A new probe of dark matter-baryon interactions in compact stellar systems

TL;DR

This paper explores how long-range dark matter-baryon interactions affect stellar systems, deriving new constraints on interaction strength using star clusters, which surpass previous limits and are applicable to various systems.

Contribution

It introduces a novel astrophysical method to constrain dark matter-baryon interactions using compact stellar systems, independent of dark matter mass.

Findings

Derived a new upper bound on interaction strength, 

Constraint is independent of dark matter mass and stellar system properties

Applicable to multiple stellar systems, including ultrafaint dwarf galaxies

Abstract

We investigate the astrophysical consequences of an attractive long-range interaction between dark matter and baryonic matter. Our study highlights the role of this interaction in inducing dynamical friction between dark matter and stars, which can significantly influence the evolution of compact stellar systems. Using the star cluster in Eridanus II as a case study, we derive a new stringent upper bound on the interaction strength $\tilde{\alpha}\leq 314.5$ for the interaction range $\lambda = 1$ pc. This constraint is independent of the dark matter mass and can improve the existing model-independent limits on $\tilde{\alpha}$ by a few orders of magnitude. Furthermore, we observe that the constraint is insensitive to the mass of the stellar system and the dark matter density in the stellar system as long as the system is dark matter dominated. This new approach can be applied to many other stellar systems, and we obtain comparable constraints from compact stellar halos observed in ultrafaint dwarf galaxies.