Time-frequency track distance for comparing continuous gravitational wave signals

TL;DR

This paper introduces a new time-frequency track distance measure for semicoherent continuous gravitational wave searches, improving candidate clustering and search sensitivity by better capturing parameter space structure.

Contribution

It presents a novel distance metric based on time-frequency tracks, enhancing the analysis of continuous wave signals in gravitational wave data.

Findings

Demonstrated improved search sensitivity in neutron star binary system searches

Replaced ad hoc distance measures with the new proposal in candidate clustering

Applicable to various quasi-monochromatic continuous wave signals

Abstract

Searches for continuous gravitational waves from unknown sources attempt to detect long-lasting gravitational radiation by identifying Doppler-modulated signatures in the data. Semicoherent methods allow for wide parameter space surveys, identifying interesting regions to be followed up using more sensitive (and computationally expensive) tools. Thus, it is required to properly understand the parameter space structure under study, as failing to do so could significantly affect the effectiveness of said strategies. We introduce a new measure for distances in parameter space suited for semicoherent continuous wave searches. This novel approach, based on comparing time-frequency tracks, can be applied to any kind of quasi-monochromatic continuous wave signals and adapts itself to the underlying structure of the parameter space under study. In a first application to the post-processing stage of an all-sky search for continuous waves from neutron stars in binary systems, we demonstrate a search sensitivity improvement by solely replacing previous ad hoc distance measures in the candidate clustering procedure by the new proposal.