Gravitational wave asteroseismology with fast rotating neutron stars

TL;DR

This paper studies the damping and growth times of f-mode oscillations in rapidly rotating neutron stars using a relativistic framework, providing empirical formulas for gravitational wave asteroseismology.

Contribution

First to analyze f-mode damping/growth times in fast rotating neutron stars within a general relativistic setting, offering practical empirical formulas for gravitational wave analysis.

Findings

Damping times vary with rotation rate and EoS.

Empirical formulas accurately predict damping/growth times.

Results align with Newtonian limits in appropriate cases.

Abstract

We investigate damping and growth times of the f-mode for rapidly rotating stars and a variety of different polytropic equations of state in the Cowling approximation. We discuss the differences in the eigenfunctions of co- and counterrotating modes and compute the damping times of the f-mode for several EoS and all rotation rates up to the Kepler-limit. This is the first study of the damping/growth time of this type of oscillations for fast rotating neutron stars in a general relativistic framework. We use these frequencies and damping/growth times to create robust empirical formulae which can be used for gravitational wave asteroseismology. The estimation of the damping/growth time is based on the quadrupole formula and our results agree very well with Newtonian ones in the appropriate limit.