Estimation of Host Galaxy Extinction for SNe Ia

Type Ia supernovae are used as fundamental probes of the cosmological parameters, based on a tight empirical relation between their peak luminosity and the width of their light curve. However, it has been recognized that SNe Ia are not “standard” candles, since important variations in their peak luminosities are observed, as a function of the metallicity, age, environment, and morphological type of the supernova hosts. The largest correction in the standardization scheme is related to extinction. While extinction in the Milky Way (MW) Galaxy is usually known and extinction between galaxies can be assumed to be zero, the value of extinction in the SN Ia host galaxy (Ahost) is determined with much more uncertainty. In this paper, we provide an estimate of the Ahost value based on statistical modeling. To do this, we generate, based on MaNGA data, a set of galaxies in the vicinity of the MW, and distribute the parameters of the galaxies and the positions of SNe Ia in them. As a result, using a simplified model for the distribution of interstellar matter, which is the same for all the sampled galaxies, we can estimate the probability that Ahost exceeds a certain value. Our estimates show, in particular, that in almost all cases, Ahost > 0.10 mag V, and in 25% of cases, Ahost > 0.25 mag V.