Imre Bartos: "The black hole that should not exist, and other recent surprises in gravitational wave astrophysics"
Since their first discovery in 2015, gravitational-wave and multi-messenger observations yielded several "surprises." The LIGO and Virgo observatories detected more and heavier black holes than anticipated; multi-messenger emission from neutron star merger GW170817 showed structured high-energy outflow; and earlier month, LIGO announced the discovery of a particularly heavy black hole that could have not come from stellar core collapse. In the next five years, LIGO's expected detection rate is set to increase twentyfold, to roughly one event every hour, promising many more surprises and new questions we can address. I will discuss several of the new interesting directions in gravitational-wave and multi-messenger observations that began only recently and promise to substantially enrich the field in the next five years.