Eur. Phys. J. A (2021) 57: 31
https://doi.org/10.1140/epja/s10050-021-00342-w

Regular Article – Theoretical Physics

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

¹ School of Physics and Optoelectronics, South China University of Technology, 510641, Guangzhou, People’s Republic of China
² School of Physics and Astronomy, Sun Sat-Sen University, 519082, Zhuhai, People’s Republic of China

^c wendehua@scut.edu.cn

Received: 30 July 2020
Accepted: 2 January 2021
Published online: 18 January 2021

Abstract

Based on the distribution of tidal deformabilities and component masses of binary neutron star merger GW170817, the parametric equation of state (EOS) is employed to probe the nuclear symmetry energy and the properties of the 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 and pressure at twice the saturation density of nuclear matter can be constrained within $E_{\mathit{sym}}(2{\rho }_0)=34.5_{-2.3}^{+20.5}$ MeV and $P(2{\rho }_0)=3.{81}_{-2.32}^{+1.18}\times {10}^{34}$ dyn cm${}^{-2}$ at 90% credible level, respectively. 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 $\le R_{1.4}\le$ 13.20 km and $133\le {\mathrm{\Lambda }}_{1.4}\le 686$ at 90% credible level, with the most probable value of ${\overline{R}}_{1.4}$ = 12.60 km and ${\overline{\mathrm{\Lambda }}}_{1.4}$ = 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 stellar radius, and a smaller tidal deformability.