Prompt flare and disk formation in tidal disruptions by massive black holes

Abstract

The ubiquitous observational signature in the disruption of a star by a massive black hole is a bright UV/X-ray flare with a light curve decaying at late times as t-5=3. The flare is the product of the stellar debris falling back towards the black hole, self-intersecting, and eventually forming an accretion disk. The time elapsing between the disruption of the star as it passes periapsis, the onset of the subsequent flare from material falling back, and the ultimate formation of the accretion disk depends on the black hole mass, the characteristics of the star, and the strength of the encounter. We present preliminary results from a class of tidal disruption events that until now have not been considered in which the disruption-flare-disk sequence develops promptly. These tidal disruption events are from ultra-close encounters between main-sequence stars and intermediate mass black holes.