Hybrid stars in the light of GW170817

TL;DR

This paper investigates how the gravitational wave event GW170817 constrains the properties of hybrid stars by analyzing their equations of state and tidal deformability, leading to limits on star radii and quark matter parameters.

Contribution

It introduces a method to constrain hybrid star equations of state using GW170817 data, combining relativistic mean field and quark matter models with Gibbs' construction.

Findings

Tidal deformability constraints limit the quark matter model parameters.

Upper bounds on radii of 1.4 and 1.6 solar mass stars are established.

The maximum mass of hybrid stars is consistent with observed neutron star masses.

Abstract

We have studied the effect of tidal deformability constraint given by the binary neutron star merger event GW170817 on the equations of state (EOS) of hybrid stars. The EOS are constructed by matching the hadronic EOS described by relativistic mean field (RMF) model and parameter sets NL3, TM1 and NL3$\omega\rho$ with the quark matter EOS described by modified MIT bag model, via Gibbs' construction. It is found that the tidal deformability constraints along with the lower bound on maximum mass ($M_{\rm max}=2.01\pm0.04M_\odot$) significantly limit the bag model parameter space ($B_{\rm eff}^{1/4}$, $a_4$). We also obtain upper limits on the radius of $1.4M_\odot$ and $1.6M_\odot$ stars as $R_{1.4}\leq13.2-13.5$ km and $R_{1.6}\leq13.2-13.4$ km, respectively for different hadronic EOS considered here.