$f$-mode oscillations of compact stars with realistic equations of state in dynamical spacetime

TL;DR

This paper uses 3D numerical relativity simulations to accurately measure the fundamental oscillation modes of realistic neutron star equations of state, validating methods against perturbative approaches and universal relations.

Contribution

It extends previous studies by analyzing $f$-modes with realistic equations of state in full dynamical spacetime, demonstrating the effectiveness of simplified simulations for mode extraction.

Findings

Good agreement with perturbation methods for $f$-mode frequencies

Universal relations are validated and compared with earlier models

Single star perturbation simulations can approximate binary neutron star inspiral results

Abstract

In this study, we perform full three dimensional numerical relativity simulations of non-rotating general relativistic stars. Extending the studies for polytropic equation of state, we investigate the accuracy and robustness of numerical scheme on measuring fundamental ($f$)-mode frequency for realistic equations of state (EoS). We use various EoS with varying range of stiffness and numerically evolve perturbed stellar models for several mass configurations (in the range of $1.2 - 2.0$ $M_{\odot}$) for each of these EoS. Using the gravitational waveform obtained from the simulations we extract the $f$-modes of the stars. The obtained results are tested against the pre-existing perturbation methods and find good agreement. Validity and deviation of universal relations have been carried out and are compared with earlier results under Cowling approximation as well as perturbative approaches. We also show that even using perturbed single star simulations can provide good agreement with $f$-modes extracted from inspiral phase of binary neutron star simulations which are computationally more expensive.