Supernova rates and stellar populations

TL;DR

This paper reviews how supernova rates in different stellar populations inform us about their progenitors, revealing that type Ia supernovae originate from both young and old stars, with rates influenced by galaxy properties.

Contribution

It provides a comprehensive analysis of supernova rates across various galaxy types, highlighting the bimodal delay time distribution for type Ia supernovae progenitors.

Findings

Type Ia supernovae come from both young and old stellar populations.

Supernova rates vary with galaxy color, morphology, and environment.

A bimodal delay time distribution explains the observed rate variations.

Abstract

We discuss the results about the nature of type Ia Supernovae that can be derived by studying their rates in different stellar populations. While the evolution of SN photometry and spectra can constrain the explosion mechanism, the SN rate depends on the progenitor system. We review the current available data on rates as a function of parent galaxy color, morphology, star formation rate, radio luminosity and environment. By studying the variation of the rates with the color of the parent galaxy, a strong evidence was established that type Ia SNe come from both young and old stars. The dependence of the rates with the radio power of the parent galaxy is best reproduced by a bimodal distribution of delay time between the formation of the progenitor and its explosion as a SN. Cluster early-type galaxies show higher type Ia SN rate with respect to field galaxies, and this effect can be due either to traces of young stars or to differences in the delay time distribution.