Formation of Pop II star clusters in the aftermath of a pair instability supernova

TL;DR

This study uses cosmological radiation hydrodynamical simulations to explore how Pop II star clusters form after pair instability supernovae, revealing the impact of supernova feedback on early star formation in the universe.

Contribution

It provides the first detailed simulation-based analysis of Pop II star cluster formation post-PISN, including feedback effects and star formation regulation in early dark matter halos.

Findings

PISN evacuates gas from halos ≤ 3×10^6 M⊙, halting star formation for 30 Myr.

Pop II star clusters of 923 M⊙ and 6800 M⊙ form in larger halos.

Star formation is episodic and mainly regulated by supernova feedback.

Abstract

Pop II stars formed a few hundred million years after the Big Bang were key drivers of cosmic reionization and building blocks of high redshift galaxies. How and when these stars formed is a subject of ongoing research. We conduct cosmological radiation hydrodynamical simulations to investigate the formation of Pop II star clusters in dark matter halos forming at $z=10-25$ in the aftermath of a pair instability supernova (PISN). Our simulations model the formation of Pop III and Pop II stars in a self-consistent manner along with their radiative, chemical and SN feedback in halos of $\rm 5 \times 10^5- 7 \times 10^7~M_{\odot}$. We find that a PISN evacuates the gas from halos $\rm \leq 3 \times 10^{6}~M_{\odot}$ and thereafter shuts off in situ star formation for at-least 30 Myr. Pop II stellar clusters of $\rm 923~M_{\odot}$ and $\rm 6800~M_{\odot}$ form in halos of $\rm 3.5 \times 10^7~M_{\odot}$ and $\rm 7.2 \times 10^7~M_{\odot}$, respectively. The mode of star formation is highly episodic and mainly regulated by Pop II SN feedback. The average star formation rates are $\rm 10^{-5}-10^{-4}~M_{\odot}/yr$ and the star formation efficiency is less than 1\%.