational potential energy by scattering off nuclei, thereby heating the white dwarf and igniting the flame front that precedes SNIa. We combine data on SNIa masses with data on the ages of SNIa-adjacent stars. This combination reveals a $ 3 \\sigma$ inverse correlation between SNIa masses and ignition ages, which could result from increased capture of dark matter in 1.4 versus 1.1 solar mass white dwarfs. Future studies of SNIa in galactic centers will provide additional tests of dark-matter-induced type Ia ignition. Remarkably, both bosonic and fermionic SNI...

  9. Alfven Wave-Driven Supernova Explosion

    E-Print Network [OSTI]

    T. K. Suzuki; K. Sumiyoshi; S. Yamada

    2007-12-06

    We investigate the role of Alfven waves in the core-collapse supernova (SN) explosion. We assume that Alfven waves are generated by convections inside a proto-neutron star (PNS) and emitted from its surface. Then these waves propagate outwards, dissipate via nonlinear processes, and heat up matter around a stalled prompt shock. To quantitatively assess the importance of this process for the revival of the stalled shock, we perform 1D time-dependent hydrodynamical simulations, taking into account the heating via the dissipation of Alfven waves that propagate radially outwards along open flux tubes. We show that the shock revival occurs if the surface field strength is larger than ~2e15 G and if the amplitude of velocity fluctuation at the PNS surface is larger than 20% of the local sound speed. Interestingly, the Alfven wave mechanism is self-regulating in the sense that the explosion energy is not very sensitive to the surface field strength and initial amplitude of Alfven waves as long as they are larger than the threshold values given above.

  10. Contrasting formulations of cosmological perturbations in a magnetic FLRW cosmology

    E-Print Network [OSTI]

    Hector J. Hortua; Leonardo Castañeda

    2015-11-19

    In this paper we contrasted two cosmological perturbation theory formalisms, the 1+3 covariant gauge invariant and the gauge invariant by comparing their gauge invariant variables associated with magnetic field defined in each approach. In the first part we give an introduction to each formalism assuming the presence of a magnetic field. We found that gauge invariant quantities defined by 1+3 covariant approach are related with spatial variations of the magnetic field (defined in the gauge invariant formalism) between two closed fundamental observers. This relation was computed by choosing the comoving gauge in the gauge invariant approach in a magnetized universe. Furthermore, we have derived the gauge transformations for electromagnetic potentials in the gauge invariant approach and the Maxwell's equations have been written in terms of these potentials.

  11. Loop quantum cosmology and the fate of cosmological singularities

    E-Print Network [OSTI]

    Singh, Parampreet

    2015-01-01

    Singularities in general relativity such as the big bang and big crunch, and exotic singularities such as the big rip are the boundaries of the classical spacetimes. These events are marked by a divergence in the curvature invariants and the breakdown of the geodesic evolution. Recent progress on implementing techniques of loop quantum gravity to cosmological models reveals that such singularities may be generically resolved because of the quantum gravitational effects. Due to the quantum geometry, which replaces the classical differential geometry at the Planck scale, the big bang is replaced by a big bounce without any assumptions on the matter content or any fine tuning. In this manuscript, we discuss some of the main features of this approach and the results on the generic resolution of singularities for the isotropic as well as anisotropic models. Using effective spacetime description of the quantum theory, we show the way quantum gravitational effects lead to the universal bounds on the energy density, ...

  12. Constraints on Type IIn Supernova Progenitor Outbursts from the Lick Observatory Supernova Search

    E-Print Network [OSTI]

    Bilinski, Christopher; Li, Weidong; Williams, G Grant; Zheng, WeiKang; Filippenko, Alexei V

    2015-01-01

    We searched through roughly 12 years of archival survey data acquired by the Katzman Automatic Imaging Telescope (KAIT) as part of the Lick Observatory Supernova Search (LOSS) in order to detect or place limits on possible progenitor outbursts of Type IIn supernovae (SNe~IIn). The KAIT database contains multiple pre-SN images for 5 SNe~IIn (plus one ambiguous case of a SN IIn/imposter) within 50 Mpc. No progenitor outbursts are found using the false discovery rate (FDR) statistical method in any of our targets. Instead, we derive limiting magnitudes (LMs) at the locations of the SNe. These limiting magnitudes (typically reaching $m_R \\approx 19.5\\,\\mathrm{mag}$) are compared to outbursts of SN 2009ip and $\\eta$ Car, plus additional simulated outbursts. We find that the data for SN 1999el and SN 2003dv are of sufficient quality to rule out events $\\sim40$ days before the main peak caused by initially faint SNe from blue supergiant (BSG) precursor stars, as in the cases of SN 2009ip and SN 2010mc. These SNe~IIn...

  13. The effect of weak lensing on distance estimates from supernovae

    SciTech Connect (OSTI)

    Smith, Mathew; Maartens, Roy [Department of Physics, University of the Western Cape, Cape Town 7535 (South Africa); Bacon, David J.; Nichol, Robert C.; Campbell, Heather; D'Andrea, Chris B. [Institute of Cosmology and Gravitation, University of Portsmouth, Portsmouth, PO1 3FX (United Kingdom); Clarkson, Chris [Astrophysics, Cosmology and Gravity Centre (ACGC), Department of Mathematics and Applied Mathematics, University of Cape Town, Rondebosch 7701 (South Africa); Bassett, Bruce A. [South African Astronomical Observatory, P.O. Box 9, Observatory 7935 (South Africa); Cinabro, David [Wayne State University, Department of Physics and Astronomy, Detroit, MI 48202 (United States); Finley, David A.; Frieman, Joshua A. [Center for Particle Astrophysics, Fermi National Accelerator Laboratory, P.O. Box 500, Batavia, IL 60510 (United States); Galbany, Lluis [CENTRA Centro Multidisciplinar de Astrofísica, Instituto Superior Técnico, Av. Rovisco Pais 1, 1049-001 Lisbon (Portugal); Garnavich, Peter M. [Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Olmstead, Matthew D. [Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112 (United States); Schneider, Donald P. [Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802 (United States); Shapiro, Charles [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, La Canada Flintridge, CA 91109 (United States); Sollerman, Jesper, E-mail: matsmith2@gmail.com [The Oskar Klein Centre, Department of Astronomy, AlbaNova, SE-106 91 Stockholm (Sweden)

    2014-01-01

    Using a sample of 608 Type Ia supernovae from the SDSS-II and BOSS surveys, combined with a sample of foreground galaxies from SDSS-II, we estimate the weak lensing convergence for each supernova line of sight. We find that the correlation between this measurement and the Hubble residuals is consistent with the prediction from lensing (at a significance of 1.7?). Strong correlations are also found between the residuals and supernova nuisance parameters after a linear correction is applied. When these other correlations are taken into account, the lensing signal is detected at 1.4?. We show, for the first time, that distance estimates from supernovae can be improved when lensing is incorporated, by including a new parameter in the SALT2 methodology for determining distance moduli. The recovered value of the new parameter is consistent with the lensing prediction. Using cosmic microwave background data from WMAP7, H {sub 0} data from Hubble Space Telescope and Sloan Digital Sky Survey (SDSS) Baryon acoustic oscillations measurements, we find the best-fit value of the new lensing parameter and show that the central values and uncertainties on ? {sub m} and w are unaffected. The lensing of supernovae, while only seen at marginal significance in this low-redshift sample, will be of vital importance for the next generation of surveys, such as DES and LSST, which will be systematics-dominated.

  14. Simulations of stripped core-collapse supernovae in close binaries

    E-Print Network [OSTI]

    Rimoldi, Alex; Rossi, Elena Maria

    2015-01-01

    We perform smoothed-particle hydrodynamical simulations of the explosion of a helium star in a close binary system, and study the effects of the explosion on the companion star as well as the effect of the presence of the companion on the supernova remnant. By simulating the mechanism of the supernova from just after core bounce until the remnant shell passes the stellar companion, we are able to separate the various effects leading to the final system parameters. In the final system, we measure the mass stripping and ablation from, and the velocity kick imparted to, the companion star, as well as the structure of the supernova shell. The presence of the companion star produces a conical cavity in the expanding supernova remnant, and loss of material from the companion causes the supernova remnant to be more metal-rich on one side and more hydrogen-rich (from the companion material) around the cavity. Following the removal of mass from the companion, we study its subsequent evolution and compare it with a sin...

  15. On the nature of rapidly fading Type II supernovae

    E-Print Network [OSTI]

    Moriya, Takashi J; Ergon, Mattias; Blinnikov, Sergei I

    2015-01-01

    It has been suggested that Type II supernovae with rapidly fading light curves (a.k.a. Type IIL supernovae) are explosions of progenitors with low-mass hydrogen-rich envelopes which are of the order of 1 Msun. We investigate light-curve properties of supernovae from such progenitors. We confirm that such progenitors lead to rapidly fading Type II supernovae. We find that the luminosity of supernovae from such progenitors with the canonical explosion energy of 1e51 erg and 56Ni mass of 0.05 Msun can increase temporarily shortly before all the hydrogen in the envelope recombines. As a result, a bump appears in their light curves. The bump appears because the heating from the nuclear decay of 56Ni can keep the bottom of hydrogen-rich layers in the ejecta ionized, and thus the photosphere can stay there for a while. We find that the light-curve bump becomes less significant when we make explosion energy larger (>~ 2e51 erg), 56Ni mass smaller (<~ 0.01 Msun), 56Ni mixed in the ejecta, or the progenitor radius l...

  16. Simulations of Turbulent Thermonuclear Burning in Type Ia Supernovae

    E-Print Network [OSTI]

    W. Hillebrandt; M. Reinecke; W. Schmidt; F. K. Roepke; C. Travaglio; J. C. Niemeyer

    2004-05-11

    Type Ia supernovae have recently received considerable attention because it appears that they can be used as "standard candles" to measure cosmic distances out to billions of light years away from us. Observations of type Ia supernovae seem to indicate that we are living in a universe that started to accelerate its expansion when it was about half its present age. These conclusions rest primarily on phenomenological models which, however, lack proper theoretical understanding, mainly because the explosion process, initiated by thermonuclear fusion of carbon and oxygen into heavier elements, is difficult to simulate even on supercomputers. Here, we investigate a new way of modeling turbulent thermonuclear deflagration fronts in white dwarfs undergoing a type Ia supernova explosion. Our approach is based on a level set method which treats the front as a mathematical discontinuity and allows for full coupling between the front geometry and the flow field. New results of the method applied to the problem of type Ia supernovae are obtained. It is shown that in 2-D with high spatial resolution and a physically motivated subgrid scale model for the nuclear flames numerically "converged" results can be obtained, but for most initial conditions the stars do not explode. In contrast, simulations in 3-D, do give the desired explosions and many of their properties, such as the explosion energies, lightcurves and nucleosynthesis products, are in very good agreement with observed type Ia supernovae.

  17. Exploring the Neutrino Mass Hierarchy Probability with Meteoritic Supernova Material, ?-Process Nucleosynthesis, and ?13 Mixing

    E-Print Network [OSTI]

    G. J. Mathews; T. Kajino; W. Aoki; W. Fujiya; J. B. Pitts

    2012-04-17

    There is recent evidence that some SiC X grains from the Murchison meteorite may contain supernova-produced {\

  18. Stochastic cosmology, theories of perturbations and Lifshitz gravity

    E-Print Network [OSTI]

    Khalatnikov, I M

    2015-01-01

    We review some works of E M Lifshitz connected with gravity and cosmology and also some later works, connected with his ideas. The main topics of this review are the stochastic cosmology of an anisotropic universe and of an isotropic universe with the scalar field, the quasi-isotropic (gradient) expansion in cosmology and Horava-Lifshitz gravity and cosmology.

  19. Improved Cosmological Parameter Constraints from CMB and H(z) Data

    E-Print Network [OSTI]

    Daniel G. Figueroa; Licia Verde; Raul Jimenez

    2008-10-27

    We discuss the cosmological degeneracy between the Hubble parameter H(z), the age of the universe and cosmological parameters describing simple variations from the minimal LCDM model. We show that independent determinations of the Hubble parameter H(z) such as those recently provided by Simon et al., Phys. Rev. D 71 (2005) 123001, combined with Cosmic Microwave Background data, can provide stringent constraints on possible deviations from the LCDM model. In particular we find that this data combination constrains at the 68% (95%) confidence level the following parameters: sum of the neutrino masses < 0.5 (1.0) eV, number of relativistic neutrino species N_rel = 4.1^{+0.4}_{-0.9} (^{+1.1}_{-1.5}), dark energy equation of state parameter w = -0.95 +- 0.17 (+- 0.32), and curvature \\Omega_k = 0.002 +- 0.006 (+- 0.014), in excellent agreement with dataset combinations involving Cosmic Microwave Background, Supernovae and Baryon Acoustic Oscillations. This offers a valuable consistency check for systematic errors.

  20. Curvature pressure in a cosmology with a tired-light redshift

    E-Print Network [OSTI]

    David F. Crawford

    1999-09-06

    A hypothesis of curvature pressure is used to derive a static and stable cosmology with a tired-light redshift. The idea is that the high energy particles in the inter-galactic medium do not travel along geodesics because of the strong electrostatic forces. The result is a reaction back on the medium that is seen as an additional pressure. Combined with the explanation of the Hubble redshift as a gravitational interaction results in a static and stable cosmology. The predicted Hubble constant is 60.2 km/s/Mpc, the predicted background microwave temperature is 3 degrees and quasar luminosity functions and angular size distributions are shown to be consistent with the model. Since most observations that imply dark matter rely on redshift data it is argued that there is no dark matter. Observations of quasar absorption lines, supernovae light curves and the Butcher-Oemler effect are discussed. The curvature pressure is important for stellar structure and may explain the solar neutrino deficiency.

  1. Horava Gravity in the Effective Field Theory formalism: from cosmology to observational constraints

    E-Print Network [OSTI]

    Frusciante, Noemi; Vernieri, Daniele; Hu, Bin; Silvestri, Alessandra

    2015-01-01

    We consider Horava gravity within the framework of the EFT of dark energy and modified gravity. We work out a complete mapping of the theory into the EFT language for an action including all the operators which are relevant for linear perturbations with up to sixth order spatial derivatives. We then employ an updated version of the EFTCAMB/EFTCosmoMC package to study the cosmology of the low-energy limit of Horava gravity and place constraints on its parameters using several cosmological data sets. In particular we consider two cases: the first in which the three parameters of the low-energy theory are all varied and a second case that is tuned to evade PPN constraints, reducing the number of free parameters to two. We employ data sets which include the CMB TT and lensing power spectra by Planck 2013, WMAP low-l polarization spectra, the WiggleZ galaxy power spectrum, the local Hubble measurements, Supernovae data from SNLS, SDSS and HST and the BAO measurements from BOSS, SDSS and 6dFGS. For both cases we es...

  2. Bolometric Light Curves of Type Ia Supernovae G. Contardo 1;2 , B. Leibundgut 1

    E-Print Network [OSTI]

    Leibundgut, Bruno

    Bolometric Light Curves of Type Ia Supernovae G. Contardo 1;2 , B. Leibundgut 1 1 European Southern, Karl­Schwarzschild­Straße 1, D­85748 Garch­ ing, Germany 1.1 Light Curves of Type Ia Supernovae Substantial information about the processes in supernovae is contained in their light curves. They track

  3. Nucleosynthesis Supernova Explosions Final Stages of Stellar Evolution For Take Away Final Stages of Stellar Evolution

    E-Print Network [OSTI]

    Hörandel, Jörg R.

    Nucleosynthesis Supernova Explosions Final Stages of Stellar Evolution For Take Away Final Stages.XII.2006 Seminar on Astroparticle Physics - Cosmic Rays #12;Nucleosynthesis Supernova Explosions Final are supernova explosions and which different types exist? Where do heavy elements come from? #12;Nucleosynthesis

  4. Primordial Magnetic Fields in Cosmology

    E-Print Network [OSTI]

    Iain A. Brown

    2008-12-09

    Magnetic fields have been observed in galaxies, clusters of galaxies and probably in superclusters. While mechanisms exist to generate these in the late universe, it is possible that magnetic fields have existed since very early times. This thesis is concerned with methods to predict the form of such imprints. We review in detail a standard, linearised cosmology before introducing an electromagnetic field. We then consider the intrinsic statistics of the magnetic stresses in two ways, analytically and via static realisations. We construct the power spectra, some of which we present for the first time. At the one- and three-point level we find significant intrinsic non-Gaussianities. Finally we turn to the observable impacts a primordial magnetic field. Assuming coherence, the statistics of the source can be mapped onto the CMB in a simple manner. We demonstrate that our approach is valid by reproducing the signals for Gaussian power law fields on the microwave sky. [ABRIDGED

  5. Neutrino mass in cosmology: status and prospects

    E-Print Network [OSTI]

    Yvonne Y. Y. Wong

    2011-11-06

    I give an overview of the effects of neutrino masses in cosmology, focussing on the role they play in the evolution of cosmological perturbations. I discuss how recent observations of the cosmic microwave background anisotropies and the large-scale matter distribution can probe neutrino masses with greater precision than current laboratory experiments. I describe several new techniques that will be used to probe cosmology in the future, as well as recent advances in the computation of the nonlinear matter power spectrum and related observables.

  6. ESC Supernova spectroscopy of non-ESC targets

    E-Print Network [OSTI]

    A. H. Harutyunyan; P. Pfahler; A. Pastorello; S. Taubenberger; M. Turatto; E. Cappellaro; S. Benetti; N. Elias-Rosa; H. Navasardyan; S. Valenti; V. Stanishev; F. Patat; M. Riello; G. Pignata; W. Hillebrandt

    2008-04-11

    We present the spectra of 36 Supernovae (SNe) of various types, obtained by the European Supernova Collaboration. Because of the spectral classification and the phase determination at their discovery the SNe did not warrant further study, and the spectra we present are the only available for the respective objects. In this paper we present and discuss this material using a new software for the automated classification of SNe spectra. As a validation of the software, we verify the classification and phase estimate reported for these objects in their discovery / classification circulars. For the comparison, the software uses the library of template spectra of Padova-Asiago Supernova Archive (ASA). For each spectrum of our sample we present a brief, individual discussion, highlighting the main characteristics and possible peculiarities. The comparison with ASA spectra confirms the previous classification of all objects and refines the age estimates. For our software we determine numerical limits of "safe" spectral classification and the uncertainties of the phase determination.

  7. Pair Instability Supernovae of Very Massive Population III Stars

    E-Print Network [OSTI]

    Chen, Ke-Jung; Woosley, Stan; Almgren, Ann; Whalen, Daniel

    2014-01-01

    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 Msun 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 collapse, to capture any dynamical instabilities that may be seeded by collapse 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 ari...

  8. Neutrinos and the Supernova Origin of the Elements

    E-Print Network [OSTI]

    Yong-Zhong Qian

    2000-08-30

    Intense fluxes of neutrinos are emitted by the hot neutron star produced in a supernova. The electron neutrino and antineutrino capture reactions on neutrons and protons, respectively, provide heating to drive a wind from the hot neutron star. The same reactions also determine the neutron-richness of the wind material. Nucleosynthesis via rapid neutron capture, the r-process, may occur in the wind material as it expands away from the neutron star. The neutron-richness of the wind material, and hence, the r-process nucleosynthesis therein, are sensitive to mixing between the muon (or tauon) neutrino/antineutrino and the electron (or sterile) neutrino/antineutrino. Indirect arguments and direct tests for the supernova origin of the r-process elements are discussed with a goal to establish supernova r-process nucleosynthesis as an important probe for neutrino mixing.

  9. ASASSN-15lh: The Most Luminous Supernova Ever Discovered

    E-Print Network [OSTI]

    Dong, Subo; Prieto, J L; Jha, S W; Stanek, K Z; Holoien, T W -S; Kochanek, C S; Thompson, T A; Morrell, N; Thompson, I B; Basu, U; Beacom, J F; Bersier, D; Brimacombe, J; Brown, J S; Chen, Ping; Conseil, E; Danilet, A B; Falco, E; Grupe, D; Kiyota, S; Masi, G; Nicholls, B; Olivares, F; Pignata, G; Pojmanski, G; Simonian, G V; Szczygiel, D M; Wozniak, P R

    2015-01-01

    We report the discovery and early evolution of ASASSN-15lh, the most luminous supernova ever found. At redshift z=0.2326, ASASSN-15lh reached an absolute magnitude of M_{u,AB} ~ -23.5 and bolometric luminosity L_bol ~ 2.2x10^45 ergs/s, which is >~ 2 times more luminous than any previously known supernova. Its spectra match the hydrogen-poor sub-class of super-luminous supernovae (SLSNe-I), whose energy sources and progenitors are poorly understood. In contrast to known SLSNe-I, most of which reside in star-forming, dwarf galaxies, its host appears to be a luminous galaxy (M_V ~ -22; M_K ~ -25.1) with little star formation. In the two months since its first detection, ASASSN-15lh has radiated ~7.5x10^51 ergs, challenging the popular magnetar model for the engine of SLSNe-I.

  10. Neutrinos and nucleosynthesis in core-collapse supernovae

    SciTech Connect (OSTI)

    Fröhlich, C.; Casanova, J. [Department of Physics, North Carolina State University, Raleigh, NC, 27695 (United States); Hempel, M.; Liebendörfer, M. [Departement für Physik, Universität Basel, CH-4056 Basel (Switzerland); Melton, C. A. [Department of Physics, North Carolina State University, Raleigh, NC 27695 (United States); Perego, A. [Institut für Kernphysik, Technische Universität Darmstadt, D-64289 Darmstadt (Germany)

    2014-01-01

    Massive stars (M > 8-10 M{sub ?}) undergo core collapse at the end of their life and explode as supernova with ~ 10?¹ erg of kinetic energy. While the detailed supernova explosion mechanism is still under investigation, reliable nucleosynthesis calculations based on successful explosions are needed to explain the observed abundances in metal-poor stars and to predict supernova yields for galactic chemical evolution studies. To predict nucleosynthesis yields for a large number of progenitor stars, computationally efficient explosion models are required. We model the core collapse, bounce and subsequent explosion of massive stars assuming spherical symmetry and using detailed microphysics and neutrino physics combined with a novel method to artificially trigger the explosion (PUSH). We discuss the role of neutrinos, the conditions in the ejecta, and the resulting nucleosynthesis.

  11. Optical and NIR observations of the nearby type Ia supernova SN 2014J

    E-Print Network [OSTI]

    Srivastav, Shubham; Kumar, Brajesh; Anupama, G C; Sahu, D K; Ojha, D K; Prabhu, T P

    2016-01-01

    Optical and NIR observations of the type Ia supernova SN 2014J in M82 are presented. The observed light curves are found to be similar to normal SNe Ia, with a decline rate parameter $\\Delta m_{15}(B) = 1.08 \\pm 0.03$. The supernova reached $B$-band maximum on JD 2456690.14, at an apparent magnitude $m_B(max) = 11.94$. The optical spectra show a red continuum with deep interstellar Na~{\\sc i} absorption, but otherwise resemble those of normal SNe Ia. The Si~{\\sc ii} $\\lambda 6355$ feature indicates a velocity of $\\sim 12\\,000$ km s$^{-1}$ at $B$-band maximum, which places SN 2014J at the border of the Normal Velocity and High Velocity group of SNe Ia. The velocity evolution of SN 2014J places it in the Low Velocity Gradient subclass, whereas the equivalent widths of Si~{\\sc ii} features near $B$-band maximum place it at the border of the Core Normal and Broad Line subclasses of SNe Ia. An analytic model fit to the bolometric light curve indicates that a total of $\\sim 1.3$ M$_{\\odot}$ was ejected in the explo...

  12. Type Ia Supernovae and the Hubble Constant

    E-Print Network [OSTI]

    D. Branch

    1998-01-08

    The focus of this review is the work that has been done during the 1990s on using Type Ia supernovae (SNe Ia) to measure the Hubble constant ($H_0$). SNe Ia are well suited for measuring $H_0$. A straightforward maximum-light color criterion can weed out the minority of observed events that are either intrinsically subluminous or substantially extinguished by dust, leaving a majority subsample that has observational absolute-magnitude dispersions of less than $\\sigma_{obs}(M_B) \\simeq \\sigma_{obs}(M_V) \\simeq 0.3$ mag. Correlations between absolute magnitude and one or more distance-independent SN Ia or parent-galaxy observables can be used to further standardize the absolute magnitudes to better than 0.2 mag. The absolute magnitudes can be calibrated in two independent ways --- empirically, using Cepheid-based distances to parent galaxies of SNe Ia, and physically, by light curve and spectrum fitting. At present the empirical and physical calibrations are in agreement at $M_B \\simeq M_V \\simeq -19.4$ or -19.5. Various ways that have been used to match Cepheid-calibrated SNe Ia or physical models to SNe Ia that have been observed out in the Hubble flow have given values of $H_0$ distributed throughout the range 54 to 67 km/s Mpc$^{-1}$. Astronomers who want a consensus value of $H_0$ from SNe Ia with conservative errors could, for now, use $60 \\pm 10$ km/s Mpc^{-1}$.

  13. Cosmology and fundamental physics with the Euclid satellite

    E-Print Network [OSTI]

    Luca Amendola; Stephen Appleby; David Bacon; Tessa Baker; Marco Baldi; Nicola Bartolo; Alain Blanchard; Camille Bonvin; Stefano Borgani; Enzo Branchini; Clare Burrage; Stefano Camera; Carmelita Carbone; Luciano Casarini; Mark Cropper; Claudia deRham; Cinzia di Porto; Anne Ealet; Pedro G. Ferreira; Fabio Finelli; Juan Garcia-Bellido; Tommaso Giannantonio; Luigi Guzzo; Alan Heavens; Lavinia Heisenberg; Catherine Heymans; Henk Hoekstra; Lukas Hollenstein; Rory Holmes; Ole Horst; Knud Jahnke; Thomas D. Kitching; Tomi Koivisto; Martin Kunz; Giuseppe La Vacca; Marisa March; Elisabetta Majerotto; Katarina Markovic; David Marsh; Federico Marulli; Richard Massey; Yannick Mellier; David F. Mota; Nelson Nunes; Will Percival; Valeria Pettorino; Cristiano Porciani; Claudia Quercellini; Justin Read; Massimiliano Rinaldi; Domenico Sapone; Roberto Scaramella; Constantinos Skordis; Fergus Simpson; Andy Taylor; Shaun Thomas; Roberto Trotta; Licia Verde; Filippo Vernizzi; Adrian Vollmer; Yun Wang; Jochen Weller; Tom Zlosnik

    2015-10-22

    Euclid is a European Space Agency medium class mission selected for launch in 2019 within the Cosmic Vision 2015-2025 programme. The main goal of Euclid is to understand the origin of the accelerated expansion of the Universe. Euclid will explore the expansion history of the Universe and the evolution of cosmic structures by measuring shapes and redshifts of galaxies as well as the distribution of clusters of galaxies over a large fraction of the sky. Although the main driver for Euclid is the nature of dark energy, Euclid science covers a vast range of topics, from cosmology to galaxy evolution to planetary research. In this review we focus on cosmology and fundamental physics, with a strong emphasis on science beyond the current standard models. We discuss five broad topics: dark energy and modified gravity, dark matter, initial conditions, basic assumptions and questions of methodology in the data analysis. This review has been planned and carried out within Euclid's Theory Working Group and is meant to provide a guide to the scientific themes that will underlie the activity of the group during the preparation of the Euclid mission.

  14. Cosmology and fundamental physics with the Euclid satellite

    E-Print Network [OSTI]

    Luca Amendola; Stephen Appleby; David Bacon; Tessa Baker; Marco Baldi; Nicola Bartolo; Alain Blanchard; Camille Bonvin; Stefano Borgani; Enzo Branchini; Clare Burrage; Stefano Camera; Carmelita Carbone; Luciano Casarini; Mark Cropper; Claudia deRham; Cinzia di Porto; Anne Ealet; Pedro G. Ferreira; Fabio Finelli; Juan Garcia-Bellido; Tommaso Giannantonio; Luigi Guzzo; Alan Heavens; Lavinia Heisenberg; Catherine Heymans; Henk Hoekstra; Lukas Hollenstein; Rory Holmes; Ole Horst; Knud Jahnke; Thomas D. Kitching; Tomi Koivisto; Martin Kunz; Giuseppe La Vacca; Marisa March; Elisabetta Majerotto; Katarina Markovic; David Marsh; Federico Marulli; Richard Massey; Yannick Mellier; David F. Mota; Nelson Nunes; Will Percival; Valeria Pettorino; Cristiano Porciani; Claudia Quercellini; Justin Read; Massimiliano Rinaldi; Domenico Sapone; Roberto Scaramella; Constantinos Skordis; Fergus Simpson; Andy Taylor; Shaun Thomas; Roberto Trotta; Licia Verde; Filippo Vernizzi; Adrian Vollmer; Yun Wang; Jochen Weller; Tom Zlosnik

    2012-06-06

    Euclid is a European Space Agency medium class mission selected for launch in 2019 within the Cosmic Vision 2015-2025 programme. The main goal of Euclid is to understand the origin of the accelerated expansion of the Universe. Euclid will explore the expansion history of the Universe and the evolution of cosmic structures by measuring shapes and redshifts of galaxies as well as the distribution of clusters of galaxies over a large fraction of the sky. Although the main driver for Euclid is the nature of dark energy, Euclid science covers a vast range of topics, from cosmology to galaxy evolution to planetary research. In this review we focus on cosmology and fundamental physics, with a strong emphasis on science beyond the current standard models. We discuss five broad topics: dark energy and modified gravity, dark matter, initial conditions, basic assumptions and questions of methodology in the data analysis. This review has been planned and carried out within Euclid's Theory Working Group and is meant to provide a guide to the scientific themes that will underlie the activity of the group during the preparation of the Euclid mission.

  15. Supernova progenitor constraints from circumstellar interaction: Type II

    E-Print Network [OSTI]

    Robert J. Cumming; Peter Lundqvist

    1996-10-03

    All types of supernovae (SNe), except Type Ia, have been observed to interact with their immediate circumstellar medium (CSM). This interaction can reveal their progenitor's histories, and constrain our ideas about the evolution of massive stars. As examples of the latest progress in this areas, we present some new results on two SNe: a 3D picture of the triple-ring nebula around SN 1987A, and observations of the less well-known but rather intriguing SN 1994W. In the process we introduce Type IIn supernovae (SN IIn; Schlegel 1990) as an important new probe of massive star evolution.

  16. Fake conformal symmetry in conformal cosmological models

    E-Print Network [OSTI]

    Pi, So-Young

    We examine the local conformal invariance (Weyl invariance) in tensor-scalar theories used in recently proposed conformal cosmological models. We show that the Noether currents associated with Weyl invariance in these ...

  17. An Issue to the Cosmological Constant Problem

    E-Print Network [OSTI]

    R. Triay

    2005-04-07

    According to general relativity, the present analysis shows on geometrical grounds that the cosmological constant problem is an artifact due to the unfounded link of this fundamental constant to vacuum energy density of quantum fluctuations.

  18. Cosmology of hidden sector with Higgs portal

    E-Print Network [OSTI]

    Cabi, Serkan

    2009-01-01

    In this thesis, we are investigating cosmological implications of hidden sector models which involve scalar fields that do not interact with the Standard Model gauge interactions, but couple directly to the Higgs field. ...

  19. Primordial nucleosynthesis: A cosmological point of view

    SciTech Connect (OSTI)

    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.

  20. Dimensionless constants, cosmology and other dark matters

    E-Print Network [OSTI]

    Max Tegmark; Anthony Aguirre; Martin J Rees; Frank Wilczek

    2006-01-11

    We identify 31 dimensionless physical constants required by particle physics and cosmology, and emphasize that both microphysical constraints and selection effects might help elucidate their origin. Axion cosmology provides an instructive example, in which these two kinds of arguments must both be taken into account, and work well together. If a Peccei-Quinn phase transition occurred before or during inflation, then the axion dark matter density will vary from place to place with a probability distribution. By calculating the net dark matter halo formation rate as a function of all four relevant cosmological parameters and assessing other constraints, we find that this probability distribution, computed at stable solar systems, is arguably peaked near the observed dark matter density. If cosmologically relevant WIMP dark matter is discovered, then one naturally expects comparable densities of WIMPs and axions, making it important to follow up with precision measurements to determine whether WIMPs account for all of the dark matter or merely part of it.

  1. Cosmology on the Beach: Kendrick Smith

    ScienceCinema (OSTI)

    George Smoot

    2010-01-08

    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. Nonsingular cosmology from evolutionary quantum gravity

    E-Print Network [OSTI]

    Francesco Cianfrani; Giovanni Montani; Fabrizio Pittorino

    2014-10-30

    We provide a cosmological implementation of the evolutionary quantum gravity, describing an isotropic Universe, in the presence of a negative cosmological constant and a massive (preinflationary) scalar field. We demonstrate that the considered Universe has a nonsingular quantum behavior, associated to a primordial bounce, whose ground state has a high occupation number. Furthermore, in such a vacuum state, the super-Hamiltonian eigenvalue is negative, corresponding to a positive emerging dust energy density. The regularization of the model is performed via a polymer quantum approach to the Universe scale factor and the proper classical limit is then recovered, in agreement with a preinflationary state of the Universe. Since the dust energy density is redshifted by the Universe deSitter phase and the cosmological constant does not enter the ground state eigenvalue, we get a late-time cosmology, compatible with the present observations, endowed with a turning point in the far future.

  3. Cosmology at the Beach Lecture: David Hughes

    ScienceCinema (OSTI)

    David Hughes

    2010-01-08

    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. Cosmology at the Beach Lecture: Anne Green

    ScienceCinema (OSTI)

    Ann Green

    2010-01-08

    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.  

  5. Cosmology at the Beach Lecture: Simon White

    ScienceCinema (OSTI)

    Simon White

    2010-01-08

    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.

  6. Cosmology on the Beach - George Smoot

    ScienceCinema (OSTI)

    George Smoot

    2010-01-08

    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.

  7. Cosmological applications of weak gravitational flexion 

    E-Print Network [OSTI]

    Rowe, Barnaby Thomas Peter

    Modern cosmology has reached an important juncture, at which the ability to make measurements of unprecedented accuracy has led to conclusions that are a fundamental challenge to natural science. The discovery that, in ...

  8. Primordial nucleosynthesis in higher dimensional cosmology

    E-Print Network [OSTI]

    S. Chatterjee

    2009-11-13

    We investigate nucleosynthesis and element formation in the early universe in the framework of higher dimensional cosmology. For this purpose we utilize a previous solution of the present author, which may be termed as the generalized Friedmann-Robertson-Walker model. We find that temperature decays less rapidly in higher dimensional cosmology, which we believe may have nontrivial consequences \\emph{vis-a-vis} primordial physics.

  9. Quasi-local energy for cosmological models

    E-Print Network [OSTI]

    Chiang-Mei Chen; Jian-Liang Liu; James M. Nester

    2007-05-15

    First we briefly review our covariant Hamiltonian approach to quasi-local energy, noting that the Hamiltonian-boundary-term quasi-local energy expressions depend on the chosen boundary conditions and reference configuration. Then we present the quasi-local energy values resulting from the formalism applied to homogeneous Bianchi cosmologies. Finally we consider the quasi-local energies of the FRW cosmologies. Our results do not agree with certain widely accepted quasi-local criteria.

  10. Gravitational particle production in bouncing cosmologies

    E-Print Network [OSTI]

    Jaume Haro; Emilio Elizalde

    2015-09-03

    It is argued that the Universe reheating in bouncing cosmologies could be explained via gravitational particle production, as due to a sudden phase transition in the contracting regime. To this end, it is shown that gravitational production of massive particles conformally coupled with gravity in a matter-ekpyrotic bouncing Universe, where the sudden phase transition occurs in the contracting regime, yields a reheating temperature which is in good agreement with cosmological observations.

  11. $O(d,d)$-Covariant String Cosmology

    E-Print Network [OSTI]

    M. Gasperini; G. Veneziano

    1991-12-17

    The recently discovered $O(d,d)$ symmetry of the space of slowly varying cosmological string vacua in $d+1$ dimensions is shown to be preserved in the presence of bulk string matter. The existence of $O(d,d)$ conserved currents allows all the equations of string cosmology to be reduced to first-order differential equations. The perfect-fluid approximation is not $O(d,d)$-invariant, implying that stringy fluids possess in general a non-vanishing viscosity.

  12. Path Integral and Effective Hamiltonian in Loop Quantum Cosmology

    E-Print Network [OSTI]

    Haiyun Huang; Yongge Ma; Li Qin

    2011-06-27

    We study the path integral formulation of Friedmann universe filled with a massless scalar field in loop quantum cosmology. All the isotropic models of $k=0,+1,-1$ are considered. To construct the path integrals in the timeless framework, a multiple group-averaging approach is proposed. Meanwhile, since the transition amplitude in the deparameterized framework can be expressed in terms of group-averaging, the path integrals can be formulated for both deparameterized and timeless frameworks. Their relation is clarified. It turns out that the effective Hamiltonian derived from the path integral in deparameterized framework is equivalent to the effective Hamiltonian constraint derived from the path integral in timeless framework, since they lead to same equations of motion. Moreover, the effective Hamiltonian constraints of above models derived in canonical theory are confirmed by the path integral formulation.

  13. Supernova Remnants in the Magellanic Clouds. VI. The DEML316 Supernova Remnants

    E-Print Network [OSTI]

    R. M. Williams; Y. -H. Chu

    2005-09-22

    The DEML316 system contains two shells, both with the characteristic signatures of supernova remnants (SNRs). We analyze Chandra and XMM-Newton data for DEML316, investigating its spatial and spectral X-ray features. Our Chandra observations resolve the structure of the northeastern SNR (Shell A) as a bright inner ring and a set of "arcs" surrounded by fainter diffuse emission. The spectrum is well fit by a thermal plasma model with temperature ~1.4 keV; we do not find significant spectral differences for different regions of this SNR. The southwestern SNR (Shell B) exhibits an irregular X-ray outline, with a brighter interior ring of emission including a bright knot of emission. Overall the emission of the SNR is well described by a thermal plasma of temperature ~0.6 keV. The Bright Knot, however, is spectrally distinct from the rest of the SNR, requiring the addition of a high-energy spectral component consistent with a power-law spectrum of photon index 1.6--1.8. We confirm the findings of Nishiuchi et al. (2001) that the spectra of these shells are notably different, with Shell A requiring a high iron abundance for a good spectral fit, implying a Type Ia origin. We further explicitly compare abundance ratios to model predictions for Type Ia and Type II supernovae. The low ratios for Shell A (O/Fe of 1.5 and Ne/Fe of 0.2) and the high ratios for Shell B (O/Fe of 30--130 and Ne/Fe of 8--16) are consistent with Type Ia and Type II origins, respectively. The difference between the SNR progenitor types casts some doubt on the suggestion that these SNRs are interacting with one another.

  14. Loop quantum cosmology and the fate of cosmological singularities

    E-Print Network [OSTI]

    Parampreet Singh

    2015-09-30

    Singularities in general relativity such as the big bang and big crunch, and exotic singularities such as the big rip are the boundaries of the classical spacetimes. These events are marked by a divergence in the curvature invariants and the breakdown of the geodesic evolution. Recent progress on implementing techniques of loop quantum gravity to cosmological models reveals that such singularities may be generically resolved because of the quantum gravitational effects. Due to the quantum geometry, which replaces the classical differential geometry at the Planck scale, the big bang is replaced by a big bounce without any assumptions on the matter content or any fine tuning. In this manuscript, we discuss some of the main features of this approach and the results on the generic resolution of singularities for the isotropic as well as anisotropic models. Using effective spacetime description of the quantum theory, we show the way quantum gravitational effects lead to the universal bounds on the energy density, the Hubble rate and the anisotropic shear. We discuss the geodesic completeness in the effective spacetime and the resolution of all of the strong singularities. It turns out that despite the bounds on energy density and the Hubble rate, there can be divergences in the curvature invariants. However such events are geodesically extendible, with tidal forces not strong enough to cause inevitable destruction of the in-falling objects.

  15. Cosmological Constraints from Hubble Parameter on f(R) Cosmologies

    E-Print Network [OSTI]

    F. C. Carvalho; E. M. Santos; J. S. Alcaniz; J. Santos

    2008-11-10

    Modified $f(R)$ gravity in the Palatini approach has been presently applied to Cosmology as a realistic alternative to dark energy. In this concern, a number of authors have searched for observational constraints on several $f(R)$ gravity functional forms using mainly data of type Ia supenovae (SNe Ia), Cosmic Microwave Background ({\\rm CMB}) radiation and Large Scale Structure ({\\rm LSS}). In this paper, by considering a homogeneous and isotropic flat universe, we use determinations of the Hubble function $H(z)$, which are based on differential age method, to place bounds on the free parameters of the $f(R) = R - \\beta/R^{n}$ functional form. We also combine the $H(z)$ data with constraints from Baryon Acoustic Oscillations ({\\rm BAO}) and {\\rm CMB} measurements, obtaining ranges of values for $n$ and $\\beta$ in agreement with other independent analyses. We find that, for some intervals of $n$ and $\\beta$, models based on $f(R) = R - \\beta/R^{n}$ gravity in the Palatini approach, unlike the metric formalism, can produce the sequence of radiation-dominated, matter-dominated, and accelerating periods without need of dark energy.

  16. Type IIn supernovae as sources of high energy neutrinos

    E-Print Network [OSTI]

    Zirakashvili, V N

    2015-01-01

    It is shown that high-energy astrophysical neutrinos observed in the IceCube experiment can be produced by protons accelerated in extragalactic Type IIn supernova remnants by shocks propagating in the dense circumstellar medium. The nonlinear diffusive shock acceleration model is used for description of particle acceleration.

  17. A static universe is consistent with type Ia supernovae observations

    E-Print Network [OSTI]

    David F. Crawford

    2015-04-18

    This paper considers the hypothesis that the universe is static and demonstrates that type Ia supernova observations which appear to provide strong support for time dilation (and thus for an expanding universe) are equally consistent with a static universe. It is shown that a property of the standard calibration method means that regardless of what redshift dependence the measured light curve widths may have the calibrated widths always have little or no redshift dependence. An important consideration is the Phillips relation, a correlation between the peak-luminosity and the width of type Ia supernovae. Using the Phillips relation the analysis of a recent compilation of type Ia supernova observations is re-examined and it is shown that these observations are fully consistent with a static universe. It is also argued that the photometric redshift relation and spectroscopic ages are fully consistent with a static universe. As a separate but related issue it is shown that in the static model the density distribution of type Ia supernovae as a function of redshift agrees with the observations. All the evidence shows that the hypothesis is consistent with a static universe.

  18. Pair instability supernovae of very massive population III stars

    SciTech Connect (OSTI)

    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 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

    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.

  19. How to See the Supernova Berkeley Lab Just Discovered

    Broader source: Energy.gov [DOE]

    According to astronomers, this is the closest and brightest supernova of this type detected in the last 30 years and will be closely studied for years to come. In this video, Berkeley Lab's Peter Nugent explains how to find the event with a small telescope or pair of binoculars.

  20. A fast contour descriptor algorithm for supernova imageclassification

    SciTech Connect (OSTI)

    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.

  1. The Number of Supernovae from Primordial Stars in the Universe

    E-Print Network [OSTI]

    John H. Wise; Tom Abel

    2004-11-19

    Recent simulations of the formation of the first luminous objects in the universe predict isolated very massive stars to form in dark matter halos with virial temperatures large enough to allow significant amounts of molecular hydrogen to form. We construct a semi-analytic model based on the Press-Schechter formalism and calibrate the minimum halos mass that may form a primordial star with the results from extensive adaptive mesh refinement simulations. The model also includes star formation in objects with virial temperatures in excess of ten thousand Kelvin. The free parameters are tuned to match the optical depth measurements by the WMAP satellite. The models explicitly includes the negative feedback of the destruction of molecular hydrogen by a soft UV background which is computed self-consistently. We predict high redshift supernova rates as one of the most promising tools to test the current scenario of primordial star formation. The supernova rate from primordial stars peaks at redshifts ~20. Using an analytic model for the luminosities of pair-instability supernovae we predict observable magnitudes and discuss possible observational strategies. Such supernovae would release enough metals corresponding to a uniform enrichment to a few hundred thousands of solar metalicity. If some of these stars produce gamma ray bursts our rates will be directly applicable to understanding the anticipated results from the SWIFT satellite. This study highlights the great potential for the James Webb space telescope in probing cosmic structure at redshifts greater than 20.

  2. SUPERNOVA NUCLEOSYNTHESIS AS A TOOL TO ANALYZE THE EXPLOSION MECHANISM

    E-Print Network [OSTI]

    Rauscher, Thomas

    SUPERNOVA NUCLEOSYNTHESIS AS A TOOL TO ANALYZE THE EXPLOSION MECHANISM F.­K. Thielemann 1;4 , F for the explosion and ejection of matter. This affects the nucleosynthesis products via two main uncertainties, (i energy responsible for explosive nucleosynthesis. Thus, observations can constrain these quantities. Type

  3. Asymmetric supernova remnants generated by Galactic, massive runaway stars

    E-Print Network [OSTI]

    Meyer, D M -A; Mackey, J; Velazquez, P F; Gusdorf, A

    2015-01-01

    After the death of a runaway massive star, its supernova shock wave interacts with the bow shocks produced by its defunct progenitor, and may lose energy, momentum, and its spherical symmetry before expanding into the local interstellar medium (ISM). We investigate whether the initial mass and space velocity of these progenitors can be associated with asymmetric supernova remnants. We run hydrodynamical models of supernovae exploding in the pre-shaped medium of moving Galactic core-collapse progenitors. We find that bow shocks that accumulate more than about 1.5 Mo generate asymmetric remnants. The shock wave first collides with these bow shocks 160-750 yr after the supernova, and the collision lasts until 830-4900 yr. The shock wave is then located 1.35-5 pc from the center of the explosion, and it expands freely into the ISM, whereas in the opposite direction it is channelled into the region of undisturbed wind material. This applies to an initially 20 Mo progenitor moving with velocity 20 km/s and to our i...

  4. Limits on Enhanced Radio Wave Scattering by Supernova Remnants

    E-Print Network [OSTI]

    Laura G. Spitler; Steven R. Spangler

    2005-06-28

    We report multifrequency observations with the NRAO Very Long Baseline Array (VLBA) of the compact radio sources J0128+6306 and J0547+2721, which are viewed through the supernova remnants G127.1+0.5 and S147, respectively. Observations were made at frequencies of 1.427, 1.667, 2.271, and 4.987 GHz. The lines of sight to these sources pass through the shock wave and upstream and downstream turbulent layers of their respective supernova remnants, and thus might detect cosmic-ray generated turbulence produced during the Fermi acceleration process. For both sources, we detect interstellar scattering, characterized by a component of the angular size which scales as the square of the observing wavelength. The magnitude of the scattering is characterized by an effective scattering angular size theta_S0 at a frequency of 1 GHz of 13.2 +/- 2.6 milliarcseconds (mas) for J0128+6306 and 6.7 +/- 2.2 mas for J0547+2721. These angular sizes are consistent with the ``incidental'' scattering for any line of sight out of the galaxy at similar galactic latitudes and longitudes. There is therefore no evidence for enhanced turbulence at these supernova remnants. We establish upper limits to the supernova remnant-associated scattering measures of 8.1-14.8 m^-20/3-pc for J0128+6306 and 3.0 m^-20/3-pc for J0547+2721.

  5. Automata groups 

    E-Print Network [OSTI]

    Muntyan, Yevgen

    2010-01-16

    automata over the alphabet of 2 letters and 2-state automata over the 3-letter alphabet. We continue the classification work started by the research group at Texas A&M University ([BGK+07a, BGK+07b]) and further reduce the number of pairwise nonisomorphic...

  6. Cosmological Hints of Modified Gravity ?

    E-Print Network [OSTI]

    Di Valentino, Eleonora; Silk, Joseph

    2015-01-01

    The recent measurements of Cosmic Microwave Background temperature and polarization anisotropies made by the Planck satellite have provided impressive confirmation of the $\\Lambda$CDM cosmological model. However interesting hints of slight deviations from $\\Lambda$CDM have been found, including a $95 \\%$ c.l. preference for a "modified gravity" structure formation scenario. In this paper we confirm the preference for a modified gravity scenario from Planck 2015 data, find that modified gravity solves the so-called $A_{lens}$ anomaly in the CMB angular spectrum, and constrains the amplitude of matter density fluctuations to $\\sigma_8=0.815_{-0.048}^{+0.032}$, in better agreement with weak lensing constraints. Moreover, we find a lower value for the reionization optical depth of $\\tau=0.059\\pm0.020$ (to be compared with the value of $\\tau= 0.079 \\pm 0.017$ obtained in the standard scenario), more consistent with recent optical and UV data. We check the stability of this result by considering possible degeneraci...

  7. The ART of Cosmological Simulations

    E-Print Network [OSTI]

    Stefan Gottloeber; Anatoly Klypin

    2008-03-31

    We describe the basic ideas of MPI parallelization of the N-body Adaptive Refinement Tree (ART) code. The code uses self-adaptive domain decomposition where boundaries of the domains (parallelepipeds) constantly move -- with many degrees of freedom -- in the search of the minimum of CPU time. The actual CPU time spent by each MPI task on previous time-step is used to adjust boundaries for the next time-step. For a typical decomposition of 5^3 domains, the number of possible changes in boundaries is 3^{84}. We describe two algorithms of finding minimum of CPU time for configurations with a large number of domains. Each MPI task in our code solves the N-body problem where the large-scale distribution of matter outside of the boundaries of a domain is represented by relatively few temporary large particles created by other domains. At the beginning of a zero-level time-step, domains create and exchange large particles. Then each domain advances all its particles for many small time-steps. At the end of the large step, the domains decide where to place new boundaries and re-distribute particles. The scheme requires little communications between processors and is very efficient for large cosmological simulations.

  8. Cosmology with Strong Lensing Systems

    E-Print Network [OSTI]

    Cao, Shuo; Gavazzi, Raphaël; Piórkowska, Aleksandra; Zhu, Zong-Hong

    2015-01-01

    In this paper, we assemble a catalog of 118 strong gravitational lensing systems from SLACS, BELLS, LSD and SL2S surveys and use them to constrain the cosmic equation of state. In particular we consider two cases of dark energy phenomenology: $XCDM$ model where dark energy is modeled by a fluid with constant $w$ equation of state parameter and in Chevalier - Polarski - Linder (CPL) parametrization where $w$ is allowed to evolve with redshift: $w(z) = w_0 + w_1 \\frac{z}{1+z}$. We assume spherically symmetric mass distribution in lensing galaxies, but relax the rigid assumption of SIS model in favor to more general power-law index $\\gamma$, also allowing it to evolve with redshifts $\\gamma(z)$. Our results for the $XCDM$ cosmology show the agreement with values (concerning both $w$ and $\\gamma$ parameters) obtained by other authors. We go further and constrain the CPL parameters jointly with $\\gamma(z)$. The resulting confidence regions for the parameters are much better than those obtained with a similar metho...

  9. Initial data for rotating cosmologies

    E-Print Network [OSTI]

    Piotr Bizo?; Stefan Pletka; Walter Simon

    2015-08-28

    We revisit the construction of maximal initial data on compact manifolds in vacuum with positive cosmological constant via the conformal method. We discuss, extend and apply recent results of Hebey et al. [19] and Premoselli [31] which yield existence, non-existence, (non-)uniqueness and (linearisation-) stability of solutions of the Lichnerowicz equation, depending on its coefficients. We then focus on so-called $(t,\\phi)$-symmetric data as "seed manifolds", and in particular on Bowen-York data on the round hypertorus $\\mathbb{S}^2 \\times \\mathbb{S}$ (a slice of Nariai) and on Kerr-deSitter. In the former case, we clarify the bifurcation structure of the axially symmetric solutions of the Lichnerowicz equation in terms of the angular momentum as bifurcation parameter, using a combination of analytical and numerical techniques. As to the latter example, we show how dynamical data can be constructed in a natural way via conformal rescalings of Kerr-deSitter data.

  10. Gamma-ray Burst Cosmology

    E-Print Network [OSTI]

    Wang, F Y; Liang, E W

    2015-01-01

    Gamma-ray bursts (GRBs) are the most luminous electromagnetic explosions in the Universe, which emit up to $8.8\\times10^{54}$ erg isotropic equivalent energy in the hard X-ray band. The high luminosity makes them detectable out to the largest distances yet explored in the Universe. GRBs, as bright beacons in the deep Universe, would be the ideal tool to probe the properties of high-redshift universe: including the cosmic expansion and dark energy, star formation rate, the reionization epoch and the metal enrichment history of the Universe. In this article, we review the luminosity correlations of GRBs, and implications for constraining the cosmological parameters and dark energy. Observations show that the progenitors of long GRBs are massive stars. So it is expected that long GRBs are tracers of star formation rate. We also review the high-redshift star formation rate derived from GRBs, and implications for the cosmic reionization history. The afterglows of GRBs generally have broken power-law spectra, so it...

  11. Observational constraints and cosmological parameters

    E-Print Network [OSTI]

    Antony Lewis

    2006-04-02

    I discuss the extraction of cosmological parameter constraints from the recent WMAP 3-year data, both on its own and in combination with other data. The large degeneracies in the first year data can be largely broken with the third year data, giving much better parameter constraints from WMAP alone. The polarization constraint on the optical depth is crucial to obtain the main results, including n_s < 1 in basic six-parameter models. Almost identical constraints can also be obtained using only temperature data with a prior on the optical depth. I discuss the modelling of secondaries when extracting parameter constraints, and show that the effect of CMB lensing is about as important as SZ and slightly increases the inferred value of the spectral index. Constraints on correlated matter isocurvature modes are not radically better than before, and the data is consistent with a purely adiabatic spectrum. Combining WMAP 3-year data with data from the Lyman-alpha forest suggests somewhat higher values for sigma_8 than from WMAP alone.

  12. Initial data for rotating cosmologies

    E-Print Network [OSTI]

    Piotr Bizo?; Stefan Pletka; Walter Simon

    2015-06-09

    We revisit the construction of maximal initial data on compact manifolds in vacuum with positive cosmological constant via the conformal method. We discuss, extend and apply recent results of Hebey et al. [19] and Premoselli [31] which yield existence, non-existence, (non-)uniqueness and (linearisation-) stability of solutions of the Lichnerowicz equation, depending on its coefficients. We then focus on so-called $(t,\\phi)$-symmetric data as "seed manifolds", and in particular on Bowen-York data on the round hypertorus $\\mathbb{S}^2 \\times \\mathbb{S}$ (a slice of Nariai) and on Kerr-deSitter. In the former case, we clarify the bifurcation structure of the axially symmetric solutions of the Lichnerowicz equation in terms of the angular momentum as bifurcation parameter, using a combination of analytical and numerical techniques. As to the latter example, we show how dynamical data can be constructed in a natural way via conformal rescalings of Kerr-deSitter data.

  13. The First Second of a Type-II Supernova: Convection, Accretion, and Shock Propagation

    E-Print Network [OSTI]

    H. -Thomas Janka; Ewald Mueller

    1995-03-03

    One- and two-dimensional hydrodynamical simulations of neutrino-driven supernova explosions are discussed. The simulations cover the phase between the stagnation of the prompt shock and about one second after core bounce. Systematic variation of the neutrino fluxes from the neutrino sphere shows that the explosion energy, explosion time scale, initial mass of the protoneutron star, and explosive nucleosynthesis of iron-group elements depend sensitively on the strength of the neutrino heating during the first few 100 ms after shock formation. Convective overturn in the neutrino-heated region behind the shock is a crucial help for the explosion only in a narrow window of neutrino luminosities. Here powerful explosions can be obtained only in the multi-dimensional case. For higher core-neutrino fluxes also spherically symmetrical models yield energetic explosions, while for lower luminosities even with convection no strong explosions occur.

  14. Aspherical nucleosynthesis in a core-collapse supernova with 25 M {sub ?} standard progenitor

    SciTech Connect (OSTI)

    Popov, M. V. [École Normale Supérieure de Lyon, CRAL (UMR CNRS 5574), Université de Lyon 1, 46 allée d'Italie, F-69007 Lyon (France); Filina, A. A.; Baranov, A. A.; Chardonnet, P. [LAPTh, Université de Savoie, 9, Chemin de Bellevue BP 110, F-74941 Annecy-le-Vieux Cedex (France); Chechetkin, V. M. [Keldysh Institute of Applied Mathematics RAS, Miusskaya sq. 4, 125047 Moscow (Russian Federation)

    2014-03-01

    The problem of nucleosynthesis was studied within an aspherical supernova model. The explosive burning was computed in a star of 25 M {sub ?} initial mass on its final stage of evolution. The chemical composition of a presupernova was taken from realistic evolutionary computations. A piecewise parabolic method on a local stencil was applied to simulate the hydrodynamics of the explosion. The gravity was recomputed by a Poisson solver on a fine grid as the explosion developed. A detailed yield of chemical elements was performed as a post-processing step using the tracer particles method. The produced nuclei formed a layer-like structure enclosing large fragments of nickel and iron-group isotopes that were pushed away from the central region by an explosion along the polar direction. The light nuclei were preferentially moving along the equatorial plane forming a torus-like structure.

  15. Excited-state OH Masers and Supernova Remnants

    E-Print Network [OSTI]

    Ylva M. Pihlström; Vincent L. Fish; Loránt O. Sjouwerman; Laura K. Zschaechner; Philip B. Lockett; Moshe Elitzur

    2007-12-29

    The collisionally pumped, ground-state 1720 MHz maser line of OH is widely recognized as a tracer for shocked regions and observed in star forming regions and supernova remnants. Whereas some lines of excited states of OH have been detected and studied in star forming regions, the subject of excited-state OH in supernova remnants -- where high collision rates are to be expected -- is only recently being addressed. Modeling of collisional excitation of OH demonstrates that 1720, 4765 and 6049 MHz masers can occur under similar conditions in regions of shocked gas. In particular, the 6049 and 4765 MHz masers become more significant at increased OH column densities where the 1720 MHz masers begin to be quenched. In supernova remnants, the detection of excited-state OH line maser emission could therefore serve as a probe of regions of higher column densities. Using the Very Large Array, we searched for excited-state OH in the 4.7, 7.8, 8.2 and 23.8 GHz lines in four well studied supernova remnants with strong 1720 MHz maser emission (SgrAEast, W28, W44 and IC443). No detections were made, at typical detection limits of around 10 mJy/beam. The search for the 6 GHz lines were done using Effelsberg since the VLA receivers did not cover those frequencies, and are reported on in an accompanying letter (Fish, Sjouwerman & Pihlstrom 2007). We also cross-correlated the positions of known supernova remnants with the positions of 1612 MHz maser emission obtained from blind surveys. No probable associations were found, perhaps except in the SgrAEast region. The lack of detections of excited-state OH indicates that the OH column densities suffice for 1720 MHz inversion but not for inversion of excited-state transitions, consistent with the expected results for C-type shocks.

  16. Inhomogeneity-induced variance of cosmological parameters

    E-Print Network [OSTI]

    Alexander Wiegand; Dominik J. Schwarz

    2012-02-18

    Modern cosmology relies on the assumption of large-scale isotropy and homogeneity of the Universe. However, locally the Universe is inhomogeneous and anisotropic. So, how can local measurements (at the 100 Mpc scale) be used to determine global cosmological parameters (defined at the 10 Gpc scale)? We use Buchert's averaging formalism and determine a set of locally averaged cosmological parameters in the context of the flat Lambda cold dark matter model. We calculate their ensemble means (i.e. their global values) and variances (i.e. their cosmic variances). We apply our results to typical survey geometries and focus on the study of the effects of local fluctuations of the curvature parameter. By this means we show, that in the linear regime cosmological backreaction and averaging can be reformulated as the issue of cosmic variance. The cosmic variance is found largest for the curvature parameter and discuss some of its consequences. We further propose to use the observed variance of cosmological parameters to measure the growth factor. [abbreviated

  17. Two superluminous supernovae from the early universe discovered by the supernova legacy survey

    SciTech Connect (OSTI)

    Howell, D. A. [Las Cumbres Observatory Global Telescope Network, 6740 Cortona Drive, Suite 102, Goleta, CA 93117 (United States); Kasen, D. [Departments of Physics and Astronomy, University of California, Berkeley, Berkeley, CA 94720-7300 (United States); Lidman, C. [Australian Astronomical Observatory, P.O. Box 915, North Ryde, NSW 1670 (Australia); Sullivan, M. [School of Physics and Astronomy, University of Southampton, Southampton SO17 1BJ (United Kingdom); Conley, A. [Center for Astrophysics and Space Astronomy, University of Colorado, 389 UCB, Boulder, CO 80309-389 (United States); Astier, P.; Balland, C.; Guy, J.; Hardin, D.; Pain, R.; Regnault, N. [LPNHE, CNRS-IN2P3 and University of Paris VI and VII, F-75005 Paris (France); Carlberg, R. G. [Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON M5S 3H8 (Canada); Fouchez, D. [CPPM, CNRS-IN2P3 and University Aix Marseille II, Case 907, F-13288 Marseille Cedex 9 (France); Palanque-Delabrouille, N.; Rich, J.; Ruhlmann-Kleider, V. [DSM/IRFU/SPP, CEA-Saclay, F-91191 Gif-sur-Yvette (France); Perrett, K. [DRDC Ottawa, 3701 Carling Avenue, Ottawa, ON K1A 0Z4 (Canada); Pritchet, C. J. [Department of Physics and Astronomy, University of Victoria, P.O. Box 3055, Victoria, BC V8W 3P6 (Canada)

    2013-12-20

    We present spectra and light curves of SNLS 06D4eu and SNLS 07D2bv, two hydrogen-free superluminous supernovae (SNe) discovered by the Supernova Legacy Survey. At z = 1.588, SNLS 06D4eu is the highest redshift superluminous SN with a spectrum, at M{sub U} = –22.7 it is one of the most luminous SNe ever observed, and it gives a rare glimpse into the rest-frame ultraviolet where these SNe put out their peak energy. SNLS 07D2bv does not have a host galaxy redshift, but on the basis of the SN spectrum, we estimate it to be at z ? 1.5. Both SNe have similar observer-frame griz light curves, which map to rest-frame light curves in the U band and UV, rising in ?20 rest-frame days or longer and declining over a similar timescale. The light curves peak in the shortest wavelengths first, consistent with an expanding blackbody starting near 15,000 K and steadily declining in temperature. We compare the spectra with theoretical models, and we identify lines of C II, C III, Fe III, and Mg II in the spectra of SNLS 06D4eu and SCP 06F6 and find that they are consistent with an expanding explosion of only a few solar masses of carbon, oxygen, and other trace metals. Thus, the progenitors appear to be related to those suspected for SNe Ic. A high kinetic energy, 10{sup 52} erg, is also favored. Normal mechanisms of powering core-collapse or thermonuclear SNe do not seem to work for these SNe. We consider models powered by {sup 56}Ni decay and interaction with circumstellar material, but we find that the creation and spin-down of a magnetar with a period of 2 ms, a magnetic field of 2 × 10{sup 14} G, and a 3 M {sub ?} progenitor provides the best fit to the data.

  18. SUPERNOVAE AND AGN DRIVEN GALACTIC OUTFLOWS

    SciTech Connect (OSTI)

    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 an appropriate relation between M {sub .} and M{sub h} and an appropriate opacity of dust grains in infrared (K band), this ratio has the attractive property of being minimum at a certain halo mass scale (M{sub h} {approx} 10{sup 12}-10{sup 12.5} M {sub Sun }) that signifies the crossover of AGN domination in outflow properties from starburst activity at lower masses. We find that stellar mass for massive galaxies scales as M {sub *}{proportional_to}M {sup 0.26} {sub h}, and for low-mass galaxies, M {sub *}{proportional_to}M {sup 5/3} {sub h}.

  19. Fluctuations in strongly coupled cosmologies

    SciTech Connect (OSTI)

    Bonometto, Silvio A. [Department of Physics, Astronomy Unit, Trieste University, Via Tiepolo 11, I 34143 Trieste (Italy); Mainini, Roberto, E-mail: bonometto@oats.inaf.it, E-mail: mainini@mib.infn.it [Department of Physics G. Occhialini, Milano-Bicocca University, Piazza della Scienza 3, I 20126 Milano (Italy)

    2014-03-01

    In the early Universe, a dual component made of coupled CDM and a scalar field ?, if their coupling ? > (3){sup 1/2}/2, owns an attractor solution, making them a stationary fraction of cosmic energy during the radiation dominated era. Along the attractor, both such components expand ?a{sup ?4} and have early density parameters ?{sub d} = 1/(4?{sup 2}) and ?{sub c} = 2 ?{sub d} (field and CDM, respectively). In a previous paper it was shown that, if a further component, expanding ?a{sup ?3}, breaks such stationary expansion at z ? 3–5 × 10{sup 3}, cosmic components gradually acquire densities consistent with observations. This paper, first of all, considers the case that this component is warm. However, its main topic is the analysis of fluctuation evolution: out of horizon modes are then determined; their entry into horizon is numerically evaluated as well as the dependence of Meszaros effect on the coupling ?; finally, we compute: (i) transfer function and linear spectral function; (ii) CMB C{sub l} spectra. Both are close to standard ?CDM models; in particular, the former one can be so down to a scale smaller than Milky Way, in spite of its main DM component being made of particles of mass < 1 keV. The previously coupled CDM component, whose present density parameter is O(10{sup ?3}), exhibits wider fluctuations ??/?, but approximately ?-independent ?? values. We discuss how lower scale features of these cosmologies might ease quite a few problems that ?CDM does not easily solve.

  20. Beyond the Cosmological Standard Model

    E-Print Network [OSTI]

    Austin Joyce; Bhuvnesh Jain; Justin Khoury; Mark Trodden

    2014-12-15

    After a decade and a half of research motivated by the accelerating universe, theory and experiment have a reached a certain level of maturity. The development of theoretical models beyond \\Lambda, or smooth dark energy, often called modified gravity, has led to broader insights into a path forward, and a host of observational and experimental tests have been developed. In this review we present the current state of the field and describe a framework for anticipating developments in the next decade. We identify the guiding principles for rigorous and consistent modifications of the standard model, and discuss the prospects for empirical tests. We begin by reviewing attempts to consistently modify Einstein gravity in the infrared, focusing on the notion that additional degrees of freedom introduced by the modification must screen themselves from local tests of gravity. We categorize screening mechanisms into three broad classes: mechanisms which become active in regions of high Newtonian potential, those in which first derivatives become important, and those for which second derivatives are important. Examples of the first class, such as f(R) gravity, employ the familiar chameleon or symmetron mechanisms, whereas examples of the last class are galileon and massive gravity theories, employing the Vainshtein mechanism. In each case, we describe the theories as effective theories. We describe experimental tests, summarizing laboratory and solar system tests and describing in some detail astrophysical and cosmological tests. We discuss future tests which will be sensitive to different signatures of new physics in the gravitational sector. Parts that are more relevant to theorists vs. observers/experimentalists are clearly indicated, in the hope that this will serve as a useful reference for both audiences, as well as helping those interested in bridging the gap between them.

  1. Sweetspot: Near-infrared observations of 13 type Ia supernovae from a new NOAO survey probing the nearby smooth Hubble flow

    SciTech Connect (OSTI)

    Weyant, Anja; Wood-Vasey, W. Michael [Pittsburgh Particle physics, Astrophysics, and Cosmology Center (PITT PACC), Physics and Astronomy Department, University of Pittsburgh, Pittsburgh, PA 15260 (United States); Allen, Lori; Joyce, Richard; Matheson, Thomas [National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ 85719 (United States); Garnavich, Peter M. [Department of Physics, 225 Nieuwland Science Hall, Notre Dame, IN 46556 (United States); Jha, Saurabh W., E-mail: anw19@pitt.edu [Department of Physics and Astronomy, Rutgers, the State University of New Jersey, 136 Frelinghuysen Road, Piscataway, NJ 08854 (United States)

    2014-04-01

    We present 13 Type Ia supernovae (SNe Ia) observed in the rest-frame near-infrared (NIR) from 0.02 < z < 0.09 with the WIYN High-resolution Infrared Camera on the WIYN 3.5 m telescope. With only one to three points per light curve and a prior on the time of maximum from the spectrum used to type the object, we measure an H-band dispersion of spectroscopically normal SNe Ia of 0.164 mag. These observations continue to demonstrate the improved standard brightness of SNe Ia in an H band, even with limited data. Our sample includes two SNe Ia at z ? 0.09, which represent the most distant rest-frame NIR H-band observations published to date. This modest sample of 13 NIR SNe Ia represent the pilot sample for {sup S}weetSpot{sup —}a 3 yr NOAO Survey program that will observe 144 SNe Ia in the smooth Hubble flow. By the end of the survey we will have measured the relative distance to a redshift of z ? 0.05%-1%. Nearby Type Ia supernova (SN Ia) observations such as these will test the standard nature of SNe Ia in the rest-frame NIR, allow insight into the nature of dust, and provide a critical anchor for future cosmological SN Ia surveys at higher redshift.

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

    SciTech Connect (OSTI)

    Brown, Peter J.; Smitka, Michael T.; Krisciunas, Kevin; Wang, Lifan [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); Kuin, Paul; De Pasquale, Massimiliano [Mullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking Surrey, RH5 6NT (United Kingdom); Scalzo, Richard [Research School of Astronomy and Astrophysics, The Australian National University, Mount Stromlo Observatory, Cotter Road, Weston Creek, ACT 2611 (Australia); Holland, Stephen [Space Telescope Science Center 3700 San Martin Drive, Baltimore, MD 21218 (United States); Milne, Peter, E-mail: pbrown@physics.tamu.edu [Steward Observatory, University of Arizona, Tucson, AZ 85719 (United States)

    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.

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

    SciTech Connect (OSTI)

    Inserra, C.; Smartt, S. J., E-mail: c.inserra@qub.ac.uk [Astrophysics Research Centre, School of Mathematics and Physics, Queens University Belfast, Belfast BT7 1NN (United Kingdom)

    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 ?M {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.

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

    SciTech Connect (OSTI)

    Kimm, Taysun; Cen, Renyue [Department of Astrophysical Sciences, Princeton University, Peyton Hall, Princeton, NJ 08544 (United States)

    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.

  5. THE SUPERNOVA THAT DESTROYED A PROTOGALAXY: PROMPT CHEMICAL ENRICHMENT AND SUPERMASSIVE BLACK HOLE GROWTH

    SciTech Connect (OSTI)

    Whalen, Daniel J.; Johnson, Jarrett L.; Smidt, Joseph [T-2, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Meiksin, Avery [Institute for Astronomy, University of Edinburgh, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom); Heger, Alexander [Monash Centre for Astrophysics, Monash University, Victoria 3800 (Australia); Even, Wesley; Fryer, Chris L. [CCS-2, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2013-09-01

    The first primitive galaxies formed from accretion and mergers by z {approx} 15, and were primarily responsible for cosmological reionization and the chemical enrichment of the early cosmos. But a few of these galaxies may have formed in the presence of strong Lyman-Werner UV fluxes that sterilized them of H{sub 2}, preventing them from forming stars or expelling heavy elements into the intergalactic medium prior to assembly. At masses of 10{sup 8} M{sub Sun} and virial temperatures of 10{sup 4} K, these halos began to rapidly cool by atomic lines, perhaps forming 10{sup 4}-10{sup 6} M{sub Sun} Pop III stars and, later, the seeds of supermassive black holes. We have modeled the explosion of a supermassive Pop III star in the dense core of a line-cooled protogalaxy with the ZEUS-MP code. We find that the supernova (SN) expands to a radius of {approx}1 kpc, briefly engulfing the entire galaxy, but then collapses back into the potential well of the dark matter. Fallback fully mixes the interior of the protogalaxy with metals, igniting a violent starburst and fueling the rapid growth of a massive black hole at its center. The starburst would populate the protogalaxy with stars in greater numbers and at higher metallicities than in more slowly evolving, nearby halos. The SN remnant becomes a strong synchrotron source that can be observed with eVLA and eMERLIN and has a unique signature that easily distinguishes it from less energetic SN remnants. Such explosions, and their attendant starbursts, may well have marked the birthplaces of supermassive black holes on the sky.

  6. Cosmological and astrophysical aspects of finite-density QCD

    E-Print Network [OSTI]

    Dominik J. Schwarz

    1998-07-23

    The different phases of QCD at finite temperature and density lead to interesting effects in cosmology and astrophysics. In this work I review some aspects of the cosmological QCD transition and of astrophysics at high baryon density.

  7. Halo expansion in cosmological hydro simulations: towards a baryonic solution of the cusp/core problem in massive spirals

    E-Print Network [OSTI]

    Maccio', Andrea V; Brook, Chris B; Wadsley, James; Couchman, H M P; Shen, Sijing; Gibson, Brad K; Quinn, Tom

    2011-01-01

    A clear prediction of the Cold Dark Matter model is the existence of cuspy dark matter halo density profiles on all mass scales. This is not in agreement with the observed rotation curves of spiral galaxies, challenging on small scales the otherwise successful CDM paradigm. In this work we employ high resolution cosmological hydro-dynamical simulations to study the effects of dissipative processes on the inner distribution of dark matter in Milky-Way like objects (M~1e12 Msun). Our simulations include supernova feedback, and the effects of the radiation pressure of massive stars before they explode as supernovae. The increased stellar feedback results in the expansion of the dark matter halo instead of contraction with respect to N-body simulations. Baryons are able to erase the dark matter cuspy distribution creating a flat, cored, dark matter density profile in the central several kpc of a massive Milky-Way like halo. The profile is well fit by a Burkert profile, with fitting parameters consistent with the ...

  8. Inflation after COBE: Lectures on inflationary cosmology

    SciTech Connect (OSTI)

    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.

  9. Gravitational collapse and the cosmological constant

    SciTech Connect (OSTI)

    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.

  10. An oblique membrane paradigm for cosmological horizon

    E-Print Network [OSTI]

    Tower Wang

    2014-11-24

    The membrane paradigm is a formalism for studying the event horizon of black holes. After analyzing it with some technical details and realizing it in the Reissner-Nordstrom black hole, we extend the paradigm to cosmological horizons. A standard membrane paradigm is established for the pure de Sitter horizon, and an oblique membrane paradigm is proposed for the trapping horizon of the Friedmann-Lemaitre-Robertson-Walker universe. In the latter case, the cosmological stretched horizon is oblique, thus the running of renormalization parameter is nonzero in the timelike direction and gives a correction to the membrane pressure. In this paradigm, the cosmological equations come from continuity equations of the membrane fluid and the bulk fluid respectively.

  11. Constraining Parameters of Generalized Cosmic Chaplygin Gas in Loop Quantum Cosmology

    E-Print Network [OSTI]

    Chayan Ranjit; Ujjal Debnath

    2014-09-20

    We have assumed the FRW universe in loop quantum cosmology (LQC) model filled with the dark matter and the Generalized Cosmic Chaplygin gas (GCCG) type dark energy where dark matter follows the linear equation of state. We present the Hubble parameter in terms of the observable parameters $\\Omega_{m0}$ and $H_{0}$ with the redshift $z$ and the other parameters like $A$, $B$, $w_{m}$, $ \\omega$ and $\\alpha$ which coming from our model. From Stern data set (12 points)\\& SNe Type Ia 292 data (from \\cite{Riess1,Riess2,Astier}) we have obtained the bounds of the arbitrary parameters by minimizing the $\\chi^{2}$ test. The best-fit values of the parameters are obtained by 66\\%, 90\\% and 99\\% confidence levels. Next due to joint analysis with Stern+BAO and Stern+BAO+CMB observations, we have also obtained the bounds of the parameters ($A,B$) by fixing some other parameters $\\alpha$, $w_{m}$ and $\\omega$. From the best fit values of the parameters, we have obtained the distance modulus $\\mu(z)$ for our theoretical GCCG model in LQC and from Supernovae Type Ia (union2 sample 552 data from [\\cite{Amanullah}] \\& Riess 292 data from [\\cite{Riess1,Riess2,Astier}]), we have concluded that our model is in agreement with the Supernovae Type Ia sample data. In addition, we have investigated in details about the various types of Future Singularities that may be formed in this model and it is notable that our model is completely free from any types of future singularities.

  12. 2006 Nature Publishing Group The association of GRB 060218 with a supernova

    E-Print Network [OSTI]

    Zhang, Bing

    6 , F. E. Marshall6 , K. O. Mason15 , A. Moretti1 , P. T. O'Brien16 , J. P. Osborne16 , K. L. Page16 Alert Telescope (BAT) instrument8 onboard the Swift9 space mission on 18.149 February 2006 Universal are measured from the BAT trigger time). Swift slewed autonomously to the newly discovered burst. The X

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

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefield MunicipalTechnical Report: Achievements ofCOMPOSITION OF VAPORS FROMSciDAC ComputationalLaboratory

  14. The INTEGRAL/SPI 511 keV Signal from Hidden Valleys in Type Ia and Core Collapse Supernova Explosions

    E-Print Network [OSTI]

    Hooman Davoudiasl; Gilad Perez

    2010-04-03

    We examine under what circumstances the INTEGRAL/SPI 511 keV signal can originate from decays of MeV-scale composite states produced by: (A) thermonuclear (type Ia) or (B) core collapse supernovae (SNe). The requisite dynamical properties that would account for the observed data are quite distinct, for cases (A) and (B). We determine these requirements in simple hidden valley models, where the escape fraction problem is naturally addressed, due to the long lifetime of the new composite states. A novel feature of scenario (A) is that the dynamics of type Ia SNe, standard candles for cosmological measurements, might be affected by our mechanism. In case (A), the mass of the state mediating between the hidden sector and the SM $\\ee$ could be a few hundred GeV and within the reach of a 500 GeV $\\ee$ linear collider. We also note that kinetic mixing of the photon with a light vector state may provide an interesting alternate mediation mechanism in this case. Scenarios based on case (B) are challenged by the need for a mechanism to transport some of the produced positrons toward the Galactic bulge, due to the inferred distribution of core collapse sources. The mass of the mediator in case (B) is typically hundreds of TeV, leading to long-lived particles that could, under certain circumstances, include a viable dark matter candidate. The appearance of long-lived particles in typical models leads to cosmological constraints and we address how a consistent cosmic history may be achieved.

  15. Our Universe from the cosmological constant

    SciTech Connect (OSTI)

    Barrau, Aurélien; 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.

  16. The Vacuum and the Cosmological Constant Problem

    E-Print Network [OSTI]

    Gerald E. Marsh

    2008-06-20

    It will be argued here that the cosmological constant problem exists because of the way the vacuum is defined in quantum field theory. It has been known for some time that for QFT to be gauge invariant certain terms--such as part of the vacuum polarization tensor--must be eliminated either explicitly or by some form of regularization followed by renormalization. It has recently been shown that lack of gauge invariance is a result of the way the vacuum is defined, and redefining the vacuum so that the theory is gauge invariant may also offer a solution to the cosmological constant problem.

  17. Cosmology as Science?: From Inflation to Eternity

    ScienceCinema (OSTI)

    None

    2011-10-06

    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

  18. High-Energy Astrophysics and Cosmology

    E-Print Network [OSTI]

    John Ellis

    2002-10-26

    Interfaces between high-energy physics, astrophysics and cosmology are reviewed, with particular emphasis on the important roles played by high-energy cosmic-ray physics. These include the understanding of atmospheric neutrinos, the search for massive cold dark matter particles and possible tests of models of quantum gravity. In return, experiments at the LHC may be useful for refining models of ultra-high-energy cosmic rays, and thereby contributing indirectly to understanding their origin. Only future experiments will be able to tell whether these are due to some bottom-up astrophysical mechanism or some top-down cosmological mechanism.

  19. Thermal relics in cosmology with bulk viscosity

    E-Print Network [OSTI]

    A. Iorio; G. Lambiase

    2014-11-28

    In this paper we discuss some consequences of cosmological models in which the primordial cosmic matter is described by a relativistic imperfect fluid. The latter takes into account the dissipative effects (bulk viscosity) arising from different cooling rates of the fluid components in the expanding Universe. We discuss, in particular, the effects of the bulk viscosity on Big Bang Nucleosynthesis and on the thermal relic abundance of particles, looking at recent results of PAMELA experiment. The latter has determined an anomalous excess of positron events, that cannot be explained by the conventional cosmology and particle physics.

  20. Thermodynamics of Ideal Gas in Cosmology

    E-Print Network [OSTI]

    Ying-Qiu Gu

    2009-10-04

    The equation of state and the state functions for the gravitational source are necessary conditions for solving cosmological model and stellar structure. The usual treatments are directly based on the laws of thermodynamics, and the physical meanings of some concepts are obscure. This letter show that, we can actually derive all explicit fundamental state functions for the ideal gas in the context of cosmology via rigorous dynamical and statistical calculation. These relations have clear physical meanings, and are valid in both non-relativistic and ultra-relativistic cases. Some features of the equation of state are important for a stable structure of a star with huge mass.