Constraining the nuclear symmetry energy and properties of neutron star from GW170817 by Bayesian analysis

TL;DR

This paper uses Bayesian analysis of GW170817 data to constrain the nuclear symmetry energy and neutron star properties, providing updated bounds on EOS parameters, radii, and tidal deformabilities.

Contribution

It introduces a Bayesian framework to derive constraints on nuclear symmetry energy and neutron star characteristics from gravitational wave data, considering causality and maximum mass limits.

Findings

Symmetry energy at twice saturation density constrained to 34.5^{+20.5}_{-2.3} MeV.

Neutron star radius constrained between 10.80 km and 13.20 km.

Tidal deformability of 1.4 solar mass neutron stars constrained between 133 and 686.

Abstract

Based on the distribution of tidal deformabilities and component masses of binary neutron star merger GW170817, the parametric equation of states (EOS) are employed to probe the nuclear symmetry energy and the properties of neutron star. To obtain a proper distribution of the parameters of the EOS that is consistent with the observation, Bayesian analysis is used and the constraints of causality and maximum mass are considered. From this analysis, it is found that the symmetry energy at twice the saturation density of nuclear matter can be constrained within $E_{sym}(2{\rho_{0}})$ = $34.5^{+20.5}_{-2.3}$ MeV at 90\% credible level. Moreover, the constraints on the radii and dimensionless tidal deformabilities of canonical neutron stars are also demonstrated through this analysis, and the corresponding constraints are 10.80 km $< R_{1.4} <$ 13.20 km and $133 < \Lambda_{1.4} < 686$ at 90\% credible level, with the most probable value of $\bar{R}_{1.4}$ = 12.60 km and $\bar{\Lambda}_{1.4}$ = 500, respectively. With respect to the prior, our result (posterior result) prefers a softer EOS, corresponding to a lower expected value of symmetry energy, a smaller radius and a smaller tidal deformability.