Searches for continuous gravitational waves from neutron stars: A twenty-year retrospective

TL;DR

This paper reviews twenty years of efforts to detect continuous gravitational waves from neutron stars, analyzing search methods, challenges, and sensitivities using LIGO and Virgo data.

Contribution

It provides a comprehensive retrospective analysis of 297 searches over two decades, highlighting progress and remaining challenges in detecting continuous gravitational waves.

Findings

297 searches analyzed from 80 papers (2003-2022)

Comparison of sensitivities and parameter space coverage

Summary of data analysis algorithms and challenges

Abstract

Seven years after the first direct detection of gravitational waves, from the collision of two black holes, the field of gravitational wave astronomy is firmly established. A first detection of continuous gravitational waves from rapidly-spinning neutron stars could be the field's next big discovery. I review the last twenty years of efforts to detect continuous gravitational waves using the LIGO and Virgo gravitational wave detectors. I summarise the model of a continuous gravitational wave signal, the challenges to finding such signals in noisy data, and the data analysis algorithms that have been developed to address those challenges. I present a quantitative analysis of 297 continuous wave searches from 80 papers, published from 2003 to 2022, and compare their sensitivities and coverage of the signal model parameter space.