Fully coherent follow-up of continuous gravitational-wave candidates

TL;DR

This paper introduces a new grid-less MADS algorithm for fully-coherent follow-up of semi-coherent gravitational wave candidates, improving detection confidence while managing computational costs.

Contribution

It presents a novel direct transition method to fully-coherent follow-up using a grid-less MADS algorithm with the F-statistic, enhancing candidate validation in gravitational wave searches.

Findings

Demonstrates the detection power of the method through Monte-Carlo simulations.

Shows the computational efficiency of the follow-up procedure.

Validates the approach on both directed and all-sky search candidates.

Abstract

The search for continuous gravitational waves from unknown isolated sources is computationally limited due to the enormous parameter space that needs to be covered and the weakness of the expected signals. Therefore semi-coherent search strategies have been developed and applied in distributed computing environments such as Einstein@Home, in order to narrow down the parameter space and identify interesting candidates. However, in order to optimally confirm or dismiss a candidate as a possible gravitational-wave signal, a fully-coherent follow-up using all the available data is required. We present a general method and implementation of a direct (2-stage) transition to a fully-coherent follow-up on semi-coherent candidates. This method is based on a grid-less Mesh Adaptive Direct Search (MADS) algorithm using the F-statistic. We demonstrate the detection power and computing cost of this follow-up procedure using extensive Monte-Carlo simulations on (simulated) semi-coherent candidates from a directed as well as from an all-sky search setup.