# Constraining nuclear matter parameters with GW170817

## TL;DR

This paper refines constraints on nuclear matter parameters using gravitational wave data from GW170817, accounting for broader models, correlations, and uncertainties, leading to more conservative bounds on key nuclear parameters.

## Contribution

It extends previous analyses by incorporating a wider range of equations of state, correlations with measured tidal deformability, and uncertainties, providing more robust bounds on nuclear matter parameters.

## Key findings

- GW170817 bounds on $K_0$, $M_0$, and $K_{sym,0}$ are more conservative.
- The analysis accounts for equation of state variations and binary mass ratio effects.
- Updated tidal deformability measurement leads to refined parameter constraints.

## Abstract

The tidal measurement of gravitational waves from the binary neutron star merger event GW170817 allows us to probe nuclear physics that suffers less from astrophysical systematics compared to neutron star radius measurements with electromagnetic wave observations. A recent work found strong correlation among neutron-star tidal deformabilities and certain combinations of nuclear parameters associated with the equation of state. These relations were then used to derive bounds on such parameters from GW170817 assuming that the relations and neutron star masses are known exactly. Here, we expand on this important work by taking into account a few new considerations: (1) a broader class of equations of state; (2) correlations with the mass-weighted tidal deformability that was directly measured with GW170817; (3) how the relations depend on the binary mass ratio; (4) the uncertainty from equation of state variation in the correlation relations; (5) adopting the updated tidal deformability measurement from GW170817. Upon these new considerations, we find GW170817 bounds on nuclear parameters (the incompressibility $K_0$, its slope $M_0$ and the curvature of symmetry energy $K_{\mathrm{sym},0}$ at nuclear saturation density) to be 81 MeV $\leq K_0 \leq$ 362 MeV, 1556 MeV $\leq M_0 \leq$ 4971 MeV, and -254 MeV $\leq K_\mathrm{sym,0} \leq$ 27 MeV, which are more conservative than previously found with systematic errors more properly taken into account.