New equations of state constrained by nuclear physics, observations, and QCD calculations of high-density nuclear matter

TL;DR

This paper develops new equations of state for neutron star and supernova simulations by integrating nuclear physics, QCD calculations, and astrophysical observations to constrain neutron star properties.

Contribution

It introduces an effective mass parametrization fitted to microscopic calculations and constrains the equation of state using nuclear theory and astrophysical data.

Findings

Constrained the equation of state using chiral EFT and QCD calculations.

Predicted neutron star radii and maximum masses within observational bounds.

Provided a range of possible thermal effects in supernova simulations.

Abstract

We present new equations of state for applications in core-collapse supernova and neutron star merger simulations. We start by introducing an effective mass parametrization that is fit to recent microscopic calculations up to twice saturation density. This is important to capture the predicted thermal effects, which have been shown to determine the proto-neutron star contraction in supernova simulations. The parameter range of the energy-density functional underlying the equation of state is constrained by chiral effective field theory results at nuclear densities as well as by functional renormalization group computations at high densities based on QCD. We further implement observational constraints from measurements of heavy neutron stars, the gravitational wave signal of GW170817, and from the recent NICER results. Finally, we study the resulting allowed ranges for the equation of state and for properties of neutron stars, including the predicted ranges for the neutron star radius and maximum mass.