# Constraining the equation of state of high-density cold matter using nuclear and astronomical measurements

## TL;DR

This paper introduces a Bayesian framework that integrates diverse nuclear and astronomical data to constrain the equation of state of cold dense matter, enhancing our understanding of neutron star properties across various densities.

## Contribution

It presents a practical Bayesian method that incorporates full posterior distributions and can be applied with different EOS parameterizations, improving constraints from current and future measurements.

## Key findings

- Different measurements constrain different density ranges of the EOS.
- Better symmetry energy data impacts sub-nuclear densities.
- Precise radius and tidal deformability measurements improve overall EOS understanding.

## Abstract

The increasing richness of data related to cold dense matter, from laboratory experiments to neutron-star observations, requires a framework for constraining the properties of such matter that makes use of all relevant information. Here, we present a rigorous but practical Bayesian approach that can include diverse evidence, such as nuclear data and the inferred masses, radii, tidal deformabilities, moments of inertia, and gravitational binding energies of neutron stars. We emphasize that the full posterior probability distributions of measurements should be used rather than, as is common, imposing a cut on the maximum mass or other quantities. Our method can be used with any parameterization of the equation of state (EOS). We use both a spectral parameterization and a piecewise polytropic parameterization with variable transition densities to illustrate the implications of current measurements and show how future measurements in many domains could improve our understanding of cold catalyzed matter. We find that different types of measurements will play distinct roles in constraining the EOS in different density ranges. For example, better symmetry energy measurements will have a major influence on our understanding of matter somewhat below nuclear saturation density but little influence above that density. In contrast, precise radius measurements or multiple tidal deformability measurements of the quality of those from GW170817 or better will improve our knowledge of the EOS over a broader density range.