The influence of Host Galaxies in Type Ia Supernova Cosmology

Understand

We use a sample of 1338 spectroscopically confirmed and photometrically classified Type Ia Supernovae (SNe Ia), sourced from the CSP, CfA, SDSS-II, and SNLS supernova samples, to examine the relationships between SNe Ia and the galaxies that host them.

• Our results provide confirmation with improved statistical significance that SNe Ia, after standardization, are on average more luminous in massive hosts (significance $\rm > 5 \sigma$), and decline more rapidly in massive hosts (significance $\rm > 9\sigma$) and in hosts with low specific star formation rates (significance $\rm > 8\sigma$).
• We study the variation of these relationships with redshift and detect no evolution.
• We split SNe Ia into pairs of subsets that are based on the properties of the hosts, and fit cosmological models to each subset.