skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Comparison of the legacy and gold type Ia supernovae dataset constraints on dark energy models

Abstract

We have performed a comparative analysis of three recent and reliable SnIa datasets available in the literature: the Full Gold (FG) dataset (157 data points 0<z<1.75), a Truncated Gold (TG) dataset (140 data points 0<z<1) and the most recent Supernova Legacy Survey (SNLS) dataset (115 data points 0<z<1). We have analyzed and compared the likelihood of cosmological constant and dynamical dark energy parametrizations allowing for crossing of the phantom divide line (PDL). We find that, even though the constraints obtained using the three datasets are consistent with each other at the 95% confidence level, the latest (SNLS) dataset shows distinct trends which are not shared by the Gold datasets. We find that the best fit dynamical w(z) obtained from the SNLS dataset does not cross the PDL w=-1 and remains above and close to the w=-1 line for the whole redshift range 0<z<1 showing no evidence for phantom behavior. The {lambda}+Cold Dark Matter (LCDM) parameter values (w{sub 0}=-1, w{sub 1}=0) almost coincide with the best fit parameters of the dynamical w(z) parametrizations. In contrast, the best fit dynamical w(z) obtained from the Gold datasets (FG and TG) clearly crosses the PDL and departs significantly from the PDL w=-1 line whilemore » the LCDM parameter values are about 2{sigma} away from the best fit w(z). In addition, the ({omega}{sub 0m},{omega}{sub {lambda}}) parameters in a LCDM parametrization without a flat prior, fit by the SNLS dataset, favor the minimal flat LCDM concordance model. The corresponding fit with the Gold datasets mildly favors a closed universe and the flat LCDM parameter values are 1{sigma}-2{sigma} away from the best fit ({omega}{sub 0m},{omega}{sub {lambda}})« less

Authors:
;  [1]
  1. Department of Physics, University of Ioannina, Ioannina (Greece)
Publication Date:
OSTI Identifier:
20774517
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. D, Particles Fields; Journal Volume: 72; Journal Issue: 12; Other Information: DOI: 10.1103/PhysRevD.72.123519; (c) 2005 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; COMPARATIVE EVALUATIONS; COSMOLOGICAL CONSTANT; COSMOLOGICAL MODELS; NONLUMINOUS MATTER; SUPERNOVAE; UNIVERSE

Citation Formats

Nesseris, S., and Perivolaropoulos, L. Comparison of the legacy and gold type Ia supernovae dataset constraints on dark energy models. United States: N. p., 2005. Web. doi:10.1103/PhysRevD.72.123519.
Nesseris, S., & Perivolaropoulos, L. Comparison of the legacy and gold type Ia supernovae dataset constraints on dark energy models. United States. doi:10.1103/PhysRevD.72.123519.
Nesseris, S., and Perivolaropoulos, L. Thu . "Comparison of the legacy and gold type Ia supernovae dataset constraints on dark energy models". United States. doi:10.1103/PhysRevD.72.123519.
@article{osti_20774517,
title = {Comparison of the legacy and gold type Ia supernovae dataset constraints on dark energy models},
author = {Nesseris, S. and Perivolaropoulos, L.},
abstractNote = {We have performed a comparative analysis of three recent and reliable SnIa datasets available in the literature: the Full Gold (FG) dataset (157 data points 0<z<1.75), a Truncated Gold (TG) dataset (140 data points 0<z<1) and the most recent Supernova Legacy Survey (SNLS) dataset (115 data points 0<z<1). We have analyzed and compared the likelihood of cosmological constant and dynamical dark energy parametrizations allowing for crossing of the phantom divide line (PDL). We find that, even though the constraints obtained using the three datasets are consistent with each other at the 95% confidence level, the latest (SNLS) dataset shows distinct trends which are not shared by the Gold datasets. We find that the best fit dynamical w(z) obtained from the SNLS dataset does not cross the PDL w=-1 and remains above and close to the w=-1 line for the whole redshift range 0<z<1 showing no evidence for phantom behavior. The {lambda}+Cold Dark Matter (LCDM) parameter values (w{sub 0}=-1, w{sub 1}=0) almost coincide with the best fit parameters of the dynamical w(z) parametrizations. In contrast, the best fit dynamical w(z) obtained from the Gold datasets (FG and TG) clearly crosses the PDL and departs significantly from the PDL w=-1 line while the LCDM parameter values are about 2{sigma} away from the best fit w(z). In addition, the ({omega}{sub 0m},{omega}{sub {lambda}}) parameters in a LCDM parametrization without a flat prior, fit by the SNLS dataset, favor the minimal flat LCDM concordance model. The corresponding fit with the Gold datasets mildly favors a closed universe and the flat LCDM parameter values are 1{sigma}-2{sigma} away from the best fit ({omega}{sub 0m},{omega}{sub {lambda}})},
doi = {10.1103/PhysRevD.72.123519},
journal = {Physical Review. D, Particles Fields},
number = 12,
volume = 72,
place = {United States},
year = {Thu Dec 15 00:00:00 EST 2005},
month = {Thu Dec 15 00:00:00 EST 2005}
}
  • Recently, many efforts have been made to build dark energy models whose equation-of-state parameter can cross the so-called phantom divide w{sub de}=-1. One of them is the so-called hessence dark energy model in which the role of dark energy is played by a noncanonical complex scalar field. In this work, we develop a simple method based on Hubble parameter H(z) to reconstruct the hessence dark energy. As examples, we use two familiar parametrizations for H(z) and fit them to the latest 182 type Ia supernovae Gold dataset. In the reconstruction, measurement errors are fully considered.
  • Models in which the dark matter of galaxy halos is in the form of white dwarfs (WDs) are examined. Major constraints, which have been previously neglected, result from the occurrence of Type Ia supernovae, which are the products of merging WDs in binary systems whose orbits decay due to the emission of gravitational wave radiation. The lack of observed supernovae in the outer regions of galaxies, together with the relatively low abundance of iron in the hot, X-ray gas of galactic halos, limit the fraction of binaries to far less than 1 percent in extant models of WD-dominated halos, formore » standard Type Ia parameters. This binary fraction is much smaller than that believed typical for luminous stars, necessitating a further peculiarity in the star-formation process during the formation of the dark halo. 44 refs.« less
  • Measurements of the distances to type Ia supernovae have produced strong evidence that the expansion of the Universe is accelerating, implying the existence of a nearly uniform component of dark energy with negative pressure. We show that constraints to this mysterious component based upon large-scale structure nicely complement the SN Ia data, and that together they require {Omega}{sub X}={rho}{sub X}/{rho}{sub crit}{element_of}(0.6,thinsp0.7) and w=p{sub X}/{rho}{sub X}{lt}{minus}0.6 (95{percent} C.L.), for the favored flat Universe. Other cosmological data support this conclusion. The simplest explanation, a cosmological constant, is consistent with this, while some of the other possibilities are not. {copyright} {ital 1999} {italmore » The American Physical Society }« less
  • It is now a known fact that if we happen to be living in the middle of a large underdense region, then we will observe an ''apparent acceleration'', even when any form of dark energy is absent. In this paper, we present a ''Minimal Void'' scenario, i.e. a ''void'' with minimal underdensity contrast (of about -0.4) and radius (∼ 200−250 Mpc/h) that can, not only explain the supernovae data, but also be consistent with the 3-yr WMAP data. We also discuss consistency of our model with various other measurements, and in particular consistency with local measurements of the Hubble parameter.more » We also point out possible observable signatures.« less
  • The rate evolution of subluminous Type Ia supernovae (SNe Ia) is presented using data from the Supernova Legacy Survey. This sub-sample represents the faint and rapidly declining light curves of the observed SN Ia population here defined by low-stretch values (s {<=} 0.8). Up to redshift z = 0.6, we find 18 photometrically identified subluminous SNe Ia, of which six have spectroscopic redshift (and three are spectroscopically confirmed SNe Ia). The evolution of the subluminous volumetric rate is constant or slightly decreasing with redshift, in contrast to the increasing SN Ia rate found for the normal stretch population, although amore » rising behavior is not conclusively ruled out. The subluminous sample is mainly found in early-type galaxies with little or no star formation, so that the rate evolution is consistent with a galactic mass-dependent behavior: r(z) = A x M{sub g} , with A = (1.1 {+-} 0.3) x 10{sup -14} SNe yr{sup -1} M{sup -1}{sub sun}.« less