1995/10/31 by David Branch, W. Romanishin, E. Baron · 4 citations
Mathematics · Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics #Biology #Galaxy #Gamma-ray bursts and supernovae #Mathematics #Physics #Statistical and numerical algorithms #Statistics #Supernova #Type (biology) #Value (mathematics) #astro-ph
paper · pdf · doi:10.1086/177402
LaTeX file, AASTeX4 style, 2 Tables and 4 Figures included separately. Postscript file available from http://www.nhn.uoknor.edu/~baron/
arxiv created 1995/11/20 · openalex publication_date 1996/07/01 · arxiv updated 2016/08/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Statistical connections between the properties of Type Ia supernovae (SNe Ia) and the B - V colors of their parent galaxies are established. Compared to SNe 1a in blue galaxies [(B - V)0^T_ <~ 0.75], SNe Ia in redder galaxies have (1) a wider dispersion in the blueshifts of their Si II λ6355 absorption features, 10 days after maximum light; (2) more rapidly declining light curves; and (3) lower luminosities. Even when the spectroscopically peculiar, very subluminous SNe Ia such as SN 1991bg are disregarded, SNe Ia in red galaxies are less luminous than those in blue galaxies by about 0.3 mag. When SNe Ia that are thought to have been significantly extinguished by dust in their parent galaxies are disregarded, those in blue galaxies have observational absolute-magnitude dispersions of only σobs_(MB_) = 0.20 and σobs_(MV_) = 0.17, which implies that their intrinsic absolute-magnitude dispersions are very small. We use six SNe Ia whose absolute magnitudes have been calibrated by means of Cepheids, which also indicate that the intrinsic absolute-magnitude dispersions of SNe Ia in blue galaxies are very small, to calibrate SNe Ia in blue galaxies and obtain H0_ = 57 +/- 4 km s-1^ Mpc-1^. This value is in excellent agreement with that obtained by Saha and coworkers, in spite of the fact that they do not take into account any dependence of SN Ia absolute magnitude on the nature of the parent galaxy. Some implications of the statistical connections between SNe Ia and the colors of their parent galaxies, for identifying the progenitor binary systems of SNe Ia and for using high-redshift SNe Ia to measure q0_ are briefly discussed.