$g$-mode oscillations of dark matter admixed neutron stars

TL;DR

This paper studies how dark matter inside neutron stars affects their gravity-driven oscillations, revealing potential observational signatures to detect dark matter presence using $g$-mode frequencies.

Contribution

It introduces a detailed model of dark matter admixed neutron stars and analyzes the impact of dark matter properties on their $g$-mode oscillation spectrum.

Findings

Dark matter fraction significantly influences $g$-mode frequencies.

An equation of state-independent constraint on dark matter fraction is proposed.

Dark matter self-interaction and nucleon effective mass affect oscillation modes.

Abstract

We investigate $g$-mode oscillations in dark matter admixed neutron stars employing a relativistic mean field model to describe hadronic matter and a model for self-interacting fermionic dark matter motivated by the neutron decay anomaly. Following the construction of such admixed configurations, we derive the equilibrium and adiabatic speeds of sound therein, leading to a computation of the star's $g$-mode spectrum in the Cowling approximation. In particular, we explore the effect of dark matter self-interaction, the nucleon effective mass and dark matter fraction on the principal $g$-mode frequency, and its first overtone. We show that the effect on $g$-mode frequency depends predominantly on the dark matter fraction, and demonstrate an equation of state-independent constraint for the latter. Prospects of identifying the presence of dark matter in neutron stars using $g$-mode are discussed.