The Progenitors of Type Ia Supernovae

TL;DR

This paper investigates the origins of Type Ia supernovae, analyzing their rates relative to star formation and stellar death, and discusses the implications for progenitor models and delay time distributions.

Contribution

It provides a detailed analysis of SN Ia rates, their relation to star formation, and challenges the single degenerate progenitor scenario based on efficiency constraints.

Findings

SN Ia rate is about 1% of stellar death rate, regardless of star formation history.

SN Ia delay time distribution follows approximately t^{-0.5}.

Single degenerate model requires uniform efficiency, which is unlikely, suggesting alternative progenitors.

Abstract

Type Ia supernovae (SNe Ia) occur in both old, passive galaxies and active, star-forming galaxies. This fact, coupled with the strong dependence of SN Ia rate on star formation rate, suggests that SNe Ia form from stars with a wide range of ages. Here we show that the rate of SN Ia explosions is about 1% of the stellar death rate, independent of star formation history. The dependence of SN Ia rate on star formation rate implies a delay time distribution proportional to t^{-0.5+-0.2}. The single degenerate channel for SNe Ia can be made to match the observed SN Ia rate -- SFR relation, but only if white dwarfs are converted to SNe Ia with uniform efficiency of ~1%, independent of mass. Since low-mass progenitors are expected to have lower conversion efficiencies than high mass progenitors, we conclude that some other progenitor scenario must be invoked to explain some, or perhaps all, SNe Ia.