Modelling the Population of Supermassive Black Hole Mergers in Our Universe

The Laser Interferometer Space Antenna (LISA) mission, which has recently been adopted by ESA, will allow for the study of supermassive black hole (SMBH) mergers via their gravitational wave signatures. These observations will complement our current methods of studying the SMBH population, namely via the gravitational wave background using the Pulsar Timing Array, and via their electromagnetic signatures using the James Webb Space Telescope. The process in which a binary SMBH system loses energy to the environment via various mechanisms, is complex and requires better theoretical understanding to produce accurate predictions. By employing cosmological simulations and analytical models we aim to investigate the masses and spins of merging SMBHs. This will allow us to study the nature of the seeds of SMBHs in our universe, specifically testing the hypothesis that they are a result of a population of primordial black holes forming after inflation.