Rapid localization of gravitational wave hosts with FIGARO

TL;DR

FIGARO is a fast, Bayesian non-parametric software that enhances gravitational wave localization, enabling rapid identification of potential host galaxies for electromagnetic follow-up, demonstrated on binary black holes and GW170817.

Contribution

The paper introduces FIGARO, a novel analytical tool that improves the speed and accuracy of gravitational wave source localization and host galaxy ranking.

Findings

FIGARO provides real-time 3D localization updates.

It effectively ranks galaxy catalog entries by host probability.

Demonstrated robustness with pp-plots and entropy-based assessment.

Abstract

The copious scientific literature produced after the detection of GW170817 electromagnetic counterpart demonstrated the importance of a prompt and accurate localization of the gravitational wave within the co-moving volume. In this letter, we present FIGARO, a ready to use and publicly available software that relies on Bayesian non-parametrics. FIGARO is designed to run in parallel with parameter estimation algorithms to provide updated three-dimensional volume localization information. Differently from any existing algorithms, the analytical nature of the FIGARO reconstruction allows a ranking of the entries of galaxy catalogues by their probability of being the host of a gravitational wave event, hence providing an additional tool for a prompt electromagnetic follow up of gravitational waves. We illustrate the features of FIGARO on binary black holes as well as on GW170817. Finally, we demonstrate the robustness of FIGARO by producing so-called pp-plots and we present a method based on information entropy to assess when, during the parameter estimation run, it is reasonable to begin releasing skymaps.