High Mass Black Holes in Soft X-Ray Transients: Gap in Black Hole Masses ?

TL;DR

This paper proposes a new evolutionary scenario for forming high-mass black holes in binaries, explaining the observed gap in black hole mass distribution through specific stellar evolution processes.

Contribution

It introduces a novel formation pathway involving common envelope evolution after helium core burning, accounting for the black hole mass gap.

Findings

High-mass black holes can form in low-mass binary systems.

The proposed scenario explains the observed mass gap in black hole populations.

Abstract

We suggest that high-mass black holes; i.e., black holes of several solar masses, can be formed in binaries with low-mass main-sequence companions, provided that the hydrogen envelope of the massive star is removed in common envelope evolution which begins only after the massive star has finished He core burning. Our evolution scenario naturally explains the gap (low probability region) in the observed black hole masses.