Role of the symmetry energy and the neutron-matter stiffness on the tidal deformability of a neutron star with unified equations of state

Abstract

The role of the symmetry energy and the neutron-matter stiffness on the tidal deformability of a cold nonaccreted neutron star is studied using a set of unified equations of state. Based on the nuclear energy-density functional theory, these equations of state provide a thermodynamically consistent treatment of all regions of the star and were calculated using functionals that were precision fitted to experimental and theoretical nuclear data. Predictions are compared to constraints inferred from the recent detection of the gravitational-wave signal GW170817 from a binary neutron-star merger and from observations of the electromagnetic counterparts.

Role of the crust in the tidal deformability of a neutron star within a unified treatment of dense matter

“…As previously shown in Ref. [14], the unified EoS based on BSk24 is consistent with this constraint. From the formula obtained in Ref.…”

“…The underlying functional was precision fitted to a large set of experimental and theoretical nuclear data [13]. We have recently shown that this unified EoS is also consistent with the various constraints inferred from the analyses of the gravitational and electromagnetic observations of GW170817 [14]. To better assess the importance of the crust, results for the Love number k 2 and the tidal deformability parameter Λ are compared in Section III to those obtained using the EoS of a purely liquid putative NS made entirely of homogeneous matter calculated with the same functional BSk24.…”

Role of dense matter in tidal deformations of inspiralling neutron stars and in gravitational waveforms with unified equations of state

“…1 of Ref. [43], these functionals remain consistent with more recent ab initio calculations. All functionals are also consistent with EoS constraints inferred from heavy-ion collisions [59,75] and with various empirical determinations of the symmetry energy at densities n n 0 (see Fig.…”

“…2 of Ref. [43]). The functionals mainly differ in their predictions for the density dependence of the symmetry energy at higher densities.…”

“…Despite the introduction of higher-order tidal Love numbers in gravitational-waveform models and their potential importance for the analyses of upcoming gravitational-wave detections of binary NS mergers, little attention has been paid so far to their nuclear-physics aspects [42]. In our previous work [43], we studied the role of the neutron-matter stiffness and of the symmetry energy in the gravitoelectric Love number k 2 and in the tidal deformability in Eq. (1) using the recent series of Brussels-Montreal unified EoSs [44][45][46], which provide a thermodynamically consistent description of all regions of a cold nonaccreted NS.…”