Influence of Fermionic Dark Matter on the Structural and Tidal Properties of Neutron Stars

TL;DR

This study examines how fermionic dark matter influences neutron star properties, revealing that dark matter distribution depends on particle mass and fraction, and constraining these parameters using recent astrophysical observations.

Contribution

It provides a systematic analysis of fermionic dark matter effects on neutron stars, integrating multiple observational constraints to limit dark matter parameters within these stars.

Findings

Dark matter can form dense cores or extended halos in neutron stars.

Constraints exclude large dark matter fractions for certain particle masses.

Dark matter presence must be limited to satisfy observational data.

Abstract

We investigate the influence of ideal Fermi gas dark matter on the observable properties of neutron stars (NSs). Our analysis considers dark matter (DM) particle masses ($\mu$) ranging from $0.2$ GeV to $1$ GeV and various DM mass fractions ($f$). By examining the coexistence of DM and baryonic matter (BM), we explore the formation of either a dense DM core or an extended dark halo within NSs. Our findings indicate that the resulting DM distribution depends critically on both $\mu$ and $f$. We systematically explore the parameter space of the fermionic DM model using two representative BM equations of state (EoSs) by applying constraints from NS radius measurements by the Neutron Star Interior Composition Explorer (NICER), observations of $2M_{\odot}$ NSs, and tidal deformability limits from the LIGO/Virgo Collaboration. This comprehensive analysis enables us to exclude specific ranges of $\mu$ and $f$, demonstrating that the amount of accumulated DM must be relatively small to satisfy current astrophysical constraints.