# Confronting gravitational-wave observations with modern nuclear physics constraints

## TL;DR

This paper explores how gravitational-wave data from neutron star mergers, combined with modern nuclear physics calculations, can constrain the dense matter equation of state and improve our understanding of neutron star interiors.

## Contribution

It demonstrates how GW observations and advanced nuclear theory together refine constraints on the neutron star equation of state, considering uncertainties and phase transitions.

## Key findings

- GW170817 data constrains neutron star EOS
- Phase transitions significantly affect EOS interpretations
- Future observations will further refine dense matter models

## Abstract

Multi-messenger observations of neutron star (NS) mergers have the potential to revolutionize nuclear astrophysics. They will improve our understanding of nucleosynthesis, provide insights about the equation of state (EOS) of strongly-interacting matter at high densities, and enable tests of the theory of gravity and of dark matter. Here, we focus on the EOS, where both gravitational waves (GWs) from neutron-star mergers and X-ray observations from space-based detectors such as NICER will provide more stringent constraints on the structure of neutron stars. Furthermore, recent advances in nuclear theory have enabled reliable calculations of the EOS at low densities using effective field theory based Hamiltonians and advanced techniques to solve the quantum many-body problem. In this paper, we address how the first observation of GWs from GW170817 can be combined with modern calculations of the EOS to extract useful insights about the EOS of matter encountered inside neutron stars. We analyze the impact of various uncertainties, the role of phase transitions in the NS core, and discuss how future observations will improve our understanding of dense matter.