KIPAC Seminar: The drivers of tidal disruption events

Abstract: Tidal disruption events (TDEs) occur when a star enters the tidal radius of a supermassive black hole (SMBH) and is shredded in a dramatic, multiwavelength event. They are one of the few probes of the non-accreting (quiescent) SMBH population. With full sky optical and X-ray surveys, we have now discovered populations of TDEs large enough for demographic studies. Translating from the observed population to constraints on quiescent SMBH demographics requires understanding both the intrinsic per-galaxy TDE rate, which varies dramatically across galaxy subtypes, and the selection effects that shape observed samples. In this talk, I will review our theoretical and observational understanding of the factors that drive TDE rates, and discuss the large uncertainties, spanning galaxy evolution, nuclear stellar dynamics, and survey selection, which prevent constraints on the broader SMBH population. I will highlight two lines of attack to better understand these factors: multiwavelength TDE searches to identify the role of selection effects in discovery, and a detailed, parsec-to-megaparsec study of a TDE host galaxy. The host galaxy work doubles as a probe of the sub-L* galaxy population itself, where TDEs offer a unique window into the nuclear regions of galaxies otherwise difficult to study at scales of tens of parsecs.