Neutron Stars as Dark Matter Probes

TL;DR

This paper investigates whether dark matter accumulation and annihilation in neutron stars could produce observable effects or lead to their collapse, providing constraints on dark matter properties.

Contribution

It offers a detailed analysis of dark matter accretion effects on neutron stars and derives bounds on dark matter-nucleon cross sections for various masses.

Findings

Dark matter annihilation heats neutron stars minimally, unlikely to be observable.

Non-annihilating dark matter can cause neutron star collapse in dense regions.

Derived cross section thresholds for neutron star collapse across dark matter masses.

Abstract

We examine whether the accretion of dark matter onto neutron stars could ever have any visible external effects. Captured dark matter which subsequently annihilates will heat the neutron stars, although it seems the effect will be too small to heat close neutron stars at an observable rate whilst those at the galactic centre are obscured by dust. Non-annihilating dark matter would accumulate at the centre of the neutron star. In a very dense region of dark matter such as that which may be found at the centre of the galaxy, a neutron star might accrete enough to cause it to collapse within a period of time less than the age of the Universe. We calculate what value of the stable dark matter-nucleon cross section would cause this to occur for a large range of masses.