Properties of binary components and remnant in GW170817 using equations of state in finite temperature field theory models

TL;DR

This paper analyzes the properties of binary neutron stars and their remnants in GW170817 using finite temperature equations of state, deriving relations for radii and tidal deformabilities, and exploring thermal effects on the remnant's structure.

Contribution

It introduces an analytical relation between neutron star radii and tidal deformability and examines thermal effects on the remnant's properties at finite temperature.

Findings

Upper bound on neutron star radius is 13 km.

Thermal effects enlarge the remnant radius.

Higher entropy reduces the Kepler frequency.

Abstract

We investigate gross properties of binary components and remnant in GW170817 using equations of state within the finite temperature field theoretical models. We also adopt finite temperature equations of state in the density dependent hadron field theory for this study. Properties of binary components are studied using zero temperature equations of state. Particularly, we investigate tidal deformabilities and radii of binary components in light of GW170817. An analytical expression relating the radii and the combined tidal deformability is obtained for binary neutron star masses in the range $1.1M_{\odot}\lesssim M\lesssim 1.6 M_{\odot}$. The upper bound on the tidal deformability gives the upper bound on the neutron star radius as 13 km. Next, the role of finite temperature on the remnant in GW170817 is explored. In this case, we investigate the gravitational and baryon mass, radius, Kepler frequency and moment of inertia of the rigidly rotating remnant for different equations of state at fixed entropy per baryon. The remnant radius is enlarged due to thermal effects compared with the zero temperature case. Consequently, it is found that the Kepler frequency is much lower at higher entropy per baryon than that of the case at zero temperature. These findings are consistent with the results found in the literature.