Constraining nuclear parameters using Gravitational waves from f-mode Oscillations in Neutron Stars

TL;DR

This paper demonstrates how gravitational wave observations from neutron star f-mode oscillations can be used within a Bayesian framework to constrain nuclear parameters and the neutron star equation of state, especially with multiple events.

Contribution

It introduces a Bayesian asteroseismology method to constrain nuclear parameters using gravitational wave data from neutron star oscillations, considering realistic detector sensitivities.

Findings

Single event constrains nucleon effective mass within 10-5%

Multiple events constrain all nuclear parameters to 2-3%

Uncertainties in neutron star radius and EOS properties are quantified

Abstract

Gravitational waves (GW) emanating from unstable quasi-normal modes in Neutron Stars (NS) could be accessible with the improved sensitivity of the current GW detectors or with the next-generation GW detectors and, therefore, can be employed to study the NS interior. Assuming f-mode excitation in isolated pulsars with typical energy of pulsar glitches and considering potential f-mode GW candidates for A+ (upgraded LIGO detectors operating at 5th observation run design sensitivity) and Einstein Telescope (ET), we demonstrate the inverse problem of NS asteroseismology within a Bayesian formalism to constrain the nuclear parameters and NS Equation of State (EOS). We describe the NS interior within relativistic mean field formalism. Taking the example of glitching pulsars, we find that for a single event in A+ and ET, among the nuclear parameters, the nucleon effective mass ($m^*$) within 90\% credible interval (CI) can be restricted within $10\%$ and $5\%$, respectively. At the same time, the incompressibility ($K$) and the slope of the symmetry energy ($L$) are only loosely constrained. Considering multiple (10) events in A+ and ET, all the nuclear parameters are well constrained, especially $m^*$, which can be constrained to 3\% and 2\% in A+ and ET, respectively. Uncertainty in the observables of a $1.4M_{\odot}$ NS such as radius ($R_{1.4M_{\odot}}$), f-mode frequency ($f_{1.4M_{\odot}}$), damping time ($\tau_{1.4M_{\odot}}$) and a few EOS properties including squared speed of sound ($c_s^2$) are also estimated.