Did supermassive black holes form by direct collapse?

TL;DR

This paper explores the direct collapse mechanism for forming supermassive black holes, emphasizing rapid gas infall in galactic nuclei leading to massive seed black holes without prior star formation.

Contribution

It provides a physics-based overview of the direct collapse process and characterizes the properties of accreting envelopes that enable rapid black hole growth.

Findings

Black holes can form via direct collapse without star formation.

Seed black holes can reach masses of 10^3-10^4 solar masses rapidly.

Accreting envelopes facilitate super-Eddington growth rates.

Abstract

Rapid infall of gas in the nuclei of galaxies could lead to the formation of black holes by direct collapse, without first forming stars. Black holes formed in this way would have initial masses of a few solar masses, but would be embedded in massive envelopes that would allow them to grow at a highly super-Eddington rate. Thus, seed black holes as large as 10^3-10^4 solar masses could form very rapidly. I will sketch the basic physics of the direct collapse process and the properties of the accreting envelopes.