Astronomy Colloquium

Nuclear star clusters around supermassive black holes are likely the most collisional stellar systems in the Universe and are also embedded in extremely deep gravitational potential. Consequently, unique stellar dynamical processes and interactions are expected to take place. For example, collisions and mergers between stars and compact objects are likely to happen in this environment. I will explore these collisions and mergers and their product and will connect between them and some of the observed puzzles in galactic nuclei and in particular our own Galactic Center. Specifically, I will offer possible connections between those merger products and (1) the perplexing population of young stars that are isotropically distributed (S-stars) in a region that is hostile to star formation, (2)  the new class of cold stars in this same region that are two orders of magnitude larger than typical stars (e.g., the "gas-like cloud" G2), (3) stellar black hole-black hole binary mergers and LIGO observations, and (4) supermassive black-hole merger with a stellar-mass compact objects and future LISA observations. Recent developments in our understanding of the underlining physics of three- to few- body dynamics offer the opportunity to address puzzles at these extreme places in our Universe.