Impact of the neutron-star deformability on equation of state parameters

TL;DR

This study uses Bayesian inference to analyze how neutron star tidal deformability influences the parameters of the nuclear equation of state, revealing mass-dependent correlations and the impact of prior assumptions.

Contribution

It introduces a correlation-free meta-modeling approach to better understand the sensitivity of EOS parameters to tidal deformability across neutron star masses.

Findings

Low $L_{sym}$ and $K_{sym}$ favored by GW170817 data.

Strong correlation between tidal deformability and EOS parameters for stars below 1.6 solar masses.

Higher mass stars show increased sensitivity of tidal deformability to higher-order EOS parameters.

Abstract

We use a Bayesian inference analysis to explore the sensitivity of Taylor expansion parameters of the nuclear equation of state (EOS) to the neutron star dimensionless tidal deformability ($\Lambda$) on 1 to 2 solar masses neutron stars. A global power law dependence between tidal deformability and compactness parameter (M/R) is verified over this mass region. To avoid superfluous correlations between the expansion parameters, we use a correlation-free EOS model based on a recently published meta-modeling approach. We find that assumptions in the prior distribution strongly influence the constraints on $\Lambda$. The $\Lambda$ constraints obtained from the neutron star merger event GW170817 prefer low values of $L_\text{sym}$ and $K_\text{sym}$, for a canonical neutron star with 1.4 solar mass. For neutron star with mass $<1.6$ solar mass, $L_\text{sym}$ and $K_\text{sym}$ are highly correlated with the tidal deformability. For more massive neutron stars, the tidal deformability is more strongly correlated with higher order Taylor expansion parameters.