RSAA Colloquium: Dr Evgeni Grishin from Monash University

Stellar Tango in the Hearts of Galaxies
 

The centres of galaxies are among the most extreme environments in the Universe, where millions of stars and black holes can be packed into remarkably compact regions around a supermassive black hole. In some galaxies, these environments are further shaped by massive and luminous discs of gas, creating a rich laboratory for gravitational interactions. The resulting dynamics can drive extraordinary phenomena, from black-hole mergers and gravitational waves to stellar disruptions and explosions. Yet how these processes interact and evolve over cosmic timescales remains poorly understood. I will review the governing processes that shape the dynamics of stars and black holes in dense galactic nuclei, including the effects of gas surrounding active supermassive black holes. 

Recent work explores how complex gravitational interactions can shape the formation and evolution of compact objects and produce distinctive observable signatures. I will discuss how these theoretical studies connect the dynamics of individual stars and black holes to observations from current and next-generation facilities, including LIGO–Virgo–KAGRA, the Vera C. Rubin Observatory and the future LISA mission, providing new ways to probe the hidden lives of stars and black holes at the hearts of galaxies.