Multi-messenger detectability of continuous gravitational waves from the near future to next generation detectors

TL;DR

This paper assesses the likelihood of detecting continuous gravitational waves with upcoming and next-generation detectors, highlighting the implications for astrophysics and pulsar theories based on detection prospects.

Contribution

It systematically evaluates the detectability of continuous gravitational waves from known objects using current and future detectors, updating previous estimates and discussing implications.

Findings

Detection likely with near-future upgrades if current theories hold.

Next-generation detectors could detect many continuous gravitational wave sources.

Non-detection in upcoming years would challenge existing pulsar formation theories.

Abstract

Continuous gravitational waves have the potential to transform gravitational wave astronomy and yield fresh insights into astrophysics, nuclear and particle physics, and condensed matter physics. We evaluate their detectability by combining various theoretical and observational arguments from the literature and systematically applying those arguments to known astronomical objects and future gravitational wave detectors. We detail and update previous estimates made in support of Cosmic Explorer [M. Evans et al., arXiv:2306.13745; I. Gupta et al., Class. Quantum Grav. 41, 245001 (2024)]. It is commonly argued that the spins of accreting neutron stars are regulated by gravitational wave emission and that millisecond pulsars contain a young pulsar's magnetic field buried under accreted material. If either of these arguments holds, the first detection of continuous gravitational waves is likely with near future upgrades of current detectors, and many detections are likely with next generation detectors such as Cosmic Explorer and the Einstein Telescope. A lack of detections in the next several years would begin to raise serious doubts about current theories of millisecond pulsar formation.