The very first Pop III stars and their relation to bright z~6 quasars

TL;DR

This paper explores the connection between the earliest Pop III stars and bright quasars at redshift 6, showing that early star remnants can grow into supermassive black holes consistent with observations, despite diverse environments.

Contribution

It introduces a feedback model linking Pop III star remnants to supermassive black holes at z~6, aligning theoretical growth with observed quasar luminosity functions.

Findings

Pop III star remnants are found in diverse environments, not just massive halos.

Seed black holes can grow to over 10^{9.5} solar masses by z=6 with Eddington accretion.

A simple feedback model reproduces the observed quasar luminosity function at z~6.

Abstract

We discuss the link between dark matter halos hosting the first PopIII stars formed at redshift z > 40 and the rare, massive, halos that are generally considered to host bright z~6 quasars. We show that within the typical volume occupied by one bright high-z QSO the remnants of the first several thousands PopIII stars formed do not end up in the most massive halos at z~6, but rather live in a large variety of environments. The black hole seeds planted by these very first PopIII stars can easily grow to M > 10^{9.5} Msun by z=6 assuming Eddington accretion with radiative efficiency epsilon~0.1. Therefore quenching of the accretion is crucial to avoid an overabundance of supermassive black holes. We implement a simple feedback model for the growth of the seeds planted by PopIII stars and obtain a z~6 BH mass function consistent with the observed QSO luminosity function.