Gravity seminar - Rachel Gray [UNUSUAL DAY AND PLACE] Seminar

Abstract: 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 Hubble tension. However, in order for this measurement to be made, additional redshift information is required. In the scenario where the merger is observed without a confirmed electromagnetic counterpart - true for all but one of the 90 detections from the LIGO-Virgo-KAGRA collaboration to date - galaxy surveys, and the population of gravitational waves themselves, can be used to provide this missing information. I will introduce these latest methods and look at what the gravitational wave detections from the LIGO-Virgo-KAGRA collaboration can tell us so far, and how they might pave the way for solving the Hubble tension.