Generation of massive stellar black holes by rapid gas accretion in primordial dense clusters

TL;DR

This paper proposes that massive stellar black holes in the 50-135 solar mass range can form through rapid gas accretion in dense primordial clusters, filling the predicted mass gap.

Contribution

It introduces a new formation channel for massive black holes via gas accretion in early dense clusters, explaining observations of black hole binaries in the mass gap.

Findings

Black holes can grow rapidly in dense clusters during early stages.

Predicted black hole binaries in the mass gap are detectable by LIGO.

The mass gap can be filled by accretion-driven growth in primordial environments.

Abstract

Supernova theory suggests that black holes of a stellar origin cannot attain masses in the range of 50-135 solar masses in isolation. We argue here that this mass gap is filled in by black holes that grow by gas accretion in dense stellar clusters, such as protoglobular clusters. The accretion proceeds rapidly, during the first 10 megayears of the cluster life, before the remnant gas is depleted. We predict that binaries of black holes within the mass gap can be observed by LIGO.