Gravitational Waves from Neutron Stars: A Review

TL;DR

This review discusses how neutron stars generate gravitational waves through various mechanisms, highlighting the potential insights from detections and identifying areas needing further research.

Contribution

It provides a comprehensive overview of gravitational wave generation mechanisms in neutron stars and discusses the physics that can be learned from detections.

Findings

Neutron stars emit gravitational waves via multiple mechanisms.

Detection of gravitational waves can reveal neutron star interior physics.

Further research is needed to understand dominant physical processes.

Abstract

Neutron stars are excellent emitters of gravitational waves. Squeezing matter beyond nuclear densities invites exotic physical processes, many of which violently transfer large amounts of mass at relativistic velocities, disrupting spacetime and generating copious quantities of gravitational radiation. I review mechanisms for generating gravitational waves with neutron stars. This includes gravitational waves from radio and millisecond pulsars, magnetars, accreting systems and newly born neutron stars, with mechanisms including magnetic and thermoelastic deformations, various stellar oscillation modes and core superfluid turbulence. I also focus on what physics can be learnt from a gravitational wave detection, and where additional research is required to fully understand the dominant physical processes at play.