Rates, Progenitors and Cosmic Mix of Type Ia Supernovae

TL;DR

This paper reviews the distribution of delay times for Type Ia supernovae, critiques empirical models, discusses theoretical models accommodating various progenitors, and explores how the mix of progenitor channels may vary over cosmic time, affecting observations.

Contribution

It critically evaluates empirical delay time distributions, discusses theoretical models for progenitors, and investigates potential cosmic evolution of supernova progenitor channels.

Findings

Empirical delay time distributions are affected by dubious assumptions.

Theoretical models can accommodate both prompt and tardy supernovae.

The mix of progenitor channels may vary with cosmic time, influencing supernova properties.

Abstract

Following an episode of star formation, Type Ia supernova events occur over an extended period of time, following a distribution of delay times (DDT). We critically discuss some empirically-based DDT functions that have been proposed in recent years, some favoring very early (prompt) events, other very late (tardy) ones, and therefore being mutually exclusive. We point out that in both cases the derived DDT functions are affected by dubious assumptions, and therefore there is currently no ground for claiming either a DDT strongly peaked at early times, or at late ones. Theoretical DDT functions are known to accommodate both prompt as well as late SNIa events, and can account for all available observational constraints. Recent observational evidence exists that both single degenerate and double degenerate precursors may be able of producing SNIa events. We then explore on the basis of plausible theoretical models the possible variation with cosmic time of the mix between the events produced by the two different channels, which in principle could lead to systematics effects on the SNIa properties with redshift.