Can local White Dwarfs constrain Dark Matter interactions?

TL;DR

This study explores how nearby white dwarfs can be used to constrain dark matter interactions, especially for high-mass DM particles, by analyzing their properties and gamma-ray data, complementing terrestrial detection methods.

Contribution

It models white dwarf interiors and uses astrophysical observations to estimate dark matter capture and evaporation, highlighting the potential of future gamma-ray telescopes to probe DM interactions.

Findings

Future gamma-ray telescopes can probe DM-nucleon cross sections down to 10^{-41} cm^2.

White dwarf observations can provide competitive constraints on multi-TeV dark matter.

No significant gamma-ray excess detected in current Fermi-LAT data.

Abstract

We investigate whether nearby white dwarfs (WDs) can constrain dark matter (DM) interactions with ordinary matter. As experimental sensitivity improves, driven by the Gaia mission, the sample volume of nearby WDs has been increasing over recent years. We carefully select a sample of ten cold, isolated, non-magnetic WDs within 13~pc of the Sun. We model their carbon-oxygen interior using a finite temperature relativistic equation of state and model atmospheres to infer their core temperatures. This enables us to perform a thorough estimation of the DM capture rate and evaporation mass using actual astrophysical observations. Given the low local DM density, we focus on DM that annihilates into long-lived mediators, which escape the WD and later decay into photons. While \textit{Fermi}-LAT data shows no significant gamma-ray excess, future telescopes, CTA North \& South, LHAASO, SWGO, could probe DM-nucleon cross sections down to $\sim 10^{-41}~\text{cm}^2$ for DM masses above the TeV scale. Our results are competitive with current direct detection bounds (e.g., LZ) in the multi-TeV regime. This work underscores the importance of systematic WD studies in the broader landscape of DM detection and demonstrates the synergy between astrophysical and terrestrial searches in exploring DM interactions.