Postprocessing methods used in the search for continuous gravitational-wave signals from the Galactic Center

TL;DR

This paper introduces advanced data selection and postprocessing techniques that enhance the sensitivity and reliability of continuous gravitational-wave searches from the Galactic Center, enabling exploration of lower-significance candidates and faster upper limit derivation.

Contribution

It presents novel data selection, candidate vetting, and upper limit methods that improve search sensitivity and efficiency in gravitational-wave data analysis.

Findings

Data selection improved sensitivity by 20-30%.

Postprocessing reliably rules out false candidates.

Faster upper limit computation method developed.

Abstract

The search for continuous gravitational-wave signals requires the development of techniques that can effectively explore the low-significance regions of the candidate set. In this paper we present the methods that were developed for a search for continuous gravitational-wave signals from the Galactic Center [1]. First, we present a data-selection method that increases the sensitivity of the chosen data set by 20%-30% compared to the selection methods used in previous directed searches. Second, we introduce postprocessing methods that reliably rule out candidates that stem from random fluctuations or disturbances in the data. In the context of [J. Aasi et al., Phys. Rev. D 88, 102002 (2013)] their use enabled the investigation of candidates three standard deviations below the loudest expected candidate in Gaussian noise from the entire search. Such low-significance regions had not been explored in continuous gravitational-wave searches before. We finally present a new procedure for deriving upper limits on the gravitational-wave amplitude, which is several times faster with respect to the standard injection-and-search approach commonly used.