Gravitational waves from rotating neutron stars

TL;DR

This review explores the mechanisms behind gravitational wave emission from rotating neutron stars, focusing on their deformation due to crustal strains, magnetic fields, and superfluid vortices, and discusses detection prospects and implications.

Contribution

It synthesizes recent research on neutron star deformations and gravitational wave detectability, highlighting new ideas about precession and potential observational signatures.

Findings

Crustal strains and magnetic fields can sustain neutron star deformations.

Magnus forces from superfluid vortices may contribute to star deformation.

Detection of gravitational waves could reveal neutron star internal dynamics.

Abstract

In this review we examine the dynamics and gravitational wave detectability of rotating strained neutron stars. The discussion is divided into two halves: triaxial stars, and precessing stars. We summarise recent work on how crustal strains and magnetic fields can sustain triaxiality, and suggest that Magnus forces connected with pinned superfluid vortices might contribute to deformation also. The conclusions that could be drawn following the successful gravitational wave detection of a triaxial star are discussed, and areas requiring further study identified. The latest ideas regarding free precession are then outlined, and the recent suggestion of Middleditch et al (2000a,b) that the remnant of SN1987A contains a freely precessing star, spinning-down by gravitational wave energy loss, is examined critically. We describe what we would learn about neutron stars should the gravitational wave detectors prove this hypothesis to be correct.