Revisiting The First Galaxies: The epoch of Population III stars

TL;DR

This study uses advanced simulations to explore how the earliest stars influenced galaxy evolution, revealing that Population III stars could persist longer than previously thought and that their transition to Population II stars is rapid within galaxies.

Contribution

It provides new insights into the duration and impact of Population III star formation and the transition to Population II stars in the early universe through cosmological hydrodynamic simulations.

Findings

Pop III stars seed galaxies with metals but can't sustain large outflows.

Pop III star formation may continue until z~6 in unenriched regions.

Within galaxies, Pop II stars dominate metal production after 20-200 Myr.

Abstract

We investigate the transition from primordial Population III (Pop III) star formation to normal Pop II star formation in the first galaxies using new cosmological hydrodynamic simulations. We find that while the first stars seed their host galaxies with metals, they cannot sustain significant outflows to enrich the intergalactic medium, even assuming a top-heavy initial mass function. This means that Pop III star formation could potentially continue until z~6 in different unenriched regions of the universe, before being ultimately shut off by cosmic reionization. Within an individual galaxy, the metal production and stellar feedback from Pop II stars overtake Pop III stars in 20-200 Myr, depending on galaxy mass.