Confronting nuclear equation of state in the presence of dark matter using GW170817 observation in relativistic mean field theory approach

TL;DR

This paper investigates how dark matter inside neutron stars affects their properties and gravitational wave signals, showing that dark matter can soften the equation of state and align models with GW170817 observations.

Contribution

It introduces a relativistic mean field model with dark matter interaction, demonstrating that dark matter admixture can reconcile stiff equations of state with gravitational wave constraints.

Findings

Dark matter softens the neutron star equation of state.

Dark matter reduces the tidal deformability of neutron stars.

Certain models with dark matter satisfy GW170817 constraints.

Abstract

We confront admixture of dark matter inside neutron star using gravitational wave constraints coming from binary neutron star merger. We consider a relativistic mean field model including $\sigma-\omega-\rho$ meson interaction with NL3 parameterization. We study fermionic dark matter interacting with nucleonic matter via Higgs portal mechanism. We show that admixture of dark matter inside the neutron star soften the equation state and lower the value of tidal deformability. Gravitational wave GW170817 observation puts an upper bound on tidal deformability of a binary neutron star with low spin prior at 90\% confidence level, which disfavors stiff equation of state such as Walecka model with NL3 parameterization. However, we show that Walecka model with NL3 parameterization with a fermionic dark matter component satisfy the tidal deformability bound coming from the GW170817 observation.