GOLUM: A fast and precise methodology to search for, and analyze, strongly lensed gravitational-wave events

TL;DR

This paper introduces GOLUM, a rapid and accurate method for detecting and analyzing strongly lensed gravitational-wave events, facilitating the study of multiple images with reduced computational effort.

Contribution

GOLUM provides a novel, efficient approach to analyze multiple strongly-lensed gravitational-wave images by leveraging posterior information, enabling large-scale and faster lensing studies.

Findings

Enables joint analysis of more than two images

Reduces computational cost significantly

Facilitates large-scale lensing studies

Abstract

Like light, gravitational waves can be gravitationally lensed by massive objects along their travel path. Strong lensing produces several images from the same binary coalescence and is forecasted to have a promising rate in ground-based gravitational detectors. To search for this effect in the data, one would, in principle, have to analyze all the possible combinations of the individual detected events, whose number will be ever-increasing. To keep up with the rising computational cost, we propose a fast and precise methodology to analyze strongly-lensed gravitational wave events. The method works by effectively using the posterior of the first image as prior for the second image. Thanks to its increased speed tractability, this method enables the joint analysis of more than two images. In addition, it opens the door to new strong lensing studies where a large number of injections is required.