Constraining the growth of massive black holes with a statistical multi-messenger approach

Early active black holes seen by JWST, pulsar-timing evidence for a gravitational-wave background and stellar tidal disruptions probe different parts of black-hole growth. This talk presents L-GalaxiesBH, which follows black holes and their host galaxies from early formation to the present. Combining these observations constrains growth models, including the abundance of rapidly growing early objects, massive binaries nearby and elusive intermediate-mass systems.