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Astro Seminar

Cosmology with Dark Sirens and Galaxy Catalogues

Speaker: Rachel Gray (Queen Mary University London)
Date: Wednesday 16 November 2022
Time: 14:00
Venue: N3.28/Zoom

Gravitational wave signals from compact binary mergers are of huge interest to the cosmology community due to their ability to act as standard sirens, providing measurements of luminosity distance which are independent of the cosmic distance ladder. This opens up new ways of measuring cosmological parameters, with particular focus on the Hubble constant, with the hopes of arbitrating the current tension. In order for this measurement to be made, additional redshift information is required, and in the case where the merger is observed without a confirmed electromagnetic counterpart - true for all but one of the 90 detections to date - galaxy catalogues can be used to provide the redshifts of possible host galaxies. Here I will introduce the 'dark siren' method, then discuss how some of the difficulties of this analysis - including galaxy catalogue incompleteness, unreliable redshift estimates, and the impact population assumptions - are handled, as well as looking at the most recent results.