Is timing noise important in the gravitational wave detection of neutron stars?

TL;DR

This paper investigates whether timing noise in pulsars affects gravitational wave detection, finding it mainly impacts young pulsars with larger-than-expected triaxialities, and discusses implications for search strategies and neutron star physics.

Contribution

It assesses the significance of timing noise in GW detection of neutron stars and proposes hierarchical search methods to mitigate its effects.

Findings

Timing noise affects young pulsars with large triaxialities.

Timing noise limits coherent GW search durations.

Detecting timing noise in GW signals probes neutron star physics.

Abstract

In this paper we ask whether the phenomenon of timing noise long known in electromagnetic pulsar astronomy is likely to be important in gravitational wave (GW) observations of spinning-down neutron stars. We find that timing noise is strong enough to be of importance only in the young pulsars, which must have larger triaxialities than theory predicts for their GW emission to be detectable. However, assuming that their GW emission is detectable, we list the pulsars for which timing noise is important, either because it is strong enough that its neglect by the observer would render the source undetectable, or else because it is a measurable feature of the GW signal. We also find that timing noise places a limit on the observation duration of a coherent blind GW search, and suggest that hierarchical search techniques might be able to cope with this problem. Demonstration of the presence or absence of timing noise in the GW channel would give a new probe of neutron star physics.