Tidal Deformability of Dark Matter Admixed Neutron Stars

TL;DR

This paper investigates how the presence of dark matter in neutron stars affects their tidal deformability, providing a potential method to infer dark matter properties from gravitational wave observations.

Contribution

It introduces a two-fluid model to compute tidal Love numbers for dark matter admixed neutron stars and explores their implications for dark matter parameter constraints.

Findings

Tidal deformability sharply changes with dark matter fraction.

Self-similarity in deformability-mass relations aids dark matter parameter study.

Dark matter significantly influences neutron star tidal properties.

Abstract

The tidal properties of a neutron star are measurable in the gravitational waves emitted from inspiraling binary neutron stars, and they have been used to constrain the neutron star equation of state. In the same spirit, we study the dimensionless tidal deformability of dark matter admixed neutron stars. The tidal Love number is computed in a two-fluid framework. The dimensionless tidal Love number and dimensionless tidal deformability are computed for dark matter admixed stars with the dark matter modelled as ideal Fermi gas or self-interactive bosons. The dimensionless tidal deformability shows a sharp change from being similar to that of a pure normal matter star to that of a pure dark matter star, within a narrow range of intermediate dark matter mass fraction. Based on this result, we illustrate an approach to study the dark matter parameters through the tidal properties of massive compact stars, making use of the self-similarity of the dimensionless tidal deformability-mass relations when the dark matter mass fraction is high.