Low Mass Black Holes from Dark Core Collapse

TL;DR

This paper proposes a novel formation channel for low mass black holes via dark matter accretion and core collapse, explaining black holes below the stellar evolution limit and suggesting observational tests through merger rate redshift dependence.

Contribution

It introduces a new mechanism for low mass black hole formation involving dark matter-induced core collapse, expanding understanding beyond stellar evolution models.

Findings

Dark matter accretion can induce stellar core collapse into black holes.

Redshift dependence of merger rates can test the dark matter transmutation hypothesis.

Proposes observational strategies to distinguish this formation channel.

Abstract

Unusual masses of black holes being discovered by gravitational wave experiments pose fundamental questions about the origin of these black holes. Black holes with masses smaller than the Chandrasekhar limit $\approx1.4\,M_\odot$ are essentially impossible to produce through stellar evolution. We propose a new channel for production of low mass black holes: stellar objects catastrophically accrete non-annihilating dark matter, and the small dark core subsequently collapses, eating up the host star and transmuting it into a black hole. The wide range of allowed dark matter masses allows a smaller effective Chandrasekhar limit, and thus smaller mass black holes. We point out several avenues to test our proposal, focusing on the redshift dependence of the merger rate. We show that redshift dependence of the merger rate can be used as a probe of the transmuted origin of low mass black holes.