Dr. Evgeni Grishin

Abstract: The dynamical and hydrodynamical evolution of stars and stellar remnants is greatly affected by the dense galactic nuclei (GN) environment. We explore the complex interplay of several physical processes that shape the properties, rates and environments of nuclear transients and black hole (BH) mergers and gravitational-wave (GW) events: i) We show how stellar dynamics shape the rate and properties of stellar BH and NS dynamical evolution and mergers ii) For active galactic nuclei (AGN), we study how the presence of an accretion disc modifies the light curves of exploding supernovae and their relation to other nuclear transients. iii) We examine the gravitational torques in AGN discs that drive BH’s radial migration. We find that thermal diffusion greatly alters the existence and nature of migration traps in AGN discs, which are believed to be responsible for massive hierarchical GW mergers. We find that GW mergers predominantly occur in low-luminosity AGNs. We use detailed recoil kicks and AGN models to study the efficiency of BH mergers for different generations. iv) If time permits, we show how exotic axion dark-matter theories could be constrained via pulsar timing of pulsar binaries in galactic cores.