Sample records for group supernova cosmology

  1. Cosmology with Supernovae

    E-Print Network [OSTI]

    P. Ruiz-Lapuente

    2003-04-07T23:59:59.000Z

    This review gives an update of the cosmological use of SNe Ia and the progress made in testing their properties from the local universe to high-z. The cosmological road from high-z supernovae down to Galactic SNe Ia is followed in search of the answer to standing questions on their nature and their validity as cosmological indicators.

  2. Cosmological Insights from Supernovae

    E-Print Network [OSTI]

    P. Ruiz-Lapuente

    1998-10-26T23:59:59.000Z

    While low-z Type Ia supernovae are used to measure the present rate of expansion of the Universe, high-z Type Ia measure its variation due to the cosmic matter-energy content. Results from those determinations imply a low matter density Universe with a non-zero cosmological constant (vacuum-energy component). The expansion rate of the Universe accelerates, according to these determinations. The validity of the Type Ia supernova approach for this cosmological research is addressed. An account is given of additional prospects to further investigate through supernovae what the Universe is made of. Those attempts range from constraining the large scale dark matter distribution to further test and interpret the presence of a vacuum energy component.

  3. 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)

    2014-06-24T23:59:59.000Z

    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.

  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.

    2004-01-01T23:59:59.000Z

    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

    2015-01-01T23:59:59.000Z

    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.

    2008-01-01T23:59:59.000Z

    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.

    2008-01-01T23:59:59.000Z

    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]

    2006-01-01T23:59:59.000Z

    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.

    2005-01-01T23:59:59.000Z

    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. Probing Cosmological Isotropy With Type IA Supernovae

    E-Print Network [OSTI]

    Bengaly, C A P; Alcaniz, J S

    2015-01-01T23:59:59.000Z

    We investigate the validity of the Cosmological Principle by mapping the cosmological parameters $H_0$ and $q_0$ through the celestial sphere. In our analysis, performed in a low-redshift regime to follow a model-independent approach, we use two compilations of type Ia Supernovae (SNe Ia), namely the Union2.1 and the JLA datasets. Firstly, we show that the angular distributions for both SNe Ia datasets are statistically anisotropic at high confidence level ($p$-value $<$ 0.0001), in particular the JLA sample. Then we find that the cosmic expansion and acceleration are mainly of dipolar type, with maximal anisotropic expansion [acceleration] pointing towards $(l,b) \\simeq (326^{\\circ},12^{\\circ})$ [$(l,b) \\simeq (174^{\\circ},27^{\\circ})$], and $(l,b) \\simeq (58^{\\circ},-60^{\\circ})$ [$(l,b) \\simeq (225^{\\circ},51^{\\circ})$] for the Union2.1 and JLA data, respectively. Secondly, we use a geometrical method to test the hypothesis that the non-uniformly distributed SNe Ia events could introduce anisotropic imp...

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

    E-Print Network [OSTI]

    Meyers, Joshua Evan

    2012-01-01T23:59:59.000Z

    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

  12. Study of Supernovae Important for Cosmology

    E-Print Network [OSTI]

    Baklanov, P V; Potashov, M Sh; Dolgov, A D

    2015-01-01T23:59:59.000Z

    The dense shell method for the determination of distances to type IIn supernovae has been briefly reviewed. Applying our method to SN 2006gy, SN 2009ip, and SN 2010jl supernovae, we have obtained distances in excellent agreement with the previously known distances to the parent galaxies. The dense shell method is based on the radiation hydrodynamic model of a supernova. The method of the blackbody model, as well as the correctness of its application for simple estimates of distances from observation data, has been justified.

  13. Scrutinizing Exotic Cosmological Models Using ESSENCE Supernova Data Combined With Other Cosmological Probes

    SciTech Connect (OSTI)

    Davis, Tamara M.; Mortsell, E.; Sollerman, J.; Becker, A.C.; Blondin, S.; Challis, P.; Clocchiatti, A.; Filippenko, A.V.; Foley, R.J.; Garnavich, P.M.; Jha, S.; Krisciunas, K.; Kirshner, R.P.; Leibundgut, B.; Li, W.; Matheson, T.; Miknaitis, G.; Pignata, G.; Rest, A.; Riess, A.G.; Schmidt, B.P.; /Bohr Inst. /Stockholm U. /Washington U.,

    2007-01-25T23:59:59.000Z

    The first cosmological results from the ESSENCE supernova survey (Wood-Vasey et al. 2007) are extended to a wider range of cosmological models including dynamical dark energy and non-standard cosmological models. We fold in a greater number of external data sets such as the recent Higher-z release of high-redshift supernovae (Riess et al. 2007) as well as several complementary cosmological probes. Model comparison statistics such as the Bayesian and Akaike information criteria are applied to gauge the worth of models. These statistics favor models that give a good fit with fewer parameters. Based on this analysis, the preferred cosmological model is the flat cosmological constant model, where the expansion history of the universe can be adequately described with only one free parameter describing the energy content of the universe. Amongst the more exotic models that provide good fits to the data, we note a preference for models whose best-fit parameters reduce them to the cosmological constant model.

  14. Non-Cosmological FRB's from Young Supernova Remnant Pulsars

    E-Print Network [OSTI]

    Connor, Liam; Pen, Ue-Li

    2015-01-01T23:59:59.000Z

    We propose a new extragalactic but non-cosmological explanation for FRB's based on very young pulsars in supernova remnants. Within a few hundred years of a core-collapse supernova the ejecta is confined within $\\sim$1 pc, providing a high enough column density of free electrons for the observed 500-1500 pc/cm$^3$. By extrapolating a Crab-like pulsar to its infancy in an environment like that of SN 1987A, we hypothesize such an object could emit supergiant pulses sporadically which would be bright enough to be seen at a few hundred megaparsecs. In this scenario Faraday rotation at the source gives RM's much larger than the expected cosmological contribution. If the emission were pulsar-like, then the polarization vector could swing over the duration of the burst, which is not expected from non-rotating objects. In this model, the scattering, large DM, and commensurate RM all come from one place which is not the case for the cosmological interpretation. The model also provides testable predictions of the flux ...

  15. Testing Cosmological Models with Type Ic Super Luminous Supernovae

    E-Print Network [OSTI]

    Wei, Jun-Jie; Melia, Fulvio

    2015-01-01T23:59:59.000Z

    The use of type Ic Super Luminous Supernovae (SLSN Ic) to examine the cosmological expansion introduces a new standard ruler with which to test theoretical models. The sample suitable for this kind of work now includes 11 SLSNe Ic, which have thus far been used solely in tests involving $\\Lambda$CDM. In this paper, we broaden the base of support for this new, important cosmic probe by using these observations to carry out a one-on-one comparison between the $R_{\\rm h}=ct$ and $\\Lambda$CDM cosmologies. We individually optimize the parameters in each cosmological model by minimizing the $\\chi^{2}$ statistic. We also carry out Monte Carlo simulations based on these current SLSN Ic measurements to estimate how large the sample would have to be in order to rule out either model at a $\\sim 99.7\\%$ confidence level. The currently available sample indicates a likelihood of $\\sim$$70-80\\%$ that the $R_{\\rm h}=ct$ Universe is the correct cosmology versus $\\sim$$20-30\\%$ for the standard model. These results are suggest...

  16. COSMOLOGY WITH PHOTOMETRICALLY CLASSIFIED TYPE Ia SUPERNOVAE FROM THE SDSS-II SUPERNOVA SURVEY

    SciTech Connect (OSTI)

    Campbell, Heather; D'Andrea, Chris B; Nichol, Robert C.; Smith, Mathew; Lampeitl, Hubert [Institute of Cosmology and Gravitation, University of Portsmouth, Portsmouth, PO1 3FX (United Kingdom)] [Institute of Cosmology and Gravitation, University of Portsmouth, Portsmouth, PO1 3FX (United Kingdom); Sako, Masao [Department of Physics and Astronomy, University of Pennsylvania, 209 South 33rd Street, Philadelphia, PA 19104 (United States)] [Department of Physics and Astronomy, University of Pennsylvania, 209 South 33rd Street, Philadelphia, PA 19104 (United States); Olmstead, Matthew D.; Brown, Peter; Dawson, Kyle S. [Department of Physics and Astronomy, University of Utah, 115 South 1400 East 201, Salt Lake City, UT 84112 (United States)] [Department of Physics and Astronomy, University of Utah, 115 South 1400 East 201, Salt Lake City, UT 84112 (United States); Bassett, Bruce [Mathematics Department, University of Cape Town, Rondebosch, Cape Town (South Africa)] [Mathematics Department, University of Cape Town, Rondebosch, Cape Town (South Africa); Biswas, Rahul; Kuhlmann, Steve [Argonne National Laboratory, 9700 South Cass Avenue, Lemont, IL 60439 (United States)] [Argonne National Laboratory, 9700 South Cass Avenue, Lemont, IL 60439 (United States); Cinabro, David [Department of Physics and Astronomy, Wayne State University, Detroit, MI 48126 (United States)] [Department of Physics and Astronomy, Wayne State University, Detroit, MI 48126 (United States); Dilday, Ben [Las Cumbres Observatory Global Telescope Network, 6740 Cortona Dr., Suite 102, Goleta, CA 93117 (United States)] [Las Cumbres Observatory Global Telescope Network, 6740 Cortona Dr., Suite 102, Goleta, CA 93117 (United States); Foley, Ryan J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)] [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Frieman, Joshua A. [Department of Astronomy and Astrophysics, The University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 (United States)] [Department of Astronomy and Astrophysics, The University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 (United States); Garnavich, Peter [Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States)] [Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Hlozek, Renee [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States)] [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Jha, Saurabh W. [Department of Physics and Astronomy, Rutgers University, 136 Frelinghuysen Road, Piscataway, NJ 08854 (United States)] [Department of Physics and Astronomy, Rutgers University, 136 Frelinghuysen Road, Piscataway, NJ 08854 (United States); Kunz, Martin, E-mail: Heather.Campbell@port.ac.uk [African Institute for Mathematical Sciences, Muizenberg, 7945, Cape Town (South Africa)] [African Institute for Mathematical Sciences, Muizenberg, 7945, Cape Town (South Africa); and others

    2013-02-15T23:59:59.000Z

    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. Our photometric-classification method is based on the SN classification technique of Sako et al., aided by host-galaxy redshifts (0.05 < z < 0.55). SuperNova ANAlysis simulations of our methodology estimate that we have an SN Ia classification efficiency of 70.8%, with only 3.9% contamination from core-collapse (non-Ia) SNe. We demonstrate that this level of contamination has no effect on our cosmological constraints. We quantify and correct for our selection effects (e.g., Malmquist bias) using simulations. When fitting to a flat {Lambda}CDM cosmological model, we find that our photometric sample alone gives {Omega} {sub m} = 0.24{sup +0.07} {sub -0.05} (statistical errors only). If we relax the constraint on flatness, then our sample provides competitive joint statistical constraints on {Omega} {sub m} and {Omega}{sub {Lambda}}, comparable to those derived from the spectroscopically confirmed Three-year Supernova Legacy Survey (SNLS3). Using only our data, the statistics-only result favors an accelerating universe at 99.96% confidence. Assuming a constant wCDM cosmological model, and combining with H {sub 0}, cosmic microwave background, and luminous red galaxy data, we obtain w = -0.96{sup +0.10} {sub -0.10}, {Omega} {sub m} = 0.29{sup +0.02} {sub -0.02}, and {Omega} {sub k} = 0.00{sup +0.03} {sub -0.02} (statistical errors only), which is competitive with similar spectroscopically confirmed SNe Ia analyses. Overall this comparison is reassuring, considering the lower redshift leverage of the SDSS-II SN sample (z < 0.55) and the lack of spectroscopic confirmation used herein. These results demonstrate the potential of photometrically classified SN Ia samples in improving cosmological constraints.

  17. 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

    2015-01-01T23:59:59.000Z

    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...

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

    E-Print Network [OSTI]

    S. Blinnikov; E. Sorokina

    2002-12-30T23:59:59.000Z

    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.

  19. Fundamental Cosmology from Precision Spectroscopy: II. Synergies with supernovae

    E-Print Network [OSTI]

    Leite, A C O

    2015-01-01T23:59:59.000Z

    In previous work [Amendola {\\it et al.}, Phys. Rev. D86 (2012) 063515], Principal Component Analysis based methods to constrain the dark energy equation of state using Type Ia supernovae and other low redshift probes were extended to spectroscopic tests of the stability fundamental couplings, which can probe higher redshifts. Here we use them to quantify the gains in sensitivity obtained by combining spectroscopic measurements expected from ESPRESSO at the VLT and the high-resolution ultra-stable spectrograph for the E-ELT (known as ELT-HIRES) with future supernova surveys. In addition to simulated low and intermediate redshift supernova surveys, we assess the dark energy impact of high-redshift supernovas detected by JWST and characterized by the E-ELT or TMT. Our results show that a detailed characterization of the dark energy properties beyond the acceleration phase (i.e., deep in the matter era) is viable, and may reach as deep as redshift 4.

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

    SciTech Connect (OSTI)

    Kim, Alex G

    2010-12-10T23:59:59.000Z

    I present an analysis for fitting cosmological parameters from a Hubble Diagram of a standard candle with unknown intrinsic magnitude dispersion. The dispersion is determined from the data themselves, simultaneously with the cosmological parameters. This contrasts with the strategies used to date. The advantages of the presented analysis are that it is done in a single fit (it is not iterative), it provides a statistically founded and unbiased estimate of the intrinsic dispersion, and its cosmological-parameter uncertainties account for the intrinsic dispersion uncertainty. Applied to Type Ia supernovae, my strategy provides a statistical measure to test for sub-types and assess the significance of any magnitude corrections applied to the calibrated candle. Parameter bias and differences between likelihood distributions produced by the presented and currently-used fitters are negligibly small for existing and projected supernova data sets.

  1. Sampling the Probability Distribution of Type Ia Supernova Lightcurve Parameters in Cosmological Analysis

    E-Print Network [OSTI]

    Dai, Mi

    2015-01-01T23:59:59.000Z

    In order to obtain robust cosmological constraints from Type Ia supernova (SN Ia) data, we have applied Markov Chain Monte Carlo (MCMC) to SN Ia lightcurve fitting. We develop a method for sampling the resultant probability density distributions (pdf) of the SN Ia lightcuve parameters in the MCMC likelihood analysis to constrain cosmological parameters. Applying this method to the Joint Lightcurve Analysis (JLA) data set of SNe Ia, we find that sampling the SN Ia lightcurve parameter pdf's leads to cosmological parameters closer to that of a flat Universe with a cosmological constant, compared to the usual practice of using only the best fit values of the SN Ia lightcurve parameters. Our method will be useful in the use of SN Ia data for precision cosmology.

  2. Supernovae

    E-Print Network [OSTI]

    Trimble, VL

    1981-01-01T23:59:59.000Z

    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.

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

    SciTech Connect (OSTI)

    Kim, Alex G.; Miquel, Ramon

    2005-09-26T23:59:59.000Z

    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.

  4. 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)

    2014-07-01T23:59:59.000Z

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

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

    SciTech Connect (OSTI)

    Milne, Peter A. [University of Arizona, Steward Observatory, 933 North Cherry Avenue, Tucson, AZ 85719 (United States); Brown, Peter J. [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); Roming, Peter W. A. [Space Science and Engineering Division, Southwest Research Corporation, P.O. Drawer 28510, San Antonio, TX 78228-0510 (United States); Bufano, Filomena [Universidad Andres Bello, Departmento de Cincias Fisicas, Avda. Republica 220, Santiago (Chile); Gehrels, Neil, E-mail: pbrown@physics.tamu.edu [NASA-Goddard Space Flight Center, Astrophysics Science Division, Codes 660.1 and 662, Greenbelt, MD 20771 (United States)

    2013-12-10T23:59:59.000Z

    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.

  6. What do the cosmological supernova data really tell us?

    E-Print Network [OSTI]

    Semiz, ?brahim

    2015-01-01T23:59:59.000Z

    Not much by themselves, aparently. We try to reconstruct the scale factor $a(t)$ of the universe from the SNe Ia data, i.e. the luminosity distance $d_{L}(z)$, using only the cosmological principle and the assumption that gravitation is governed by a metric theory. In our hence "model-independent," or "cosmographic" study, we fit functions to $d_{L}(z)$ rather than $a(t)$, since $d_{L}(z)$ is what is measured. We find that the acceleration history of the universe cannot be reliably determined in this approach due to the irregularity and parametrization-dependence of the results. However, adding the GRB data to the dataset cures most of the irregularities, at the cost of compromising the model-independent nature of the study slightly. Then we can determine the redshift of transition to cosmic acceleration as $z_{\\rm t} \\sim 0.50 \\pm 0.09$ for a flat universe (larger for positive spatial curvature). If Einstein gravity (GR) is assumed, we find a redshift at which the density of the universe predicted from the $...

  7. What do the cosmological supernova data really tell us?

    E-Print Network [OSTI]

    ?brahim Semiz; A. Kaz?m Çaml?bel

    2015-05-15T23:59:59.000Z

    Not much by themselves, aparently. We try to reconstruct the scale factor $a(t)$ of the universe from the SNe Ia data, i.e. the luminosity distance $d_{L}(z)$, using only the cosmological principle and the assumption that gravitation is governed by a metric theory. In our hence "model-independent," or "cosmographic" study, we fit functions to $d_{L}(z)$ rather than $a(t)$, since $d_{L}(z)$ is what is measured. We find that the acceleration history of the universe cannot be reliably determined in this approach due to the irregularity and parametrization-dependence of the results. However, adding the GRB data to the dataset cures most of the irregularities, at the cost of compromising the model-independent nature of the study slightly. Then we can determine the redshift of transition to cosmic acceleration as $z_{\\rm t} \\sim 0.50 \\pm 0.09$ for a flat universe (larger for positive spatial curvature). If Einstein gravity (GR) is assumed, we find a redshift at which the density of the universe predicted from the $d_{L}(z)$ data is independent of curvature. We use this point to derive an upper limit on matter density, hence a lower limit on the density of dark energy. While these limits do not improve the generally accepted ones, they are derived *only using the $d_{L}(z)$ data*.

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

    E-Print Network [OSTI]

    Perlmutter, S.

    2010-01-01T23:59:59.000Z

    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.

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

    E-Print Network [OSTI]

    2008-01-01T23:59:59.000Z

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

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

    E-Print Network [OSTI]

    Kim, Alex G

    2011-01-01T23:59:59.000Z

    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

  11. 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)

    2014-06-01T23:59:59.000Z

    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.

  12. Constructing a cosmological model-independent Hubble diagram of type Ia supernovae with cosmic chronometers

    E-Print Network [OSTI]

    Li, Zhengxiang; Yu, Hongwei; Zhu, Zong-Hong; Alcaniz, J S

    2015-01-01T23:59:59.000Z

    We apply two methods to reconstruct the Hubble parameter $H(z)$ as a function of redshift from 15 measurements of the expansion rate obtained from age estimates of passively evolving galaxies. These reconstructions enable us to derive the luminosity distance to a certain redshift $z$, calibrate the light-curve fitting parameters accounting for the (unknown) intrinsic magnitude of type Ia supernova (SNe Ia) and construct cosmological model-independent Hubble diagrams of SNe Ia. In order to test the compatibility between the reconstructed functions of $H(z)$, we perform a statistical analysis considering the latest SNe Ia sample, the so-called JLA compilation. We find that, while one of the reconstructed functions leads to a value of the local Hubble parameter $H_0$ in excellent agreement with the one reported by the Planck collaboration, the other requires a higher value of $H_0$, which is consistent with recent measurements of this quantity from Cepheids and other local distance indicators.

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

    E-Print Network [OSTI]

    Goobar, A.

    2008-01-01T23:59:59.000Z

    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

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

    E-Print Network [OSTI]

    Kim, Alex G.; Miquel, Ramon

    2005-01-01T23:59:59.000Z

    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

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

    E-Print Network [OSTI]

    Perlmutter, S.

    2010-01-01T23:59:59.000Z

    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-

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

    E-Print Network [OSTI]

    Podariu, Silviu; Nugent, Peter; Ratra, Bharat

    2000-01-01T23:59:59.000Z

    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. Hubble Space Telescope and Ground-Based Observations of Type Ia Supernovae at Redshift 0.5: Cosmological Implications

    E-Print Network [OSTI]

    A. Clocchiatti; B. Schmidt; A. Filippenko; P. Challis; A. Coil; R. Covarrubias; A. Diercks; P. Garnavich; L. Germany; R. Gilliland; C. Hogan; S. Jha; R. Kirshner; B. Leibundgut; D. Leonard; W. Li; T. Matheson; M. Phillips; J. Prieto; D. Reiss; A. Riess; R. Schommer; R. Smith; A. Soderberg; J. Spyromilio; C. Stubbs; N. Suntzeff; J. Tonry; P. Woudt; for the High Z SN Search Collaboration

    2005-10-05T23:59:59.000Z

    We present observations of the Type Ia supernovae (SNe) 1999M, 1999N, 1999Q, 1999S, and 1999U, at redshift z~0.5. They were discovered in early 1999 with the 4.0~m Blanco telescope at Cerro Tololo Inter-American Observatory by the High-z Supernova Search Team (HZT) and subsequently followed with many ground-based telescopes. SNe 1999Q and 1999U were also observed with the Hubble Space Telescope. We computed luminosity distances to the new SNe using two methods, and added them to the high-z Hubble diagram that the HZT has been constructing since 1995. The new distance moduli confirm the results of previous work. At z~0.5, luminosity distances are larger than those expected for an empty universe, implying that a ``Cosmological Constant,'' or another form of ``dark energy,'' has been increasing the expansion rate of the Universe during the last few billion years.

  18. Hubble Space Telescope and Ground-Based Observations of Type Ia Supernovae at Redshift 0.5: Cosmological Implications

    E-Print Network [OSTI]

    Clocchiatti, A; Filippenko, A V; Challis, P; Coil, A; Covarrubias, R; Diercks, A H; Garnavich, P M; Germany, L; Gilliland, R L; Hogan, C; Jha, S; Kirshner, R; Leibundgut, B; Leonard, D; Li, W; Matheson, T; Phillips, M; Prieto, J; Reiss, D; Riess, A; Schommer, R; Smith, R; Soderberg, A M; Spyromilio, J; Stubbs, C; Suntzeff, N; Tonry, J; Woudt, P

    2006-01-01T23:59:59.000Z

    We present observations of the Type Ia supernovae (SNe) 1999M, 1999N, 1999Q, 1999S, and 1999U, at redshift z~0.5. They were discovered in early 1999 with the 4.0~m Blanco telescope at Cerro Tololo Inter-American Observatory by the High-z Supernova Search Team (HZT) and subsequently followed with many ground-based telescopes. SNe 1999Q and 1999U were also observed with the Hubble Space Telescope. We computed luminosity distances to the new SNe using two methods, and added them to the high-z Hubble diagram that the HZT has been constructing since 1995. The new distance moduli confirm the results of previous work. At z~0.5, luminosity distances are larger than those expected for an empty universe, implying that a ``Cosmological Constant,'' or another form of ``dark energy,'' has been increasing the expansion rate of the Universe during the last few billion years.

  19. 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

    2012-11-05T23:59:59.000Z

    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.

  20. The $m$-$z$ relation for type Ia supernovae, locally inhomogeneous cosmological models, and the nature of dark matter

    E-Print Network [OSTI]

    Helbig, Phillip

    2015-01-01T23:59:59.000Z

    The $m$-$z$ relation for type Ia supernovae is one of the key pieces of evidence supporting the cosmological `concordance model' with $\\lambda_0 \\approx 0.7$ and $\\Omega_0 \\approx 0.3$. However, it is well known that the $m$-$z$ relation depends not only on $\\lambda_0$ and $\\Omega_0$ (with $H_0$ as a scale factor) but also on the density of matter along the line of sight, which is not necessarily the same as the large-scale density. I investigate to what extent the measurement of $\\lambda_0$ and $\\Omega_0$ depends on this density when it is characterized by the parameter $\\eta$ ($0 \\le \\eta \\le 1$), which describes the ratio of density along the line of sight to the overall density. I also discuss what constraints can be placed on $\\eta$, both with and without constraints on $\\lambda_0$ and $\\Omega_0$ in addition to those from the $m$-$z$ relation for type~Ia supernovae.

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

    E-Print Network [OSTI]

    Andrzej Borowiec; Wlodzimierz Godlowski; Marek Szydlowski

    2006-08-03T23:59:59.000Z

    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.

  2. Evolution of cosmological perturbations in a renormalization-group-driven inflationary scenario

    SciTech Connect (OSTI)

    Contillo, Adriano [SISSA, Via Bonomea 265, I-34136 Trieste (Italy) and INFN, Sezione di Trieste, I-34127 Trieste (Italy)

    2011-04-15T23:59:59.000Z

    A gauge-invariant, linear cosmological perturbation theory of an almost homogeneous and isotropic universe with dynamically evolving Newton constant G and cosmological constant {Lambda} is presented. The equations governing the evolution of the comoving fractional spatial gradients of the matter density, G and {Lambda}, are thus obtained. Explicit solutions are discussed in cosmologies, featuring an accelerated expansion, where both G and {Lambda} vary according to renormalization group equations in the vicinity of an ultraviolet fixed point. Finally, a similar analysis is carried out in the late universe regime described by the part of the renormalization group trajectory close to the Gaussian fixed point.

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

    E-Print Network [OSTI]

    2001-01-01T23:59:59.000Z

    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. Snapping Supernovae at z>1.7

    E-Print Network [OSTI]

    Aldering, Greg

    2009-01-01T23:59:59.000Z

    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

  5. Aspherical supernovae

    SciTech Connect (OSTI)

    Kasen, Daniel Nathan

    2004-05-21T23:59:59.000Z

    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?

  6. The kinematics of the Local Group in a cosmological context

    E-Print Network [OSTI]

    Forero-Romero, Jaime E; Bustamante, Sebastian; Gottloeber, Stefan; Yepes, Gustavo

    2013-01-01T23:59:59.000Z

    Recent observations constrained the tangential velocity of M31 with respect to the Milky Way (MW) to be v_tan<34.4 km/s and the radial velocity to be in the range v_rad=-109+/- 4.4 km/s (van der Marel et al. 2012). 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 LCDM. The comparison of the ensembles of simulated pairs with the observed 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_tot), angular momentum (l_orb) and the dimensionless spin parameter, lambda. Our main results are: (i) the preferred radial and tangential velocities for pairs in LCDM are v_rad=-80+/-20 km/s, v_tan=50+/-10 km/s, (ii) pairs around that region are 3 to 13 times more common than pairs within the observational values, (iii) 15%to 24% of LG-like pairs in LCDM have energy and angular momentum...

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

    E-Print Network [OSTI]

    2001-01-01T23:59:59.000Z

    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.

  8. Thermonuclear Supernovae

    E-Print Network [OSTI]

    F. K. Roepke

    2008-04-14T23:59:59.000Z

    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.

  9. Numerical solutions of Einstein's equations for cosmological spacetimes with spatial topology S3 and symmetry group U(1)

    E-Print Network [OSTI]

    Florian Beyer; Leon Escobar; Jörg Frauendiener

    2015-05-21T23:59:59.000Z

    We apply a single patch pseudo-spectral scheme based on integer spin-weighted spherical harmonics presented in [1, 2] to Einstein's equations. The particular hyperbolic reduction of Einstein's equations which we use is obtained by a covariant version of the generalized harmonic formalism and Geroch's symmetry reduction. In this paper we focus on spacetimes with a spatial S3-topology and symmetry group U(1). We discuss analytical and numerical issues related to our implementation. As a test, we reproduce numerically exact inhomogeneous cosmological solutions of the vacuum Einstein field equations obtained in [3].

  10. Numerical solutions of Einstein's equations for cosmological spacetimes with spatial topology S3 and symmetry group U(1)

    E-Print Network [OSTI]

    Beyer, Florian; Frauendiener, Jörg

    2015-01-01T23:59:59.000Z

    We apply a single patch pseudo-spectral scheme based on integer spin-weighted spherical harmonics presented in [1, 2] to Einstein's equations. The particular hyperbolic reduction of Einstein's equations which we use is obtained by a covariant version of the generalized harmonic formalism and Geroch's symmetry reduction. In this paper we focus on spacetimes with a spatial S3-topology and symmetry group U(1). We discuss analytical and numerical issues related to our implementation. As a test, we reproduce numerically exact inhomogeneous cosmological solutions of the vacuum Einstein field equations obtained in [3].

  11. The First Ten Years of Swift Supernovae

    E-Print Network [OSTI]

    Brown, Peter J; Milne, Peter A

    2015-01-01T23:59:59.000Z

    The Swift Gamma Ray Burst Explorer has proven to be an incredible platform for studying the multiwavelength properties of supernova explosions. In its first ten years, Swift has observed over three hundred supernovae. The ultraviolet observations reveal a complex diversity of behavior across supernova types and classes. Even amongst the standard candle type Ia supernovae, ultraviolet observations reveal distinct groups. When the UVOT data is combined with higher redshift optical data, the relative populations of these groups appear to change with redshift. Among core-collapse supernovae, Swift discovered the shock breakout of two supernovae and the Swift data show a diversity in the cooling phase of the shock breakout of supernovae discovered from the ground and promptly followed up with Swift. Swift observations have resulted in an incredible dataset of UV and X-ray data for comparison with high-redshift supernova observations and theoretical models. Swift's supernova program has the potential to dramaticall...

  12. Aspherical supernovae

    E-Print Network [OSTI]

    Kasen, Daniel Nathan

    2004-01-01T23:59:59.000Z

    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

  13. Cosmological constraints from the virial mass function of nearby galaxy groups and clusters

    E-Print Network [OSTI]

    Hill, James Colin

    2008-01-01T23:59:59.000Z

    In this thesis, I present a new determination of the cluster mass function in a volume ~107 h-03 70 Mpc3 using the ROSAT-2MASS-FAST Group Survey (R2FGS). R2FGS is an X-ray-selected sample of systems from the ROSAT All-Sky ...

  14. The nearby supernova factory

    E-Print Network [OSTI]

    2004-01-01T23:59:59.000Z

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

  15. 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)

    2012-09-15T23:59:59.000Z

    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.

  16. The ESSENCE Supernova Survey: Survey Optimization, Observations, and Supernova Photometry

    SciTech Connect (OSTI)

    Miknaitis, Gajus; Pignata, G.; Rest, A.; Wood-Vasey, W.M.; Blondin, S.; Challis, P.; Smith, R.C.; Stubbs, C.W.; Suntzeff, N.B.; Foley, R.J.; Matheson, T.; Tonry, J.L.; Aguilera, C.; Blackman, J.W.; Becker, A.C.; Clocchiatti, A.; Covarrubias, R.; Davis, T.M.; Filippenko, A.V.; Garg, A.; Garnavich, P.M.; /Fermilab /Chile U., Catolica /Cerro-Tololo

    2007-01-08T23:59:59.000Z

    We describe the implementation and optimization of the ESSENCE supernova survey, which we have undertaken to measure the equation of state parameter of the dark energy. We present a method for optimizing the survey exposure times and cadence to maximize our sensitivity to the dark energy equation of state parameter w = P/{rho}c{sup 2} for a given fixed amount of telescope time. For our survey on the CTIO 4m telescope, measuring the luminosity distances and redshifts for supernovae at modest redshifts (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 and in near real-time. Since making cosmological inferences with supernovae relies crucially on accurate measurement of their brightnesses, we describe our efforts to establish a thorough calibration of the CTIO 4m natural photometric system. In its first four years, ESSENCE has discovered and spectroscopically confirmed 102 type Ia SNe, at redshifts from 0.10 to 0.78, identified through an impartial, effective methodology for spectroscopic classification and redshift determination. We present the resulting light curves for the all type Ia supernovae found by ESSENCE and used in our measurement of w, presented in Wood-Vasey et al. (2007).

  17. Supernovae. Part II: The aftermath

    E-Print Network [OSTI]

    Trimble, V

    1983-01-01T23:59:59.000Z

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

  18. Core-collapse Supernovae

    SciTech Connect (OSTI)

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

    2013-01-01T23:59:59.000Z

    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 (growing to gigameter scale) down to femtometer scale nuclear reactions. Carrying 10$^{51}$ ergs 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.

  19. SOUSA's Swift Supernova Siblings

    E-Print Network [OSTI]

    Brown, Peter J

    2015-01-01T23:59:59.000Z

    Swift has observed over three hundred supernovae in its first ten years. Photometry from the Ultra-Violet Optical Telescope (UVOT) is being compiled in the Swift Optical/Ultraviolet Supernovae Archive (SOUSA). The diversity of supernovae leads to a wide dynamic range of intrinsic properties. The intrinsic UV brightness of supernovae as a function of type and epoch allows one to understand the distance ranges at which Swift can reliably detect supernovae. The large Swift sample also includes supernovae from the same galaxy as other Swift supernovae. Through the first ten years, these families include 34 supernovae from 16 host galaxies (two galaxies have each hosted three Swift supernovae).

  20. 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

    1999-07-27T23:59:59.000Z

    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.

  1. 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)

    2013-08-10T23:59:59.000Z

    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}.

  2. Unparticle effects in Supernovae cooling

    E-Print Network [OSTI]

    Prasanta Kumar Das

    2007-11-08T23:59:59.000Z

    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.

  3. Supernovae. Old supernova dust factory revealed at the Galactic center.

    E-Print Network [OSTI]

    Lau, RM; Herter, TL; Morris, MR; Li, Z; Adams, JD

    2015-01-01T23:59:59.000Z

    results suggest that supernovae may indeed be the dominantsupports the paradigm that supernovae are an important dustmetal-enriched ejecta, supernovae (SNe) are believed to be

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

    E-Print Network [OSTI]

    Ellis, R; Ellis, Richard; Sullivan, Mark

    2000-01-01T23:59:59.000Z

    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.

  5. Dust around Type Ia supernovae

    E-Print Network [OSTI]

    Wang, Lifan

    2005-01-01T23:59:59.000Z

    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

  6. Supernovae and the IGM

    E-Print Network [OSTI]

    James Binney

    2000-08-23T23:59:59.000Z

    An energetic argument implies that a galaxy like the Milky Way is blowing a powerful wind that carries away most of the heavy elements currently synthesized and has impacted the IGM out to at least 180 kpc. Rich clusters of galaxies appear to be closed systems in which most heavy elements are ejected from galaxies. More supernovae are required than the yield of core-collapse SNe from a Salpeter IMF. X-ray observations imply that the IGM in groups and clusters as been strongly preheated. SNe probably cannot supply the required energy, which must come from AGN.

  7. K-corrections and extinction corrections for Type Ia supernovae

    SciTech Connect (OSTI)

    Nugent, Peter; Kim, Alex; Perlmutter, Saul

    2002-05-21T23:59:59.000Z

    The measurement of the cosmological parameters from Type Ia supernovae hinges on our ability to compare nearby and distant supernovae accurately. Here we present an advance on a method for performing generalized K-corrections for Type Ia supernovae which allows us to compare these objects from the UV to near-IR over the redshift range 0 < z < 2. We discuss the errors currently associated with this method and how future data can improve upon it significantly. We also examine the effects of reddening on the K-corrections and the light curves of Type Ia supernovae. Finally, we provide a few examples of how these techniques affect our current understanding of a sample of both nearby and distant supernovae.

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

    E-Print Network [OSTI]

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

    1999-10-02T23:59:59.000Z

    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.

  9. Supernovae as stellar objects

    E-Print Network [OSTI]

    W. Hillebrandt; M. Reinecke; J. C. Niemeyer

    2000-12-04T23:59:59.000Z

    Type Ia supernovae (SN Ia) are generally believed to be the result of the thermonuclear disruption of Chandrasekhar-mass carbon-oxygen white dwarfs, mainly because such thermonuclear explosions can account for the right amount of nickel, which is needed to explain the light curves and the late-time spectra, and the abundances of intermediate-mass nuclei which dominate the spectra near maximum light. Because of their enormous brightness and apparent homogeneity SN Ia have become an important tool to measure cosmological parameters. In this article the present understanding of the physics of thermonuclear explosions is reviewed. In particular, we focus our attention on subsonic ("deflagration") fronts, i.e. we investigate fronts propagating by heat diffusion and convection rather than by compression. Models based upon this mode of nuclear burning have been applied very successfully to the SN Ia problem, and are able to reproduce many of their observed features remarkably well. However, the models also indicate that SN Ia may differ considerably from each other, which is of importance if they are to be used as standard candles.

  10. Relics of subluminous supernovae in metal-poor stars

    E-Print Network [OSTI]

    Takuji Tsujimoto; Toshikazu Shigeyama

    2003-01-14T23:59:59.000Z

    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.

  11. Rates and progenitors of type Ia supernovae

    E-Print Network [OSTI]

    Wood-Vasey, William Michael

    2004-01-01T23:59:59.000Z

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

  12. 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

    2015-01-01T23:59:59.000Z

    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.

  13. Bodo Ziegler VERA seminar Wien 27.10.2011 2011 Nobel Prize in Physics: Supernovae explosions and the Accelerating Universe

    E-Print Network [OSTI]

    Ziegler, Bodo Leonhardt

    and the Accelerating Universe Bodo Ziegler Nobel Prize for Physics 2011 Institute for Astronomy University of Vienna Nobel Prize in Physics: Supernovae explosions and the Accelerating Universe For the discovery Prize in Physics: Supernovae explosions and the Accelerating Universe Overview Basic Cosmology Stellar

  14. 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

  15. Neutrino flavor transformation in core-collapse supernovae

    E-Print Network [OSTI]

    Cherry, John F.; Cherry, John F.

    2012-01-01T23:59:59.000Z

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

  16. SUPERNOVAE - FEWER AND FURTHER BETWEEN

    E-Print Network [OSTI]

    TRIMBLE, V

    1988-01-01T23:59:59.000Z

    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

  17. Supernovae. Part I: The events

    E-Print Network [OSTI]

    Trimble, V

    1982-01-01T23:59:59.000Z

    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,

  18. THE BERKELEY AUTOMATED SUPERNOVA SEARCH

    E-Print Network [OSTI]

    Kare, J.T.

    2010-01-01T23:59:59.000Z

    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),

  19. Conformally Friedmann-Lemaitre-Robertson-Walker cosmologies

    E-Print Network [OSTI]

    Visser, Matt

    2015-01-01T23:59:59.000Z

    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...

  20. Atomic and molecular supernovae

    SciTech Connect (OSTI)

    Liu, W.

    1997-12-01T23:59:59.000Z

    Atomic and molecular physics of supernovae is discussed with an emphasis on the importance of detailed treatments of the critical atomic and molecular processes with the best available atomic and molecular data. The observations of molecules in SN 1987A are interpreted through a combination of spectral and chemical modelings, leading to strong constraints on the mixing and nucleosynthesis of the supernova. The non-equilibrium chemistry is used to argue that carbon dust can form in the oxygen-rich clumps where the efficient molecular cooling makes the nucleation of dust grains possible. For Type Ia supernovae, the analyses of their nebular spectra lead to strong constraints on the supernova explosion models.

  1. Supernova Hunting with Supercomputers

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

    Berkeley researchers provide "roadmap" and tools for finding and studying Type Ia supernovae in their natural habitat May 20, 2015 | Tags: Astrophysics, Edison Contact: Linda...

  2. Search for: supernovae | DOE PAGES

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

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

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

    E-Print Network [OSTI]

    Yong-Seon Song; Wayne Hu

    2005-07-29T23:59:59.000Z

    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.

  4. Marginal evidence for cosmic acceleration from Type Ia supernovae

    E-Print Network [OSTI]

    Nielsen, Jeppe Trøst; Sarkar, Subir

    2015-01-01T23:59:59.000Z

    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.

  5. A Supernova Riddle

    E-Print Network [OSTI]

    Douglas C. Leonard

    2007-12-24T23:59:59.000Z

    Analysis of the polarization of light from supernovae can reveal the shape and distribution of matter ejected from exploding stars. Here we review the young field of Type Ia supernova spectropolarimetry and critically evaluate, and place in context, the recent work of Wang et al. (2007, Science, 315, 212) in which a suggestive trend is found in data from 17 Type Ia events.

  6. Public reaction to a v = -125 supernova

    E-Print Network [OSTI]

    Hockey, T; Trimble, V

    2010-01-01T23:59:59.000Z

    A. Green, Historical Supernovae and their Remnants (Oxford30 pc). On the other hand, supernovae reach absolute visualcase of core-collapse supernovae, the more common sort ——

  7. Supernovae: Little bear's mass loss rate

    E-Print Network [OSTI]

    Trimble, VL

    1985-01-01T23:59:59.000Z

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

  8. 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

    2007-01-01T23:59:59.000Z

    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.

  9. Supernova Recognition using Support Vector Machines

    E-Print Network [OSTI]

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

    2006-01-01T23:59:59.000Z

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

  10. Does Standard Cosmology Express Cosmological Principle Faithfully?

    E-Print Network [OSTI]

    Ding-fang Zeng; Hai-jun Zhao

    2005-06-30T23:59:59.000Z

    In 1+1 dimensional case, Einstein equation cannot give us any information on the evolution of the universe because the Einstein tensor of the system is identically zero. We study such a 1+1 dimensional cosmology and find the metric of it according to cosmological principle and special relativity, but the results contradict the usual expression of cosmological principle of standard cosmology. So we doubt in 1+3 dimensional case, cosmological principle is expressed faithfully by standard cosmology.

  11. Supersymmetric quantum cosmological billiards

    SciTech Connect (OSTI)

    Kleinschmidt, Axel; Koehn, Michael; Nicolai, Hermann [Physique Theorique et Mathematique and International Solvay Institutes, Universite Libre de Bruxelles, Boulevard du Triomphe, ULB-CP231, BE-1050 Bruxelles (Belgium); Max-Planck-Institut fuer Gravitationsphysik, Albert-Einstein-Institut, Am Muehlenberg 1, DE-14476 Golm (Germany)

    2009-09-15T23:59:59.000Z

    D=11 supergravity near a spacelike singularity admits a cosmological billiard description based on the hyperbolic Kac-Moody group E{sub 10}. The quantization of this system via the supersymmetry constraint is shown to lead to wave functions involving automorphic (Maass wave) forms under the modular group W{sup +}(E{sub 10}) congruent with PSL{sub 2}(O) with Dirichlet boundary conditions on the billiard domain. A general inequality for the Laplace eigenvalues of these automorphic forms implies that the wave function of the Universe is generically complex and always tends to zero when approaching the initial singularity. We discuss possible implications of this result for the question of singularity resolution in quantum cosmology and comment on the differences with other approaches.

  12. Cosmological bootstrap

    E-Print Network [OSTI]

    V. V. Kiselev; S. A. Timofeev

    2012-04-04T23:59:59.000Z

    A huge value of cosmological constant characteristic for the particle physics and the inflation of early Universe are inherently related to each other: one can construct a fine-tuned superpotential, which produces a flat potential of inflaton with a constant density of energy $V=\\Lambda^4$ after taking into account for leading effects due to the supergravity, so that an introduction of small quantum loop-corrections to parameters of this superpotential naturally results in the dynamical instability relaxing the primary cosmological constant by means of inflationary regime. The model phenomenologically agrees with observational data on the large scale structure of Universe at $\\Lambda~10^{16}$ GeV.

  13. Black hole evolution: I. Supernova-regulated black hole growth

    E-Print Network [OSTI]

    Dubois, Yohan; Silk, Joseph; Devriendt, Julien; Slyz, Adrianne; Teyssier, Romain

    2015-01-01T23:59:59.000Z

    The growth of a supermassive black hole (BH) is determined by how much gas the host galaxy is able to feed it, which in turn is controlled by the cosmic environment, through galaxy mergers and accretion of cosmic flows that time how galaxies obtain their gas, but also by internal processes in the galaxy, such as star formation and feedback from stars and the BH itself. In this paper, we study the growth of a 10^12 Msun halo at z=2, which is the progenitor of an archetypical group of galaxies at z=0, and of its central BH by means of a high-resolution zoomed cosmological simulation, the Seth simulation. We study the evolution of the BH driven by the accretion of cold gas in the galaxy, and explore the efficiency of the feedback from supernovae (SNe). For a relatively inefficient energy input from SNe, the BH grows at the Eddington rate from early times, and reaches self-regulation once it is massive enough. We find that at early cosmic times z>3.5, efficient feedback from SNe forbids the formation of a settled...

  14. Nucleosynthesis in Thermonuclear Supernovae

    SciTech Connect (OSTI)

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

    2013-01-01T23:59:59.000Z

    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.

  15. Bulk viscous cosmology: statefinder and entropy

    E-Print Network [OSTI]

    M. Hu; Xin He Meng

    2005-11-23T23:59:59.000Z

    The statefinder diagnostic pair is adopted to differentiate viscous cosmology models and it is found that the trajectories of these viscous cosmology models on the statefinder pair $s-r$ plane are quite different from those of the corresponding non-viscous cases. Particularly for the quiessence model, the singular properties of state parameter $w=-1$ are obviously demonstrated on the statefinder diagnostic pair planes. We then discuss the entropy of the viscous / dissipative cosmology system which may be more practical to describe the present cosmic observations as the perfect fluid is just a global approximation to the complicated cosmic media in current universe evolution. When the bulk viscosity takes the form of $\\zeta=\\zeta_{1}\\dot{a}/a$($\\zeta_{1}$ is constant), the relationship between the entropy $S$ and the redshift $z$ is explicitly given out. We find that the entropy of the viscous cosmology is always increasing and consistent with the thermodynamics arrow of time for the universe evolution. With the parameter constraints from fitting to the 157 gold data of supernova observations, it is demonstrated that this viscous cosmology model is rather well consistent to the observational data at the lower redshifts, and together with the diagnostic statefinder pair analysis it is concluded that the viscous cosmic models tend to the favored $\\Lambda$CDM model in the later cosmic evolution, agreeable to lots of cosmological simulation results, especially to the fact of confidently observed current accelerating cosmic expansion.

  16. "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

  17. 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)

    2014-07-01T23:59:59.000Z

    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.

  18. Cosmic Supernova Rate History and Type Ia Supernova Progenitors

    E-Print Network [OSTI]

    Chiaki Kobayashi; Ken'ichi Nomoto; Takuji Tsujimoto

    2001-02-14T23:59:59.000Z

    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.

  19. Neutrino oscillations and supernovae

    E-Print Network [OSTI]

    D. V. Ahluwalia-Khalilova

    2004-04-02T23:59:59.000Z

    In a 1996 JRO Fellowship Research Proposal (Los Alamos), the author suggested that neutrino oscillations may provide a powerful indirect energy transport mechanism to supernovae explosions. The principal aim of this addendum is to present the relevant unedited text of Section 1 of that proposal. We then briefly remind, (a) of an early suggestion of Mazurek on vacuum neutrino oscillations and their relevance to supernovae explosion, and (b) Wolfenstein's result on suppression of the effect by matter effects. We conclude that whether or not neutrino oscillations play a significant role in supernovae explosions shall depend if there are shells/regions of space in stellar collapse where matter effects play no essential role. Should such regions exist in actual astrophysical situations, the final outcome of neutrino oscillations on supernovae explosions shall depend, in part, on whether or not the LNSD signal is confirmed. Importantly, the reader is reminded that neutrino oscillations form a set of flavor-oscillation clocks and these clock suffer gravitational redshift which can be as large as 20 percent. This effect must be incorporated fully into any calculation of supernova explosion.

  20. 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

    2011-01-01T23:59:59.000Z

    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 ...

  1. Do Type-Ia Supernovae Constrain the Total Equation of State?

    E-Print Network [OSTI]

    William Komp

    2007-02-01T23:59:59.000Z

    In this paper, we consider a couple of alternative dark energy models using the total equation of state of the cosmological fluid, $\\wt$. These models are fit to the recent type-Ia supernovae data and are compared to previously considered models. The first model is based on the hyperbolic tangent and provides a good estimate of the rate of the transition to dark energy domination. The second model is a cubic spline model. This model demonstrates and quantifies the non-monotonicity in the total equation of state coming from the supernovae observations. At present, the supernovae observations indicate significance to non-monotonically decreasing dark energy. We derive constraints on the spline paramters and compare and constrast the results to the Cosmological Constant dark energy model. Both the hyperbolic and splines models indicate that a precise physical notion of dark enegy is a potentially ever more mysterious quantity?

  2. Accelerated expansion from cosmological holography

    E-Print Network [OSTI]

    van Putten, Maurice H P M

    2015-01-01T23:59:59.000Z

    It is shown that holographic cosmology implies an evolving Hubble radius $c^{-1}\\dot{R}_H = -1 + 3\\Omega_m$ in the presence of a dimensionless matter density $\\Omega_m$ scaled to the closure density $3H^2/8\\pi G$, where $c$ denotes the velocity of light and $H$ and $G$ denote the Hubble parameter and Newton's constant. It reveals a dynamical dark energy and a sixfold increase in gravitational attraction to matter on the scale of the Hubble acceleration. It reproduces the transition redshift $z_t\\simeq 0.4$ to the present epoch of accelerated expansion and is consistent with $(q_0,(dq/dz)_0)$ of the deceleration parameter $q(z)=q_0+(dq/dz)_0z$ observed in Type Ia supernovae.

  3. 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

    2014-01-01T23:59:59.000Z

    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.

  4. 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)

    2014-04-15T23:59:59.000Z

    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.

  5. DUST IN A TYPE Ia SUPERNOVA PROGENITOR: SPITZER SPECTROSCOPY OF KEPLER'S SUPERNOVA REMNANT

    SciTech Connect (OSTI)

    Williams, Brian J.; Borkowski, Kazimierz J.; Reynolds, Stephen P. [Physics Department, North Carolina State University, Raleigh, NC 27695-8202 (United States); Ghavamian, Parviz [Department of Physics, Astronomy, and Geosciences, Towson University, Towson, MD 21252 (United States); Blair, William P. [Department of Physics and Astronomy, Johns Hopkins University, 3400 N. Charles St., Baltimore, MD 21218-2686 (United States); Long, Knox S. [STScI, 3700 San Martin Dr., Baltimore, MD 21218 (United States); Sankrit, Ravi, E-mail: brian.j.williams@nasa.gov [SOFIA/USRA, NASA Ames Research Center, M/S N211-3, Moffett Field, CA 94035 (United States)

    2012-08-10T23:59:59.000Z

    Characterization of the relatively poorly understood progenitor systems of Type Ia supernovae is of great importance in astrophysics, particularly given the important cosmological role that these supernovae play. Kepler's supernova remnant, the result of a Type Ia supernova, shows evidence for an interaction with a dense circumstellar medium (CSM), suggesting a single-degenerate progenitor system. We present 7.5-38 {mu}m infrared (IR) spectra of the remnant, obtained with the Spitzer Space Telescope, dominated by emission from warm dust. Broad spectral features at 10 and 18 {mu}m, consistent with various silicate particles, are seen throughout. These silicates were likely formed in the stellar outflow from the progenitor system during the asymptotic giant branch stage of evolution, and imply an oxygen-rich chemistry. In addition to silicate dust, a second component, possibly carbonaceous dust, is necessary to account for the short-wavelength Infrared Spectrograph and Infrared Array Camera data. This could imply a mixed chemistry in the atmosphere of the progenitor system. However, non-spherical metallic iron inclusions within silicate grains provide an alternative solution. Models of collisionally heated dust emission from fast shocks (>1000 km s{sup -1}) propagating into the CSM can reproduce the majority of the emission associated with non-radiative filaments, where dust temperatures are {approx}80-100 K, but fail to account for the highest temperatures detected, in excess of 150 K. We find that slower shocks (a few hundred km s{sup -1}) into moderate density material (n{sub 0} {approx} 50-250 cm{sup -3}) are the only viable source of heating for this hottest dust. We confirm the finding of an overall density gradient, with densities in the north being an order of magnitude greater than those in the south.

  6. FUZZY SUPERNOVA TEMPLATES. II. PARAMETER ESTIMATION

    SciTech Connect (OSTI)

    Rodney, Steven A. [Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218 (United States); Tonry, John L., E-mail: rodney@jhu.ed, E-mail: jt@ifa.hawaii.ed [Institute for Astronomy, University of Hawaii, Honolulu, HI 96822 (United States)

    2010-05-20T23:59:59.000Z

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

  7. Designer Cosmology

    E-Print Network [OSTI]

    Bruce A. Bassett; David Parkinson; Robert C. Nichol

    2005-07-05T23:59:59.000Z

    We highlight the flexibility of the IPSO experiment-design framework by contrasting its application to CMB, weak lensing and redshift surveys. We illustrate the latter with a 10 parameter MCMC D-optimisation of a dark energy redshift survey. When averaged over a standard dark energy model space the resulting optimal survey typically has only one or two redshift bins, located at zoptimisation we show how the statistical power of such surveys is significantly enhanced. Experiment design is aided by the richness of the figure of merit landscape which means one can impose secondary optimisation criteria at little cost. For example, one may choose either to maximally test a single model (such as \\Lambda CDM) or to get the most general model-independent constraints possible (e.g. on a whole space of dark energy models). Such freedom points to a future where cosmological experiments become increasingly specialised and optimisation increasingly important.

  8. The binary progenitor of Tycho Brahe's 1572 supernova

    E-Print Network [OSTI]

    Pilar Ruiz-Lapuente; Fernando Comeron; Javier Mendez; Ramon Canal; Stephen J. Smartt; Alexei V. Filippenko; Robert L. Kurucz; Ryan Chornock; Ryan J. Foley; Vallery Stanishev; Rodrigo Ibata

    2004-10-28T23:59:59.000Z

    The brightness of type Ia supernovae, and their homogeneity as a class, makes them powerful tools in cosmology, yet little is known about the progenitor systems of these explosions. They are thought to arise when a white dwarf accretes matter from a companion star, is compressed and undergoes a thermonuclear explosion Unless the companion star is another white dwarf (in which case it should be destroyed by the mass-transfer process itself), it should survive and show distinguishing properties. Tycho's supernova is one of the only two type Ia supernovae observed in our Galaxy, and so provides an opportunity to address observationally the identification of the surviving companion. Here we report a survey of the central region of its remnant, around the position of the explosion, which excludes red giants as the mass donor of the exploding white dwarf. We found a type G0--G2 star, similar to our Sun in surface temperature and luminosity (but lower surface gravity), moving at more than three times the mean velocity of the stars at that distance, which appears to be the surviving companion of the supernova.

  9. The type Ia supernovae and the Hubble's constant

    E-Print Network [OSTI]

    Ari Brynjolfsson

    2004-07-20T23:59:59.000Z

    The Hubble's constant is usually surmised to be a constant; but the experiments show a large spread and conflicting estimates. According to the plasma-redshift theory, the Hubble's constant varies with the plasma densities along the line of sight. It varies then slightly with the direction and the distance to a supernova and a galaxy. The relation between the magnitudes of type Ia supernovae and their observed redshifts results in an Hubble's constant with an average value in intergalactic space of 59.44 km per s per Mpc. The standard deviation from this average value is only 0.6 km per s per Mpc, but the standard deviation in a single measurement is about 8.2 km per s per Mpc. These deviations do not include possible absolute calibration errors. The experiments show that the Hubble's constant varies with the intrinsic redshifts of the Milky Way galaxy and the host galaxies for type Ia supernovae, and that it varies with the galactic latitude. These findings support the plasma-redshift theory and contradict the contemporary big-bang theory. Together with the previously reported absence of time dilation in type Ia supernovae measurements, these findings have profound consequences for the standard cosmological theory.

  10. EUNHA: a new cosmological hydro simulation code

    E-Print Network [OSTI]

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

    2014-01-01T23:59:59.000Z

    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...

  11. Overview of the nearby supernova factory

    E-Print Network [OSTI]

    2002-01-01T23:59:59.000Z

    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,

  12. High Rate for Type IC Supernovae

    E-Print Network [OSTI]

    Muller, R.A.

    2008-01-01T23:59:59.000Z

    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.

  13. 1987A: The greatest supernova since Kepler

    E-Print Network [OSTI]

    Trimble, V

    1988-01-01T23:59:59.000Z

    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

  14. A Massive Stellar Burst Before the Supernova

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

    Burst Before the Supernova February 6, 2013 | Tags: Carver, High Energy Physics, supernovae Contact: Linda Vu, lvu@lbl.gov, +1 510 495 2402 An automated supernova hunt is...

  15. Testing the cosmological constant as a candidate for dark energy

    SciTech Connect (OSTI)

    Kratochvil, Jan; Linde, Andrei; Linder, Eric V.; Shmakova, Marina

    2003-12-03T23:59:59.000Z

    It may be difficult to single out the best model of dark energy on the basis of the existing and planned cosmological observations, because many different models can lead to similar observational consequences. However, each particular model can be studied and either found consistent with observations or ruled out. In this paper, we concentrate on the possibility to test and rule out the simplest and by far the most popular of the models of dark energy, the theory described by general relativity with positive vacuum energy (the cosmological constant). We evaluate the conditions under which this model could be ruled out by the future observations made by the Supernova/Acceleration Probe SNAP (both for supernovae and weak lensing) and by the Planck Surveyor cosmic microwave background satellite.

  16. Learning from the Scatter in Type Ia Supernovae

    E-Print Network [OSTI]

    Scott Dodelson; Alberto Vallinotto

    2005-11-02T23:59:59.000Z

    Type Ia Supernovae are standard candles so their mean apparent magnitude has been exploited to learn about the redshift-distance relationship. Besides intrinsic scatter in this standard candle, additional source of scatter is caused by gravitational magnification by large scale structure. Here we probe the dependence of this dispersion on cosmological parameters and show that information about the amplitude of clustering, \\sigma_8, is contained in the scatter. In principle, it will be possible to constrain \\sigma_8 to within 5% with observations of 2000 Type Ia Supernovae. However, extracting this information requires subtlety as the distribution of magnifications is far from Gaussian. If one incorrectly assumes a Gaussian distribution, the estimate of the clustering amplitude will be biased three-\\sigma away from the true value.

  17. Snapping Supernovae at z>1.7

    E-Print Network [OSTI]

    Aldering, Greg

    2009-01-01T23:59:59.000Z

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

  18. Type Ia Supernova Cosmology in the Near-Infrared

    E-Print Network [OSTI]

    Stanishev, V; Amanullah, R; Bassett, B; Fantaye, Y T; Garnavich, P; Hlozek, R; Nordin, J; Okouma, P M; Ostman, L; Sako, M; Scalzo, R; Smith, M

    2015-01-01T23:59:59.000Z

    We main goal of this paper is to test whether the NIR peak magnitudes of SNe Ia could be accurately estimated with only a single observation obtained close to maximum light, provided the time of B band maximum and the optical stretch parameter are known. We obtained multi-epoch UBVRI and single-epoch J and H photometric observations of 16 SNe Ia in the redshift range z=0.037-0.183, doubling the leverage of the current SN Ia NIR Hubble diagram and the number of SNe beyond redshift 0.04. This sample was analyzed together with 102 NIR and 458 optical light curves (LCs) of normal SNe Ia from the literature. The analysis of 45 well-sampled NIR LCs shows that a single template accurately describes them if its time axis is stretched with the optical stretch parameter. This allows us to estimate the NIR peak magnitudes even with one observation obtained within 10 days from B-band maximum. We find that the NIR Hubble residuals show weak correlation with DM_15 and E(B-V), and for the first time we report a possible dep...

  19. Throat Cosmology

    E-Print Network [OSTI]

    Harling, B v

    2010-01-01T23:59:59.000Z

    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...

  20. Supernova Neutrinos Detection On Earth

    E-Print Network [OSTI]

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

    2009-05-12T23:59:59.000Z

    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.

  1. Nucleosynthesis in Type II Supernovae

    E-Print Network [OSTI]

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

    1997-06-03T23:59:59.000Z

    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.

  2. Collective neutrino oscillations in supernovae

    SciTech Connect (OSTI)

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

    2014-06-24T23:59:59.000Z

    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.

  3. Radio Observations of Supernova Remnants

    E-Print Network [OSTI]

    W. Reich

    2002-08-28T23:59:59.000Z

    Supernovae release an enormous amount of energy into the interstellar medium. Their remnants can observationally be traced up to several ten-thousand years. So far more than 230 Galactic supernova remnants (SNRs) have been identified in the radio range. Detailed studies of the different types of SNRs give insight into the interaction of the blast wave with the interstellar medium. Shock accelerated particles are observed, but also neutron stars left from the supernova explosion make their contribution. X-ray observations in conjunction with radio data constrain models of supernova evolution. A brief review of the origin and evolution of SNRs is given, which are compared with supernova statistics and observational limitations. In addition the morphology and characteristics of the different types of SNRs are described, including some recent results and illustrated by SNRs images mostly obtained with the Effelsberg 100-m telescope.

  4. Supernova constraints on multi-coupled dark energy

    SciTech Connect (OSTI)

    Piloyan, Arpine [Yerevan State University, Alex Manoogian 1, Yerevan 0025 (Armenia); Marra, Valerio; Amendola, Luca [Institut für Theoretische Physik, Universität Heidelberg, Philosophenweg 16, 69120 Heidelberg (Germany); Baldi, Marco, E-mail: arpine.piloyan@ysu.am, E-mail: valerio.marra@me.com, E-mail: marco.baldi5@unibo.it, E-mail: l.amendola@thphys.uni-heidelberg.de [Dipartimento di Fisica e Astronomia, Università di Bologna, Viale C. Berti-Pichat 6/2, I-40127, Bologna (Italy)

    2013-07-01T23:59:59.000Z

    The persisting consistency of ever more accurate observational data with the predictions of the standard ?CDM 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 ?CDM 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 [9] 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. Clearly, linear perturbation data and, even more, nonlinear structure formation properties are expected to put much tighter constraints on the allowed coupling range. Nonetheless, 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.

  5. Supernova Neutrinos, LSND

    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: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over Our InstagramStructure ofIndustrial Technologies IndustrialSolar ThermalSupernova

  6. 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: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742EnergyOnItemResearch >Internship Program The NIF and Photon Science|Stories SiteSupernova

  7. 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

    2008-03-25T23:59:59.000Z

    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.

  8. 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)

    2012-04-01T23:59:59.000Z

    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.

  9. Measurements of Faint Supernovae

    E-Print Network [OSTI]

    Robert A. Schommer; N. B. Suntzeff; R. C. Smith

    1999-09-04T23:59:59.000Z

    We summarize the current status of cosmological measurements using SNe Ia. Searches to an average depth of z~0.5 have found approximately 100 SNe Ia to date, and measurements of their light curves and peak magnitudes find these objects to be about 0.25mag fainter than predictions for an empty universe. These measurements imply low values for Omega_M and a positive cosmological constant, with high statistical significance. Searches out to z~1.0-1.2 for SNe Ia (peak magnitudes of I~24.5) will greatly aid in confirming this result, or demonstrate the existence of systematic errors. Multi-epoch spectra of SNe Ia at z~0.5 are needed to constrain possible evolutionary effects. I band searches should be able to find SNe Ia out to z~2. We discuss some simulations of deep searches and discovery statistics at several redshifts.

  10. The origin of supernovae confirmed | EurekAlert! Science News

    E-Print Network [OSTI]

    ... Mar-2009 The origin of supernovae confirmed ... Where do supernovae come from? Astronomers have long ... dying red supergiant stars produced supernovae . The results are published in ...

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

    E-Print Network [OSTI]

    Kim, A. G.

    2014-01-01T23:59:59.000Z

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

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

    E-Print Network [OSTI]

    Trimble, V

    2001-01-01T23:59:59.000Z

    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,

  13. A Probabilistic Approach to Classifying Supernovae Using Photometric Information

    E-Print Network [OSTI]

    Kuznetsova, Natalia V.; Connolly, Brian M.

    2008-01-01T23:59:59.000Z

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

  14. A fast contour descriptor algorithm for supernova image classification

    E-Print Network [OSTI]

    Aragon, Cecilia R.; Aragon, David Bradburn

    2006-01-01T23:59:59.000Z

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

  15. Prospective Type Ia supernova surveys from Dome A

    E-Print Network [OSTI]

    Kim, A.

    2010-01-01T23:59:59.000Z

    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

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

    E-Print Network [OSTI]

    Hsiao, E. Y.

    2008-01-01T23:59:59.000Z

    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

  17. Effect of nuclear structure on Type Ia supernova nucleosynthesis

    E-Print Network [OSTI]

    D. J. Dean

    2000-12-08T23:59:59.000Z

    The relationship among nuclear structure, the weak processes in nuclei, and astrophysics becomes quite apparent in supernova explosion and nucleosynthesis studies. In this brief article, I report on progress made in the last few years on calculating electron capture and beta-decay rates in iron-group nuclei. I also report on applications of these rates to Type-Ia nucleosynthesis studies.

  18. Revisiting the cosmological bias due to local gravitational redshifts

    E-Print Network [OSTI]

    Huang, Zhiqi

    2015-01-01T23:59:59.000Z

    A recent article by Wojtak {\\it et al} (arXiv:1504.00178) pointed out that the local gravitational redshift, despite its smallness ($\\sim 10^{-5}$), can have a noticeable ($\\sim 1\\%$) systematic effect on our cosmological parameter measurements. The authors studied a few extended cosmological models (non-flat $\\Lambda$CDM, $w$CDM, and $w_0$-$w_a$CDM) with a mock supernova dataset. We repeat this calculation and find that the $\\sim 1\\%$ biases are due to strong degeneracy between cosmological parameters. When Cosmic Microwave Background (CMB) data are added to break the degeneracy, the biases due to local gravitational redshift are negligible ($\\lesssim 0.1 \\sigma$).

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

    E-Print Network [OSTI]

    2006-01-01T23:59:59.000Z

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

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

    E-Print Network [OSTI]

    Jing Liu; Hao Wei

    2014-10-15T23:59:59.000Z

    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.

  1. The binary progenitor of Tycho Brahe's 1572 supernova

    E-Print Network [OSTI]

    Ruiz-Lapuente, P; Méndez, J; Canal, R; Smartt, S J; Filippenko, A V; Kurucz, R L; Chornock, R; Foley, R J; Stanishev, V; Ibata, R; Ruiz-Lapuente, Pilar; Comeron, Fernando; Mendez, Javier; Canal, Ramon; Smartt, Stephen J.; Filippenko, Alexei V.; Kurucz, Robert L.; Chornock, Ryan; Foley, Ryan J.; Stanishev, Vallery; Ibata, Rodrigo

    2004-01-01T23:59:59.000Z

    The brightness of type Ia supernovae, and their homogeneity as a class, makes them powerful tools in cosmology, yet little is known about the progenitor systems of these explosions. They are thought to arise when a white dwarf accretes matter from a companion star, is compressed and undergoes a thermonuclear explosion Unless the companion star is another white dwarf (in which case it should be destroyed by the mass-transfer process itself), it should survive and show distinguishing properties. Tycho's supernova is one of the only two type Ia supernovae observed in our Galaxy, and so provides an opportunity to address observationally the identification of the surviving companion. Here we report a survey of the central region of its remnant, around the position of the explosion, which excludes red giants as the mass donor of the exploding white dwarf. We found a type G0--G2 star, similar to our Sun in surface temperature and luminosity (but lower surface gravity), moving at more than three times the mean veloci...

  2. 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)

    2013-11-10T23:59:59.000Z

    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.

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

    E-Print Network [OSTI]

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

    2004-12-07T23:59:59.000Z

    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.

  4. Robust model comparison disfavors power law cosmology

    E-Print Network [OSTI]

    Shafer, Daniel L

    2015-01-01T23:59:59.000Z

    Late-time power law expansion has been proposed as an alternative to the standard cosmological model and shown to be consistent with some low-redshift data. We test power law expansion against the standard flat $\\Lambda$CDM cosmology using goodness-of-fit and model comparison criteria. We consider Type Ia supernova (SN Ia) data from two current compilations (Union2.1 and JLA) along with a current set of baryon acoustic oscillation (BAO) measurements that includes the high-redshift Lyman-$\\alpha$ forest measurements from BOSS quasars. We find that neither power law expansion nor $\\Lambda$CDM is strongly preferred over the other when the SN Ia and BAO data are analyzed separately but that power law expansion is strongly disfavored by the combination. We treat the $R_\\text{h} = ct$ cosmology (a constant rate of expansion) separately and find that it is conclusively disfavored by all combinations of data that include SN Ia observations and a poor overall fit when systematic errors in the SN Ia measurements are ig...

  5. 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

    2000-03-09T23:59:59.000Z

    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.

  6. RESULTS OF THE LICK OBSERVATORY SUPERNOVA SEARCH FOLLOW-UP PHOTOMETRY PROGRAM: BVRI LIGHT CURVES OF 165 TYPE Ia SUPERNOVAE

    SciTech Connect (OSTI)

    Ganeshalingam, Mohan; Li Weidong; Filippenko, Alexei V.; Anderson, Carmen; Foster, Griffin; Griffith, Christopher V.; Joubert, Niels; Leja, Joel; Macomber, Brent; Pritchard, Tyler; Thrasher, Patrick; Winslow, Dustin [Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States); Gates, Elinor L.; Grigsby, Bryant J.; Lowe, Thomas B. [Lick Observatory, P.O. Box 85, Mount Hamilton, CA 95140 (United States)

    2010-10-15T23:59:59.000Z

    We present BVRI light curves of 165 Type Ia supernovae (SNe Ia) from the Lick Observatory Supernova Search follow-up photometry program from 1998 through 2008. Our light curves are typically well sampled (cadence of 3-4 days) with an average of 21 photometry epochs. We describe our monitoring campaign and the photometry reduction pipeline that we have developed. Comparing our data set to that of Hicken et al., with which we have 69 overlapping supernovae (SNe), we find that as an ensemble the photometry is consistent, with only small overall systematic differences, although individual SNe may differ by as much as 0.1 mag, and occasionally even more. Such disagreement in specific cases can have significant implications for combining future large data sets. We present an analysis of our light curves which includes template fits of light-curve shape parameters useful for calibrating SNe Ia as distance indicators. Assuming the B - V color of SNe Ia at 35 days past maximum light can be presented as the convolution of an intrinsic Gaussian component and a decaying exponential attributed to host-galaxy reddening, we derive an intrinsic scatter of {sigma} = 0.076 {+-} 0.019 mag, consistent with the Lira-Phillips law. This is the first of two papers, the second of which will present a cosmological analysis of the data presented herein.

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

    E-Print Network [OSTI]

    Trimble, VL

    2006-01-01T23:59:59.000Z

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

  8. Nucleosynthesis in type Ia supernovae driven by asymmetric thermonuclear ignition

    SciTech Connect (OSTI)

    Maeda, Keiichi [Institute for the Physics and Mathematics of the Universe (IPMU), Todai Institutes for Advanced Study (TODIAS), University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8583 (Japan)

    2012-11-12T23:59:59.000Z

    Type Ia Supernovae (SNe Ia) are believed to be thermonuclear explosions of a white dwarf. They can be used as mature cosmological standardized candles, leading to the discovery of the accelerating expansion of the Universe. However, the explosion mechanism has not yet been fully clarified. In this paper, we first present nucleosynthetic features of a leading explosion scenario, namely a delayed-detonation scenario. Based on this, we propose a new and strong observational constraint on the explosion mechanism through emission lines from neutron-rich Fe-peaks. Especially, we show that an asymmetry in the explosion is likely a generic feature. We further argue that the diversity arising from various viewing angles can be an origin of observational diversities of SNe Ia seen in their spectral features (suspected possible biases in cosmology) and colors (related to the extinction estimate in cosmology). Using these new insights could open up a possibility of using SNe Ia as more precise distance indicators than currently employed.

  9. 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

  10. Towards a Cosmological Hubble Diagram for Type II-PSupernovae

    SciTech Connect (OSTI)

    Nugent, Peter; Sullivan, Mark; Ellis, Richard; Gal-Yam, Avishay; Leonard, Douglas C.; Howell, D. Andrew; Astier, Pierre; Carlberg, RaymondG.; Conley, Alex; Fabbro, Sebastien; Fouchez, Dominique; Neill, James D.; Pain, Reynald; Perrett, Kathy; Pritchet, Chris J; Regnault, Nicolas

    2006-03-20T23:59:59.000Z

    We present the first high-redshift Hubble diagram for Type II-P supernovae (SNe II-P) based upon five events at redshift upto z {approx}0.3. This diagram was constructed using photometry from the Canada-France-Hawaii Telescope Supernova Legacy Survey and absorption line spectroscopy from the Keck observatory. The method used to measure distances to these supernovae is based on recent work by Hamuy&Pinto (2002) and exploits a correlation between the absolute brightness of SNeII-P and the expansion velocities derived from the minimum of the Fe II 516.9 nm P-Cygni feature observed during the plateau phases. We present three refinements to this method which significantly improve the practicality of measuring the distances of SNe II-P at cosmologically interesting redshifts. These are an extinction correction measurement based on the V-I colors at day 50, across-correlation measurement for the expansion velocity and the ability to extrapolate such velocities accurately over almost the entire plateau phase. We apply this revised method to our dataset of high-redshift SNe II-P and find that the resulting Hubble diagram has a scatter of only 0.26 magnitudes, thus demonstrating the feasibility of measuring the expansion history, with present facilities, using a method independent of that based upon supernovae of Type Ia.

  11. Degeneracy and Discreteness in Cosmological Model Fitting

    E-Print Network [OSTI]

    Teng, Huan-Yu; Hu, Huan-Chen; Zhang, Tong-Jie

    2015-01-01T23:59:59.000Z

    We explore the degeneracy and discreteness problems in the standard cosmological model ({\\Lambda}CDM). We use the Observational Hubble Data (OHD) and the type Ia supernova (SNe Ia) data to study this issue. In order to describe the discreteness in fitting of data, we define a factor G to test the influence from each single data point and analyze the goodness of G. Our results indicate that a higher absolute value of G shows a better capability of distinguishing models, which means the parameters are restricted into smaller confidence intervals with a larger figure of merit evaluation. Consequently, we claim that the factor G is an effective way in model differentiation when using different models to fit the observational data.

  12. On the geometry of cosmological model building

    E-Print Network [OSTI]

    Erhard Scholz

    2005-11-21T23:59:59.000Z

    This article analyzes the present anomalies of cosmology from the point of view of integrable Weyl geometry. It uses P.A.M. Dirac's proposal for a weak extension of general relativity, with some small adaptations. Simple models with interesting geometrical and physical properties, not belonging to the Friedmann-Lema\\^{\\i}tre class, are studied in this frame. Those with positive spatial curvature (Einstein-Weyl universes) go well together with observed mass density $\\Omega_m$, CMB, supernovae Ia data, and quasar frequencies. They suggest a physical role for an equilibrium state of the Maxwell field proposed by I.E. Segal in the 1980s (Segal background) and for a time invariant balancing condition of vacuum energy density. The latter leads to a surprising agreement with the BF-theoretical calculation proposed by C. Castro (2002).

  13. The Effect of Host Galaxies on Type Ia Supernovae in the SDSS-II Supernova Survey

    SciTech Connect (OSTI)

    Lampeitl, Hubert; /Portsmouth U., ICG; Smith, Mathew; /Cape Town U. /Portsmouth U., ICG; Nichol, Robert C.; /Portsmouth U., ICG; Bassett, Bruce; /South African Astron. Observ. /Cape Town U.; Cinabro, David; /Wayne State U.; Dilday, Benjamin; /Rutgers U., Piscataway; Foley, Ryan J.; /Harvard-Smithsonian Ctr. Astrophys.; Frieman, Joshua A.; /Chicago U. /Fermilab; Garnavich, Peter M.; /Notre Dame U.; Goobar, Ariel; /Stockholm U., OKC; Im, Myungshin; /Seoul Natl. U. /Rutgers U., Piscataway

    2010-05-01T23:59:59.000Z

    We present an analysis of the host galaxy dependencies of Type Ia Supernovae (SNe Ia) from the full three year sample of the SDSS-II Supernova Survey. We re-discover, to high significance, the strong correlation between host galaxy type and the width of the observed SN light curve, i.e., fainter, quickly declining SNe Ia favor passive host galaxies, while brighter, slowly declining Ia's favor star-forming galaxies. We also find evidence (at between 2 to 3{sigma}) that SNe Ia are {approx_equal} 0.1 magnitudes brighter in passive host galaxies, than in star-forming hosts, after the SN Ia light curves have been standardized using the light curve shape and color variations: This difference in brightness is present in both the SALT2 and MCLS2k2 light curve fitting methodologies. We see evidence for differences in the SN Ia color relationship between passive and star-forming host galaxies, e.g., for the MLCS2k2 technique, we see that SNe Ia in passive hosts favor a dust law of R{sub V} {approx_equal} 1, while SNe Ia in star-forming hosts require R{sub V} {approx} 2. The significance of these trends depends on the range of SN colors considered. We demonstrate that these effects can be parameterized using the stellar mass of the host galaxy (with a confidence of > 4{sigma}) and including this extra parameter provides a better statistical fit to our data. Our results suggest that future cosmological analyses of SN Ia samples should include host galaxy information.

  14. Type Ia Supernova Explosion: Gravitationally Confined Detonation

    E-Print Network [OSTI]

    Tomasz Plewa; Alan Calder; Don Lamb

    2004-05-08T23:59:59.000Z

    We present a new mechanism for Type Ia supernova explosions in massive white dwarfs. The proposed scenario follows from relaxing the assumption of symmetry in the model and involves a detonation created in an unconfined environment. The explosion begins with an essentially central ignition of stellar material initiating a deflagration. This deflagration results in the formation of a buoyantly-driven bubble of hot material that reaches the stellar surface at supersonic speeds. The bubble breakout forms a strong pressure wave that laterally accelerates fuel-rich outer stellar layers. This material, confined by gravity to the white dwarf, races along the stellar surface and is focused at the location opposite to the point of the bubble breakout. These streams of nuclear fuel carry enough mass and energy to trigger a detonation just above the stellar surface. The flow conditions at that moment support a detonation that will incinerate the white dwarf and result in an energetic explosion. The stellar expansion following the deflagration redistributes stellar mass in a way that ensures production of intermediate mass and iron group elements consistent with observations. The ejecta will have a strongly layered structure with a mild amount of asymmetry following from the early deflagration phase. This asymmetry, combined with the amount of stellar expansion determined by details of the evolution (principally the energetics of deflagration, timing of detonation, and structure of the progenitor), can be expected to create a family of mildly diverse Type Ia supernova explosions.

  15. Thermonuclear supernova simulations with stochastic ignition

    E-Print Network [OSTI]

    W. Schmidt; J. C. Niemeyer

    2005-10-14T23:59:59.000Z

    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. Type Ia Supernova Explosion Models

    E-Print Network [OSTI]

    W. Hillebrandt; J. C. Niemeyer

    2000-06-21T23:59:59.000Z

    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.

  17. Lectures on Quantum Cosmology

    E-Print Network [OSTI]

    T. Christodoulakis

    2001-09-18T23:59:59.000Z

    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.

  18. Energy conditions and supernovae observations

    SciTech Connect (OSTI)

    Santos, J. [Departamento de Fisica, Universidade Federal do Rio Grande do Norte, C.P. 1641, 59072-970 Natal - RN (Brazil); Alcaniz, J. S. [Departamento de Astronomia, Observatorio Nacional, 20921-400, Rio de Janeiro - RJ (Brazil); Reboucas, M. J. [Centro Brasileiro de Pesquisas Fisicas, 22290-180 Rio de Janeiro - RJ (Brazil)

    2006-09-15T23:59:59.000Z

    In general relativity, the energy conditions are invoked to restrict general energy-momentum tensors T{sub {mu}}{sub {nu}} on physical grounds. We show that in the standard Friedmann-Lemaitre-Robertson-Walker (FLRW) approach to cosmological modeling where the equation of state of the cosmological fluid is unknown, the energy conditions provide model-independent bounds on the behavior of the distance modulus of cosmic sources as a function of the redshift. We use both the gold and the legacy samples of current type Ia supenovae to carry out a model-independent analysis of the energy conditions violation in the context of standard cosmology.

  19. Spectropolarimetric diagnostics of thermonuclear supernova explosions

    E-Print Network [OSTI]

    Lifan Wang; Dietrich Baade; Ferdinando Patat

    2006-11-29T23:59:59.000Z

    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.

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

    E-Print Network [OSTI]

    Hao Wei

    2010-08-16T23:59:59.000Z

    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.

  1. Workflow management for a cosmology collaboratory

    E-Print Network [OSTI]

    Loken, Stewart C.; McParland, Charles

    2001-01-01T23:59:59.000Z

    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

  2. Averaging Hypotheses in Newtonian Cosmology

    E-Print Network [OSTI]

    T. Buchert

    1995-12-20T23:59:59.000Z

    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.

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

    E-Print Network [OSTI]

    Capozziello, Salvatore; Saridakis, Emmanuel N

    2015-01-01T23:59:59.000Z

    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.

  4. What We Know About Dark Energy From Supernovae

    ScienceCinema (OSTI)

    Alex Filippenko

    2010-01-08T23:59:59.000Z

    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. 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)

    2014-05-09T23:59:59.000Z

    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.

  6. Sub-millimeter emission from type Ia supernova host galaxies at z=0.5

    E-Print Network [OSTI]

    D. Farrah; M. Fox; M. Rowan-Robinson; D. Clements; J. Afonso

    2003-12-03T23:59:59.000Z

    We present deep sub-millimetre observations of seventeen galaxies at z=0.5, selected through being hosts of a type 1a supernova. Two galaxies are detected directly, and the sample is detected statistically with a mean 850 micron flux of 1.01mJy +/- 0.33mJy, which is 25% - 135% higher than locally. We infer that the mean value of A_v in normal galaxies at z=0.5 is comparable to or greater than the mean A_v in local normal galaxies, in agreement with galaxy chemical evolution models and indirect observational evidence. Scaling from the local value given by Rowan-Robinson (2003) gives a mean extinction at z=0.5 of A_v = 0.56 +/- 0.17. The dust in the brightest sub-mm object in our sample is best interpreted as normal `cirrus' dust similar to that seen locally. The detection rate of our sample suggests that some sources found in blank-field sub-mm surveys may not be high redshift starbursts, but rather cirrus galaxies at moderate redshifts and with lower star formation rates. Finally, an increase in host dust extinction with redshift may impact the cosmological results from distant supernova searches. This emphasizes the need to carefully monitor dust extinction when using type Ia supernovae to measure the cosmological parameters.

  7. M Theory and Cosmology

    E-Print Network [OSTI]

    Tom Banks

    1999-11-10T23:59:59.000Z

    This is a series of lectures on M Theory for cosmologists. After summarizing some of the main properties of M Theory and its dualities I show how it can be used to address various fundamental and phenomenological issues in cosmology.

  8. Massive neutrinos and cosmology

    E-Print Network [OSTI]

    Julien Lesgourgues; Sergio Pastor

    2006-05-29T23:59:59.000Z

    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.

  9. New Developments in Cosmology

    E-Print Network [OSTI]

    J. W. Moffat

    2000-03-29T23:59:59.000Z

    A brief review is given of the present observational data in cosmology. A review of a new bimetric gravity theory with multiple light cones is presented. The physical consequences of this gravity theory for the early universe are analyzed.

  10. Cosmological Probes for Supersymmetry

    E-Print Network [OSTI]

    Khlopov, Maxim

    2015-01-01T23:59:59.000Z

    The multi-parameter character of supersymmetric dark-matter models implies the combination of their experimental studies with astrophysical and cosmological probes. The physics of the early Universe provides nontrivial effects of non-equilibrium particles and primordial cosmological structures. Primordial black holes (PBHs) are a profound signature of such structures that may arise as a cosmological consequence of supersymmetric (SUSY) models. SUSY-based mechanisms of baryosynthesis can lead to the possibility of antimatter domains in a baryon asymmetric Universe. In the context of cosmoparticle physics, which studies the fundamental relationship of the micro- and macro-worlds, the development of SUSY illustrates the main principles of this approach, as the physical basis of the modern cosmology provides cross-disciplinary tests in physical and astronomical studies.

  11. Cosmological Kinetic Mixing

    E-Print Network [OSTI]

    Ashok Das; Jorge Gamboa; Miguel Pino

    2015-04-15T23:59:59.000Z

    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.

  12. Determination of Primordial Metallicity and Mixing in the Type IIP Supernova 1993W

    SciTech Connect (OSTI)

    Baron, E.; Nugent, Peter E.; Branch, David; Hauschildt, Peter H.; Turatto, M.; Cappellaro, E.

    2002-12-11T23:59:59.000Z

    We present the results of a large grid of synthetic spectra and compare them to early spectroscopic observations of SN 1993W. This supernova was discovered close to its explosion date and at a recession velocity of 5400 km/s is located in the Hubble flow. We focus here on two early spectra that were obtained approximately 5 and 9 days after explosion. We parameterize the outer supernova envelope as a power-law density profile in homologous expansion. In order to extract information on the value of the parameters a large number of models was required. We show that very early spectra combined with detailed models can provide constraints on the value of the power law index, the ratio of hydrogen to helium in the surface of the progenitor, the progenitor metallicity and the amount of radioactive nickel mixed into the outer envelope of the supernova. The spectral fits reproduce the observed spectra exceedingly well. The spectral results combined with the early photometry predict that the explosion date was 4.7 {+-} 0.7 days before the first spectrum was obtained. The ability to obtain the metallicity from early spectra make SN IIP attractive probes of chemical evolution in the universe and by showing that we have the ability to pin down the parameters of the progenitor and mixing during the supernova explosion, it is likely to make SN IIP useful cosmological distance indicators which are at the same time complementary to SNe Ia.

  13. An integral field spectrograph for SNAP supernova studies

    E-Print Network [OSTI]

    2002-01-01T23:59:59.000Z

    identification of Type Ia supernovae and to standardize theof the mission. Keywords: SNAP, Supernovae, Integral field,measurement of some 2000 supernovae (SNe) of Type Ia up to a

  14. Visualizing Buoyant Burning Bubbles in Type Ia Supernovae at...

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

    Burning in Supernovae Buoyant Burning Bubbles in Type Ia Supernovae bubble-s.jpeg Flame ignition in type Ia supernovae leads to isolated bubbles of burning buoyant fluid. As a...

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

    E-Print Network [OSTI]

    Faccioli, Lorenzo

    2011-01-01T23:59:59.000Z

    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

  16. 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)

    2008-01-01T23:59:59.000Z

    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-

  17. The Photometric Properties of Nearby Type Ia Supernovae

    E-Print Network [OSTI]

    Ganeshalingam, Mohan

    2012-01-01T23:59:59.000Z

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

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

    E-Print Network [OSTI]

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

    2004-01-01T23:59:59.000Z

    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

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

    E-Print Network [OSTI]

    Roberts, Luke Forrest

    2012-01-01T23:59:59.000Z

    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. Supernovae Spectra (La Jolla Institute, 1980)

    SciTech Connect (OSTI)

    Meyerott, R.; Gillespie, G.H. (eds.)

    1980-01-01T23:59:59.000Z

    The workshop includes talks by invited speakers on observed supernova spectra, plasma conditions in supernova envelopes, on the present status and future requirements of atomic physics and spectroscopy that contribute to the solutions of the supernova problems. Of the 14 papers presented at the workshop, abstracts of two appeared previously in Energy Research Abstracts and abstracts of the remaining 12 were prepared separately for the data base. (GHT)

  1. Neutron Stars in Supernova Remnants and Beyond

    E-Print Network [OSTI]

    V. V. Gvaramadze

    2002-12-26T23:59:59.000Z

    We discuss a concept of off-centred cavity supernova explosion as applied to neutron star/supernova remnant associations and show how this concept could be used to preclude the anti-humane decapitating the Duck (G5.4-1.2 + G5.27-0.9) and dismembering the Swan (Cygnus Loop), as well as to search for a stellar remnant associated with the supernova remnant RCW86.

  2. Environmental impact of Supernova Remnants

    E-Print Network [OSTI]

    Dubner, Gloria

    2015-01-01T23:59:59.000Z

    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.

  3. Cosmology models with ?_M-dependent cosmological constant

    E-Print Network [OSTI]

    V. Majernik

    2002-01-07T23:59:59.000Z

    We investigate the evolution of the scale factor in a cosmological model in which the cosmological constant is given by the scalar arisen by the contraction of the stress-energy tensor.

  4. Turbulent Combustion in Type Ia Supernova Models

    E-Print Network [OSTI]

    F. K. Roepke; W. Hillebrandt

    2006-09-15T23:59:59.000Z

    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.

  5. Shock propagation and neutrino oscillation in supernova

    E-Print Network [OSTI]

    K. Takahashi; K. Sato; H. E. Dalhed; J. R. Wilson

    2003-02-26T23:59:59.000Z

    The effect of the shock propagation on neutrino oscillation in supernova is studied paying attention to evolution of average energy of $\

  6. The supernova that destroyed a galaxy

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

    scientists and collaborators capture in unprecedented detail extremely powerful supernovae explosions in the early universe and their effect on the nascent galaxies that gave...

  7. The late emission of thermonuclear supernovae

    E-Print Network [OSTI]

    Pilar Ruiz-Lapuente

    1996-04-16T23:59:59.000Z

    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.

  8. FUZZY SUPERNOVA TEMPLATES. I. CLASSIFICATION

    SciTech Connect (OSTI)

    Rodney, Steven A.; Tonry, John L., E-mail: rodney@ifa.hawaii.ed, E-mail: jt@ifa.hawaii.ed [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Dr., Honolulu, HI 96822 (United States)

    2009-12-20T23:59:59.000Z

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

  9. atypical thermonuclear supernovae: Topics by E-print Network

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

    Websites Summary: White dwarf mergers,White dwarf mergers, thermonuclear supernovae,thermonuclear supernovae fusion is ignited. Degenerate, hence runaway. 12;CO white dwarf...

  10. 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)

    2013-08-01T23:59:59.000Z

    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.

  11. 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...

  12. Testing the isotropy of the Universe by using the JLA compilation of type-Ia supernovae

    E-Print Network [OSTI]

    Lin, Hai-Nan; Chang, Zhe; Li, Xin

    2015-01-01T23:59:59.000Z

    We probe the possible anisotropy in the accelerated expanding Universe by using the JLA compilation of type-Ia supernovae. We constrain the amplitude and direction of anisotropy in the anisotropic cosmological models. For the dipole-modulated $\\Lambda$CDM model, the anisotropic amplitude has an upper bound $D<1.04\\times10^{-3}$ at the $68\\%$ confidence level. Similar results are found in the dipole-modulated $w$CDM and CPL models. Our studies show that there are no significant evidence for the anisotropic expansion of the Universe. Thus the Universe is still well compatible with the isotropy.

  13. Higgs boson cosmology

    E-Print Network [OSTI]

    Ian G. Moss

    2015-07-21T23:59:59.000Z

    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.

  14. Dimensionality and the Cosmological Constant

    E-Print Network [OSTI]

    Z. C. Wu

    2006-05-01T23:59:59.000Z

    In the Kaluza-Klein model with a cosmological constant and a flux, the external spacetime and its dimension of the created universe from a $S^s \\times S^{n-s}$ seed instanton can be identified in quantum cosmology. One can also show that in the internal space the effective cosmological constant is most probably zero.

  15. The Outermost Ejecta of Type Ia Supernovae

    E-Print Network [OSTI]

    Masaomi Tanaka; Paolo A. Mazzali; Stefano Benetti; Ken'ichi Nomoto; Nancy Elias-Rosa; Rubina Kotak; Giuliano Pignata; Vallery Stanishev; Stephan Hachinger

    2007-12-17T23:59:59.000Z

    The properties of the highest velocity ejecta of normal Type Ia supernovae (SNe Ia) are studied via models of very early optical spectra of 6 SNe. At epochs earlier than 1 week before maximum, SNe with a rapidly evolving Si II 6355 line velocity (HVG) have a larger photospheric velocity than SNe with a slowly evolving Si II 6355 line velocity (LVG). Since the two groups have comparable luminosities, the temperature at the photosphere is higher in LVG SNe. This explains the different overall spectral appearance of HVG and LVG SNe. However, the variation of the Ca II and Si II absorptions at the highest velocities (v >~ 20,000 km/s) suggests that additional factors, such as asphericity or different abundances in the progenitor white dwarf, affect the outermost layers. The C II 6578 line is marginally detected in 3 LVG SNe, suggesting that LVG undergo less intense burning. The carbon mass fraction is small, only less than 0.01 near the photosphere, so that he mass of unburned C is only <~ 0.01 Msun. Radioactive 56Ni and stable Fe are detected in both LVG and HVG SNe. Different Fe-group abundances in the outer layers may be one of the reasons for spectral diversity among SNe Ia at the earliest times. The diversity among SNe Ia at the earliest phases could also indicate an intrinsic dispersion in the width-luminosity relation of the light curve.

  16. Young Supernova Remnants: Issues and Prospects

    E-Print Network [OSTI]

    Christopher F. McKee

    2001-01-03T23:59:59.000Z

    After reviewing recent work on the dynamics of young supernova remnants (YSNRs) and discussing how YSNRs can be used as physics laboratories, I discuss several challenges: Where are the very young SNRs in the Galaxy? Can very young SNRs produce gamma ray bursts? The Connections Challenge: Can one infer the nature of the supernova and its progenitor star from observations of the YSNR?

  17. Origin of Matter from Vacuum in Conformal Cosmology

    E-Print Network [OSTI]

    D. Blaschke; V. Pervushin; D. Proskurin; S. Vinitsky; A. Gusev

    2002-06-30T23:59:59.000Z

    We introduce the hypothesis that the matter content of the universe can be a product of the decay of primordial vector bosons. The effect of the intensive cosmological creation of these primordial vector $W, ~Z $ bosons from the vacuum is studied in the framework of General Relativity and the Standard Model where the relative standard of measurement identifying conformal quantities with the measurable ones is accepted. The relative standard leads to the conformal cosmology with the z-history of masses with the constant temperature, instead of the conventional z-history of the temperature with constant masses in inflationary cosmology. In conformal cosmology both the latest supernova data and primordial nucleosynthesis are compatible with a stiff equation of state associated with one of the possible states of the infrared gravitation field. The distribution function of the created bosons in the lowest order of perturbation theory exposes a cosmological singularity as a consequence of the theorem about the absence of the massless limit of massive vector fields in quantum theory. This singularity can be removed by taking into account the collision processes leading to a thermalization of the created particles. The cosmic microwave background (CMB) temperature T=(M_W^2H_0)^{1/3} ~ 2.7 K occurs as an integral of motion for the universe in the stiff state. We show that this temperature can be attained by the CMB radiation being the final product of the decay of primordial bosons. The effect of anomalous nonconservation of baryon number due to the polarization of the Dirac sea vacuum by these primordial bosons is considered.

  18. Relativistic Fractal Cosmologies

    E-Print Network [OSTI]

    Marcelo B. Ribeiro

    2009-10-26T23:59:59.000Z

    This article reviews an approach for constructing a simple relativistic fractal cosmology whose main aim is to model the observed inhomogeneities of the distribution of galaxies by means of the Lemaitre-Tolman solution of Einstein's field equations for spherically symmetric dust in comoving coordinates. This model is based on earlier works developed by L. Pietronero and J.R. Wertz on Newtonian cosmology, whose main points are discussed. Observational relations in this spacetime are presented, together with a strategy for finding numerical solutions which approximate an averaged and smoothed out single fractal structure in the past light cone. Such fractal solutions are shown, with one of them being in agreement with some basic observational constraints, including the decay of the average density with the distance as a power law (the de Vaucouleurs' density power law) and the fractal dimension in the range 1 fractal model we find that all Friedmann models look inhomogeneous along the backward null cone, with a departure from the observable homogeneous region at relatively close ranges. It is also shown that with these same observational relations the Einstein-de Sitter model can have an interpretation where it has zero global density, a result consistent with the "zero global density postulate" advanced by Wertz for hierarchical cosmologies and conjectured by Pietronero for fractal cosmological models. The article ends with a brief discussion on the possible link between this model and nonlinear and chaotic dynamics.

  19. Neutrino Oscillations and Cosmology

    E-Print Network [OSTI]

    A. D. Dolgov

    2000-04-04T23:59:59.000Z

    Phenomenology of neutrino oscillations in vacuum and in cosmological plasma is considered. Neutrino oscillations in vacuum are usually described in plane wave approximation. In this formalism there is an ambiguity if one should assume $\\delta p =0$ and correspondingly $\\delta E\

  20. Cosmological Tests of Gravity

    E-Print Network [OSTI]

    Koyama, Kazuya

    2015-01-01T23:59:59.000Z

    Einstein's theory of General Relativity (GR) is tested accurately within the local universe i.e., the Solar System, but this leaves open the possibility that it is not a good description at the largest scales in the Universe. The standard model of cosmology assumes GR as the theory to describe gravity on all scales. In 1998, astronomers made the surprising discovery that the expansion of the Universe is accelerating, not slowing down. This late-time acceleration of the Universe has become the most challenging problem in theoretical physics. Within the framework of GR, the acceleration would originate from an unknown dark energy. Alternatively, it could be that there is no dark energy and GR itself is in error on cosmological scales. The standard model of cosmology is based on a huge extrapolation of our limited knowledge of gravity. This discovery of the late time acceleration of the Universe may require us to revise the theory of gravity and the standard model of cosmology based on GR. We will review recent ...

  1. Cosmological dynamical systems

    E-Print Network [OSTI]

    Genly Leon; Carlos R. Fadragas

    2014-12-18T23:59:59.000Z

    In this book are studied, from the perspective of the dynamical systems, several Universe models. In chapter 1 we give a bird's eye view on cosmology and cosmological problems. Chapter 2 is devoted to a brief review on some results and useful tools from the qualitative theory of dynamical systems. They provide the theoretical basis for the qualitative study of concrete cosmological models. Chapters 1 and 2 are a review of well-known results. Chapters 3, 4, 5 and 6 are devoted to our main results. In these chapters are extended and settled in a substantially different, more strict mathematical language, several results obtained by one of us in arXiv:0812.1013 [gr-qc]; arXiv:1009.0689 [gr-qc]; arXiv:0904.1577[gr-qc]; and arXiv:0909.3571 [hep-th]. In chapter 6, we provide a different approach to the subject discussed in astro-ph/0503478. Additionally, we perform a Poincar\\'e compactification process allowing to construct a global phase space containing all the cosmological information in both finite and infinite regions for all the models.

  2. 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)

    2014-05-09T23:59:59.000Z

    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.

  3. Cosmology and the Bispectrum

    SciTech Connect (OSTI)

    Sefusatti, Emiliano; /Fermilab /CCPP, New York; Crocce, Martin; Pueblas, Sebastian; Scoccimarro, Roman; /CCPP, New York

    2006-04-01T23:59:59.000Z

    The present spatial distribution of galaxies in the Universe is non-Gaussian, with 40% skewness in 50 h{sup -1} Mpc spheres, and remarkably little is known about the information encoded in it about cosmological parameters beyond the power spectrum. In this work they present an attempt to bridge this gap by studying the bispectrum, paying particular attention to a joint analysis with the power spectrum and their combination with CMB data. They address the covariance properties of the power spectrum and bispectrum including the effects of beat coupling that lead to interesting cross-correlations, and discuss how baryon acoustic oscillations break degeneracies. They show that the bispectrum has significant information on cosmological parameters well beyond its power in constraining galaxy bias, and when combined with the power spectrum is more complementary than combining power spectra of different samples of galaxies, since non-Gaussianity provides a somewhat different direction in parameter space. In the framework of flat cosmological models they show that most of the improvement of adding bispectrum information corresponds to parameters related to the amplitude and effective spectral index of perturbations, which can be improved by almost a factor of two. Moreover, they demonstrate that the expected statistical uncertainties in {sigma}s of a few percent are robust to relaxing the dark energy beyond a cosmological constant.

  4. SUPERNOVA EJECTA IN THE YOUNGEST GALACTIC SUPERNOVA REMNANT G1.9+0.3

    SciTech Connect (OSTI)

    Borkowski, Kazimierz J.; Reynolds, Stephen P. [Department of Physics, North Carolina State University, Raleigh, NC 27695-8202 (United States); Hwang, Una [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Green, David A. [Cavendish Laboratory, 19 J.J. Thomson Ave., Cambridge CB3 0HE (United Kingdom); Petre, Robert [NASA/GSFC, Code 660, Greenbelt, MD 20771 (United States); Krishnamurthy, Kalyani; Willett, Rebecca, E-mail: kborkow@unity.ncsu.edu [Department of Electrical and Computer Engineering, Duke University, Durham, NC 27708 (United States)

    2013-07-01T23:59:59.000Z

    G1.9+0.3 is the youngest known Galactic supernova remnant (SNR), with an estimated supernova (SN) explosion date of {approx}1900, and most likely located near the Galactic center. Only the outermost ejecta layers with free-expansion velocities {approx}>18,000 km s{sup -1} have been shocked so far in this dynamically young, likely Type Ia SNR. A long (980 ks) Chandra observation in 2011 allowed spatially resolved spectroscopy of heavy-element ejecta. We denoised Chandra data with the spatio-spectral method of Krishnamurthy et al., and used a wavelet-based technique to spatially localize thermal emission produced by intermediate-mass elements (IMEs; Si and S) and iron. The spatial distribution of both IMEs and Fe is extremely asymmetric, with the strongest ejecta emission in the northern rim. Fe K{alpha} emission is particularly prominent there, and fits with thermal models indicate strongly oversolar Fe abundances. In a localized, outlying region in the northern rim, IMEs are less abundant than Fe, indicating that undiluted Fe-group elements (including {sup 56}Ni) with velocities >18,000 km s{sup -1} were ejected by this SN. However, in the inner west rim, we find Si- and S-rich ejecta without any traces of Fe, so high-velocity products of O-burning were also ejected. G1.9+0.3 appears similar to energetic Type Ia SNe such as SN 2010jn where iron-group elements at such high free-expansion velocities have been recently detected. The pronounced asymmetry in the ejecta distribution and abundance inhomogeneities are best explained by a strongly asymmetric SN explosion, similar to those produced in some recent three-dimensional delayed-detonation Type Ia models.

  5. Dark Matter Triggers of Supernovae

    E-Print Network [OSTI]

    Peter W. Graham; Surjeet Rajendran; Jaime Varela

    2015-05-17T23:59:59.000Z

    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.

  6. Petascale Supernova Simulation with CHIMERA

    SciTech Connect (OSTI)

    Messer, Bronson [ORNL; Bruenn, S. W. [Florida Atlantic University; Blondin, J. M. [North Carolina State University; Mezzacappa, Anthony [ORNL; Hix, William Raphael [ORNL; Dirk, Charlotte [Florida Atlantic University

    2007-01-01T23:59:59.000Z

    CHIMERA is a multi-dimensional radiation hydrodynamics code designed to study core-collapse supernovae. The code is made up of three essentially independent parts: a hydrodynamics module, a nuclear burning module, and a neutrino transport solver combined within an operator-split approach. We describe some ma jor algorithmic facets of the code and briefly discuss some recent results. The multi-physics nature of the problem, and the specific implementation of that physics in CHIMERA, provide a rather straightforward path to effective use of multi-core platforms in the near future.

  7. Supernova Caught in the Act

    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: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of ScienceandMesa del SolStrengthening a solid ...Success Stories TouchingSupercomputingCenterSupernova

  8. Testing Cosmology with Cosmic Sound Waves

    E-Print Network [OSTI]

    Pier Stefano Corasaniti; Alessandro Melchiorri

    2008-03-25T23:59:59.000Z

    WMAP observations have accurately determined the position of the first two peaks and dips in the CMB temperature power spectrum. These encode information on the ratio of the distance to the last scattering surface to the sound horizon at decoupling. However pre-recombination processes can contaminate this distance information. In order to assess the amplitude of these effects we use the WMAP data and evaluate the relative differences of the CMB peaks and dips multipoles. We find that the position of the first peak is largely displaced with the respect to the expected position of the sound horizon scale at decoupling. In contrast the relative spacings of the higher extrema are statistically consistent with those expected from perfect harmonic oscillations. This provides evidence for a scale dependent phase shift of the CMB oscillations which is caused by gravitational driving forces affecting the propagation of sound waves before recombination. By accounting for these effects we have performed a MCMC likelihood analysis to constrain in combination with recent BAO data a constant dark energy equation w. For a flat universe we find at 95% upper limit w<-1.10, and including the HST prior w<-1.14, which are only marginally consistent with limits derived from the supernova SNLS sample. Larger limits are obtained for non-flat cosmologies. From the full CMB likelihood analysis we also estimate the values of the shift parameter R and the multipole l_a of the acoustic horizon at decoupling for several cosmologies to test their dependence on model assumptions. Although the analysis of the full CMB spectra should be always preferred, using the position of the CMB peaks and dips provide a simple and consistent method for combining CMB constraints with other datasets.

  9. Testing cosmology with cosmic sound waves

    SciTech Connect (OSTI)

    Corasaniti, Pier Stefano [LUTH, Observatoire de Paris, CNRS UMR 8102, Universite Paris Diderot, 5 Place Jules Janssen, 92195 Meudon Cedex (France); Melchiorri, Alessandro [Dipartimento di Fisica e Sezione INFN, Universita degli Studi di Roma 'La Sapienza', Ple Aldo Moro 5, 00185, Rome (Italy); CERN, Theory Division, CH-1211 Geneva 23 (Switzerland)

    2008-05-15T23:59:59.000Z

    Wilkinson Microwave Anisotropy Probe (WMAP) observations have accurately determined the position of the first two peaks and dips in the cosmic microwave background (CMB) temperature power spectrum. These encode information on the ratio of the distance to the last scattering surface to the sound horizon at decoupling. However prerecombination processes can contaminate this distance information. In order to assess the amplitude of these effects, we use the WMAP data and evaluate the relative differences of the CMB peak and dip multipoles. We find that the position of the first peak is largely displaced with respect to the expected position of the sound horizon scale at decoupling. In contrast, the relative spacings of the higher extrema are statistically consistent with those expected from perfect harmonic oscillations. This provides evidence for a scale dependent phase shift of the CMB oscillations which is caused by gravitational driving forces affecting the propagation of sound waves before recombination. By accounting for these effects we have performed a Markov Chain Monte Carlo likelihood analysis of the location of WMAP extrema to constrain, in combination with recent BAO data, a constant dark energy equation of state parameter w. For a flat universe we find a strong 2{sigma} upper limit w<-1.10, and including the Hubble Space Telescope prior, we obtain w<-1.14, which is only marginally consistent with limits derived from the Supernova Legacy Survey sample. On the other hand, we infer larger limits for nonflat cosmologies. From the full CMB likelihood analysis, we also estimate the values of the shift parameter R and the multipole l{sub a} of the acoustic horizon at decoupling for several cosmologies, to test their dependence on model assumptions. Although the analysis of the full CMB spectra should always be preferred, using the position of the CMB peaks and dips provides a simple and consistent method for combining CMB constraints with other data sets.

  10. MOST POPULATION III SUPERNOVAE ARE DUDS Robert L. Kurucz

    E-Print Network [OSTI]

    Kurucz, Robert L.

    the ``dark matter'' halo. Subject headings: supernovae --- dark matter Introduction Most of the physics predictions about dud supernovae and about ``dark matter''. Population III stars, dud supernovae, supernovae and primordial gas into a globular cluster. Model atmosphere calculations for oxygen dwarfs show that water

  11. 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

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

    E-Print Network [OSTI]

    Carl H. Gibson

    2012-11-02T23:59:59.000Z

    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.

  13. Survey gives clues to origin of Type Ia supernovae | EurekAlert! Science News

    E-Print Network [OSTI]

    ... to origin of Type Ia supernovae ... Type Ia supernovae still not understood despite their ... s behind the Type Ia supernovae they use to measure distances ...

  14. New findings show some Type Ia supernovae linked to novae | EurekAlert! Science News

    E-Print Network [OSTI]

    ... findings show some Type Ia supernovae linked to novae ... least some thermonuclear (Type Ia) supernovae come from a recurrent nova ... originators of other Type Ia supernovae . ...

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

    E-Print Network [OSTI]

    Goldhaber, G.

    2008-01-01T23:59:59.000Z

    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.

  16. 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

    2006-01-01T23:59:59.000Z

    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

  17. 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

    2007-01-01T23:59:59.000Z

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

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

    E-Print Network [OSTI]

    Barbary, Kyle Harris

    2011-01-01T23:59:59.000Z

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

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

    E-Print Network [OSTI]

    2006-01-01T23:59:59.000Z

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

  20. 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.

    2003-01-01T23:59:59.000Z

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

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

    E-Print Network [OSTI]

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

    2001-01-01T23:59:59.000Z

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

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

    E-Print Network [OSTI]

    Silverman, Jeffrey Michael

    2011-01-01T23:59:59.000Z

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

  3. 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.

    2004-01-01T23:59:59.000Z

    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 —

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

    E-Print Network [OSTI]

    Tomasz Plewa

    2006-11-24T23:59:59.000Z

    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. Dark Matter Triggers of Supernovae

    E-Print Network [OSTI]

    Graham, Peter W; Varela, Jaime

    2015-01-01T23:59:59.000Z

    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...

  6. Theoretical cosmic Type Ia supernova rates

    E-Print Network [OSTI]

    R. Valiante; F. Matteucci; S. Recchi; F. Calura

    2009-03-16T23:59:59.000Z

    The aim of this work is the computation of the cosmic Type Ia supernova rates at very high redshifts (z>2). We adopt various progenitor models in order to predict the number of explosions in different scenarios for galaxy formation and to check whether it is possible to select the best delay time distribution model, on the basis of the available observations of Type Ia supernovae. We also computed the Type Ia supernova rate in typical elliptical galaxies of different initial luminous masses and the total amount of iron produced by Type Ia supernovae in each case. It emerges that: it is not easy to select the best delay time distribution scenario from the observational data and this is because the cosmic star formation rate dominates over the distribution function of the delay times; the monolithic collapse scenario predicts an increasing trend of the SN Ia rate at high redshifts whereas the predicted rate in the hierarchical scheme drops dramatically at high redshift; for the elliptical galaxies we note that the predicted maximum of the Type Ia supernova rate depends on the initial galactic mass. The maximum occurs earlier (at about 0.3 Gyr) in the most massive ellipticals, as a consequence of downsizing in star formation. We find that different delay time distributions predict different relations between the Type Ia supernova rate per unit mass at the present time and the color of the parent galaxies and that bluer ellipticals present higher supernova Type Ia rates at the present time.

  7. Observational constraints on Visser's cosmological model

    SciTech Connect (OSTI)

    Alves, M. E. S.; Araujo, J. C. N. de; Miranda, O. D.; Wuensche, C. A. [INPE - Instituto Nacional de Pesquisas Espaciais - Divisao de Astrofisica, Av.dos Astronautas 1758, Sao Jose dos Campos, 12227-010 SP (Brazil); Carvalho, F. C. [INPE - Instituto Nacional de Pesquisas Espaciais - Divisao de Astrofisica, Av.dos Astronautas 1758, Sao Jose dos Campos, 12227-010 SP (Brazil); UERN - Universidade do Estado do Rio Grande do Norte, Mossoro, 59610-210, RN (Brazil); Santos, E. M. [UFRJ - Universidade Federal do Rio de Janeiro, Rio de Janeiro, 21945-970, RJ (Brazil)

    2010-07-15T23:59:59.000Z

    Theories of gravity for which gravitons can be treated as massive particles have presently been studied as realistic modifications of general relativity, and can be tested with cosmological observations. In this work, we study the ability of a recently proposed theory with massive gravitons, the so-called Visser theory, to explain the measurements of luminosity distance from the Union2 compilation, the most recent Type-Ia Supernovae (SNe Ia) data set, adopting the current ratio of the total density of nonrelativistic matter to the critical density ({Omega}{sub m}) as a free parameter. We also combine the SNe Ia data with constraints from baryon acoustic oscillations (BAO) and cosmic microwave background (CMB) measurements. We find that, for the allowed interval of values for {Omega}{sub m}, a model based on Visser's theory can produce an accelerated expansion period without any dark energy component, but the combined analysis (SNe Ia+BAO+CMB) shows that the model is disfavored when compared with the {Lambda}CDM model.

  8. Holography from quantum cosmology

    E-Print Network [OSTI]

    M. Rashki; S. Jalalzadeh

    2014-12-12T23:59:59.000Z

    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.

  9. Quantum cosmology: a review

    E-Print Network [OSTI]

    Martin Bojowald

    2015-01-20T23:59:59.000Z

    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.

  10. Quantum cosmology: a review

    E-Print Network [OSTI]

    Bojowald, Martin

    2015-01-01T23:59:59.000Z

    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.

  11. Weak Interaction and Cosmology

    E-Print Network [OSTI]

    P. R. Silva

    2008-04-16T23:59:59.000Z

    In this paper we examine the connection among the themes: the cosmological constant, the weak interaction and the neutrino mass. Our main propose is to review and modify the ideas first proposed by Hayakawa [ Prog. Theor. Phys.Suppl.,532(1965).], in the light of the new-fashioned features of contemporary physics. Assuming the pressure of a Fermi gas of neutrinos should be balanced by its gravitational attraction, we evaluate the mass of the background neutrino and its number.The neutrino mass here evaluated is compatible with the known value for the cosmological constant (or dark energy).Taking in account the role played by the weak forces experimented by the neutrinos, we also determined a value for the electroweak mixing angle. For sake of comparison, an alternative evaluation of the neutrino mass is also done.

  12. Axion braneworld cosmology

    E-Print Network [OSTI]

    Cosimo Bambi; Masahiro Kawasaki; Federico R. Urban

    2009-03-26T23:59:59.000Z

    We study axion cosmology in a 5D Universe, in the case of flat and warped extra dimension. The comparison between theoretical predictions and observations constrains the 5D axion decay constant and the 5D Planck mass, which has to be taken into account in building 5D axion models. The framework developed in this paper can be readily applied to other bulk fields in brane universes.

  13. Axion braneworld cosmology

    SciTech Connect (OSTI)

    Bambi, Cosimo [IPMU, University of Tokyo, Kashiwa, Chiba 277-8568 (Japan); Kawasaki, Masahiro [IPMU, University of Tokyo, Kashiwa, Chiba 277-8568 (Japan); ICRR, University of Tokyo, Kashiwa, Chiba 277-8582 (Japan); Urban, Federico R. [UBC, Department of Physics and Astronomy, Vancouver, B.C. V6T 1Z1 (Canada); KITPC, Chinese Academy of Sciences, Beijing, 100190 (China)

    2009-07-15T23:59:59.000Z

    We study axion cosmology in a 5D universe, in the case of flat and warped extra dimensions. The comparison between theoretical predictions and observations constrains the 5D axion decay constant and the 5D Planck mass, which have to be taken into account in building 5D axion models. The framework developed in this paper can be readily applied to other bulk fields in brane universes.

  14. Cosmology of Vacuum

    E-Print Network [OSTI]

    V. Burdyuzha; G. Vereshkov

    2007-12-29T23:59:59.000Z

    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.

  15. Inference for the dark energy equation of state using Type IA supernova data

    E-Print Network [OSTI]

    Christopher Genovese; Peter Freeman; Larry Wasserman; Robert Nichol; Christopher Miller

    2009-05-18T23:59:59.000Z

    The surprising discovery of an accelerating universe led cosmologists to posit the existence of "dark energy"--a mysterious energy field that permeates the universe. Understanding dark energy has become the central problem of modern cosmology. After describing the scientific background in depth, we formulate the task as a nonlinear inverse problem that expresses the comoving distance function in terms of the dark-energy equation of state. We present two classes of methods for making sharp statistical inferences about the equation of state from observations of Type Ia Supernovae (SNe). First, we derive a technique for testing hypotheses about the equation of state that requires no assumptions about its form and can distinguish among competing theories. Second, we present a framework for computing parametric and nonparametric estimators of the equation of state, with an associated assessment of uncertainty. Using our approach, we evaluate the strength of statistical evidence for various competing models of dark energy. Consistent with current studies, we find that with the available Type Ia SNe data, it is not possible to distinguish statistically among popular dark-energy models, and that, in particular, there is no support in the data for rejecting a cosmological constant. With much more supernova data likely to be available in coming years (e.g., from the DOE/NASA Joint Dark Energy Mission), we address the more interesting question of whether future data sets will have sufficient resolution to distinguish among competing theories.

  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

    2013-08-10T23:59:59.000Z

    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. Particle Physics and Cosmology

    E-Print Network [OSTI]

    P. Pralavorio

    2014-12-04T23:59:59.000Z

    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. Tycho Brahe's 1572 supernova as a standard type Ia explosion revealed from its light echo spectrum

    E-Print Network [OSTI]

    Oliver Krause; Masaomi Tanaka; Tomonori Usuda; Takashi Hattori; Miwa Goto; Stephan Birkmann; Ken'ichi Nomoto

    2008-10-28T23:59:59.000Z

    Type Ia supernovae (SNe Ia) are thermonuclear explosions of white dwarf stars in close binary systems. They play an important role as cosmological distance indicators and have led to the discovery of the accelerated expansion of the Universe. Among the most important unsolved questions are how the explosion actually proceeds and whether accretion occurs from a companion or via the merging of two white dwarfs. Tycho Brahe's supernova of 1572 (SN 1572) is thought to be one of the best candidates for a SN Ia in the Milky Way. The proximity of the SN 1572 remnant has allowed detailed studies, such as the possible identification of the binary companion, and provides a unique opportunity to test theories of the explosion mechanism and the nature of the progenitor. The determination of the yet unknown exact spectroscopic type of SN 1572 is crucial to relate these results to the diverse population of SNe Ia. Here we report an optical spectrum of Tycho Brahe's supernova near maximum brightness, obtained from a scattered-light echo more than four centuries after the direct light of the explosion swept past Earth. We find that SN 1572 belongs to the majority class of normal SNe Ia. The presence of a strong Ca II IR feature at velocities exceeding 20,000 km/s, which is similar to the previously observed polarized features in other SNe Ia, suggests asphericity in SN 1572.

  19. Tycho Brahe's 1572 supernova as a standard type Ia explosion revealed from its light echo spectrum

    E-Print Network [OSTI]

    Krause, Oliver; Usuda, Tomonori; Hattori, Takashi; Goto, Miwa; Birkmann, Stephan; Nomoto, Ken'ichi

    2008-01-01T23:59:59.000Z

    Type Ia supernovae (SNe Ia) are thermonuclear explosions of white dwarf stars in close binary systems. They play an important role as cosmological distance indicators and have led to the discovery of the accelerated expansion of the Universe. Among the most important unsolved questions are how the explosion actually proceeds and whether accretion occurs from a companion or via the merging of two white dwarfs. Tycho Brahe's supernova of 1572 (SN 1572) is thought to be one of the best candidates for a SN Ia in the Milky Way. The proximity of the SN 1572 remnant has allowed detailed studies, such as the possible identification of the binary companion, and provides a unique opportunity to test theories of the explosion mechanism and the nature of the progenitor. The determination of the yet unknown exact spectroscopic type of SN 1572 is crucial to relate these results to the diverse population of SNe Ia. Here we report an optical spectrum of Tycho Brahe's supernova near maximum brightness, obtained from a scatter...

  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)

    2013-12-01T23:59:59.000Z

    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. Quantum Vacuum Structure and Cosmology

    E-Print Network [OSTI]

    Johann Rafelski; Lance Labun; Yaron Hadad; Pisin Chen

    2009-09-16T23:59:59.000Z

    Short review of riddles that lie at the intersection of quantum theory, particle physics and cosmology; dark energy as false vacuum; discussion of a possible detection experiment.

  2. Hydrogen in Type Ic Supernovae?

    E-Print Network [OSTI]

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

    2006-05-09T23:59:59.000Z

    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.

  3. Supercomputing and the search for supernovae

    SciTech Connect (OSTI)

    Nugent, Peter

    2013-10-31T23:59:59.000Z

    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.

  4. Supercomputing and the search for supernovae

    ScienceCinema (OSTI)

    Nugent, Peter

    2014-06-23T23:59:59.000Z

    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.

  5. The SuperNova Early Warning System

    E-Print Network [OSTI]

    K. Scholberg

    2008-03-04T23:59:59.000Z

    A core collapse in the Milky Way will produce an enormous burst of neutrinos in detectors world-wide. Such a burst has the potential to provide an early warning of a supernova's appearance. I will describe the nature of the signal, the sensitivity of current detectors, and SNEWS, the SuperNova Early Warning System, a network designed to alert astronomers as soon as possible after the detected neutrino signal.

  6. The SuperNova Early Warning System

    E-Print Network [OSTI]

    Scholberg, K

    2008-01-01T23:59:59.000Z

    A core collapse in the Milky Way will produce an enormous burst of neutrinos in detectors world-wide. Such a burst has the potential to provide an early warning of a supernova's appearance. I will describe the nature of the signal, the sensitivity of current detectors, and SNEWS, the SuperNova Early Warning System, a network designed to alert astronomers as soon as possible after the detected neutrino signal.

  7. UV Light Curves of Thermonuclear Supernovae

    E-Print Network [OSTI]

    S. I. Blinnikov; E. I. Sorokina

    2000-03-17T23:59:59.000Z

    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.

  8. Cosmological model with $?_M$-dependent cosmological constant

    E-Print Network [OSTI]

    V. Majernik

    2003-10-21T23:59:59.000Z

    The idea here is to set the cosmical constant $\\lambda$ proportional to the scalar of the stress-energy tensor of the ordinary matter. We investigate the evolution of the scale factor in a cosmological model in which the cosmological constant is proportional to the scalar of the stress-energy tensor.

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

    SciTech Connect (OSTI)

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

    2004-05-12T23:59:59.000Z

    The Supernova/Acceleration Probe (SNAP) is a proposed space-based experiment designed to study the dark energy and alternative explanations of the acceleration of the Universes expansion by performing a series of complementary systematics-controlled astrophysical measurements. We here describe a self-consistent reference mission design that can accomplish this goal with the two leading measurement approaches being the Type Ia supernova Hubble diagram and a wide-area weak gravitational lensing survey. This design has been optimized to first order and is now under study for further modification and optimization. A 2-m three-mirror anastigmat wide-field telescope feeds a focal plane consisting of a 0.7 square-degree imager tiled with equal areas of optical CCDs and near infrared sensors, and a high efficiency low-resolution integral field spectrograph. The instrumentation suite provides simultaneous discovery and light-curve measurements of supernovae and then can target individual objects for detailed spectral characterization. The SNAP mission will discover thousands of Type Ia supernovae out to z = 3 and will obtain high-signal-to-noise calibrated light-curves and spectra for a subset of > 2000 supernovae at redshifts between z = 0.1 and 1.7 in a northern field and in a southern field. A wide-field survey covering one thousand square degrees in both northern and southern fields resolves {approx} 100 galaxies per square arcminute, or a total of more than 300 million galaxies. With the PSF stability afforded by a space observatory, SNAP will provide precise and accurate measurements of gravitational lensing. The high-quality data available in space, combined with the large sample of supernovae, will enable stringent control of systematic uncertainties. The resulting data set will be used to determine the energy density of dark energy and parameters that describe its dynamical behavior. The data also provide a direct test of theoretical models for the dark energy, including discrimination of vacuum energy due to the cosmological constant and various classes of dynamical scalar fields. If we assume we live in a cosmological-constant-dominated Universe, the matter density, dark energy density, and flatness of space can all be measured with SNAP supernova and weak-lensing measurements to a systematics-limited accuracy of 1 percent. For a flat universe, the density-to-pressure ratio of dark energy or equation of state w(z) can be similarly measured to 5 percent for the present value w0 and {approx} 0.1 for the time variation w' is defined as dw/d ln a bar z = 1. For a fiducial SUGRA-inspired universe, w0 and w' can be measured to an even tighter uncertainty of 0.03 and 0.06 respectively. Note that no external priors are needed. As more accurate theoretical predictions for the small-scale weak-lensing shear develop, the conservative estimates adopted here for space-based systematics should improve, allowing even tighter constraints. While the survey strategy is tailored for supernova and weak gravitational lensing observations, the large survey area, depth, spatial resolution, time-sampling, and nine-band optical to NIR photometry will support additional independent and/or complementary dark-energy measurement approaches as well as a broad range of auxiliary science programs.

  10. Cosmological solutions in bimetric gravity and their observational tests

    SciTech Connect (OSTI)

    Strauss, Mikael von; Schmidt-May, Angnis; Enander, Jonas; Mörtsell, Edvard; Hassan, S.F., E-mail: mvs@fysik.su.se, E-mail: angnis.schmidt-may@fysik.su.se, E-mail: enander@fysik.su.se, E-mail: edvard@fysik.su.se, E-mail: fawad@fysik.su.se [Department of Physics and The Oskar Klein Centre for Cosmoparticle Physics, Stockholm University, AlbaNova University Centre, SE-106 91 Stockholm (Sweden)

    2012-03-01T23:59:59.000Z

    We obtain the general cosmological evolution equations for a classically consistent theory of bimetric gravity. Their analytic solutions are demonstrated to generically allow for a cosmic evolution starting out from a matter dominated FLRW universe and relaxing towards a de Sitter (anti-de Sitter) phase at late cosmic time. In particular, we examine a subclass of models which contain solutions that are able to reproduce the expansion history of the cosmic concordance model inspite of the nonlinear couplings of the two metrics. This is demonstrated explicitly by fitting these models to observational data from Type Ia supernovae, Cosmic Microwave Background and Baryon Acoustic Oscillations. In the appendix we comment on the relation to massive gravity.

  11. 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

  12. Cosmological Galaxy Evolution with Superbubble Feedback I: Realistic Galaxies with Moderate Feedback

    E-Print Network [OSTI]

    Keller, B W; Couchman, H M P

    2015-01-01T23:59:59.000Z

    We present the first cosmological galaxy evolved using the modern smoothed particle hydrodynamics (SPH) code GASOLINE2 with superbubble feedback. We show that superbubble-driven galactic outflows powered by Type II supernovae alone can produce $\\rm{L^*}$ galaxies with flat rotation curves with circular velocities $\\sim 200\\; \\rm{km/s}$, low bulge-to-disc ratios, and stellar mass fractions that match observed values from high redshift to the present. These features are made possible by the high mass loadings generated by the evaporative growth of superbubbles. Outflows are driven extremely effectively at high redshift, expelling gas at early times and preventing overproduction of stars before $z=2$. Centrally concentrated gas in previous simulations has often lead to unrealistically high bulge to total ratios and strongly peaked rotation curves. We show that supernova-powered superbubbles alone can produce galaxies that agree well with observed properties without the need for additional feedback mechanisms or ...

  13. Combustion Group Group members

    E-Print Network [OSTI]

    Wang, Wei

    Combustion Group Group members: Thierry Poinsot, Emilien Courtine, Luc Vervisch, Benjamin Farcy 2014 #12;Combustion Group Combustion Physics and Modeling Pollutants, Emissions, and Soot Formation Thermoacoustics and Combustion Dynamics Research focus § Examine mechanisms responsible for flame stabilization

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

    SciTech Connect (OSTI)

    Nugent, Peter E; Hsiao, E.Y.; Conley, A.; Howell, D.A.; Sullivan, M.; Pritchet, C.J.; Carlberg, R.G.; Nugent, P.E.; Phillips, M.M.

    2007-03-20T23:59:59.000Z

    With the advent of large dedicated Type Ia supernova (SN Ia) surveys, K-corrections of SNe Ia and their uncertainties have become especially important in the determination of cosmological parameters. While K-corrections are largely driven by SN Ia broadband colors, it is shown here that the diversity in spectral features of SNe Ia can also be important. For an individual observation, the statistical errors from the inhomogeneity in spectral features range from 0.01 (where the observed and rest-frame filters are aligned) to 0.04 (where the observed and rest-frame filters are misaligned). To minimize the systematic errors caused by an assumed SN Ia spectral energy distribution (SED), we outline a prescription for deriving a mean spectral template time series that incorporates a large and heterogeneous sample of observed spectra. We then remove the effects of broadband colors and measure the remaining uncertainties in the K-corrections associated with the diversity in spectral features. Finally, we present a template spectroscopic sequence near maximum light for further improvement on the K-correction estimate. A library of ~;;600 observed spectra of ~;;100 SNe Ia from heterogeneous sources is used for the analysis.

  15. The magnification of SN 1997ff, the farthest known supernova

    SciTech Connect (OSTI)

    Benitez, Narciso; Riess, Adam; Nugent, Peter; Dickinson, Mark; Chornock, Ryan; Filippenko, Alexei V.

    2002-09-03T23:59:59.000Z

    With a redshift of z {approx} 1.7, SN 1997ff is the most distant type Ia supernova discovered so far. This SN is close to several bright, z = 0.6-0.9 galaxies, and we consider the effects of lensing by those objects on the magnitude of SN 1997ff. We estimate their velocity dispersions using the Tully-Fisher and Faber-Jackson relations corrected for evolution effects, and calculate, applying the multiple-plane lensing formalism, that SN 1997ff is magnified by 0.34{+-}0.12 mag. Due to the spatial configuration of the foreground galaxies, the shear from individual lenses partially cancels out,and the total distortion induced on the host galaxy is considerably smaller than that produced by a single lens having the same magnification. After correction for lensing, the revised distance to SN 1997ff is m-M = 45.49 {+-} 0.34 mag, which improves the agreement with the {Omega}{sub M} = 0.35, {Omega}{Lambda} = 0.65 cosmology expected from lower-redshift SNe Ia, and is inconsistent at the {approx} 3 sigma confidence level with a uniform gray dust model or a simple evolution model.

  16. Type Ia Supernova Explosion Models: Homogeneity versus Diversity

    E-Print Network [OSTI]

    W. Hillebrandt; J. C. Niemeyer; M. Reinecke

    2000-05-30T23:59:59.000Z

    Type Ia supernovae (SN Ia) are generally believed to be the result of the thermonuclear disruption of Chandrasekhar-mass carbon-oxygen white dwarfs, mainly because such thermonuclear explosions can account for the right amount of Ni-56, which is needed to explain the light curves and the late-time spectra, and the abundances of intermediate-mass nuclei which dominate the spectra near maximum light. Because of their enormous brightness and apparent homogeneity SN Ia have become an important tool to measure cosmological parameters. In this article the present understanding of the physics of thermonuclear explosions is reviewed. In particular, we focus our attention on subsonic (``deflagration'') fronts, i.e. we investigate fronts propagating by heat diffusion and convection rather than by compression. Models based upon this mode of nuclear burning have been applied very successfully to the SN Ia problem, and are able to reproduce many of their observed features remarkably well. However, the models also indicate that SN Ia may differ considerably from each other, which is of importance if they are to be used as standard candles.

  17. Theoretical Clues to the Ultraviolet Diversity of Type Ia Supernovae

    E-Print Network [OSTI]

    Brown, Peter J; Milne, Peter; Roming, Peter W A; Wang, Lifan

    2015-01-01T23:59:59.000Z

    The effect of metallicity on the observed light of Type Ia supernovae (SNe Ia) could lead to systematic errors as the absolute magnitudes of local and distant SNe Ia are compared to measure luminosity distances and determine cosmological parameters. The UV light may be especially sensitive to metallicity, though different modeling methods disagree as to the magnitude, wavelength dependence, and even the sign of the effect. The outer density structure, ^56 Ni, and to a lesser degree asphericity, also impact the UV. We compute synthetic photometry of various metallicity-dependent models and compare to UV/optical photometry from the Swift Ultra-Violet/Optical Telescope. We find that the scatter in the mid-UV to near-UV colors is larger than predicted by changes in metallicity alone and is not consistent with reddening. We demonstrate that a recently employed method to determine relative abundances using UV spectra can be done using UVOT photometry, but we warn that accurate results require an accurate model of t...

  18. MOND cosmology from holographic principle

    E-Print Network [OSTI]

    Zhang, Hongsheng

    2011-01-01T23:59:59.000Z

    We derive the MOND cosmology which is uniquely corresponding to the original MOND in galaxies via holographic approach of gravity. It inherits the key merit of MOND, that is, it reduces the byronic matter and mysterious non-byronic dark matter (dark matter for short) in the standard cosmology into byronic matter only. For the first time we derive the critical parameter in MOND, i.e., the transition acceleration $a_c$ on cosmological scale. We thus solve the long-standing coincidence problem $a_c\\sim cH_{0}$. More interestingly, a term like age-graphic dark energy emerges naturally. In the frame of this MOND cosmology, we only need byronic matter to describe both dark matter and dark energy in standard cosmology.

  19. Cosmology with decaying particles

    SciTech Connect (OSTI)

    Turner, M.S.

    1984-09-01T23:59:59.000Z

    We consider a cosmological model in which an unstable massive relic particle species (denoted by X) has an initial mass density relative to baryons ..beta../sup -1/ identically equal rho/sub X//rho/sub B/ >> 1, and then decays recently (redshift z less than or equal to 1000) into particles which are still relativistic today (denoted by R). We write down and solve the coupled equations for the cosmic scale factor a(t), the energy density in the various components (rho/sub X/, rho/sub R/, rho/sub B/), and the growth of linear density perturbations (delta rho/rho). The solutions form a one parameter (..beta..) family of solutions; physically ..beta../sup -1/ approx. = (..cap omega../sub R//..cap omega../sub NR/) x (1 + z/sub D/) = (ratio today of energy density of relativistic to nonrelativistic particles) x (1 + redshift of (decay)). We discuss the observational implications of such a cosmological model and compare our results to earlier results computed in the simultaneous decay approximation. In an appendix we briefly consider the case where one of the decay products of the X is massive and becomes nonrelativistic by the present epoch. 21 references.

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

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

    The Rise and Fall of Core-Collapse Supernovae The Rise and Fall of Core-Collapse Supernovae 2D and 3D Models Shed New Light on What Fuels an Exploding Star July 2, 2015 | Tags:...

  1. SNEWS: The SuperNova Early Warning System

    E-Print Network [OSTI]

    Antonioli, P

    2004-01-01T23:59:59.000Z

    This paper provides a technical description of the SuperNova Early Warning System (SNEWS), an international network of experiments with the goal of providing an early warning of a galactic supernova.

  2. SNEWS: The SuperNova Early Warning System

    E-Print Network [OSTI]

    P. Antonioli

    2004-07-30T23:59:59.000Z

    This paper provides a technical description of the SuperNova Early Warning System (SNEWS), an international network of experiments with the goal of providing an early warning of a galactic supernova.

  3. 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 will be devoted to them. We will point out, however, that because thermonuclear supernovae occur from a quite

  4. Supernova rates and stellar populations

    E-Print Network [OSTI]

    F. Mannucci

    2007-08-03T23:59:59.000Z

    We discuss the results about the nature of type Ia Supernovae that can be derived by studying their rates in different stellar populations. While the evolution of SN photometry and spectra can constrain the explosion mechanism, the SN rate depends on the progenitor system. We review the current available data on rates as a function of parent galaxy color, morphology, star formation rate, radio luminosity and environment. By studying the variation of the rates with the color of the parent galaxy, a strong evidence was established that type Ia SNe come from both young and old stars. The dependence of the rates with the radio power of the parent galaxy is best reproduced by a bimodal distribution of delay time between the formation of the progenitor and its explosion as a SN. Cluster early-type galaxies show higher type Ia SN rate with respect to field galaxies, and this effect can be due either to traces of young stars or to differences in the delay time distribution.

  5. 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

    1997-06-03T23:59:59.000Z

    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.

  6. Powerful gravitational-wave bursts from supernova neutrino oscillations

    E-Print Network [OSTI]

    Herman J. Mosquera Cuesta; Karen Fiuza

    2004-07-26T23:59:59.000Z

    During supernova core collapse and bounce resonant active-to-active, as well as active-to-sterile, neutrino ($\

  7. Cosmic Rays from Supernovae Proven to Hit Earth

    Broader source: Energy.gov [DOE]

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

  8. Cosmological constraints from the Hubble parameter on f(R) cosmologies

    SciTech Connect (OSTI)

    Carvalho, F C; Alcaniz, J S [Observatorio Nacional, 20921-400 Rio de Janeiro-RJ (Brazil)] [Observatorio Nacional, 20921-400 Rio de Janeiro-RJ (Brazil); Santos, E M [Centro Brasileiro de Pesquisas Fisicas, 22290-180, Rio de Janeiro-RJ (Brazil)] [Centro Brasileiro de Pesquisas Fisicas, 22290-180, Rio de Janeiro-RJ (Brazil); Santos, J, E-mail: fabiocc@das.inpe.br, E-mail: emoura@cbpf.br, E-mail: alcaniz@on.br, E-mail: janilo@dfte.ufrn.br [Departamento de Fisica, Universidade Federal do Rio Grande do Norte, 59072-970 Natal-RN (Brazil)] [Departamento de Fisica, Universidade Federal do Rio Grande do Norte, 59072-970 Natal-RN (Brazil)

    2008-09-15T23:59:59.000Z

    Modified f(R) gravity in the Palatini approach has been recently applied in cosmology as a realistic alternative to dark energy. In this regard, a number of authors have searched for observational constraints on several f(R) gravity functional forms using mainly data from type Ia supernovae, cosmic microwave background (CMB) radiation and large scale structure. In this paper, considering a homogeneous and isotropic flat universe, we use determinations of the Hubble function H(z), which are based on a differential age method, to place bounds on the free parameters of the f(R) = R-{beta}/R{sup n} functional form. We also combine the H(z) data with constraints from baryon acoustic oscillations and 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{sup n} gravity in the Palatini approach, unlike the metric formalism, can produce a sequence of radiation-dominated, matter-dominated, and accelerating periods without the need for dark energy.

  9. Superluminous supernovae: No threat from Eta Carinae

    E-Print Network [OSTI]

    Brian C. Thomas; Adrian L. Melott; Brian D. Fields; Barbara J. Anthony-Twarog

    2007-09-25T23:59:59.000Z

    Recently Supernova 2006gy was noted as the most luminous ever recorded, with a total radiated energy of ~10^44 Joules. It was proposed that the progenitor may have been a massive evolved star similar to eta Carinae, which resides in our own galaxy at a distance of about 2.3 kpc. eta Carinae appears ready to detonate. Although it is too distant to pose a serious threat as a normal supernova, and given its rotation axis is unlikely to produce a Gamma-Ray Burst oriented toward the Earth, eta Carinae is about 30,000 times nearer than 2006gy, and we re-evaluate it as a potential superluminous supernova. We find that given the large ratio of emission in the optical to the X-ray, atmospheric effects are negligible. Ionization of the atmosphere and concomitant ozone depletion are unlikely to be important. Any cosmic ray effects should be spread out over ~10^4 y, and similarly unlikely to produce any serious perturbation to the biosphere. We also discuss a new possible effect of supernovae, endocrine disruption induced by blue light near the peak of the optical spectrum. This is a possibility for nearby supernovae at distances too large to be considered "dangerous" for other reasons. However, due to reddening and extinction by the interstellar medium, eta Carinae is unlikely to trigger such effects to any significant degree.

  10. Cosmological perturbations on local systems

    E-Print Network [OSTI]

    Gregory S. Adkins; Jordan McDonnell; Richard N. Fell

    2006-12-22T23:59:59.000Z

    We study the effect of cosmological expansion on orbits--galactic, planetary, or atomic--subject to an inverse-square force law. We obtain the laws of motion for gravitational or electrical interactions from general relativity--in particular, we find the gravitational field of a mass distribution in an expanding universe by applying perturbation theory to the Robertson-Walker metric. Cosmological expansion induces an ($\\ddot a/a) \\vec r$ force where $a(t)$ is the cosmological scale factor. In a locally Newtonian framework, we show that the $(\\ddot a/a) \\vec r$ term represents the effect of a continuous distribution of cosmological material in Hubble flow, and that the total force on an object, due to the cosmological material plus the matter perturbation, can be represented as the negative gradient of a gravitational potential whose source is the material actually present. We also consider the effect on local dynamics of the cosmological constant. We calculate the perihelion precession of elliptical orbits due to the cosmological constant induced force, and work out a generalized virial relation applicable to gravitationally bound clusters.

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

    E-Print Network [OSTI]

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

    2015-01-01T23:59:59.000Z

    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-...

  12. Cosmological Collider Physics

    E-Print Network [OSTI]

    Arkani-Hamed, Nima

    2015-01-01T23:59:59.000Z

    We study the imprint of new particles on the primordial cosmological fluctuations. New particles with masses comparable to the Hubble scale produce a distinctive signature on the non-gaussianities. This feature arises in the squeezed limit of the correlation functions of primordial fluctuations. It consists of particular power law, or oscillatory, behavior that contains information about the masses of new particles. There is an angular dependence that gives information about the spin. We also have a relative phase that crucially depends on the quantum mechanical nature of the fluctuations and can be viewed as arising from the interference between two processes. While some of these features were noted before in the context of specific inflationary scenarios, here we give a general description emphasizing the role of symmetries in determining the final result.

  13. The Mixmaster cosmological metrics

    E-Print Network [OSTI]

    Charles W. Misner

    1994-05-27T23:59:59.000Z

    This paper begins with a short presentation of the Bianchi IX or ``Mixmaster'' cosmological model, and some ways of writing the Einstein equations for it. There is then an interlude describing how I came to a study of this model, and then a report of some mostly unpublished work from a Ph.\\ D. thesis of D. M. (Prakash) Chitre relating approximate solutions to geodesic flows on finite volume negative curvature Riemannian manifolds, for which he could quote results on ergodicity. A final section restates studies of a zero measure set of solutions which in first approximation appear to have only a finite number of Kasner epochs before reaching the singularity. One finds no plausible case for such behavior in better approximations.

  14. Protein folding and cosmology

    E-Print Network [OSTI]

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

    1997-06-04T23:59:59.000Z

    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.

  15. Signatures of Explosion Models for SN ~Ia & Cosmology

    E-Print Network [OSTI]

    P. Hoeflich

    2004-09-07T23:59:59.000Z

    We give an overview of the current understanding of Type Ia supernovae relevant for their use as cosmological distance indicators. We present the physical basis to understand their homogeneity of the observed light curves and spectra and the observed correlations. SNe Ia have been well established as distance indicators on the 10 % level. However, the quest for the nature of the dark energy requires improvements in the accuracy to the 2 to 3 % level, we must understand the diversity within the SNe Ia population, and its evolution with redshift. Based on detailed models for the progenitors, explosions, light curves and spectra, we discuss signatures of thermonuclear explosions, and the implications for cosmology. We emphasize the relation between LC properties and spectra because, for local SNe~Ia, the diversity becomes apparent the combination of spectra and LCs whereas, by enlarge, we have to for high-z objects. At some examples, we show how we can actually probe the properties of the progenitor, its environment, and details of the explosion physics.

  16. 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)

    2013-10-20T23:59:59.000Z

    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.

  17. Cosmology and the weak interaction

    SciTech Connect (OSTI)

    Schramm, D.N. (Fermi National Accelerator Lab., Batavia, IL (USA)):(Chicago Univ., IL (USA))

    1989-12-01T23:59:59.000Z

    The weak interaction plays a critical role in modern Big Bang cosmology. This review will emphasize two of its most publicized cosmological connections: Big Bang nucleosynthesis and Dark Matter. The first of these is connected to the cosmological prediction of Neutrino Flavours, N{sub {nu}} {approximately} 3 which is now being confirmed at SLC and LEP. The second is interrelated to the whole problem of galaxy and structure formation in the universe. This review will demonstrate the role of the weak interaction both for dark matter candidates and for the problem of generating seeds to form structure. 87 refs., 3 figs., 5 tabs.

  18. Dark-energy dependent test of general relativity at cosmological scales

    E-Print Network [OSTI]

    Zolnierowski, Yves

    2015-01-01T23:59:59.000Z

    The $\\Lambda$CDM framework offers a remarkably good description of our universe with a very small number of free parameters, which can be determined with high accuracy from currently available data. However, this does not mean that the associated physical quantities, such as the curvature of the universe, have been directly measured. Similarly, general relativity is assumed, but not tested. Testing the relevance of general relativity for cosmology at the background level includes a verification of the relation between its energy contents and the curvature of space. Using an extended Newtonian formulation, we propose an approach where this relation can be tested. Using the recent measurements on cosmic microwave background, baryonic acoustic oscillations and the supernova Hubble diagram, we show that the prediction of general relativity is well verified in the framework of standard $\\Lambda$CDM assumptions, i.e. an energy content only composed of matter and dark energy, in the form of a cosmological constant o...

  19. Cosmological moduli problem, supersymmetry breaking, and stability in postinflationary cosmology

    SciTech Connect (OSTI)

    Banks, T.; Berkooz, M. [Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08855-0849 (United States)] [Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08855-0849 (United States); Steinhardt, P.J. [Department of Physics, University of Pennsylvania, Philadelphia, Pennsylvania 19104 (United States)] [Department of Physics, University of Pennsylvania, Philadelphia, Pennsylvania 19104 (United States)

    1995-07-15T23:59:59.000Z

    We review scenarios that have been proposed to solve the cosmological problem caused by moduli in string theory, the postmodern Polonyi problem (PPP). In particular, we discuss the difficulties encountered by the apparently ``trivial`` solution of this problem, in which moduli masses are assumed to arise from nonperturbative, SUSY-preserving, dynamics at a scale higher than that of SUSY breaking. This suggests a powerful {ital cosmological} {ital vacuum} {ital selection} {ital principle} in superstring theory. However, we argue that if one eschews the possibility of cancellations between different exponentials of the inverse string coupling, the mechanism described above cannot stabilize the dilaton. Thus, even if supersymmetric dynamics gives mass to the other moduli in string theory, the dilaton mass must be generated by SUSY breaking, and dilaton domination of the energy density of the Universe cannot be avoided. We conclude that the only proposal for solving the PPP that works is the intermediate scale inflation scenario of Randall and Thomas. However, we point out that all extant models have ignored unavoidably large inhomogeneities in the cosmological moduli density at very early times, and speculate that the effects associated with nonlinear gravitational collapse of these inhomogeneities may serve as an efficient mechanism for converting moduli into ordinary matter. As an important by-product of this investigation we show that in a postinflationary universe minima of the effective potential with a negative cosmological constant are not stationary points of the classical equations of scalar field cosmology. Instead, such points lead to catastrophic gravitational collapse of that part of the Universe which is attracted to them. Thus postinflationary cosmology dynamically chooses non-negative values of the cosmological constant. This implies that supersymmetry {ital must} be broken in any sensible inflationary cosmology. (Abstract Truncated)

  20. Jet Induced Supernovae-Hydrodynamics and Observational Consequences

    E-Print Network [OSTI]

    A. Khokhlov; Peter Hoeflich

    2000-11-01T23:59:59.000Z

    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.

  1. Probing Exotic Physics With Supernova Neutrinos

    SciTech Connect (OSTI)

    Kelso, Chris; Hooper, Dan

    2010-09-01T23:59:59.000Z

    Future galactic supernovae will provide an extremely long baseline for studying the properties and interactions of neutrinos. In this paper, we discuss the possibility of using such an event to constrain (or discover) the effects of exotic physics in scenarios that are not currently constrained and are not accessible with reactor or solar neutrino experiments. In particular, we focus on the cases of neutrino decay and quantum decoherence. We calculate the expected signal from a core-collapse supernova in both current and future water Cerenkov, scintillating, and liquid argon detectors, and find that such observations will be capable of distinguishing between many of these scenarios. Additionally, future detectors will be capable of making strong, model-independent conclusions by examining events associated with a galactic supernova's neutronization burst.

  2. Tidally-induced thermonuclear Supernovae

    E-Print Network [OSTI]

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

    2008-11-13T23:59:59.000Z

    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.

  3. Hydrogen issue in Core Collapse Supernovae

    E-Print Network [OSTI]

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

    2006-11-06T23:59:59.000Z

    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.

  4. 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)

    2013-11-01T23:59:59.000Z

    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}.

  5. Deflagrations and Detonations in Thermonuclear Supernovae

    E-Print Network [OSTI]

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

    2004-06-03T23:59:59.000Z

    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.

  6. Combustion Group Group members

    E-Print Network [OSTI]

    Wang, Wei

    Combustion Group Group members: Thierry Poinsot, Emilien Courtine, Luc Vervisch, Benjamin Farcy § New combustion and energy-conversion concepts #12;Introduction Combustion research thrusts Combustion Dynamics and Flame-Stabilization Research objectives § Obtain fundamental understanding of combustion

  7. MOND cosmology from entropic force

    E-Print Network [OSTI]

    Hongsheng Zhang; Xin-Zhou Li

    2012-07-11T23:59:59.000Z

    We derive the MOND cosmology which is uniquely corresponding to the original MOND at galaxy scales via entropic gravity method. It inherits the key merit of MOND, that is, it reduces the baryonic matter and non-baryonic dark matter into baryonic matter only. For the first time we obtain the critical parameter in MOND, i.e., the transition acceleration $a_c$ at cosmological scale. We thus solve the long-standing coincidence problem $a_c\\sim cH_{0}$. More interestingly, a term like age-graphic dark energy emerges naturally. In the frame of this MOND cosmology, we only need baryonic matter to describe both dark matter and dark energy in standard cosmology.

  8. Rip Cosmology via Inhomogeneous Fluid

    E-Print Network [OSTI]

    V. V. Obukhov; A. V. Timoshkin; E. V Savushkin

    2013-09-18T23:59:59.000Z

    The conditions for the appearance of the Little Rip, Pseudo Rip and Quasi Rip universes in the terms of the parameters in the equation of state of some dark fluid are investigated. Several examples of the Rip cosmologies are investigated.

  9. Thermodynamics in Loop Quantum Cosmology

    E-Print Network [OSTI]

    Li-Fang Li; Jian-Yang Zhu

    2008-12-18T23:59:59.000Z

    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.

  10. Precision cosmology and the landscape

    SciTech Connect (OSTI)

    Bousso, Raphael; Bousso, Raphael

    2006-10-01T23:59:59.000Z

    After reviewing the cosmological constant problem -- why is Lambda not huge? -- I outline the two basic approaches that had emerged by the late 1980s, and note that each made a clear prediction. Precision cosmological experiments now indicate that the cosmological constant is nonzero. This result strongly favors the environmental approach, in which vacuum energy can vary discretely among widely separated regions in the universe. The need to explain this variation from first principles constitutes an observational constraint on fundamental theory. I review arguments that string theory satisfies this constraint, as it contains a dense discretuum of metastable vacua. The enormous landscape of vacua calls for novel, statistical methods of deriving predictions, and it prompts us to reexamine our description of spacetime on the largest scales. I discuss the effects of cosmological dynamics, and I speculate that weighting vacua by their entropy production may allow for prior-free predictions that do not resort to explicitly anthropic arguments.

  11. Constraining fundamental physics from cosmology

    E-Print Network [OSTI]

    Bird, Simeon

    2011-10-11T23:59:59.000Z

    I use mathematical models and numerical simulations to constrain cosmological inflation, the seeds of structure, and the mass of the neutrino. I revisit arguments that simple models of inflation with a small red tilt in the scalar power spectrum...

  12. Bimetric gravity is cosmologically viable

    E-Print Network [OSTI]

    Akrami, Yashar; Könnig, Frank; Schmidt-May, Angnis; Solomon, Adam R

    2015-01-01T23:59:59.000Z

    Bimetric theory describes gravitational interactions in the presence of an extra spin-2 field. Previous work has suggested that its cosmological solutions are generically plagued by instabilities. We show that by taking the Planck mass for the second metric, $M_f$, to be small, these instabilities can be pushed back to unobservably early times. In this limit, the theory approaches general relativity with an effective cosmological constant which is, remarkably, determined by the spin-2 interaction scale. This provides a late-time expansion history which is extremely close to $\\Lambda$CDM, but with a technically-natural value for the cosmological constant. We find $M_f$ should be no larger than the electroweak scale in order for cosmological perturbations to be stable by big-bang nucleosynthesis.

  13. 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

    2014-11-18T23:59:59.000Z

    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, but models where dark matter decays into radiation are sharply limited. 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)

  14. Supernova Legacy Survey (SNLS) : real time operations and photometric analysis

    E-Print Network [OSTI]

    N. Palanque-Delabrouille; for the SNLS collaboration

    2005-09-15T23:59:59.000Z

    Type Ia supernovae (SN Ia) have provided the first evidence for an accelerating universe and for the existence of an unknown ``dark energy'' driving this expansion. The 5-year Supernova Legacy Survey (SNLS) will deliver \\~700 type Ia supernovae and as many type II supernovae with well-sampled light curves in 4 filters g', r', i' and z'. The current status of the project will be presented, along with the real time processing leading to the discovery and spectroscopic observation of the supernovae. We also present an offline selection of the SN candidates which aims at identifying and eliminating potential selection biases.

  15. ?CDM cosmology from matter only

    E-Print Network [OSTI]

    Herman Telkamp

    2015-04-08T23:59:59.000Z

    I discuss a matter-only interpretation of {\\Lambda}CDM cosmology, based on conservation of energy and assuming a Machian definition of inertia. {\\Lambda}CDM cosmology can be linked to a Newtonian cosmic potential, subject to a propagating gravitational horizon. In a matter-only universe where total energy is conserved, Machian inertia related to the evolving potential may cause both deceleration and acceleration of recession.

  16. JLF User Group

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

    systems, such as, the hydrodynamics instabilities that may develop in core-collapse supernovae or a radiative shocks in a supernova remnants. She has lead experiments at the Omega...

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

    SciTech Connect (OSTI)

    Dilday, Benjamin; /Chicago U.

    2008-08-01T23:59:59.000Z

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

  18. 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

    2007-01-29T23:59:59.000Z

    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.

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

    E-Print Network [OSTI]

    2008-01-01T23:59:59.000Z

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

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

    E-Print Network [OSTI]

    2008-01-01T23:59:59.000Z

    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

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

    E-Print Network [OSTI]

    Hjorth, Jens

    2013-01-01T23:59:59.000Z

    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.

  2. Axion cold dark matter in nonstandard cosmologies

    SciTech Connect (OSTI)

    Visinelli, Luca; Gondolo, Paolo [Department of Physics and Astronomy, University of Utah, 115 South 1400 East 201, Salt Lake City, Utah 84112-0830 (United States)

    2010-03-15T23:59:59.000Z

    We study the parameter space of cold dark matter axions in two cosmological scenarios with nonstandard thermal histories before big bang nucleosynthesis: the low-temperature reheating (LTR) cosmology and the kination cosmology. If the Peccei-Quinn symmetry breaks during inflation, we find more allowed parameter space in the LTR cosmology than in the standard cosmology and less in the kination cosmology. On the contrary, if the Peccei-Quinn symmetry breaks after inflation, the Peccei-Quinn scale is orders of magnitude higher than standard in the LTR cosmology and lower in the kination cosmology. We show that the axion velocity dispersion may be used to distinguish some of these nonstandard cosmologies. Thus, axion cold dark matter may be a good probe of the history of the Universe before big bang nucleosynthesis.

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

    E-Print Network [OSTI]

    Reginald T Cahill

    2007-06-05T23:59:59.000Z

    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.

  4. Multipole expansion method for supernova neutrino oscillations

    E-Print Network [OSTI]

    Duan, Huaiyu

    2014-01-01T23:59:59.000Z

    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.

  5. Multipole expansion method for supernova neutrino oscillations

    E-Print Network [OSTI]

    Huaiyu Duan; Shashank Shalgar

    2014-12-24T23:59:59.000Z

    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. Rates and Progenitors of Type Ia Supernovae

    E-Print Network [OSTI]

    William Michael Wood-Vasey

    2005-05-30T23:59:59.000Z

    The remarkable uniformity of Type Ia supernovae (SNe Ia) has allowed astronomers to use them as distance indicators to measure the properties and expansion history of the Universe. However, SNe Ia exhibit intrinsic variation in both their spectra and observed brightness. To reduce these systematic uncertainties, we need a deeper understanding of the observed variations in SNe Ia. Toward this end, the Nearby Supernova Factory (SNfactory) has been designed to discover hundreds of SNe Ia in a systematic and automated fashion and study them in detail. 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 SNe Ia. This dissertation presents a new method for analyzing the true sensitivity of a multi-epoch supernova search and finds a SN Ia rate from $z\\sim0.01$--0.1 of $r_V = 4.26 (+1.39 -1.93) (+0.10 - 0.10)$ SNe Ia/yr/Mpc$^3$ 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 SNe Ia.

  7. Explosions inside Ejecta and Most Luminous Supernovae

    E-Print Network [OSTI]

    S. I. Blinnikov

    2008-12-28T23:59:59.000Z

    The extremely luminous supernova SN2006gy is explained in the same way as other SNIIn events: light is produced by a radiative shock propagating in a dense circumstellar envelope formed by a previous weak explosion. The problems in the theory and observations of multiple-explosion SNe IIn are briefly reviewed.

  8. Models of Type Ia Supernova Explosions

    E-Print Network [OSTI]

    J. C. Niemeyer; M. Reinecke; W. Hillebrandt

    2002-03-21T23:59:59.000Z

    Type Ia supernovae have become an indispensable tool for studying the expansion history of the universe, yet our understanding of the explosion mechanism is still incomplete. We describe the variety of discussed scenarios, sketch the most relevant physics, and report recent advances in multidimensional simulations of Chandrasekhar mass white dwarf explosions.

  9. Models of Type Ia Supernova Explosions

    E-Print Network [OSTI]

    Niemeyer, J C; Hillebrandt, W

    2002-01-01T23:59:59.000Z

    Type Ia supernovae have become an indispensable tool for studying the expansion history of the universe, yet our understanding of the explosion mechanism is still incomplete. We describe the variety of discussed scenarios, sketch the most relevant physics, and report recent advances in multidimensional simulations of Chandrasekhar mass white dwarf explosions.

  10. Plasma Redshift, Time Dilation, and Supernovas Ia

    E-Print Network [OSTI]

    Ari Brynjolfsson

    2004-07-20T23:59:59.000Z

    The measurements of the absolute magnitudes and redshifts of supernovas Ia show that conventional physics, which includes plasma redshift, fully explains the observed magnitude-redshift relation of the supernovas. The only parameter that is required is the Hubble constant, which in principle can be measured independently. The contemporary theory of the expansion of the universe (Big Bang) requires in addition to the Hubble constant several adjustable parameters, such as an initial explosion, the dark matter parameter, and a time adjustable dark energy parameter for explaining the supernova Ia data. The contemporary Big Bang theory also requires time dilation of distant events as an inherent premise. The contention is usually that the light curves of distant supernovas show or even prove the time dilation. In the present article, we challenge this assertion. We document and show that the previously reported data in fact indicate that there is no time dilation. The data reported by Riess et al. in the Astrophysical Journal in June 2004 confirm the plasma redshift, the absence of time dilation, dark matter, and dark energy.

  11. Varying constants quantum cosmology

    E-Print Network [OSTI]

    Katarzyna Leszczynska; Adam Balcerzak; Mariusz P. Dabrowski

    2015-01-26T23:59:59.000Z

    We discuss minisuperspace models within the framework of varying physical constants theories including $\\Lambda$-term. In particular, we consider the varying speed of light (VSL) theory and varying gravitational constant theory (VG) using the specific ans\\"atze for the variability of constants: $c(a) = c_0 a^n$ and $G(a)=G_0 a^q$. We find that most of the varying $c$ and $G$ minisuperspace potentials are of the tunneling type which allows to use WKB approximation of quantum mechanics. Using this method we show that the probability of tunneling of the universe "from nothing" ($a=0)$ to a Friedmann geometry with the scale factor $a_t$ is large for growing $c$ models and is strongly suppressed for diminishing $c$ models. As for $G$ varying, the probability of tunneling is large for $G$ diminishing, while it is small for $G$ increasing. In general, both varying $c$ and $G$ change the probability of tunneling in comparison to the standard matter content (cosmological term, dust, radiation) universe models.

  12. Dark matter and cosmology

    SciTech Connect (OSTI)

    Schramm, D.N.

    1992-03-01T23:59:59.000Z

    The cosmological dark matter problem is reviewed. The Big Bang Nucleosynthesis constraints on the baryon density are compared with the densities implied by visible matter, dark halos, dynamics of clusters, gravitational lenses, large-scale velocity flows, and the {Omega} = 1 flatness/inflation argument. It is shown that (1) the majority of baryons are dark; and (2) non-baryonic dark matter is probably required on large scales. It is also noted that halo dark matter could be either baryonic or non-baryonic. Descrimination between ``cold`` and ``hot`` non-baryonic candidates is shown to depend on the assumed ``seeds`` that stimulate structure formation. Gaussian density fluctuations, such as those induced by quantum fluctuations, favor cold dark matter, whereas topological defects such as strings, textures or domain walls may work equally or better with hot dark matter. A possible connection between cold dark matter, globular cluster ages and the Hubble constant is mentioned. Recent large-scale structure measurements, coupled with microwave anisotropy limits, are shown to raise some questions for the previously favored density fluctuation picture. Accelerator and underground limits on dark matter candidates are also reviewed.

  13. Dark matter and cosmology

    SciTech Connect (OSTI)

    Schramm, D.N.

    1992-03-01T23:59:59.000Z

    The cosmological dark matter problem is reviewed. The Big Bang Nucleosynthesis constraints on the baryon density are compared with the densities implied by visible matter, dark halos, dynamics of clusters, gravitational lenses, large-scale velocity flows, and the {Omega} = 1 flatness/inflation argument. It is shown that (1) the majority of baryons are dark; and (2) non-baryonic dark matter is probably required on large scales. It is also noted that halo dark matter could be either baryonic or non-baryonic. Descrimination between cold'' and hot'' non-baryonic candidates is shown to depend on the assumed seeds'' that stimulate structure formation. Gaussian density fluctuations, such as those induced by quantum fluctuations, favor cold dark matter, whereas topological defects such as strings, textures or domain walls may work equally or better with hot dark matter. A possible connection between cold dark matter, globular cluster ages and the Hubble constant is mentioned. Recent large-scale structure measurements, coupled with microwave anisotropy limits, are shown to raise some questions for the previously favored density fluctuation picture. Accelerator and underground limits on dark matter candidates are also reviewed.

  14. SUPERNOVA LIGHT CURVES POWERED BY FALLBACK ACCRETION

    SciTech Connect (OSTI)

    Dexter, Jason; Kasen, Daniel, E-mail: jdexter@berkeley.edu [Departments of Physics and Astronomy, University of California, Berkeley, CA 94720 (United States)

    2013-07-20T23:59:59.000Z

    Some fraction of the material ejected in a core collapse supernova explosion may remain bound to the compact remnant, and eventually turn around and fall back. We show that the late time ({approx}>days) power potentially associated with the accretion of this 'fallback' material could significantly affect the optical light curve, in some cases producing super-luminous or otherwise peculiar supernovae. We use spherically symmetric hydrodynamical models to estimate the accretion rate at late times for a range of progenitor masses and radii and explosion energies. The accretion rate onto the proto-neutron star or black hole decreases as M-dot {proportional_to}t{sup -5/3} at late times, but its normalization can be significantly enhanced at low explosion energies, in very massive stars, or if a strong reverse shock wave forms at the helium/hydrogen interface in the progenitor. If the resulting super-Eddington accretion drives an outflow which thermalizes in the outgoing ejecta, the supernova debris will be re-energized at a time when photons can diffuse out efficiently. The resulting light curves are different and more diverse than previous fallback supernova models which ignored the input of accretion power and produced short-lived, dim transients. The possible outcomes when fallback accretion power is significant include super-luminous ({approx}> 10{sup 44} erg s{sup -1}) Type II events of both short and long durations, as well as luminous Type I events from compact stars that may have experienced significant mass loss. Accretion power may unbind the remaining infalling material, causing a sudden decrease in the brightness of some long duration Type II events. This scenario may be relevant for explaining some of the recently discovered classes of peculiar and rare supernovae.

  15. Probing thermonuclear supernova explosions with neutrinos

    E-Print Network [OSTI]

    A. Odrzywolek; T. Plewa

    2011-03-27T23:59:59.000Z

    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.

  16. Supernova Enrichment of Dwarf Spheroidal Galaxies

    E-Print Network [OSTI]

    P. Chris Fragile; Stephen D. Murray; Peter Anninos; Douglas N. C. Lin

    2003-03-10T23:59:59.000Z

    (Abridged) Many dwarf galaxies exhibit sub-Solar metallicities, with some star-to-star variation, despite often containing multiple generations of stars. The total metal content in these systems is much less than expected from the heavy element production of massive stars in each episode of star formation. Such a deficiency implies that a substantial fraction of the enriched material has been lost from these small galaxies. Mass ejection from dwarf galaxies may have important consequences for the evolution of the intergalactic medium and for the evolution of massive galaxies, which themselves may have formed via the merger of smaller systems. We report here the results of three-dimensional simulations of the evolution of supernova-enriched gas within dwarf spheroidal galaxies (dSph's), with the aim of determining the retention efficiency of supernova ejecta. We consider two galaxy models, selected to represent opposite ends of the dSph sequence. For each model galaxy we investigate a number of scenarios, ranging from a single supernova in smooth gas distributions to more complex multiple supernovae in highly disturbed gas distributions. The results of these investigations suggest that, for low star-formation efficiencies, it is difficult to completely expel the enriched material from the galaxy. Most of the enriched gas is, however, lost from the core of the galaxy following multiple supernovae, especially if the interstellar medium is already highly disturbed by processes such as photo-ionization and stellar winds. If subsequent star formation occurs predominantly within the core where most of the residual gas is concentrated, then these results could explain the poor self-enrichment efficiency observed in dwarf galaxies.

  17. Explosion Models for Type Ia Supernovae: A Comparison with Observed Light Curves, distances, H_o and q_o

    E-Print Network [OSTI]

    P. Hoeflich; A. Khokkhlov

    1996-02-06T23:59:59.000Z

    Theoretical monochromatic light curves and photospheric expansion velocities are compared with observations of 27 Type Ia supernovae (SNe Ia). A set of 37 models has been considered which encompasses all currently discussed explosion scenarios for Type Ia supernovae including deflagrations, detonations, delayed detonations, pulsating delayed detonations and tamped detonations of Chandra- mass, and Helium detonations of low mass white dwarfs. The explosions are calculated using one-dimensional Lagrangian hydro and radiation-hydro codes with incorporated nuclear networks. Subsequently, light curves are constructed using our LC scheme which includes an implicit radiation transport, expansion opacities, a Monte-Carlo $\\gamma $-ray transport, and molecular and dust formation. For some supernovae, results of detailed non-LTE calculations have been considered. Observational properties of our series of models are discussed, the relation between the absolute brightness, post-maximum decline rates, the colors at several moments of time, etc. All models with a Ni production larger than 0.4 solar masses produce light curves of similar brightness. The influence of the cosmological red shift on the light curves and on the correction for interstellar reddening is discussed. Based on data rectification of the standard deviation, a quantitative procedure to fit the observations has been used to the determine the free parameters, i.e. the correct model, the distance, the reddening, and the time of the explosion. The results are discussed in detail and applied to determine Ho and qo.

  18. Abundance anomalies in metal-poor stars from Population III supernova ejecta hydrodynamics

    E-Print Network [OSTI]

    Sluder, Alan; Safranek-Shrader, Chalence; Milosavljevic, Milos; Bromm, Volker

    2015-01-01T23:59:59.000Z

    We present a simulation of the long-term evolution of a Population III supernova remnant in a cosmological minihalo. Employing passive Lagrangian tracer particles, we investigate how chemical stratification and anisotropy in the explosion can affect the abundances of the first low-mass, metal-enriched stars. We find that reverse shock heating can leave the inner mass shells at entropies too high to cool, leading to carbon-enhancement in the re-collapsing gas. This hydrodynamic selection effect could explain the observed incidence of carbon-enhanced metal-poor (CEMP) stars at low metallicity. We further explore how anisotropic ejecta distributions, recently seen in direct numerical simulations of core-collapse explosions, may translate to abundances in metal-poor stars. We find that some of the observed scatter in the Population II abundance ratios can be explained by an incomplete mixing of supernova ejecta, even in the case of only one contributing enrichment event. We demonstrate that the customary hypothes...

  19. Cosmological constant and quantum gravitational corrections to the running fine structure constant

    E-Print Network [OSTI]

    David J. Toms

    2008-09-23T23:59:59.000Z

    The quantum gravitational contribution to the renormalization group behavior of the electric charge in Einstein-Maxwell theory with a cosmological constant is considered. Quantum gravity is shown to lead to a contribution to the running charge not present when the cosmological constant vanishes. This re-opens the possibility, suggested by Robinson and Wilczek, of altering the scaling behaviour of gauge theories at high energies although our result differs. We show the possibility of an ultraviolet fixed point that is linked directly to the cosmological constant.

  20. Galaxy Cosmological Mass Function

    E-Print Network [OSTI]

    Amanda R. Lopes; Alvaro Iribarrem; Marcelo B. Ribeiro; William R. Stoeger

    2014-12-03T23:59:59.000Z

    We study the galaxy cosmological mass function (GCMF) in a semi-empirical relativistic approach using observational data provided by galaxy redshift surveys. Starting from the theory of Ribeiro & Stoeger (2003, arXiv:astro-ph/0304094) between the mass-to-light ratio, the selection function obtained from the luminosity function (LF) data and the luminosity density, the average luminosity $L$ and the average galactic mass $\\mathcal{M}_g$ are computed in terms of the redshift. $\\mathcal{M}_g$ is also alternatively estimated by a method that uses the galaxy stellar mass function (GSMF). Comparison of these two forms of deriving the average galactic mass allows us to infer a possible bias introduced by the selection criteria of the survey. We used the FORS Deep Field galaxy survey sample of 5558 galaxies in the redshift range $0.5 light ratio and its GSMF data. Assuming ${\\mathcal{M}_{g_0}} \\approx 10^{11} \\mathcal{M}_\\odot$ as the local value of the average galactic mass, the LF approach results in $L_{B} \\propto (1+z)^{(2.40 \\pm 0.03)}$ and $\\mathcal{M}_g \\propto (1+z)^{(1.1\\pm0.2)}$. However, using the GSMF results produces $\\mathcal{M}_g \\propto (1+z)^{(-0.58 \\pm 0.22)}$. We chose the latter result as it is less biased. We then obtained the theoretical quantities of interest, such as the differential number counts, to calculate the GCMF, which can be fitted by a Schechter function. The derived GCMF follows theoretical predictions in which the less massive objects form first, being followed later by more massive ones. In the range $0.5 < z < 2.0$ the GCMF has a strong variation that can be interpreted as a higher rate of galaxy mergers or as a strong evolution in the star formation history of these galaxies.

  1. 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

    2003-06-18T23:59:59.000Z

    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.

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

    E-Print Network [OSTI]

    Graham, J.R.

    2011-01-01T23:59:59.000Z

    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

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

    E-Print Network [OSTI]

    Ellis, R. S.

    2008-01-01T23:59:59.000Z

    Cardelli et al. (1989), CCM) and extinction-correct eachuxes unrelated to dust. The CCM and SALT laws have a similarextinction” in the UV than the CCM law (Guy et al. 2007). To

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

    E-Print Network [OSTI]

    2008-01-01T23:59:59.000Z

    ?0.050) (5) Maximum light, CCM R B =4.1 F ? + Const. MaximumCardelli et al. (1989), CCM) and extinction-correct eachuxes unrelated to dust. The CCM and SALT laws have a similar

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

    E-Print Network [OSTI]

    Meyers, Joshua Evan

    2012-01-01T23:59:59.000Z

    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

  6. Simulating Reionization in Numerical Cosmology

    E-Print Network [OSTI]

    Aaron Sokasian; Tom Abel; Lars E. Hernquist

    2001-05-10T23:59:59.000Z

    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.

  7. Cosmological AMR MHD with Enzo

    SciTech Connect (OSTI)

    Xu, Hao [Los Alamos National Laboratory; Li, Hui [Los Alamos National Laboratory; Li, Shengtai [Los Alamos National Laboratory

    2009-01-01T23:59:59.000Z

    In this work, we present EnzoMHD, the extension of the cosmological code Enzoto include magnetic fields. We use the hyperbolic solver of Li et al. (2008) for the computation of interface fluxes. We use constrained transport methods of Balsara & Spicer (1999) and Gardiner & Stone (2005) to advance the induction equation, the reconstruction technique of Balsara (2001) to extend the Adaptive Mesh Refinement of Berger & Colella (1989) already used in Enzo, though formulated in a slightly different way for ease of implementation. This combination of methods preserves the divergence of the magnetic field to machine precision. We use operator splitting to include gravity and cosmological expansion. We then present a series of cosmological and non cosmologjcal tests problems to demonstrate the quality of solution resulting from this combination of solvers.

  8. Cosmological dark energy effects from entanglement

    E-Print Network [OSTI]

    S. Capozziello; O. Luongo; S. Mancini

    2013-02-24T23:59:59.000Z

    The thorny issue of relating information theory to cosmology is here addressed by assuming a possible connection between quantum entanglement measures and observable universe. In particular, we propose a cosmological toy model, where the equation of state of the cosmological fluid, which drives the today observed cosmic acceleration, can be inferred from quantum entanglement between different cosmological epochs. In such a way the dynamical dark energy results as byproduct of quantum entanglement.

  9. 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.

    2005-01-01T23:59:59.000Z

    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¨

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

    E-Print Network [OSTI]

    Kim, Alex G.; Miquel, Ramon

    2007-01-01T23:59:59.000Z

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

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

    E-Print Network [OSTI]

    Garavini, G.; Supernova Cosmology Project

    2008-01-01T23:59:59.000Z

    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

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

    E-Print Network [OSTI]

    Pennypacker, Carl R.

    2008-01-01T23:59:59.000Z

    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,

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

    E-Print Network [OSTI]

    Goldhaber, G.

    2008-01-01T23:59:59.000Z

    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

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

    E-Print Network [OSTI]

    Nugent, Peter

    2005-01-01T23:59:59.000Z

    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

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

    E-Print Network [OSTI]

    2004-01-01T23:59:59.000Z

    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

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

    E-Print Network [OSTI]

    2004-01-01T23:59:59.000Z

    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

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

    E-Print Network [OSTI]

    TRIMBLE, V

    1982-01-01T23:59:59.000Z

    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,

  18. Semi-supervised Learning for Photometric Supernova Classification

    E-Print Network [OSTI]

    Richards, Joseph W; Freeman, Peter E; Schafer, Chad M; Poznanski, Dovi

    2011-01-01T23:59:59.000Z

    We present a semi-supervised method for photometric supernova typing. Our approach is to first use the nonlinear dimension reduction technique diffusion map to detect structure in a database of supernova light curves and subsequently employ random forest classification on a spectroscopically confirmed training set to learn a model that can predict the type of each newly observed supernova. We demonstrate that this is an effective method for supernova typing. As supernova numbers increase, our semi-supervised method efficiently utilizes this information to improve classification, a property not enjoyed by template based methods. Applied to supernova data simulated by Kessler et al. (2010b) to mimic those of the Dark Energy Survey, our methods achieve (cross-validated) 96% Type Ia purity and 86% Type Ia efficiency on the spectroscopic sample, but only 56% Type Ia purity and 48% efficiency on the photometric sample due to their spectroscopic followup strategy. To improve the performance on the photometric sample...

  19. Quasar Structure and Cosmological Feedback

    E-Print Network [OSTI]

    Martin Elvis

    2006-06-05T23:59:59.000Z

    Feedback from quasars and AGNs is being invoked frequently in several cosmological settings. Currently, order of magnitude, or more, uncertainties in the structure of both the wind and the 'obscuring torus' make predictions highly uncertain. To make testable models of this 'cosmological feedback' it is essential to understand the detailed structure of AGNs sufficiently well to predict their properties for the whole quasar population, at all redshifts. Progress in both areas is rapid, and I describe the near-term prospects for reducing these uncertainties for 'slow' (non-relativistic) AGN winds and the obscuring torus.

  20. Noncommutative models in patch cosmology

    SciTech Connect (OSTI)

    Calcagni, Gianluca [Dipartimento di Fisica, Universita di Parma, Parco Area delle Scienze 7/A, I-43100 Parma (Italy) and INFN-Gruppo Collegato di Parma, Parco Area delle Scienze 7/A, I-43100 Parma (Italy)

    2004-11-15T23:59:59.000Z

    We consider several classes of noncommutative inflationary models within an extended version of patch cosmological braneworlds, starting from a maximally invariant generalization of the action for scalar and tensor perturbations to a noncommutative brane embedded in a commutative bulk. Slow-roll expressions and consistency relations for the cosmological observables are provided, both in the UV and IR region of the spectrum; the inflaton field is assumed to be either an ordinary scalar field or a Born-Infeld tachyon. The effects of noncommutativity are then analyzed in a number of ways and energy regimes.

  1. Stringy Model of Cosmological Dark Energy

    E-Print Network [OSTI]

    Irina Ya. Aref'eva

    2007-10-16T23:59:59.000Z

    A string field theory(SFT) nonlocal model of the cosmological dark energy providing w<-1 is briefly surveyed. We summarize recent developments and open problems, as well as point out some theoretical issues related with others applications of the SFT nonlocal models in cosmology, in particular, in inflation and cosmological singularity.

  2. 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

    2015-01-01T23:59:59.000Z

    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.

  3. Supernova neutrino oscillations: A simple analytical approach

    E-Print Network [OSTI]

    G. L. Fogli; E. Lisi; D. Montanino; A. Palazzo

    2001-11-15T23:59:59.000Z

    Analyses of observable supernova neutrino oscillation effects require the calculation of the electron (anti)neutrino survival probability P_ee along a given supernova matter density profile. We propose a simple analytical prescription for P_ee, based on a double-exponential form for the crossing probability and on the concept of maximum violation of adiabaticity. In the case of two-flavor transitions, the prescription is shown to reproduce accurately, in the whole neutrino oscillation parameter space, the results of exact numerical calculations for generic (realistic or power-law) profiles. The analytical approach is then generalized to cover three-flavor transitions with (direct or inverse) mass spectrum hierarchy, and to incorporate Earth matter effects. Compact analytical expressions, explicitly showing the symmetry properties of P_ee, are provided for practical calculations.

  4. Merging White Dwarfs and Thermonuclear Supernovae

    E-Print Network [OSTI]

    van Kerkwijk, Marten H

    2012-01-01T23:59:59.000Z

    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.

  5. Reverse-Shock in Tycho's Supernova Remnant

    E-Print Network [OSTI]

    Lu, F J; Zheng, S J; Zhang, S N; Long, X; Aschenbach, B

    2015-01-01T23:59:59.000Z

    Thermal X-ray emission from young supernova remnants (SNRs) is usually dominated by the emission lines of the supernova (SN) ejecta, which are widely believed being crossed and thus heated by the inwards propagating reverse shock (RS). Previous works using imaging X-ray data have shown that the ejecta are heated by the RS by locating the peak emission region of the most recently ionized matter, which is found well separated towards the inside from the outermost boundary. Here we report the discovery of a systematic increase of the Sulfur (S) to Silicon (Si) K$\\alpha$ line flux ratio with radius in Tycho's SNR. This allows us, for the first time, to present continuous radial profiles of the ionization age and, furthermore, the elapsed ionization time since the onset of the ionization, which tells the propagation history of the ionization front into the SNR ejecta.

  6. On neutron star/supernova remnant associations

    E-Print Network [OSTI]

    V. V. Gvaramadze

    2001-04-01T23:59:59.000Z

    It is pointed out that a cavity supernova (SN) explosion of a moving massive star could result in a significant offset of the neutron star (NS) birth-place from the geometrical centre of the supernova remnant (SNR). Therefore: a) the high implied transverse velocities of a number of NSs (e.g. PSR B1610-50, PSR B1757-24, SGR0525-66) could be reduced; b) the proper motion vector of a NS should not necessarily point away from the geometrical centre of the associated SNR; c) the circle of possible NS/SNR associations could be enlarged. An observational test is discussed, which could allow to find the true birth-places of NSs associated with middle-aged SNRs, and thereby to get more reliable estimates of their transverse velocities.

  7. Super Luminous Supernova and Gamma Ray Bursts

    E-Print Network [OSTI]

    Shlomo Dado; Arnon Dar

    2012-11-08T23:59:59.000Z

    We use a simple analytical model to derive a closed form expression for the bolometric light-curve of super-luminus supernovae (SLSNe) powered by a plastic collision between the fast ejecta from core collapse supernovae (SNe) of types Ib/c and IIn and slower massive circum-stellar shells, ejected during the late stage of the life of their progenitor stars preceding the SN explosion. We demonstrate that this expression reproduces well the bolometric luminosity of SLSNe with and without an observed gamma ray burst (GRB), and requires only a modest amount ($M < 0.1\\,M_\\odot$) of radioactive $^{56}$Ni synthesized in the SN explosion in order to explain their late-time luminosity. Long duration GRBs can be produced by ordinary SNe of type Ic rather than by 'hypernovae' - a subclass of superenergetic SNeIb/c.

  8. Tycho Brahe's supernova: light from centuries past

    E-Print Network [OSTI]

    Pilar Ruiz-Lapuente

    2003-08-30T23:59:59.000Z

    The light curve of SN 1572 is described in the terms used nowadays to characterize SNeIa. By assembling the records of the observations done in 1572--74 and evaluating their uncertainties, it is possible to recover the light curve and the color evolution of this supernova. It is found that, within the SNe Ia family, the event should have been a SNIa with a normal rate of decline, its stretch factor being {\\it s} $\\sim$ 0.9. Visual light curve near maximum, late--time decline and the color evolution sustain this conclusion. After correcting for extinction, the luminosity of this supernova is found to be M$_{V}$ $=$ --19.58 --5 log (D/3.5 kpc) $\\pm$ 0.42.

  9. Tycho Brahe's supernova: light from centuries past

    E-Print Network [OSTI]

    Ruiz-Lapuente, P

    2003-01-01T23:59:59.000Z

    The light curve of SN 1572 is described in the terms used nowadays to characterize SNeIa. By assembling the records of the observations done in 1572--74 and evaluating their uncertainties, it is possible to recover the light curve and the color evolution of this supernova. It is found that, within the SNe Ia family, the event should have been a SNIa with a normal rate of decline, its stretch factor being {\\it s} $\\sim$ 0.9. Visual light curve near maximum, late--time decline and the color evolution sustain this conclusion. After correcting for extinction, the luminosity of this supernova is found to be M$_{V}$ $=$ --19.58 --5 log (D/3.5 kpc) $\\pm$ 0.42.

  10. 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)

    2014-05-01T23:59:59.000Z

    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.

  11. Neutrino Nucleosynthesis of radioactive nuclei in supernovae

    E-Print Network [OSTI]

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

    2015-01-01T23:59:59.000Z

    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 < 76 $ and ii) by considering modern supernova neutrino spectra which have substantially lower average energies compared to those previously adopted in neutrino 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 $\

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

    E-Print Network [OSTI]

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

    2015-01-01T23:59:59.000Z

    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...

  13. THE DISCOVERY OF THE MOST DISTANT KNOWN TYPE Ia SUPERNOVA AT REDSHIFT 1.914

    SciTech Connect (OSTI)

    Jones, David O.; Rodney, Steven A.; Riess, Adam G. [Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218 (United States); Mobasher, Bahram [Department of Physics and Astronomy, University of California, Riverside, CA 92521 (United States); Dahlen, Tomas; Casertano, Stefano; Koekemoer, Anton [Space Telescope Science Institute, Baltimore, MD 21218 (United States); McCully, Curtis; Keeton, Charles R.; Patel, Brandon [Department of Physics and Astronomy, Rutgers, State University of New Jersey, Piscataway, NJ 08854 (United States); Frederiksen, Teddy F.; Hjorth, Jens [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark); Strolger, Louis-Gregory [Department of Physics, Western Kentucky University, Bowling Green, KY 42101 (United States); Wiklind, Tommy G. [Joint ALMA Observatory, ESO, Santiago (Chile); Challis, Peter [Harvard/Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Graur, Or [School of Physics and Astronomy, Tel-Aviv University, Tel-Aviv 69978 (Israel); Hayden, Brian; Garnavich, Peter [Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Weiner, Benjamin J. [Department of Astronomy, University of Arizona, Tucson, AZ 85721 (United States); Filippenko, Alexei V. [Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States); and others

    2013-05-10T23:59:59.000Z

    We present the discovery of a Type Ia supernova (SN) at redshift z = 1.914 from the CANDELS multi-cycle treasury program on the Hubble Space Telescope (HST). This SN was discovered in the infrared using the Wide-Field Camera 3, and it is the highest-redshift Type Ia SN yet observed. We classify this object as a SN Ia by comparing its light curve and spectrum with those of a large sample of Type Ia and core-collapse SNe. Its apparent magnitude is consistent with that expected from the {Lambda}CDM concordance cosmology. We discuss the use of spectral evidence for classification of z > 1.5 SNe Ia using HST grism simulations, finding that spectral data alone can frequently rule out SNe II, but distinguishing between SNe Ia and SNe Ib/c can require prohibitively long exposures. In such cases, a quantitative analysis of the light curve may be necessary for classification. Our photometric and spectroscopic classification methods can aid the determination of SN rates and cosmological parameters from the full high-redshift CANDELS SN sample.

  14. The Physics of Core-Collapse Supernovae

    E-Print Network [OSTI]

    S. Woosley; H. -T. Janka

    2006-01-12T23:59:59.000Z

    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.

  15. Nucleosynthesis in O-Ne-Mg Supernovae

    SciTech Connect (OSTI)

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

    2007-12-18T23:59:59.000Z

    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.

  16. X-rays from Supernova Remnants

    E-Print Network [OSTI]

    B. Aschenbach

    2002-08-28T23:59:59.000Z

    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.

  17. The Carnegie Supernova Project: The Low-Redshift Survey

    E-Print Network [OSTI]

    Mario Hamuy; Gastón Folatelli; Nidia I. Morrell; Mark M. Phillips; Nicholas B. Suntzeff; S. E. Persson; Miguel Roth; Sergio Gonzalez; Wojtek Krzeminski; Carlos Contreras; Wendy L. Freedman; D. C. Murphy; Barry F. Madore; P. Wyatt; José Maza; Alexei V. Filippenko; Weidong Li; P. A. Pinto

    2005-12-01T23:59:59.000Z

    Supernovae are essential to understanding the chemical evolution of the Universe. Type Ia supernovae also provide the most powerful observational tool currently available for studying the expansion history of the Universe and the nature of dark energy. Our basic knowledge of supernovae comes from the study of their photometric and spectroscopic properties. However, the presently available data sets of optical and near-infrared light curves of supernovae are rather small and/or heterogeneous, and employ photometric systems that are poorly characterized. Similarly, there are relatively few supernovae whose spectral evolution has been well sampled, both in wavelength and phase, with precise spectrophotometric observations. The low-redshift portion of the Carnegie Supernova Project (CSP) seeks to remedy this situation by providing photometry and spectrophotometry of a large sample of supernovae taken on telescope/filter/detector systems that are well understood and well characterized. During a five-year program which began in September 2004, we expect to obtain high-precision u'g'r'i'BVYJHKs light curves and optical spectrophotometry for about 250 supernovae of all types. In this paper we provide a detailed description of the CSP survey observing and data reduction methodology. In addition, we present preliminary photometry and spectra obtained for a few representative supernovae during the first observing campaign.

  18. Earth Matter Effects in Detection of Supernova Neutrinos

    E-Print Network [OSTI]

    X. -H. Guo; Bing-Lin Young

    2006-05-11T23:59:59.000Z

    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{\

  19. Acquiring information about neutrino parameters by detecting supernova neutrinos

    SciTech Connect (OSTI)

    Huang, Ming-Yang; Guo, Xin-Heng [College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Young, Bing-Lin [Department of Physics and Astronomy, Iowa State University, Ames, Iowa 5001 (United States); Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing 100190 (China)

    2010-08-01T23:59:59.000Z

    We consider the supernova shock effects, the Mikheyev-Smirnov-Wolfenstein effects, the collective effects, and the Earth matter effects in the detection of type II supernova neutrinos on the Earth. It is found that the event number of supernova neutrinos depends on the neutrino mass hierarchy, the neutrino mixing angle {theta}{sub 13}, and neutrino masses. Therefore, we propose possible methods to identify the mass hierarchy and acquire information about {theta}{sub 13} and neutrino masses by detecting supernova neutrinos. We apply these methods to some current neutrino experiments.

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

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

    National Laboratory (Berkeley Lab), to expose fleeting cosmic events such as supernovae. For the first time ever, scientists have direct confirmation that a Wolf-Rayet...

  1. 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

  2. Cosmological parameter constraints from SDSS luminous red galaxies: a new treatment of large-scale clustering

    E-Print Network [OSTI]

    Ariel G. Sanchez; M. Crocce; A. Cabre; C. M. Baugh; E. Gaztanaga

    2009-08-19T23:59:59.000Z

    We apply a new model for the spherically averaged correlation function at large pair separations to the measurement of the clustering of luminous red galaxies (LRGs) made from the SDSS by Cabre and Gaztanaga(2009). Our model takes into account the form of the BAO peak and the large scale shape of the correlation function. We perform a Monte Carlo Markov chain analysis for different combinations of datasets and for different parameter sets. When used in combination with a compilation of the latest CMB measurements, the LRG clustering and the latest supernovae results give constraints on cosmological parameters which are comparable and in remarkably good agreement, resolving the tension reported in some studies. The best fitting model in the context of a flat, Lambda-CDM cosmology is specified by Omega_m=0.261+-0.013, Omega_b=0.044+-0.001, n_s=0.96+-0.01, H_0=71.6+-1.2 km/s/Mpc and sigma_8=0.80+-0.02. If we allow the time-independent dark energy equation of state parameter to vary, we find results consistent with a cosmological constant at the 5% level using all data sets: w_DE=-0.97+-0.05. The large scale structure measurements by themselves can constrain the dark energy equation of state parameter to w_DE=-1.05+-0.15, independently of CMB or supernovae data. We do not find convincing evidence for an evolving equation of state. We provide a set of "extended distance priors" that contain the most relevant information from the CMB power spectrum and the shape of the LRG correlation function which can be used to constrain dark energy models and spatial curvature. Our model should provide an accurate description of the clustering even in much larger, forthcoming surveys, such as those planned with NASA's JDEM or ESA's Euclid mission.

  3. Dark Matter Balls Help Supernovae to Explode

    E-Print Network [OSTI]

    Froggatt, Colin D

    2015-01-01T23:59:59.000Z

    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 d...

  4. SUPERNOVA EXPLOSIONS OF SUPER-ASYMPTOTIC GIANT BRANCH STARS: MULTICOLOR LIGHT CURVES OF ELECTRON-CAPTURE SUPERNOVAE

    SciTech Connect (OSTI)

    Tominaga, Nozomu [Department of Physics, Faculty of Science and Engineering, Konan University, 8-9-1 Okamoto, Kobe, Hyogo 658-8501 (Japan); Blinnikov, Sergei I. [Institute for Theoretical and Experimental Physics (ITEP), Moscow 117218 (Russian Federation); Nomoto, Ken'ichi, E-mail: tominaga@konan-u.ac.jp, E-mail: Sergei.Blinnikov@itep.ru, E-mail: nomoto@astron.s.u-tokyo.ac.jp [Kavli Institute for the Physics and Mathematics of the Universe (WPI), University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8583 (Japan)

    2013-07-01T23:59:59.000Z

    An electron-capture supernova (ECSN) is a core-collapse supernova (CCSN) explosion of a super-asymptotic giant branch (SAGB) star with a main-sequence mass M{sub MS} {approx} 7-9.5 M{sub Sun }. 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 curve of a CCSN. Adopting the explosion properties derived by the first-principle simulation, i.e., the low explosion energy of 1.5 Multiplication-Sign 10{sup 50} erg and the small {sup 56}Ni mass of 2.5 Multiplication-Sign 10{sup -3} M{sub Sun }, we perform a multi-group radiation hydrodynamics calculation of ECSNe and present multicolor light curves of ECSNe of SAGB stars with various envelope masses and hydrogen abundances. We demonstrate that a shock breakout has a peak luminosity of L {approx} 2 Multiplication-Sign 10{sup 44} erg s{sup -1} and can evaporate circumstellar dust up to R {approx} 10{sup 17} cm for the case of carbon dust, that the plateau luminosity and plateau duration of ECSNe are L {approx} 10{sup 42} erg s{sup -1} and t {approx} 60-100 days, respectively, and that a plateau is followed by a tail with a luminosity drop by {approx}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 the 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 an ECSN model with a significantly low explosion energy of E {approx} 10{sup 48} erg.

  5. Electric Time in Quantum Cosmology

    E-Print Network [OSTI]

    Stephon Alexander; Martin Bojowald; Antonino Marciano; David Simpson

    2012-12-10T23:59:59.000Z

    Effective quantum cosmology is formulated with a realistic global internal time given by the electric vector potential. New possibilities for the quantum behavior of space-time are found, and the high-density regime is shown to be very sensitive to the specific form of state realized.

  6. Interpretation of the Cosmological Metric

    E-Print Network [OSTI]

    Richard J. Cook; M. Shane Burns

    2008-09-03T23:59:59.000Z

    The cosmological Robertson-Walker metric of general relativity is often said to have the consequences that (1) the recessional velocity $v$ of a galaxy at proper distance $\\ell$ obeys the Hubble law $v=H\\ell$, and therefore galaxies at sufficiently great distance $\\ell$ are receding faster than the speed of light $c$; (2) faster than light recession does not violate special relativity theory because the latter is not applicable to the cosmological problem, and because ``space itself is receding'' faster than $c$ at great distance, and it is velocity relative to local space that is limited by $c$, not the velocity of distant objects relative to nearby ones; (3) we can see galaxies receding faster than the speed of light; and (4) the cosmological redshift is not a Doppler shift, but is due to a stretching of photon wavelength during propagation in an expanding universe. We present a particular Robertson-Walker metric (an empty universe metric) for which a coordinate transformation shows that none of these interpretation necessarily holds. The resulting paradoxes of interpretation lead to a deeper understanding of the meaning of the cosmological metric.

  7. Noncommutative Quantum Scalar Field Cosmology

    SciTech Connect (OSTI)

    Diaz Barron, L. R.; Lopez-Dominguez, J. C.; Sabido, M. [Departamento de Fisica, DCI-Campus Leon, Universidad de Guanajuato, A.P. E-143, C.P. 37150, Guanajuato (Mexico); Yee, C. [Departamento de Matematicas, Facultad de Ciencias, Universidad Autonoma de Baja California, Ensenada, Baja California (Mexico)

    2010-07-12T23:59:59.000Z

    In this work we study noncommutative Friedmann-Robertson-Walker (FRW) cosmology coupled to a scalar field endowed with an exponential potential. The quantum scenario is analyzed in the Bohmian formalism of quantum trajectories to investigate the effects of noncommutativity in the evolution of the universe.

  8. Towards Noncommutative Supersymmetric Quantum Cosmology

    SciTech Connect (OSTI)

    Sabido, M.; Socorro, J. [Physics Department of the Division of Science and Engineering of the University of Guanajuato, Campus Leon P.O. Box E-143, 37150 Leon Gto. (Mexico); Guzman, W. [Centro Brasileiro de Pesquisas Fisicas, Rua Dr. Xavier Sigaud 150, Urca 22290-180, Rio de Janeiro, RJ (Brazil)

    2010-12-07T23:59:59.000Z

    In this work a construction of supersymmetric noncommutative cosmology is presented. We start with a ''noncommutative'' deformation of the minisuperspace variables, and by using the time reparametrization invariance of the noncommutative bosonic model we proceed to construct a super field description of the model.

  9. STATISTICS GROUP

    E-Print Network [OSTI]

    2 MOTIVATION Kyle Cranmer (NYU) CERN School HEP, Romania, Sept. 2011 What do these plots mean? 0 1 2 for Cosmology and Particle Physics CERN School HEP, Romania, Sept. 2011 The Likelihood Function A Poisson Kyle Cranmer): MARKED POISSON Kyle Cranmer (NYU) CERN School HEP, Romania, Sept. 2011 and use Monte

  10. Extending the redshift-distance relation in Cosmological General Relativity to higher redshifts

    E-Print Network [OSTI]

    John G. Hartnett

    2007-11-22T23:59:59.000Z

    The redshift-distance modulus relation, the Hubble Diagram, derived from Cosmological General Relativity has been extended to arbitrarily large redshifts. Numerical methods were employed and a density function was found that results in a valid solution of the field equations at all redshifts. The extension has been compared to 302 type Ia supernova data as well as to 69 Gamma-ray burst data. The latter however do not not truly represent a `standard candle' as the derived distance modulii are not independent of the cosmology used. Nevertheless the analysis shows a good fit can be achieved without the need to assume the existence of dark matter. The Carmelian theory is also shown to describe a universe that is always spatially flat. This results from the underlying assumption of the energy density of a cosmological constant $\\Omega_{\\Lambda} = 1$, the result of vacuum energy. The curvature of the universe is described by a \\textit{spacevelocity} metric where the energy content of the curvature at any epoch is $\\Omega_K = \\Omega_{\\Lambda} - \\Omega = 1-\\Omega$, where $\\Omega$ is the matter density of the universe. Hence the total density is always $\\Omega_K + \\Omega = 1$

  11. Diversity of Type Ia Supernovae Imprinted in Chemical Abundances

    E-Print Network [OSTI]

    Tsujimoto, Takuji

    2012-01-01T23:59:59.000Z

    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...

  12. The Nuclear Physics of Solar and Supernova Neutrino Detection

    E-Print Network [OSTI]

    W. C. Haxton

    1999-01-15T23:59:59.000Z

    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.

  13. Nickel Bubble Expansion in Type Ia Supernovae: Adiabatic Solutions

    E-Print Network [OSTI]

    Chih-Yueh Wang

    2008-06-20T23:59:59.000Z

    This paper presents hydrodynamical and radiation-hydrodynamical simulations of the nickel bubble effect in Type Ia supernovae, comparison of results to self-similar solutions, and application to observations of Type Ia supernova remnants, with a particular emphasis on Tycho's SNR.

  14. Synthetic Spectrum Methods for Three-Dimensional Supernova Models

    E-Print Network [OSTI]

    R. C. Thomas

    2003-10-21T23:59:59.000Z

    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. Cosmological Analysis of Pilgrim Dark Energy in Loop Quantum Cosmology

    E-Print Network [OSTI]

    Jawad, Abdul

    2015-01-01T23:59:59.000Z

    The proposal of pilgrim dark energy is based on speculation that phantom-like dark energy (with strong enough resistive force) can prevent black hole formation in the universe. We explore this phenomenon in loop quantum cosmology framework by taking Hubble horizon as an infra-red cutoff in pilgrim dark energy. We evaluate the cosmological parameters such as Hubble, equation of state parameter, squared speed of sound and also cosmological planes like $\\omega_{\\vartheta}-\\omega'_{\\vartheta}$ and $r-s$ on the basis of pilgrim dark energy parameter ($u$) and interacting parameter ($d^2$). It is found that values of Hubble parameter lies in the range $74^{+0.005}_{-0.005}$. It is mentioned here that equation state parameter lies within the ranges $-1\\mp0.00005$ for $u=2, 1$ and $(-1.12,-1), (-5,-1)$ for $u=-1,-2$, respectively. Also, $\\omega_{\\vartheta}-\\omega'_{\\vartheta}$ planes provide $\\Lambda$CDM limit, freezing and thawing regions for all cases of $u$. It is also interesting to mention here that $\\omega_{\\va...

  16. Diffuse supernova neutrinos: oscillation effects, stellar cooling and progenitor mass dependence

    SciTech Connect (OSTI)

    Lunardini, Cecilia [Arizona State University, Tempe, AZ, 85287-1504 (United States); Tamborra, Irene, E-mail: Cecilia.Lunardini@asu.edu, E-mail: tamborra@mpp.mpg.de [Max-Planck-Institut für Physik (Werner-Heisenberg-Institut) Föhringer Ring 6, 80805 München (Germany)

    2012-07-01T23:59:59.000Z

    We estimate the diffuse supernova neutrino background (DSNB) using the recent progenitor-dependent, long-term supernova simulations from the Basel group and including neutrino oscillations at several post-bounce times. Assuming multi-angle matter suppression of collective effects during the accretion phase, we find that oscillation effects are dominated by the matter-driven MSW resonances, while neutrino-neutrino collective effects contribute at the 5–10% level. The impact of the neutrino mass hierarchy, of the time-dependent neutrino spectra and of the diverse progenitor star population is 10% or less, small compared to the uncertainty of at least 25% of the normalization of the supernova rate. Therefore, assuming that the sign of the neutrino mass hierarchy will be determined within the next decade, the future detection of the DSNB will deliver approximate information on the MSW-oscillated neutrino spectra. With a reliable model for neutrino emission, its detection will be a powerful instrument to provide complementary information on the star formation rate and for learning about stellar physics.

  17. 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

    2006-10-05T23:59:59.000Z

    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

  18. Delayed detonations in full-star models of Type Ia supernova explosions

    E-Print Network [OSTI]

    F. K. Roepke; J. C. Niemeyer

    2007-03-14T23:59:59.000Z

    Aims: We present the first full-star three-dimensional explosion simulations of thermonuclear supernovae including parameterized deflagration-to-detonation transitions that occur once the flame enters the distributed burning regime. Methods: Treating the propagation of both the deflagration and the detonation waves in a common front-tracking approach, the detonation is prevented from crossing ash regions. Results: Our criterion triggers the detonation wave at the outer edge of the deflagration flame and consequently it has to sweep around the complex structure and to compete with expansion. Despite the impeded detonation propagation, the obtained explosions show reasonable agreement with global quantities of observed type Ia supernovae. By igniting the flame in different numbers of kernels around the center of the exploding white dwarf, we set up three different models shifting the emphasis from the deflagration phase to the detonation phase. The resulting explosion energies and iron group element productions cover a large part of the diversity of type Ia supernovae. Conclusions: Flame-driven deflagration-to-detonation transitions, if hypothetical, remain a possibility deserving further investigation.

  19. Kepler's Supernova Remnant: The view at 400 Years

    E-Print Network [OSTI]

    W. P. Blair

    2004-10-04T23:59:59.000Z

    October 2004 marks the 400th anniversary of the sighting of SN 1604, now marked by the presence of an expanding nebulosity known as Kepler's supernova remnant. Of the small number of remnants of historical supernovae, Kepler's remnant remains the most enigmatic. The supernova type, and hence the type of star that exploded, is still a matter of debate, and even the distance to the remnant is uncertain by more than a factor of two. As new and improved multiwavength observations become available, and as the time baseline of observations gets longer, Kepler's supernova remnant is slowly revealing its secrets. I review recent and current observations of Kepler's supernova remnant and what they indicate about this intriguing object.

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

    E-Print Network [OSTI]

    Hu, Yazhou; Li, Nan; Wang, Shuang

    2015-01-01T23:59:59.000Z

    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...

  1. Gravitational Radiation From Cosmological Turbulence

    E-Print Network [OSTI]

    Arthur Kosowsky; Andrew Mack; Tinatin Kahniashvili

    2002-06-27T23:59:59.000Z

    An injection of energy into the early Universe on a given characteristic length scale will result in turbulent motions of the primordial plasma. We calculate the stochastic background of gravitational radiation arising from a period of cosmological turbulence, using a simple model of isotropic Kolmogoroff turbulence produced in a cosmological phase transition. We also derive the gravitational radiation generated by magnetic fields arising from a dynamo operating during the period of turbulence. The resulting gravitational radiation background has a maximum amplitude comparable to the radiation background from the collision of bubbles in a first-order phase transition, but at a lower frequency, while the radiation from the induced magnetic fields is always subdominant to that from the turbulence itself. We briefly discuss the detectability of such a signal.

  2. The Schwarzschild Static Cosmological Model

    E-Print Network [OSTI]

    P. H. Pereyra

    2009-04-16T23:59:59.000Z

    The present work describes an immersion in 5D of the interior Schwarzschild solution of the general relativity equations. The model theory is defined in the context of a flat 5D space time matter Minkowski model, using a Tolman like technique, which shows via Lorentz transformations that the solution is compatible with homogeneity and isotropy,thus obeying the cosmological principle. These properties permit one to consider the solution in terms of a cosmological model. In this model, the Universe may be treated as an idealized star with constant density and variable pressure, where each observer can be the center of the same. The observed redshift appears as a static gravitational effect which obeys the sufficiently verified and generally accepted square distance law. The Buchdahl stability theorem establishes a limit of distance observation with density dependence.

  3. Cosmology: a bird's eye view

    E-Print Network [OSTI]

    Alan A. Coley; Sigbjorn Hervik; Woei Chet Lim

    2006-05-15T23:59:59.000Z

    In this essay we discuss the difference in views of the Universe as seen by two different observers. While one of the observers follows a geodesic congruence defined by the geometry of the cosmological model, the other observer follows the fluid flow lines of a perfect fluid with a linear equation of state. We point out that the information these observers collect regarding the state of the Universe can be radically different; while one observes a non-inflating ever-expanding ever-lasting universe, the other observer can experience a dynamical behaviour reminiscent to that of quintessence or even that of a phantom cosmology leading to a 'big rip' singularity within finite time (but without the need for exotic forms of matter).

  4. Thermodynamics of decaying vacuum cosmologies

    SciTech Connect (OSTI)

    Lima, J.A. [Physics Department, Brown University, Providence, Rhode Island 02912 (United States)] [Physics Department, Brown University, Providence, Rhode Island 02912 (United States); [Departamento de Fisica Teorica e Experimental, Universidade Federal do Rio Grande do Norte, 59072-970, Natal, RN (Brazil)

    1996-08-01T23:59:59.000Z

    The thermodynamic behavior of decaying vacuum cosmologies is investigated within a manifestly covariant formulation. Such a process corresponds to a continuous, irreversible energy flow from the vacuum component to the created matter constituents. It is shown that if the specific entropy per particle remains constant during the process, the equilibrium relations are preserved. In particular, if the vacuum decays into photons, the energy density {rho} and average number density of photons {ital n} scale with the temperature as {rho}{approximately}{ital T}{sup 4} and {ital n}{approximately}{ital T}{sup 3}. The temperature law is determined and a generalized Planckian-type form of the spectrum, which is preserved in the course of the evolution, is also proposed. Some consequences of these results for decaying vacuum FRW-type cosmologies as well as for models with {open_quote}{open_quote}adiabatic{close_quote}{close_quote} photon creation are discussed. {copyright} {ital 1996 The American Physical Society.}

  5. Cosmographic Hubble fits to the supernova data

    E-Print Network [OSTI]

    Celine Cattoen; Matt Visser

    2008-09-03T23:59:59.000Z

    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.

  6. Cosmology, Thermodynamics and Matter Creation

    E-Print Network [OSTI]

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

    2007-08-24T23:59:59.000Z

    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.

  7. Probing supernova physics with neutrino oscillations

    E-Print Network [OSTI]

    H. Minakata; H. Nunokawa; R. Tomas; J. W. F. Valle

    2002-07-26T23:59:59.000Z

    We point out that solar neutrino oscillations with large mixing angle as evidenced in current solar neutrino data have a strong impact on strategies for diagnosing collapse-driven supernova (SN) through neutrino observations. Such oscillations induce a significant deformation of the energy spectra of neutrinos, thereby allowing us to obtain otherwise inaccessible features of SN neutrino spectra. We demonstrate that one can determine temperatures and luminosities of non-electron flavor neutrinos by observing bar{nu}_{e} from galactic SN in massive water Cherenkov detectors by the charged current reactions on protons.

  8. 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)

    2013-06-20T23:59:59.000Z

    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.

  9. Strangulation in Galaxy Groups

    E-Print Network [OSTI]

    Kawata, Daisuke

    2007-01-01T23:59:59.000Z

    We use a cosmological chemodynamical simulation to study how the group environment impacts the star formation properties of disk galaxies. The simulated group has a total mass of M~8x10^12 Msun and a total X-ray luminosity of L_X~10^41 erg s^-1. Our simulation suggests that ram pressure is not sufficient in this group to remove the cold disk gas from a V_rot~150 km s^-1 galaxy. However, the majority of the hot gas in the galaxy is stripped over a timescale of approximately 1 Gyr. Since the cooling of the hot gas component provides a source for new cold gas, the stripping of the hot component effectively cuts off the supply of cold gas. This in turn leads to a quenching of star formation. The galaxy maintains the disk component after the cold gas is consumed leading to a galaxy with S0 properties. Our self-consistent simulation suggests that this strangulation mechanism works even in low mass groups, providing an explanation for the lower star formation rates in group galaxies relative to galaxies in the field...

  10. Strangulation in Galaxy Groups

    E-Print Network [OSTI]

    Daisuke Kawata; John S. Mulchaey

    2007-11-20T23:59:59.000Z

    We use a cosmological chemodynamical simulation to study how the group environment impacts the star formation properties of disk galaxies. The simulated group has a total mass of M~8x10^12 Msun and a total X-ray luminosity of L_X~10^41 erg s^-1. Our simulation suggests that ram pressure is not sufficient in this group to remove the cold disk gas from a V_rot~150 km s^-1 galaxy. However, the majority of the hot gas in the galaxy is stripped over a timescale of approximately 1 Gyr. Since the cooling of the hot gas component provides a source for new cold gas, the stripping of the hot component effectively cuts off the supply of cold gas. This in turn leads to a quenching of star formation. The galaxy maintains the disk component after the cold gas is consumed, which may lead to a galaxy similar to an S0. Our self-consistent simulation suggests that this strangulation mechanism works even in low mass groups, providing an explanation for the lower star formation rates in group galaxies relative to galaxies in the field.

  11. Chameleon gravity on cosmological scales

    E-Print Network [OSTI]

    H. Farajollahi; A. Salehi

    2012-06-25T23:59:59.000Z

    In conventional approach to the chameleon mechanism, by assuming a static and spherically symmetric solutions in which matter density and chameleon field are given by $\\rho=\\rho(r)$ and $\\phi=\\phi(r)$, it has been shown that mass of chameleon field is matter density-dependent. In regions of high matter density such as earth, chameleon field is massive, in solar system it is low and in cosmological scales it is very low. In this article we revisit the mechanism in cosmological scales by assuming a redshift dependence of the matter density and chameleon field, i.e. $\\rho=\\rho(z)$, $\\phi=\\phi(z)$. To support our analysis, we best fit the model parameters with the observational data. The result shows that in cosmological scales, the mass of chameleon field increases with the redshift, i.e. more massive in higher redshifts. We also find that in both cases of power-law and exponential potential function, the current universe acceleration can be explained by the low mass chameleon field. In comparison with the high redshift observational data, we also find that the model with power-law potential function is in better agreement with the observational data.

  12. Multiverse Understanding of Cosmological Coincidences

    E-Print Network [OSTI]

    Raphael Bousso; Lawrence J. Hall; Yasunori Nomura

    2009-07-30T23:59:59.000Z

    There is a deep cosmological mystery: although dependent on very different underlying physics, the timescales of structure formation, of galaxy cooling (both radiatively and against the CMB), and of vacuum domination do not differ by many orders of magnitude, but are all comparable to the present age of the universe. By scanning four landscape parameters simultaneously, we show that this quadruple coincidence is resolved. We assume only that the statistical distribution of parameter values in the multiverse grows towards certain catastrophic boundaries we identify, across which there are drastic regime changes. We find order-of-magnitude predictions for the cosmological constant, the primordial density contrast, the temperature at matter-radiation equality, the typical galaxy mass, and the age of the universe, in terms of the fine structure constant and the electron, proton and Planck masses. Our approach permits a systematic evaluation of measure proposals; with the causal patch measure, we find no runaway of the primordial density contrast and the cosmological constant to large values.

  13. Multiverse understanding of cosmological coincidences

    SciTech Connect (OSTI)

    Bousso, Raphael; Hall, Lawrence J.; Nomura, Yasunori [Center for Theoretical Physics, Department of Physics, University of California, Berkeley, California 94720-7300 (United States) and Lawrence Berkeley National Laboratory, Berkeley, California 94720-8162 (United States)

    2009-09-15T23:59:59.000Z

    There is a deep cosmological mystery: although dependent on very different underlying physics, the time scales of structure formation, of galaxy cooling (both radiatively and against the CMB), and of vacuum domination do not differ by many orders of magnitude, but are all comparable to the present age of the universe. By scanning four landscape parameters simultaneously, we show that this quadruple coincidence is resolved. We assume only that the statistical distribution of parameter values in the multiverse grows towards certain catastrophic boundaries we identify, across which there are drastic regime changes. We find order-of-magnitude predictions for the cosmological constant, the primordial density contrast, the temperature at matter-radiation equality, the typical galaxy mass, and the age of the universe, in terms of the fine structure constant and the electron, proton and Planck masses. Our approach permits a systematic evaluation of measure proposals; with the causal patch measure, we find no runaway of the primordial density contrast and the cosmological constant to large values.

  14. Fluid observers and tilting cosmology

    E-Print Network [OSTI]

    A. A. Coley; S. Hervik; W. C. Lim

    2006-05-24T23:59:59.000Z

    We study perfect fluid cosmological models with a constant equation of state parameter $\\gamma$ in which there are two naturally defined time-like congruences, a geometrically defined geodesic congruence and a non-geodesic fluid congruence. We establish an appropriate set of boost formulae relating the physical variables, and consequently the observed quantities, in the two frames. We study expanding spatially homogeneous tilted perfect fluid models, with an emphasis on future evolution with extreme tilt. We show that for ultra-radiative equations of state (i.e., $\\gamma>4/3$), generically the tilt becomes extreme at late times and the fluid observers will reach infinite expansion within a finite proper time and experience a singularity similar to that of the big rip. In addition, we show that for sub-radiative equations of state (i.e., $\\gamma < 4/3$), the tilt can become extreme at late times and give rise to an effective quintessential equation of state. To establish the connection with phantom cosmology and quintessence, we calculate the effective equation of state in the models under consideration and we determine the future asymptotic behaviour of the tilting models in the fluid frame variables using the boost formulae. We also discuss spatially inhomogeneous models and tilting spatially homogeneous models with a cosmological constant.

  15. 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

  16. The Berry phase in inflationary cosmology

    E-Print Network [OSTI]

    Barun Kumar Pal; Supratik Pal; B. Basu

    2013-04-25T23:59:59.000Z

    We derive an analogue of the Berry phase associated with inflationary cosmological perturbations of quantum mechanical origin by obtaining the corresponding wavefunction. We have further shown that cosmological Berry phase can be completely envisioned through the observable parameters, viz. spectral indices. Finally, physical significance of this phase is discussed from the point of view of theoretical and observational aspects with some possible consequences of this quantity in inflationary cosmology.

  17. Cosmological Constant and Axions in String Theory

    SciTech Connect (OSTI)

    Svrcek, Peter; /Stanford U., Phys. Dept. /SLAC

    2006-08-18T23:59:59.000Z

    String theory axions appear to be promising candidates for explaining cosmological constant via quintessence. In this paper, we study conditions on the string compactifications under which axion quintessence can happen. For sufficiently large number of axions, cosmological constant can be accounted for as the potential energy of axions that have not yet relaxed to their minima. In compactifications that incorporate unified models of particle physics, the height of the axion potential can naturally fall close to the observed value of cosmological constant.

  18. 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]

    2006-01-01T23:59:59.000Z

    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

  19. First trillion particle cosmological simulation completed

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

    trillion particle cosmological simulation completed A team of astrophysicists and computer scientists has created high-resolution cyber images of our cosmos. December 3, 2014...

  20. Vacuum Energy and the Cosmological Constant

    E-Print Network [OSTI]

    A. C. Melissinos

    2001-12-19T23:59:59.000Z

    We discuss a numerical relation between the cosmological constant and the vacuum energy arising from the Casimir effect in extra dimensions

  1. Variable cosmological term - geometry and physics

    E-Print Network [OSTI]

    Irina Dymnikova

    2000-10-04T23:59:59.000Z

    We describe the dynamics of a cosmological term in the spherically symmetric case by an r-dependent second rank symmetric tensor \\Lambda_{\\mu\

  2. Landscape predictions from cosmological vacuum selection

    SciTech Connect (OSTI)

    Bousso, Raphael; Bousso, Raphael; Yang, Sheng

    2007-04-23T23:59:59.000Z

    In Bousso-Polchinski models with hundreds of fluxes, we compute the effects of cosmological dynamics on the probability distribution of landscape vacua. Starting from generic initial conditions, we find that most fluxes are dynamically driven into a different and much narrower range of values than expected from landscape statistics alone. Hence, cosmological evolution will access only a tiny fraction of the vacua with small cosmological constant. This leads to a host of sharp predictions. Unlike other approaches to eternal inflation, the holographic measure employed here does not lead to staggering, an excessive spread of probabilities that would doom the string landscape as a solution to the cosmological constant problem.

  3. The Physics Of Supernova Neutrino Oscillations

    E-Print Network [OSTI]

    Kneller, James P

    2015-01-01T23:59:59.000Z

    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...

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

    SciTech Connect (OSTI)

    Strauss, Michael A. [Princeton University

    2013-08-23T23:59:59.000Z

    The physical relation between the properties of Type Ia supernovae and their host galaxies is investigated. Such supernovae are used to constrain the properties of dark energy, making it crucial to understand their physical properties and to check for systematic effects relating to the stellar populations of the progenitor stars from which these supernovae arose. This grant found strong evidence for two distinct populations of supernovae, and correlations between the progenitor stellar populations and the nature of the supernova light curves.

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

    SciTech Connect (OSTI)

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

    2004-04-23T23:59:59.000Z

    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.

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

    E-Print Network [OSTI]

    Jens Thomas; Hartmut Schulz

    2001-03-18T23:59:59.000Z

    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.

  7. Particle acceleration at supernova shocks in young stellar clusters

    E-Print Network [OSTI]

    Bykov, A M; Osipov, S M

    2011-01-01T23:59:59.000Z

    We briefly discuss models of energetic particle acceleration by supernova shock in active starforming regions at different stages of their evolution. Strong shocks may strongly amplify magnetic fields due to cosmic ray driven instabilities. We discuss the magnetic field amplification emphasizing the role of the long-wavelength instabilities. Supernova shock propagating in the vicinity of a powerful stellar wind in a young stellar cluster is argued to increase the maximal CR energies at a given evolution stage of supernova remnant (SNR) and can convert a sizeable fraction of the kinetic energy release into energetic particles.

  8. The CHilean Automatic Supernova sEarch (CHASE)

    E-Print Network [OSTI]

    Pignata, G; Hamuy, M; Antezana, R; Gonzalez, L; Gonzalez, P; Lopez, P; Silva, S; Folatelli, G; Iturra, D; Cartier, R; Forster, F; Conuel, B; Reichart, D; Ivarsen, K; Crain, A; Foster, D; Nysewander, M; LaCluyze, A

    2015-01-01T23:59:59.000Z

    The CHASE project started in 2007 with the aim of providing young southern supernovae (SNe) to the Carnegie Supernova Project (CSP) and Millennium Center for Supernova Studies (MCSS) follow-up programs. So far CHASE has discovered 33 SNe with an average of more than 2.5 SNe per month in 2008. In addition to the search we are carrying out a follow-up program targeting bright SNe. Our fully automated data reduction allows us to follow the evolution on the light curve in real time, triggering further observations if something potentially interesting is detected

  9. Will Jets Identify the Progenitors of Type Ia Supernovae?

    E-Print Network [OSTI]

    Mario Livio; Adam Riess; William Sparks

    2002-04-26T23:59:59.000Z

    We use the fact that a Type Ia supernova has been serendipitously discovered near the jet of the active galaxy 3C 78 to examine the question of whether jets can enhance accretion onto white dwarfs. One interesting outcome of such a jet-induced accretion process is an enhanced rate of novae in the vicinity of jets. We present results of observations of the jet in M87 which appear to have indeed discovered 11 novae in close proximity to the jet. We show that a confirmation of the relation between jets and novae and Type Ia supernovae can finally identify the elusive progenitors of Type Ia supernovae.

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

    E-Print Network [OSTI]

    Carles Badenes; Eduardo Bravo; Kazimierz J. Borkowski

    2003-09-03T23:59:59.000Z

    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.

  11. Numerical simulations of super-luminous supernovae of type IIn

    E-Print Network [OSTI]

    Dessart, Luc; Hillier, D John

    2015-01-01T23:59:59.000Z

    We present numerical simulations that include 1-D Eulerian multi-group radiation-hydrodynamics, 1-D non-LTE radiative transfer, and 2-D polarised radiative transfer for super-luminous interacting supernovae (SNe). Our reference model is a ~10Msun inner shell with 10^51erg ramming into a ~3Msun cold outer shell (the circumstellar-medium, or CSM) that extends from 10^15cm to 2x10^16cm and moves at 100km/s. We discuss the light curve evolution, which cannot be captured adequately with a grey approach. In these interactions, the shock-crossing time through the optically-thick CSM is much longer than the photon diffusion time. Radiation is thus continuously leaking from the shock through the CSM, in disagreement with the shell-shocked model that is often invoked. Our spectra redden with time, with a peak distribution in the near-UV during the first month gradually shifting to the optical range over the following year. Initially Balmer lines exhibit a narrow line core and the broad line wings that are characteristi...

  12. 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)

    2013-07-01T23:59:59.000Z

    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.

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

    E-Print Network [OSTI]

    Sharov, G S

    2015-01-01T23:59:59.000Z

    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.

  14. Mapping the Heavens: Probing Cosmology with the Sloan Digital Sky Survey

    SciTech Connect (OSTI)

    Frieman, Josh (University of Chicago) [University of Chicago

    2006-12-04T23:59:59.000Z

    This talk will provide an overview of results from the on-going Sloan Digital Sky Survey (SDSS), the most ambitious mapping of the Universe yet undertaken, focusing on those with implications for cosmology. It will include a virtual fly-through of the survey that reveals the 3-dimensional large-scale structure of the galaxy distribution. Recent measurements of this large-scale structure, in combination with observations of the cosmic microwave background, have provided independent evidence for a Universe dominated by dark matter and dark energy as well as insights into how galaxies and larger-scale structures formed. I will also describe early results from the SDSS Supernova Survey, which aims to provide more precise constraints on the nature of dark energy. Future planned surveys from the ground and from space will build on these foundations to probe the history of the cosmic expansion--and thereby the dark energy--with even greater precision.

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

    E-Print Network [OSTI]

    R. Kantowski; R. C. Thomas

    2001-06-18T23:59:59.000Z

    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 $\

  16. 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)

    2014-05-02T23:59:59.000Z

    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.

  17. Axion Bounds from Precision Cosmology

    SciTech Connect (OSTI)

    Raffelt, G. G. [Max-Planck-Institut fuer Physik (Werner-Heisenberg-Institut), 80805 Muenchen (Germany); Hamann, J.; Hannestad, S. [Department of Physics and Astronomy, University of Aarhus, 8000 Aarhus C (Denmark); Mirizzi, A. [II. Institut fuer Theoretische Physik, Universitaet Hamburg, 22761 Hamburg (Germany); Wong, Y. Y. Y. [Institut fuer Theoretische Teilchenphysik und Kosmologie, RWTH Aachen, 52056 Aachen (Germany)

    2010-08-30T23:59:59.000Z

    Depending on their mass, axions produced in the early universe can leave different imprints in cosmic structures. If axions have masses in the eV-range, they contribute a hot dark matter fraction, allowing one to constrain m{sub a} in analogy to neutrinos. In the more favored scenario where axions play the role of cold dark matter and if reheating after inflation does not restore the Peccei-Quinn symmetry, the axion field provides isocurvature fluctuations that are severely constrained by precision cosmology. There remains a small sliver in parameter space where isocurvature fluctuations could still show up in future probes.

  18. 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

    2015-01-01T23:59:59.000Z

    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...

  19. The type Ia supernova SNLS-03D3bb from a super-Chandrasekhar-masswhite dwarf star

    SciTech Connect (OSTI)

    Howell, D.Andrew; Sullivan, Mark; Nugent, Peter E.; Ellis,Richard S.; Conley, Alexander J.; Le Borgne, Damien; Carlberg, RaymondG.; Guy, Julien; Balam, David; Basa, Stephane; Fouchez, Dominique; Hook,Isobel M.; Hsiao, Eric Y.; Neill, James D.; Pain, Reynald; Perrett,Kathryn M.; Pritchet, Christopher J.

    2006-02-01T23:59:59.000Z

    The acceleration of the expansion of the universe, and theneed for Dark Energy, were inferred from the observations of Type Iasupernovae (SNe Ia) 1;2. There is consensus that SNeIa are thermonuclearexplosions that destroy carbon-oxygen white dwarf stars that accretematter from a companion star3, although the nature of this companionremains uncertain. SNe Ia are thought to be reliable distance indicatorsbecause they have a standard amount of fuel and a uniform trigger theyare predicted to explode when the mass of the white dwarf nears theChandrasekhar mass 4 - 1.4 solar masses. Here we show that the highredshift supernova SNLS-03D3bb has an exceptionally high luminosity andlow kinetic energy that both imply a super-Chandrasekhar mass progenitor.Super-Chandrasekhar mass SNeIa shouldpreferentially occur in a youngstellar population, so this may provide an explanation for the observedtrend that overluminous SNe Ia only occur in young environments5;6. Sincethis supernova does not obey the relations that allow them to becalibrated as standard candles, and since no counterparts have been foundat low redshift, future cosmology studies will have to considercontamination from such events.

  20. 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)

    2013-11-10T23:59:59.000Z

    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.

  1. Cosmological birefringence induced by neutrino current

    E-Print Network [OSTI]

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

    2007-11-29T23:59:59.000Z

    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.

  2. No hair theorem for inhomogeneous cosmologies

    SciTech Connect (OSTI)

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

    1986-03-01T23:59:59.000Z

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

  3. Vacuum Fluctuations and the Cosmological Constant

    E-Print Network [OSTI]

    Shi Qi

    2006-04-29T23:59:59.000Z

    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.

  4. Surface brightness in plasma-redshift cosmology

    E-Print Network [OSTI]

    Ari Brynjolfsson

    2006-05-31T23:59:59.000Z

    In 2001 Lori M. Lubin and Allan Sandage, using big-bang cosmology for interpreting the data, found the surface brightness of galaxies to be inversely proportional to about the third power of (1+z), while the contemporary big-bang cosmology predicts that the surface brightness is inversely proportional to the fourth power of (1+z). In contrast, these surface brightness observations are in agreement with the predictions of the plasma-redshift cosmology. Lubin and Sandage (2001) and Barden et al. (2005), who surmised the big-bang expansion, interpreted the observations to indicate that the diameters of galaxies are inversely proportional to (1+z). In contrast, when assuming plasma-redshift cosmology, the diameters of galaxies are observed to be constant independent of redshift and any expansion. Lubin and Sandage (2001) and Barden et al. (2005), when using big-bang cosmology, observed the average absolute magnitude of galaxies to decrease with redshift; while in plasma redshift cosmology it is a constant. Lubin and Sandage and Barden et al. suggested that a coherent evolution could explain the discrepancy between the observed relations and those predicted in the big-bang cosmology. We have failed to find support for this explanation. We consider the observed relations between the redshift and the surface-brightness, the galaxy diameter, and the absolute magnitude to be robust confirmations of plasma-redshift cosmology.

  5. Phases of a Type Ia supernova explosion

    E-Print Network [OSTI]

    J. C. Niemeyer

    1998-02-13T23:59:59.000Z

    In the framework of the Chandrasekhar mass white dwarf model for Type Ia supernovae, various stages of the explosion are described in terms of the burning regimes of the thermonuclear flame front. In the early flamelet regime following the ``smoldering'' phase prior to the explosion, the flame is sufficiently thin and fast to remain laminar on small scales. As the white dwarf density declines, the thermal flame structure becomes subject to penetration by turbulent eddies, and it enters the ``distributed burning'' regime. A specific control parameter for this transition is proposed. Furthermore, we outline an argument for the coincidence of the transition between burning regimes with the onset of a deflagration-detonation-transition (DDT) in the late phase of the explosion.

  6. Ultra-stripped supernovae: progenitors and fate

    E-Print Network [OSTI]

    Tauris, Thomas M; Podsiadlowski, Philipp

    2015-01-01T23:59:59.000Z

    The explosion of ultra-stripped stars in close binaries can lead to ejecta masses supernovae (SNe). In particular, we examine the binary parameter space leading to electron-capture (EC SNe) and iron core-collapse SNe (Fe CCSNe), respectively, and determine the amount of helium ejected with applications to their observational classification as Type Ib or Type Ic. We mainly evolve systems where the SN progenitors are helium star donors of initial mass M_He = 2.5 - 3.5 M_sun in tight binaries with orbital periods of P_orb = 0.06 - 2.0 days, and hosting an accreting NS, but we also discuss the evolution of wide...

  7. Neutrino Oscillations and the Supernova 1987A Signal

    E-Print Network [OSTI]

    B. Jegerlehner; F. Neubig; G. Raffelt

    1996-03-29T23:59:59.000Z

    We study the impact of neutrino oscillations on the interpretation of the supernova (SN) 1987A neutrino signal by means of a maximum-likelihood analysis. We focus on oscillations between $\\overline\

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

    E-Print Network [OSTI]

    Adam Burrows

    1997-03-02T23:59:59.000Z

    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.

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

    E-Print Network [OSTI]

    Yang, Haifeng

    2015-01-01T23:59:59.000Z

    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.

  10. Supernova deleptonization asymmetry: Impact on self-induced flavor conversion

    E-Print Network [OSTI]

    Sovan Chakraborty; Georg Raffelt; Hans-Thomas Janka; Bernhard Mueller

    2014-12-01T23:59:59.000Z

    During the accretion phase of a core-collapse supernova (SN), the deleptonization flux has recently been found to develop a global dipole pattern (LESA---Lepton Emission Self-sustained Asymmetry). The $\

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

    E-Print Network [OSTI]

    Burrows, A

    1998-01-01T23:59:59.000Z

    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.

  12. Closest Type Ia Supernova in Decades Solves a Cosmic Mystery

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

    PTF 11kly as it appeared in the nearby M101 galaxy. (Images: Peter Nugent) Type Ia supernovae (SN Ia's) are the extraordinarily bright and remarkably similar "standard candles"...

  13. Infrared Spectroscopy of Molecular Supernova Remnants

    E-Print Network [OSTI]

    William T. Reach; Jeonghee Rho

    2000-07-27T23:59:59.000Z

    We present Infrared Space Observatory spectroscopy of sites in the supernova remnants W28, W44, and 3C391, where blast waves are impacting molecular clouds. Atomic fine-structure lines were detected from C, N, O, Si, P, and Fe. The S(3) and S(9) lines of H2 were detected for all three remnants. The observations require both shocks into gas with moderate (~ 100 /cm3) and high (~10,000 /cm3) pre-shock densities, with the moderate density shocks producing the ionic lines and the high density shock producing the molecular lines. No single shock model can account for all of the observed lines, even at the order of magnitude level. We find that the principal coolants of radiative supernova shocks in moderate-density gas are the far-infrared continuum from dust grains surviving the shock, followed by collisionally-excited [O I] 63.2 and [Si II] 34.8 micron lines. The principal coolant of the high-density shocks is collisionally-excited H2 rotational and ro-vibrational line emission. We systematically examine the ground-state fine structure of all cosmically abundant elements, to explain the presence or lack of all atomic fine lines in our spectra in terms of the atomic structure, interstellar abundances, and a moderate-density, partially-ionized plasma. The [P II] line at 60.6 microns is the first known astronomical detection. There is one bright unidentified line in our spectra, at 74.26 microns. The presence of bright [Si II] and [Fe II] lines requires partial destruction of the dust. The required gas-phase abundance of Fe suggests 15-30% of the Fe-bearing grains were destroyed. The infrared continuum brightness requires ~1 Msun of dust survives the shock, suggesting about 1/3 of the dust mass was destroyed, in agreement with the depletion estimate and with theoretical models for dust destruction.

  14. 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)

    2013-12-01T23:59:59.000Z

    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.

  15. Analogue models for FRW cosmologies

    E-Print Network [OSTI]

    Carlos Barcelo; Stefano Liberati; Matt Visser

    2003-05-16T23:59:59.000Z

    It is by now well known that various condensed matter systems may be used to mimic many of the kinematic aspects of general relativity, and in particular of curved-spacetime quantum field theory. In this essay we will take a look at what would be needed to mimic a cosmological spacetime -- to be precise a spatially flat FRW cosmology -- in one of these analogue models. In order to do this one needs to build and control suitable time dependent systems. We discuss here two quite different ways to achieve this goal. One might rely on an explosion, physically mimicking the big bang by an outflow of whatever medium is being used to carry the excitations of the analogue model, but this idea appears to encounter dynamical problems in practice. More subtly, one can avoid the need for any actual physical motion (and avoid the dynamical problems) by instead adjusting the propagation speed of the excitations of the analogue model. We shall focus on this more promising route and discuss its practicality.

  16. Statistical Mechanics and Quantum Cosmology

    E-Print Network [OSTI]

    B. L. Hu

    1995-11-29T23:59:59.000Z

    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.

  17. 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)

    2012-12-01T23:59:59.000Z

    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.

  18. Frequency Dependence of Radio Images of Supernova Remnants

    E-Print Network [OSTI]

    A. V. Karnaushenko; E. Yu. Bannikova; V. M. Kontorovich

    2007-12-10T23:59:59.000Z

    Radio images of supernova remnants in the framework of diffusion model are discussed. The distribution profiles of synchrotron radiation intensity for spherical injection source of relativistic electrons are reduced at different frequencies. An explanation of the observational data obtained on UTR-2, according to which the size of the supernova remnant at decametric waves is larger than the remnant size at high frequencies, is given.

  19. THE ENGINES BEHIND SUPERNOVAE AND GAMMA-RAY BURSTS

    SciTech Connect (OSTI)

    FRYER, CHRISTOPHER LEE [Los Alamos National Laboratory

    2007-01-23T23:59:59.000Z

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

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

    E-Print Network [OSTI]

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

    2015-01-01T23:59:59.000Z

    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...

  1. 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).

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

    E-Print Network [OSTI]

    2005-01-01T23:59:59.000Z

    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.

  3. Group X

    SciTech Connect (OSTI)

    Fields, Susannah

    2007-08-16T23:59:59.000Z

    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.

  4. Simulating galactic outflows with kinetic supernova feedback

    E-Print Network [OSTI]

    Claudio Dalla Vecchia; Joop Schaye

    2008-05-07T23:59:59.000Z

    Feedback from star formation is thought to play a key role in the formation and evolution of galaxies, but its implementation in cosmological simulations is currently hampered by a lack of numerical resolution. We present and test a sub-grid recipe to model feedback from massive stars in cosmological smoothed particle hydrodynamics simulations. The energy is distributed in kinetic form among the gas particles surrounding recently formed stars. The impact of the feedback is studied using a suite of high-resolution simulations of isolated disc galaxies embedded in dark halos with total mass 10^{10} and 10^{12} Msol/h. We focus in particular on the effect of pressure forces on wind particles within the disc, which we turn off temporarily in some of our runs to mimic a recipe that has been widely used in the literature. We find that this popular recipe gives dramatically different results because (ram) pressure forces on expanding superbubbles determine both the structure of the disc and the development of large-scale outflows. Pressure forces exerted by expanding superbubbles puff up the disc, giving the dwarf galaxy an irregular morphology and creating a galactic fountain in the massive galaxy. Hydrodynamic drag within the disc results in a strong increase of the effective mass loading of the wind for the dwarf galaxy, but quenches much of the outflow in the case of the high-mass galaxy.

  5. Cosmological Vacuum in Unified Theories

    E-Print Network [OSTI]

    V. N. Pervushin; V. I Smirichinski

    1997-09-30T23:59:59.000Z

    The unification of the Einstein theory of gravity with a conformal invariant version of the standard model for electroweak interaction without the Higgs potential is considered. In this theory, a module of the Higgs field is absorbed by the scale factor component of metric so that the evolution of the Universe and the elementary particle masses have one and the same cosmological origin and the flat space limit corresponds to the $\\sigma$-model version of the standard model. The red shift formula and Hubble law are obtained under the assumption of homogeneous matter distribution. We show that the considered theory leads to a very small vacuum density of the Higgs field $\\rho_\\phi^{Cosmic}=10^{-34}\\rho_{cr}$ in contrast with the theory with the Higgs potential $\\rho_\\phi^{Higgs}=10^{54}\\rho_{cr}$.

  6. Constraints on small-scale cosmological fluctuations from SNe lensing dispersion

    E-Print Network [OSTI]

    Ben-Dayan, Ido

    2015-01-01T23:59:59.000Z

    We provide predictions on small-scale cosmological density power spectrum from supernova lensing dispersion. Parameterizing the primordial power spectrum with running $\\alpha$ and running of running $\\beta$ of the spectral index, we exclude large positive $\\alpha$ and $\\beta$ parameters which induce too large lensing dispersions over current observational upper bound. We ran cosmological N-body simulations of collisionless dark matter particles to investigate non-linear evolution of the primordial power spectrum with positive running parameters. The initial small-scale enhancement of the power spectrum is largely erased when entering into the non-linear regime. For example, even if the linear power spectrum at $k>10h {\\rm Mpc}^{-1}$ is enhanced by $1-2$ orders of magnitude, the enhancement much decreases to a factor of $2-3$ at late time ($z \\leq 1.5$). Therefore, the lensing dispersion induced by the dark matter fluctuations weakly constrains the running parameters. When including baryon-cooling effects (whi...

  7. A Quantum Cosmology: No Dark Matter, Dark Energy nor Accelerating Universe

    E-Print Network [OSTI]

    Reginald T Cahill

    2007-09-18T23:59:59.000Z

    We show that modelling the universe as a pre-geometric system with emergent quantum modes, and then constructing the classical limit, we obtain a new account of space and gravity that goes beyond Newtonian gravity even in the non-relativistic limit. This account does not require dark matter to explain the spiral galaxy rotation curves, and explains as well the observed systematics of black hole masses in spherical star systems, the bore hole $g$ anomalies, gravitational lensing and so on. As well the dynamics has a Hubble expanding universe solution that gives an excellent parameter-free account of the supernovae and gamma-ray-burst red-shift data, without dark energy or dark matter. The Friedmann-Lema\\^{i}tre-Robertson-Walker (FLRW) metric is derived from this dynamics, but is shown not satisfy the General Relativity based Friedmann equations. It is noted that General Relativity dynamics only permits an expanding flat 3-space solution if the energy density in the pressure-less dust approximation is non-zero. As a consequence dark energy and dark matter are required in this cosmological model, and as well the prediction of a future exponential accelerating Hubble expansion. The FLRW $\\Lambda$CDM model data-based parameter values, $\\Omega_\\Lambda=0.73$, $\\Omega_{DM}=0.27$, are derived within the quantum cosmology model, but are shown to be merely artifacts of using the Friedmann equations in fitting the red-shift data.

  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

    1998-06-25T23:59:59.000Z

    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. Phenomenology for Supernova Ia Data Based on a New Cosmic Time

    E-Print Network [OSTI]

    Charles B. Leffert

    2007-07-26T23:59:59.000Z

    A new phenomenological theory for the expansion of our universe is presented. Because fundamental supporting theory is still in development, its discussion is not presented in this paper. The theory is based on a new algebraic expression for cosmic time G Rho t^2=3/32Pi, which correctly predicts the WMAP measured cosmological constants and the fundamental Hubble parameter H(t) for the expansion of the universe. A replacement for dark matter, called here "dark mass", is proposed which scales as with the expansion and incorporated. It does not react with ordinary matter, except gravitationally, and produces flat rotational curves for spiral galaxies. Also a new expression for the approaching velocity of radiation in a closed 3-sphere expanding universe is given that accounts for the early degrading negative approach of radiation for z > 1.7. The expression is v = Hr-c. Combining these three elements produces a luminosity distance dL that successfully predicts the apparent magnitude of exploding supernova Ia stars and even the new gamma ray bursts with no need for dark energy or acceleration of the expansion of the universe.

  10. 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)

    2014-01-01T23:59:59.000Z

    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%.

  11. 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)

    2013-11-20T23:59:59.000Z

    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.

  12. THE IMPACT OF METALLICITY ON THE RATE OF TYPE Ia SUPERNOVAE

    SciTech Connect (OSTI)

    Kistler, Matthew D. [California Institute of Technology, Mail Code 350-17, Pasadena, CA 91125 (United States); Stanek, K. Z.; Kochanek, Christopher S.; Thompson, Todd A. [Center for Cosmology and Astro-Particle Physics, Ohio State University, Columbus, OH 43210 (United States); Prieto, Jose L. [Carnegie Observatories, 813 Santa Barbara Street, Pasadena, CA 91101 (United States)

    2013-06-20T23:59:59.000Z

    The metallicity of a star strongly affects both its evolution and the properties of the stellar remnant that results from its demise. It is generally accepted that stars with initial masses below {approx}8 M{sub Sun} leave behind white dwarfs and that some sub-population of these lead to Type Ia supernovae (SNe Ia). However, it is often tacitly assumed that metallicity has no effect on the rate of SNe Ia. We propose that a consequence of the effects of metallicity is to significantly increase the SN Ia rate in lower-metallicity galaxies, in contrast to previous expectations. This is because lower-metallicity stars leave behind higher-mass white dwarfs, which should be easier to bring to explosion. We first model SN Ia rates in relation to galaxy masses and ages alone, finding that the elevation in the rate of SNe Ia in lower-mass galaxies measured by Lick Observatory SN Search is readily explained. However, we then see that models incorporating this effect of metallicity agree just as well. Using the same parameters to estimate the cosmic SN Ia rate, we again find good agreement with data up to z Almost-Equal-To 2. We suggest that this degeneracy warrants more detailed examination of host galaxy metallicities. We discuss additional implications, including for hosts of high-z SNe Ia, the SN Ia delay time distribution, super-Chandrasekhar SNe, and cosmology.

  13. 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)

    2013-08-20T23:59:59.000Z

    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.

  14. Isotropic cosmological singularities: other matter models

    E-Print Network [OSTI]

    K. P. Tod

    2002-09-20T23:59:59.000Z

    Isotropic cosmological singularities are singularities which can be removed by rescaling the metric. In some cases already studied (gr-qc/9903008, gr-qc/9903009, gr-qc/9903018) existence and uniqueness of cosmological models with data at the singularity has been established. These were cosmologies with, as source, either perfect fluids with linear equations of state or massless, collisionless particles. In this article we consider how to extend these results to a variety of other matter models. These are scalar fields, massive collisionless matter, the Yang-Mills plasma of Choquet-Bruhat, or matter satisfying the Einstein-Boltzmann equation.

  15. A natural cosmological constant from chameleons

    E-Print Network [OSTI]

    Horatiu Nastase; Amanda Weltman

    2015-04-06T23:59:59.000Z

    We present a simple model where the effective cosmological constant appears from chameleon scalar fields. For a Kachru-Kallosh-Linde-Trivedi (KKLT)-inspired form of the potential and a particular chameleon coupling to the local density, patches of approximately constant scalar field potential cluster around regions of matter with density above a certain value, generating the effect of a cosmological constant on large scales. This construction addresses both the cosmological constant problem (why $\\Lambda$ is so small, yet nonzero) and the coincidence problem (why $\\Lambda$ is comparable to the matter density now).

  16. Experimental signatures of cosmological neutrino condensation

    E-Print Network [OSTI]

    Mofazzal Azam; Jitesh R. Bhatt; Utpal Sarkar

    2010-11-02T23:59:59.000Z

    Superfluid condensation of neutrinos of cosmological origin at a low enough temperature can provide simple and elegant solution to the problems of neutrino oscillations and the accelerated expansion of the universe. It would give rise to a late time cosmological constant of small magnitude and also generate tiny Majorana masses for the neutrinos as observed from their flavor oscillations. We show that carefully prepared beta decay experiments in the laboratory would carry signatures of such a condensation, and thus, it would be possible to either establish or rule out neutrino condensation of cosmological scale in laboratory experiments.

  17. Cosmological constant in scale-invariant theories

    SciTech Connect (OSTI)

    Foot, Robert; Kobakhidze, Archil; Volkas, Raymond R. [School of Physics, University of Melbourne, Victoria 3010 (Australia)

    2011-10-01T23:59:59.000Z

    The incorporation of a small cosmological constant within radiatively broken scale-invariant models is discussed. We show that phenomenologically consistent scale-invariant models can be constructed which allow a small positive cosmological constant, providing certain relation between the particle masses is satisfied. As a result, the mass of the dilaton is generated at two-loop level. Another interesting consequence is that the electroweak symmetry-breaking vacuum in such models is necessarily a metastable ''false'' vacuum which, fortunately, is not expected to decay on cosmological time scales.

  18. Towards the cosmological constant problem

    E-Print Network [OSTI]

    Eun Kyung Park; Pyung Seong Kwon

    2014-12-15T23:59:59.000Z

    We apply a new self-tuning mechanism to the well-known Kachru-Kallosh-Linde-Trivedi (KKLT) model to address the cosmological constant problem. In this mechanism the cosmological constant $\\lambda$ contains a supersymmetry breaking term ${\\mathcal E}_{\\rm SB}$ besides the usual scalar potential ${\\mathcal V}_{\\rm scalar}$ of the $N=1$ supergravity, which is distinguished from the usual theories where $\\lambda$ is directly identified with ${\\mathcal V}_{\\rm scalar}$ alone. Also in this mechanism, whether $\\lambda$ vanishes or not is basically determined by the tensor structure of the scalar potential density, not by the zero or nonzero values of the scalar potential itself. As a result of this application we find that the natural scenario for the vanishing $\\lambda$ of the present universe is to take one of the AdS (rather than dS) vacua of KKLT as the background vacuum of our present universe. This AdS vacuum scenario does not suffer from the problematics of the dS vacua of KKLT. The background vacuum is stable both classically and quantum mechanically (no tunneling instabilities), and the value $\\lambda =0$ is also stable against quantum corrections because in this scenario the perturbative corrections of ${\\mathcal V}_{\\rm scalar}$ and quantum fluctuations $\\delta_Q {\\hat I}_{\\rm brane}^{(NS)} + \\delta_Q {\\hat I}_{\\rm brane}^{(R)}$ on the branes are all gauged away by an automatic cancelation between ${\\mathcal V}_{\\rm scalar} + \\delta_Q {\\hat I}_{\\rm brane}^{(NS)} + \\delta_Q {\\hat I}_{\\rm brane}^{(R)}$ and ${\\mathcal E}_{\\rm SB}$.

  19. Inflation with stable anisotropic hair: is it cosmologically viable?

    E-Print Network [OSTI]

    Sigbjørn Hervik; David F. Mota; Mikjel Thorsrud

    2011-12-21T23:59:59.000Z

    Recently an inflationary model with a vector field coupled to the inflaton was proposed and the phenomenology studied for the Bianchi type I spacetime. It was found that the model demonstrates a counter-example to the cosmic no-hair theorem since there exists a stable anisotropically inflationary fix-point. One of the great triumphs of inflation, however, is that it explains the observed flatness and isotropy of the universe today without requiring special initial conditions. Any acceptable model for inflation should thus explain these observations in a satisfactory way. To check whether the model meets this requirement, we introduce curvature to the background geometry and consider axisymmetric spacetimes of Bianchi type II,III and the Kantowski-Sachs metric. We show that the anisotropic Bianchi type I fix-point is an attractor for the entire family of such spacetimes. The model is predictive in the sense that the universe gets close to this fix-point after a few e-folds for a wide range of initial conditions. If inflation lasts for N e-folds, the curvature at the end of inflation is typically of order exp(-2N). The anisotropy in the expansion rate at the end of inflation, on the other hand, while being small on the one-percent level, is highly significant. We show that after the end of inflation there will be a period of isotropization lasting for about 2N/3 e-folds. After that the shear scales as the curvature and becomes dominant around N e-folds after the end of inflation. For plausible bounds on the reheat temperature the minimum number of e-folds during inflation, required for consistency with the isotropy of the supernova Ia data, lays in the interval (21,48). Thus the results obtained for our restricted class of spacetimes indicates that inflation with anisotropic hair is cosmologically viable.

  20. Metal Enrichment of the Intergalactic Medium in Cosmological Simulations

    E-Print Network [OSTI]

    Anthony Aguirre; Lars Hernquist; Joop Schaye; Neal Katz; David H. Weinberg; Jeffrey Gardner

    2001-07-17T23:59:59.000Z

    Observations have established that the diffuse intergalactic medium (IGM) at z ~ 3 is enriched to ~0.1-1% solar metallicity and that the hot gas in large clusters of galaxies (ICM) is enriched to 1/3-1/2 solar metallicity at z=0. Metals in the IGM may have been removed from galaxies (in which they presumably form) during dynamical encounters between galaxies, by ram-pressure stripping, by supernova-driven winds, or as radiation-pressure driven dust efflux. This study develops a method of investigating the chemical enrichment of the IGM and of galaxies, using already completed cosmological simulations. To these simulations, we add dust and (gaseous) metals, distributing the dust and metals in the gas according to three simple parameterized prescriptions, one for each enrichment mechanism. These prescriptions are formulated to capture the basic ejection physics, and calibrated when possible with empirical data. Our results indicate that dynamical removal of metals from >~ 3*10^8 solar mass galaxies cannot account for the observed metallicity of low-column density Ly-alpha absorbers, and that dynamical removal from >~ 3*10^10 solar mass galaxies cannot account for the ICM metallicities. Dynamical removal also fails to produce a strong enough mass-metallicity relation in galaxies. In contrast, either wind or radiation-pressure ejection of metals from relatively large galaxies can plausibly account for all three sets of observations (though it is unclear whether metals can be distributed uniformly enough in the low-density regions without overly disturbing the IGM, and whether clusters can be enriched quite as much as observed). We investigate in detail how our results change with variations in our assumed parameters, and how results for the different ejection processes compare. (Abridged)

  1. 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

    2012-04-09T23:59:59.000Z

    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)

  2. 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

    2012-06-06T23:59:59.000Z

    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.

  3. 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: ...

  4. Discriminating the progenitor type of supernova remnants with Iron K-shell emission

    E-Print Network [OSTI]

    Yamaguchi, Hiroya

    Supernova remnants (SNRs) retain crucial information about both their parent explosion and circumstellar material left behind by their progenitor. However, the complexity of the interaction between supernova ejecta and ...

  5. 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

    2014-01-01T23:59:59.000Z

    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...

  6. Cosmology at the Beach Lecture: Anne Green

    SciTech Connect (OSTI)

    Ann Green

    2009-04-21T23:59:59.000Z

    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. Cosmology of modified (but second order) gravity

    E-Print Network [OSTI]

    Tomi S. Koivisto

    2009-10-21T23:59:59.000Z

    This is a brief review of modified gravity cosmologies. Generically extensions of gravity action involve higher derivative terms, which can result in ghosts and instabilities. There are three ways to circumvent this: Chern-Simons terms, first order variational principle and nonlocality. We consider recent cosmological applications of these three classes of modified gravity models, in particular to the dark energy problem. The viable parameter spaces can be very efficiently constrained by taking into account cosmological data from all epochs in addition to Solar system tests and stability considerations. We make some new remarks concerning so called algebraic scalar-tensor theories, biscalar reformulation of nonlocal actions involving the inverse d'Alembertian, and a possible covariant formulation holographic cosmology with nonperturbative gravity.

  8. Cosmology on the Beach: Kendrick Smith

    ScienceCinema (OSTI)

    George Smoot

    2010-01-08T23:59:59.000Z

    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.

  9. Cosmology on the Beach - George Smoot

    ScienceCinema (OSTI)

    George Smoot

    2010-01-08T23:59:59.000Z

    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.

  10. Cosmology at the Beach Lecture: Anne Green

    ScienceCinema (OSTI)

    Ann Green

    2010-01-08T23:59:59.000Z

    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.  

  11. Cosmology at the Beach Lecture: Simon White

    ScienceCinema (OSTI)

    Simon White

    2010-01-08T23:59:59.000Z

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

  12. Cosmological Inflation and generation of Primordial Perturbations

    E-Print Network [OSTI]

    Souradeep, Tarun

    to high accuracy. The Inflationary universe, first proposed by Guth[1] is a modification of the hot big cosmology has become one of the cornerstones of modern cos- mology. Inflationary universe scenario

  13. Asymptotically Vanishing Cosmological Constant in the Multiverse

    E-Print Network [OSTI]

    Hikaru Kawai; Takashi Okada

    2011-04-21T23:59:59.000Z

    We study the problem of the cosmological constant in the context of the multiverse in Lorentzian spacetime, and show that the cosmological constant will vanish in the future. This sort of argument was started from Coleman in 1989, and he argued that the Euclidean wormholes make the multiverse partition a superposition of various values of the cosmological constant $\\Lambda$, which has a sharp peak at $\\Lambda=0$. However, the implication of the Euclidean analysis to our Lorentzian spacetime is unclear. With this motivation, we analyze the quantum state of the multiverse in Lorentzian spacetime by the WKB method, and calculate the density matrix of our universe by tracing out the other universes. Our result predicts vanishing cosmological constant. While Coleman obtained the enhancement at $\\Lambda=0$ through the action itself, in our Lorentzian analysis the similar enhancement arises from the front factor of $e^{iS}$ in the universe wave function, which is in the next leading order in the WKB approximation.

  14. 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 ...

  15. Cosmology and the S-matrix

    E-Print Network [OSTI]

    Bousso, Raphael

    2009-01-01T23:59:59.000Z

    S. Kachru, R. Kallosh, A. Linde and S. P. Trivedi: De sitter30] N. Kaloper and A. Linde: Cosmology vs. holography, hep-V. Hubeny, N. Kaloper, A. Linde, A. Mints, J. Polchinski, M.

  16. Cosmology at the Beach Lecture: David Hughes

    ScienceCinema (OSTI)

    David Hughes

    2010-01-08T23:59:59.000Z

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

  17. Cosmology on the Beach - George Smoot

    SciTech Connect (OSTI)

    George Smoot

    2009-05-06T23:59:59.000Z

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

  18. Supernova Neutrino Spectra and Applications to Flavor Oscillations

    E-Print Network [OSTI]

    Mathias Th. Keil

    2003-08-13T23:59:59.000Z

    We study the flavor-dependent neutrino spectra formation in the core of a supernova (SN) by means of Monte Carlo simulations. A high-statistics neutrino signal from a galactic SN may contain information that severely constrains the parameter space for neutrino oscillations. Therefore, reliable predictions for flavor-dependent fluxes and spectra are urgently needed. In all traditional hydrodynamic simulations the nu_mu,tau and nu_mu,tau-bar interactions commonly included are rather schematic. With our Monte Carlo simulations we find that the most relevant sources for nu_mu,tau and nu_mu,tau-bar are traditionally not included. In comparing our numerical results for all flavors we find the standard hierarchy of mean energies nu_e < nu_e-bar < nu_mu,tau, with, however, very similar values for nu_mu,tau and nu_e-bar. The luminosities of nu_mu,tau and nu_mu,tau-bar can differ by up to a factor of 2 from L_nue-bar and L_nue, the latter two are very similar. The Garching Group obtains similar results from their self-consistent simulation with the full set of interactions. These results are almost orthogonal to the previous standard picture of exactly equal luminosities of all flavors and differences in mean energies of up to a factor of 2. Existing concepts for identifying oscillation effects in a SN neutrino signal need to be revised. We present two methods for detecting the earth-matter effect that are rather independent of predictions from SN simulations.

  19. Supernova constraints on a superlight gravitino

    SciTech Connect (OSTI)

    Dicus, D.A. [Univ. of Texas, Austin, TX (United States). Dept. of Physics; Mohapatra, R.N. [Univ. of Maryland, College Park, MD (United States). Dept. of Physics; Teplitz, V.L. [Southern Methodist Univ., Dallas, TX (United States). Dept. of Physics

    1997-10-01T23:59:59.000Z

    In supergravity models with low supersymmetry breaking scale the gravitinos can be superlight, with mass in the 10{sup -6} eV to few keV range. In such a case, gravitino emission provides a new cooling mechanism for protoneutron stars and therefore can provide constraints on the mass of a superlight gravitino. This happens because the coupling to matter of superlight gravitinos is dominated by its goldstino component, whose coupling to matter of superlight gravitinos is dominated by its goldstino component, whose coupling to matter is inversely proportional to the scale of supersymmetry breaking and increases as the gravitino mass decreases. Present observations therefore provide lower limits on the gravitino mass. Using the recently revised goldstino couplings, we find that the two dominant processes in supernova cooling are e{sup +} e{sup -} {yields} GG and {gamma}+e{sup -} {yields} e{sup -} GG. They lead to a lower limit on the supersymmetry breaking scale {Lambda}{sub s} from 160 to 500 GeV for core temperatures 30 to 60 MeV and electron chemical potentials 200 to 300 MeV. The corresponding lower limits on the gravitino mass are .6 - 6 x 10{sup -6} eV.

  20. EARLY EMISSION FROM TYPE Ia SUPERNOVAE

    SciTech Connect (OSTI)

    Rabinak, Itay; Waxman, Eli [Department of Particle Physics and Astrophysics, Weizmann Institute of Science, Rehovot 76100 (Israel); Livne, Eli, E-mail: itay.rabinak@weizmann.ac.il [Racah Institute of Physics, Hebrew University, Jerusalem (Israel)

    2012-09-20T23:59:59.000Z

    A unique feature of deflagration-to-detonation (DDT) white dwarf explosion models of supernovae of type Ia is the presence of a strong shock wave propagating through the outer envelope. We consider the early emission expected in such models, which is produced by the expanding shock-heated outer part of the ejecta and precedes the emission driven by radioactive decay. We expand on earlier analyses by considering the modification of the pre-detonation density profile by the weak shocks generated during the deflagration phase, the time evolution of the opacity, and the deviation of the post-shock equation of state from that obtained for radiation pressure domination. A simple analytic model is presented and shown to provide an acceptable approximation to the results of one-dimensional numerical DDT simulations. Our analysis predicts a {approx}10{sup 3} s long UV/optical flash with a luminosity of {approx}1 to {approx}3 Multiplication-Sign 10{sup 39} erg s{sup -1}. Lower luminosity corresponds to faster (turbulent) deflagration velocity. The luminosity of the UV flash is predicted to be strongly suppressed at t > t{sub drop} {approx} 1 hr due to the deviation from pure radiation domination.

  1. Surface detonation in type Ia supernova explosions?

    E-Print Network [OSTI]

    F. K. Roepke; S. E. Woosley

    2006-09-25T23:59:59.000Z

    We explore the evolution of thermonuclear supernova explosions when the progenitor white dwarf star ignites asymmetrically off-center. Several numerical simulations are carried out in two and three dimensions to test the consequences of different initial flame configurations such as spherical bubbles displaced from the center, more complex deformed configurations, and teardrop-shaped ignitions. The burning bubbles float towards the surface while releasing energy due to the nuclear reactions. If the energy release is too small to gravitationally unbind the star, the ash sweeps around it, once the burning bubble approaches the surface. Collisions in the fuel on the opposite side increase its temperature and density and may -- in some cases -- initiate a detonation wave which will then propagate inward burning the core of the star and leading to a strong explosion. However, for initial setups in two dimensions that seem realistic from pre-ignition evolution, as well as for all three-dimensional simulations the collimation of the surface material is found to be too weak to trigger a detonation.

  2. Dark matter ignition of type Ia supernovae

    E-Print Network [OSTI]

    Bramante, Joseph

    2015-01-01T23:59:59.000Z

    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...

  3. 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)

    2013-08-01T23:59:59.000Z

    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.

  4. EVOLUTION OF PROGENITORS FOR ELECTRON CAPTURE SUPERNOVAE

    SciTech Connect (OSTI)

    Takahashi, Koh; Umeda, Hideyuki [Department of Astronomy, University of Tokyo, Tokyo 113-0033 (Japan); Yoshida, Takashi, E-mail: ktakahashi@astron.s.u-tokyo.ac.jp, E-mail: umeda@astron.s.u-tokyo.ac.jp, E-mail: yoshida@yukawa.kyoto-u.ac.jp [Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502 (Japan)

    2013-07-01T23:59:59.000Z

    We provide progenitor models for electron capture supernovae (ECSNe) with detailed evolutionary calculation. We include minor electron capture nuclei using a large nuclear reaction network with updated reaction rates. For electron capture, the Coulomb correction of rates is treated and the contribution from neutron-rich isotopes is taken into account in each nuclear statistical equilibrium (NSE) composition. We calculate the evolution of the most massive super asymptotic giant branch stars and show that these stars undergo off-center carbon burning and form ONe cores at the center. These cores become heavier up to the critical mass of 1.367 M{sub Sun} and keep contracting even after the initiation of O+Ne deflagration. Inclusion of minor electron capture nuclei causes convective URCA cooling during the contraction phase, but the effect on the progenitor evolution is small. On the other hand, electron capture by neutron-rich isotopes in the NSE region has a more significant effect. We discuss the uniqueness of the critical core mass for ECSNe and the effect of wind mass loss on the plausibility of our models for ECSN progenitors.

  5. Dark Energy and the New Cosmology

    E-Print Network [OSTI]

    Michael S. Turner

    2001-08-07T23:59:59.000Z

    A successor to the standard hot big-bang cosmology is emerging. It greatly extends the highly successful hot big-bang model. A key element of the New Standard Cosmology is dark energy, the causative agent for accelerated expansion. Dark energy is just possibly the most important problem in all of physics. The only laboratory up to the task of studying dark energy is the Universe itself.

  6. Dark spinors with torsion in cosmology

    SciTech Connect (OSTI)

    Boehmer, Christian G.; Burnett, James [Department of Mathematics, University College London, Gower Street, London, WC1E 6BT (United Kingdom)

    2008-11-15T23:59:59.000Z

    We solve one of the open problems in Einstein-Cartan theory, namely, we find a natural matter source whose spin angular momentum tensor is compatible with the cosmological principle. We analyze the resulting evolution equations and find that an epoch of accelerated expansion is an attractor. The torsion field quickly decays in that period. Our results are interpreted in the context of the standard model of cosmology.

  7. {\\Lambda}CDM cosmology from matter only

    E-Print Network [OSTI]

    Telkamp, Herman

    2015-01-01T23:59:59.000Z

    I discuss a matter-only interpretation of {\\Lambda}CDM cosmology, based on conservation of energy and assuming a Machian definition of inertia. {\\Lambda}CDM cosmology can be linked to a Newtonian cosmic potential, subject to a propagating gravitational horizon. In a matter-only universe where total energy is conserved, Machian inertia related to the evolving potential may cause both deceleration and acceleration of recession.

  8. Spinning Fluids: A Group Theoretical Approach

    E-Print Network [OSTI]

    Dario Capasso; Debajyoti Sarkar

    2014-04-07T23:59:59.000Z

    We extend the Lagrangian formulation of relativistic non-abelian fluids in group theory language. We propose a Mathisson-Papapetrou equation for spinning fluids in terms of the reduction limit of de Sitter group. The equation we find correctly boils down to the one for non-spinning fluids. We study the application of our results for an FRW cosmological background for fluids with no vorticity and for dusts in the vicinity of a Kerr black hole. We also explore two alternative approaches based on a group theoretical formulation of particles dynamics.

  9. 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

    2015-01-01T23:59:59.000Z

    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...

  10. HOST GALAXY PROPERTIES AND HUBBLE RESIDUALS OF TYPE Ia SUPERNOVAE FROM THE NEARBY SUPERNOVA FACTORY

    SciTech Connect (OSTI)

    Childress, M.; Aldering, G.; Aragon, C.; Bailey, S.; Fakhouri, H. K.; Hsiao, E. Y.; Kim, A. G.; Loken, S. [Physics Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, 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 Paris 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); Buton, C.; Kerschhaggl, M.; Kowalski, M. [Physikalisches Institut, Universitaet Bonn, Nussallee 12, D-53115 Bonn (Germany); Chotard, N.; Copin, Y.; Gangler, E. [Universite de Lyon, F-69622, Lyon (France); Universite de Lyon 1, Villeurbanne (France); CNRS/IN2P3, Institut de Physique Nucleaire de Lyon (France); and others

    2013-06-20T23:59:59.000Z

    We examine the relationship between Type Ia supernova (SN Ia) Hubble residuals and the properties of their host galaxies using a sample of 115 SNe Ia from the Nearby Supernova Factory. We use host galaxy stellar masses and specific star formation rates fitted from photometry for all hosts, as well as gas-phase metallicities for a subset of 69 star-forming (non-active galactic nucleus) hosts, to show that the SN Ia Hubble residuals correlate with each of these host properties. With these data we find new evidence for a correlation between SN Ia intrinsic color and host metallicity. When we combine our data with those of other published SN Ia surveys, we find the difference between mean SN Ia brightnesses in low- and high-mass hosts is 0.077 {+-} 0.014 mag. When viewed in narrow (0.2 dex) bins of host stellar mass, the data reveal apparent plateaus of Hubble residuals at high and low host masses with a rapid transition over a short mass range (9.8 {<=} log (M{sub *}/M{sub Sun }) {<=} 10.4). Although metallicity has been a favored interpretation for the origin of the Hubble residual trend with host mass, we illustrate how dust in star-forming galaxies and mean SN Ia progenitor age both evolve along the galaxy mass sequence, thereby presenting equally viable explanations for some or all of the observed SN Ia host bias.

  11. HOST GALAXIES OF TYPE Ia SUPERNOVAE FROM THE NEARBY SUPERNOVA FACTORY

    SciTech Connect (OSTI)

    Childress, M.; Aldering, G.; Aragon, C.; Bailey, S.; Fakhouri, H. K.; Hsiao, E. Y.; Kim, A. G.; Loken, S. [Physics Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, 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 Paris 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); Buton, C.; Kerschhaggl, M.; Kowalski, M. [Physikalisches Institut, Universitaet Bonn, Nussallee 12, D-53115 Bonn (Germany); Chotard, N.; Copin, Y.; Gangler, E. [Universite de Lyon, F-69622, Lyon (France); Universite de Lyon 1, Villeurbanne (France); CNRS/IN2P3, Institut de Physique Nucleaire de Lyon (France); and others

    2013-06-20T23:59:59.000Z

    We present photometric and spectroscopic observations of galaxies hosting Type Ia supernovae (SNe Ia) observed by the Nearby Supernova Factory. Combining Galaxy Evolution Explorer (GALEX) UV data with optical and near-infrared photometry, we employ stellar population synthesis techniques to measure SN Ia host galaxy stellar masses, star formation rates (SFRs), and reddening due to dust. We reinforce the key role of GALEX UV data in deriving accurate estimates of galaxy SFRs and dust extinction. Optical spectra of SN Ia host galaxies are fitted simultaneously for their stellar continua and emission lines fluxes, from which we derive high-precision redshifts, gas-phase metallicities, and H{alpha}-based SFRs. With these data we show that SN Ia host galaxies present tight agreement with the fiducial galaxy mass-metallicity relation from Sloan Digital Sky Survey (SDSS) for stellar masses log(M{sub *}/M{sub Sun }) > 8.5 where the relation is well defined. The star formation activity of SN Ia host galaxies is consistent with a sample of comparable SDSS field galaxies, though this comparison is limited by systematic uncertainties in SFR measurements. Our analysis indicates that SN Ia host galaxies are, on average, typical representatives of normal field galaxies.

  12. 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)

    2014-01-01T23:59:59.000Z

    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.

  13. Search for Supernova Neutrino Bursts at Super-Kamiokande

    E-Print Network [OSTI]

    Super-Kamiokande Collaboration; :; M. Ikeda; A. Takeda; Y. Fukuda; M. R. Vagins

    2007-06-15T23:59:59.000Z

    The result of a search for neutrino bursts from supernova explosions using the Super-Kamiokande detector is reported. Super-Kamiokande is sensitive to core-collapse supernova explosions via observation of their neutrino emissions. The expected number of events comprising such a burst is ~10^4 and the average energy of the neutrinos is in few tens of MeV range in the case of a core-collapse supernova explosion at the typical distance in our galaxy (10 kiloparsecs); this large signal means that the detection efficiency anywhere within our galaxy and well past the Magellanic Clouds is 100%. We examined a data set which was taken from May, 1996 to July, 2001 and from December, 2002 to October, 2005 corresponding to 2589.2 live days. However, there is no evidence of such a supernova explosion during the data-taking period. The 90% C.L. upper limit on the rate of core-collapse supernova explosions out to distances of 100 kiloparsecs is found to be 0.32 SN/year.

  14. 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

    2004-05-11T23:59:59.000Z

    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.

  15. Quantum Coherence Arguments for Cosmological Scale

    SciTech Connect (OSTI)

    Lindesay, James; /SLAC

    2005-05-27T23:59:59.000Z

    Homogeneity and correlations in the observed CMB are indicative of some form of cosmological coherence in early times. Quantum coherence in the early universe would be expected to give space-like phase coherence to any effects sourced to those times. If dark energy de-coherence is assumed to occur when the rate of expansion of the relevant cosmological scale parameter in the Friedmann-Lemaitre equations is no longer supra-luminal, a critical energy density is immediately defined. It is shown that the general class of dynamical models so defined necessarily requires a spatially flat cosmology in order to be consistent with observed structure formation. The basic assumption is that the dark energy density which is fixed during de-coherence is to be identified with the cosmological constant. It is shown for the entire class of models that the expected amplitude of fluctuations driven by the dark energy de-coherence process is of the order needed to evolve into the fluctuations observed in cosmic microwave background radiation and galactic clustering. The densities involved during de-coherence which correspond to the measured dark energy density turn out to be of the electroweak symmetry restoration scale. In an inflationary cosmology, this choice of the scale parameter in the FL equations directly relates the scale of dark energy decoherence to the De Sitter scales (associated with the positive cosmological constants) at both early and late times.

  16. Varying speed of light cosmology from a stringy short distance cutoff

    E-Print Network [OSTI]

    J. C. Niemeyer

    2001-11-26T23:59:59.000Z

    It is shown that varying speed of light cosmology follows from a string-inspired minimal length uncertainty relation. Due to the reduction of the available phase space volume per quantum mode at short wavelengths, the equation of state of ultrarelativistic particles stiffens at very high densities. This causes a stronger than usual deceleration of the scale factor which competes with a higher than usual propagation speed of the particles. Various measures for the effective propagation speed are analyzed: the group and phase velocity in the high energy tail, the thermal average of the group and phase velocity, and the speed of sound. Of these three groups, only the first provides a possible solution to the cosmological horizon problem.

  17. Varying speed of light cosmology from a stringy short distance cutoff

    E-Print Network [OSTI]

    Niemeyer, J C

    2002-01-01T23:59:59.000Z

    It is shown that varying speed of light cosmology follows from a string-inspired minimal length uncertainty relation. Due to the reduction of the available phase space volume per quantum mode at short wavelengths, the equation of state of ultrarelativistic particles stiffens at very high densities. This causes a stronger than usual deceleration of the scale factor which competes with a higher than usual propagation speed of the particles. Various measures for the effective propagation speed are analyzed: the group and phase velocity in the high energy tail, the thermal average of the group and phase velocity, and the speed of sound. Of these three groups, only the first provides a possible solution to the cosmological horizon problem.

  18. Understanding Supernova Neutrino Physics using Low-Energy Beta-Beams

    E-Print Network [OSTI]

    N. Jachowicz; G. C. McLaughlin

    2005-11-24T23:59:59.000Z

    We show that fitting linear combinations of low-energy beta-beam spectra to supernova-neutrino energy-distributions reconstructs the response of a nuclear target to a supernova flux in a very accurate way. This allows one to make direct predictions about the supernova-neutrino signal in a terrestrial neutrino detector.

  19. Neutrino Oscillation Effects on Supernova Light Element Synthesis

    E-Print Network [OSTI]

    T. Yoshida; T. Kajino; H. Yokomakura; K. Kimura; A. Takamura; D. H. Hartmann

    2006-06-02T23:59:59.000Z

    Neutrino oscillations affect light element synthesis through the neutrino-process in supernova explosions. The 7Li and 11B yields produced in a supernova explosion of a 16.2 solar-mass star model increase by factors of 1.9 and 1.3 in the case of large mixing angle solution with normal mass hierarchy and sin^{2}2theta_{13} > 0.002 compared with those without the oscillations. In the case of inverted mass hierarchy or nonadiabatic 13-mixing resonance, the increment of their yields is much smaller. Neutrino oscillations raise the reaction rates of charged-current neutrino-process reactions in the region outside oxygen-rich layers. The number ratio of 7Li/11B could be a tracer of normal mass hierarchy and relatively large theta_{13}, still satisfying sin^{2}2theta_{13} < 0.1, through future precise observations in stars having strong supernova component.

  20. Sterile neutrino oscillations in core-collapse supernova simulations

    E-Print Network [OSTI]

    Warren, MacKenzie L; Mathews, Grant; Hidaka, Jun; Kajino, Toshitaka

    2014-01-01T23:59:59.000Z

    We have made core-collapse supernova simulations that allow oscillations between electron neutrinos (or their anti particles) with right-handed sterile neutrinos. We have considered a range of mixing angles and sterile neutrino masses including those consistent with sterile neutrinos as a dark matter candidate. We examine whether such oscillations can impact the core bounce and shock reheating in supernovae. We identify the optimum ranges of mixing angles and masses that can dramatically enhance the supernova explosion by efficiently transporting electron anti-neutrinos from the core to behind the shock where they provide additional heating leading to much larger explosion kinetic energies. We show that an interesting oscillation in the neutrino luminosity develops due to a cycle of depletion of the neutrino density by conversion to sterile neutrinos that shuts off the conversion, followed by a replenished neutrino density as neutrinos transport through the core.