How the Population III Initial Mass Function Governs the Properties of the First Galaxies

TL;DR

This paper explores how the initial mass function of Population III stars influences the formation and observable properties of the first galaxies, using high-resolution simulations to predict potential signatures for future telescopic observations.

Contribution

It demonstrates the impact of different Pop III IMFs on early galaxy brightness and star formation, linking stellar initial mass distribution to observable galaxy features.

Findings

Top-heavy Pop III IMF leads to earlier but dimmer galaxies.

Massive Pop III stars produce turbulence that suppresses subsequent star formation.

Pop III IMF could be inferred from future observations of primordial galaxies.

Abstract

The properties of Population III (Pop III) stars impact many aspects of primeval structure formation such as the onset of cosmological reionization and early chemical enrichment. However, in spite of over twenty years of numerical simulations and attempts to constrain the Pop III initial mass function (IMF) by stellar archaelogy, little is known of the masses of the first stars for certain. Here, we model the effect of Pop III IMF on the properties of primeval galaxies with a suite of high-resolution radiation-hydrodynamical simulations with ENZO. We find that a top-heavy Pop III IMF results in earlier star formation but dimmer galaxies than a more conventional Salpeter-type IMF because explosions of massive Pop III stars produce more turbulence that suppresses high-mass second-generation star formation. Our models suggest that the Pop III IMF could therefore be inferred from detections of primordial galaxies, which will be principal targets of the James Webb Space Telescope and extremely large telecopes on the ground in the coming decade.