Speaker: Abbas Askar (Lund U.)
Title: Black hole dynamics in star clusters: Evolution and growth from stellar to supermassive scales
Abstract:
Over the past five years, nearly fifty merging binary black holes have been discovered through the direct detection of gravitational waves by the LIGO/Virgo collaboration. While these observations provide unprecedented insights into the demographics of black holes, they also raise important questions about the astrophysical origin and formation of these elusive binary systems. One of the formation channels for these observed gravitational wave sources are dynamical interactions in dense star cluster. In this talk, I will describe how star clusters evolve and discuss the various processes by which merging binary black holes can form in them based on results from state-of-the-art simulations of nearly two thousand stellar clusters. I will also give an overview of the main processes involved in the retention and long-term evolution of black holes in star clusters and explain how they shape the properties and merger rates for binary black holes that originate in these dense stellar environments. Additionally, it has also been suggested that massive and dense star clusters could be potential sites for forming black holes with masses between ~ 100 to 10,000 solar masses. I will discuss the key processes and caveats involved in the formation, retention and growth of these intermediate-mass black holes in the densest of star clusters. Finally, I will discuss how star clusters that host intermediate-mass black holes can potentially end up in the center of the galaxy where they may play a role in seeding the formation of supermassive black holes.
Room: ZOOM videoconference (contact justin.feng@tecnico.ulisboa.pt for URL)