Gravitational Tango in the Hearts of Galaxies

Galactic nuclei are dynamic factories of compact-object formation, evolution and mergers, imprinting gravitational-wave (GW) signals across current and future multi-messenger observatories (GW, electromagnetic and beyond). We will explore the triple-driven dynamical channel, where secular perturbations (i.e. von Zeipel–Lidov–Kozai oscillations) generate distinct orbital families and lead to characteristic, observable GW signatures. We will then turn to black holes embedded in accretion discs in active galactic nuclei (AGN), where mean-motion orbital resonances and gas torques facilitate binary formation and mergers. We derive an empirical fit for the merger probability across disc conditions and black-hole masses, and map the AGN luminosity regimes where GW merger events are expected to originate. Together, these results illustrate how gravitational dynamics in galactic centres shape the compact-object population, and how upcoming multi-messenger surveys may uncover their origins.

*Evgeny is a candidate for the department