Non-Primordial Solar Mass Black Holes

TL;DR

This paper introduces a mechanism where asymmetric fermionic dark matter can accumulate in neutron stars, leading to their collapse into solar-mass black holes, providing a potential test for dark matter properties via gravitational wave observations.

Contribution

It proposes a novel dark matter-induced neutron star collapse mechanism resulting in low-mass black holes, which is a new pathway not covered by standard stellar evolution.

Findings

Dark matter can induce neutron star collapse into black holes of about 1 solar mass.

Such black holes could be detected through gravitational wave binary merger observations.

The model's predictions are consistent with current neutron star observations.

Abstract

We propose a mechanism that can convert a sizeable fraction of neutron stars into black holes with mass $\sim 1M_\odot$, too light to be produced via standard stellar evolution. We show that asymmetric fermionic dark matter of mass $\sim$ TeV, with attractive self-interaction within the range that alleviates the problems of collisionless cold dark matter, can accumulate in a neutron star and collapse, forming a seed black hole that converts the rest of the star to a solar mass black hole. We estimate the fraction of neutron stars that can become black holes without contradicting existing neutron star observations. Like neutron stars, such solar mass black holes could be in binary systems, which may be searched for by existing and forthcoming gravitational wave detectors. The (non-)observation of binary mergers of solar mass black holes may thus test the specific nature of the dark matter.