Ensembles of unified crust and core equations of state in a nuclear-multimessenger astrophysics environment

TL;DR

This paper develops an ensemble of neutron star equations of state combining nuclear and astrophysical data to better understand crust properties and the symmetry energy parameters, highlighting the complementary roles of different data sources.

Contribution

It introduces a unified ensemble of neutron star equations of state incorporating nuclear and astrophysical data, and analyzes their combined impact on crust properties and symmetry energy constraints.

Findings

Astrophysical data better constrains $K_{sym}$ than PREX.

Both nuclear and astrophysical data influence crust property estimates.

The ensemble approach allows exploration of parameter effects on neutron star structure.

Abstract

We present an ensemble of unified neutron star crust and core equations of state, constructed using an extended Skyrme energy density functional through the crust and outer core, and appended by two piecewise polytropes at higher densities. The equations of state are parameterized by the first three coefficients in the density expansion of the symmetry energy $J,L$ and $K_{\rm sym}$, the moment of inertia of a 1.338 M$_{\odot}$ star $I_{1.338}$ and the maximum neutron star mass $M_{\rm max}$. We construct an ensemble with uniform priors on all five parameters, and then apply data filters to the ensemble to explore the effect of combining neutron skin data from PREX with astrophysical measurements of radii and tidal deformabilities from NICER and LIGO/VIRGO. Neutron skins are calculated directly using the EDFs. We demonstrate that both the nuclear data and astrophysical data play a role in constraining crust properties such as the mass, thickness and moment of inertia of the crust and the nuclear pasta layers therein, and that astrophysical data better constrains $K_{\rm sym}$ than PREX data.