학술논문
Measurements of Ω and Λ from 42 High-Redshift Supernovae
Document Type
article
Author
Perlmutter, S; Aldering, G; Goldhaber, G; Knop, RA; Nugent, P; Castro, PG; Deustua, S; Fabbro, S; Goobar, A; Groom, DE; Hook, IM; Kim, AG; Kim, MY; Lee, JC; Nunes, NJ; Pain, R; Pennypacker, CR; Quimby, R; Lidman, C; Ellis, RS; Irwin, M; McMahon, RG; Ruiz-Lapuente, P; Walton, N; Schaefer, B; Boyle, BJ; Filippenko, AV; Matheson, T; Fruchter, AS; Panagia, N; Newberg, HJM; Couch, WJ; Project, The Supernova Cosmology
Source
The Astrophysical Journal. 517(2)
Subject
Language
Abstract
We report measurements of the mass density, Omega_M, andcosmological-constant energy density, Omega_Lambda, of the universe based onthe analysis of 42 Type Ia supernovae discovered by the Supernova CosmologyProject. The magnitude-redshift data for these SNe, at redshifts between 0.18and 0.83, are fit jointly with a set of SNe from the Calan/Tololo SupernovaSurvey, at redshifts below 0.1, to yield values for the cosmologicalparameters. All SN peak magnitudes are standardized using a SN Ia lightcurvewidth-luminosity relation. The measurement yields a joint probabilitydistribution of the cosmological parameters that is approximated by therelation 0.8 Omega_M - 0.6 Omega_Lambda ~= -0.2 +/- 0.1 in the region ofinterest (Omega_M 0) = 99%, including the identified systematic uncertainties. The best-fit ageof the universe relative to the Hubble time is t_0 = 14.9{+1.4,-1.1} (0.63/h)Gyr for a flat cosmology. The size of our sample allows us to perform a varietyof statistical tests to check for possible systematic errors and biases. Wefind no significant differences in either the host reddening distribution orMalmquist bias between the low-redshift Calan/Tololo sample and ourhigh-redshift sample. The conclusions are robust whether or not awidth-luminosity relation is used to standardize the SN peak magnitudes.