UNC Physics Colloquium

Carl Rodriguez, Carnegie Mellon University

How do you Merge two Black Holes? The Present and Future of Gravitational-wave Astrophysics

Abstract
Since 2015, The Laser Interferometer Gravitational-wave Observatory (LIGO) has detected ~100 gravitational waves from merging black holes and neutron stars, inaugurating a new era of observational astronomy. But how are these systems formed in the first place, and what can that tell us about the lives and deaths of massive stars and the star clusters and galaxies that make them? In this talk, I will attempt to answer these questions by describing how massive and old star clusters, such as the globular clusters in the Milky Way, are the ideal site for the production of binary black holes. I will show how the dynamical assembly of binaries in these dense stellar environments imprints detectable features in the gravitational waves themselves, and how multiple mergers in star clusters can produce black holes with masses that cannot be formed from single or binary stars. Finally, I will place these results within the broader context of galaxy formation and assembly, describing a new project to model star clusters self-consistently from collapsing giant molecular clouds in an MHD simulation of a Milky Way-mass galaxy. These results can provide a direct link between the study of globular cluster formation, the assembly of galaxies, massive black holes, and the future of gravitational-wave astronomy.