Astrophysics Colloquium - Tidal disruptions and X-ray eruptions: stellar encounters with supermassive black holes

Time-domain surveys are now turning up a rich variety of transient events in the nuclei of galaxies, far beyond the established range of AGN variability. Many of these appear to be driven by interactions between stars and the central supermassive black hole. In this talk I will focus on two manifestations of this diverse variability: tidal disruption events (TDEs), the destruction of passing stars by extreme gravitational forces, and quasi-periodic eruptions (QPEs), soft X-ray flares repeating on timescales of hours. I will discuss our current understanding of TDE emission mechanisms and environments, as well as the remaining puzzles in the field. I will then present exciting new evidence as to the origin of the mysterious QPEs, and their connection with TDEs. We will briefly look ahead to LSST and what we hope to find in the next few years of this rapidly growing field.