The cosmic rate of Pair-Instability Supernovae

TL;DR

This paper models the cosmic rate of Pair-Instability Supernovae (PISNe) across time, highlighting the significant uncertainties and the influence of galaxy metallicity, and compares it with core-collapse supernovae to identify favorable host environments.

Contribution

It provides a new model for PISN rates over cosmic history using updated stellar evolution and galaxy evolution data, emphasizing the dominant uncertainties and metallicity dependence.

Findings

PISN rate varies by seven orders of magnitude depending on model assumptions.

Main PISN contribution comes from metallicities of 10^{-3} to 10^{-2}.

Comparison with core-collapse supernova rate highlights different host galaxy properties.

Abstract

Pair-instability supernovae (PISNe) have crucial implications for many astrophysical topics, including the search for very massive stars, the black hole mass spectrum, and galaxy chemical enrichment. To this end, we need to understand where PISNe are across cosmic time, and what are their favourable galactic environments. We present a new determination of the PISN rate as a function of redshift, obtained by combining up-to-date stellar evolution tracks from the PARSEC and FRANEC codes, with an up-to-date semi-empirical determination of the star formation rate and metallicity evolution of star-forming galaxies throughout cosmic history. We find the PISN rate to exhibit a huge dependence on the model assumptions, including the criterion to identify stars unstable to pair production, and the upper limit of the stellar initial mass function. Remarkably, the interplay between the maximum metallicity at which stars explode as PISNe, and the dispersion of the galaxy metallicity distribution, dominates the uncertainties, causing a $\sim$ seven-orders-of-magnitude PISN rate range. Furthermore, we show a comparison with the core-collapse supernova rate, and study the properties of the favourable PISN host galaxies. According to our results, the main contribution to the PISN rate comes from metallicities between $\sim 10^{-3}$ and $10^{-2}$, against the common assumption that views very-low-metallicity, Population III stars as exclusive or dominant PISN progenitors. The strong dependencies we find offer the opportunity to constrain stellar and galaxy evolution models based on possible future (or the lack of) PISN observations.