Constraining dark matter self-interaction from kinetic heating in neutron stars

TL;DR

This paper explores how dark matter self-interactions affect neutron star temperatures and discusses the potential for future telescopic observations to constrain or detect such interactions.

Contribution

It introduces the role of dark matter self-interactions in neutron star heating and proposes observational strategies to improve constraints on dark matter properties.

Findings

Dark matter self-interactions can significantly influence neutron star temperatures.

Future telescopes could detect temperature signatures indicative of dark matter self-interactions.

Observations could tighten constraints on dark matter self-interaction cross-sections by two orders of magnitude.

Abstract

Dark matter search strategies have started advancing towards the neutrino fog. In this regard, compact objects such as neutron stars have already demonstrated their ability in probing such low DM-nucleon cross-sections from dark matter induced effects. In the optically thin limit, effect of dark matter self-interaction becomes relevant and may assist the capture and thermalization of dark matter inside stars, imparting observable changes on neutron star temperatures. The resulting radiation although weak can be potentially detected by the James Webb Space Telescope and upcoming Thirty Meter Telescope and the European Extremely Large Telescope. Observation of cold neutron stars accompanied by advancements in direct detection probes would provide stringent constraints or a smoking-gun signature for dark matter self-interactions. The potential detection of a neutron star with surface temperatures $\sim (1000 - 1200)$ K in the optically thin limit can push the bounds on asymmetric dark matter self-interaction cross-section to approximately two orders of magnitude more stringent than the bullet cluster.