Fully coherent follow-up of continuous gravitational-wave candidates: an application to Einstein@Home results

TL;DR

This paper details a two-stage follow-up method for continuous gravitational-wave candidates, enhancing the analysis of Einstein@Home search results by improving detection robustness and efficiency.

Contribution

It introduces a fully coherent follow-up pipeline applied to Einstein@Home data, demonstrating its effectiveness on simulated and real signals without searching beyond first-order spindown.

Findings

Efficient follow-up pipeline validated with simulated signals.

Robustness against second-order spindown evaluated.

Successful application to hardware-injected and real outliers.

Abstract

We characterize and present the details of the follow-up method used on the most significant outliers of the Hough Einstein@Home all-sky search for continuous gravitational waves arXiv:1207.7176. This follow-up method is based on the two-stage approach introduced in arXiv:1303.2471, consisting of a semicoherent refinement followed by a fully coherent zoom. We quantify the efficiency of the follow-up pipeline using simulated signals in Gaussian noise. This pipeline does not search beyond first-order frequency spindown, and therefore we also evaluate its robustness against second-order spindown. We present the details of the Hough Einstein@Home follow-up (arXiv:1207.7176) on three hardware-injected signals and on the 8 most significant outliers of unknown origin.