Three years of X-ray light curve of swift J164449.3+573451

Swift J164449.3+573451 was initially detected as a bright and highly variable X-ray transient in March 2011, and soon revealed itself as an object that had no analog in the previous six years of Swift operations. It has been intensively observed over a very broad range of frequencies and interpreted as emission from a jet activated in the tidal disruption event of star in a close-by encounter with a quiescent supermassive black hole in the center of a distant galaxy. Here we present the definitive XRT team light curve for Swift J164449.3₊573451 and discuss its implications in the framework of current theoretical models. We show that the light curve decayed roughly as a t^-4/3 power law for about a year and a half before shut off. The steep turnoff of the jet, dropping an order of magnitude in 24 hours, seems to be consistent with the shutdown of the jet as the accretion disk transitioned from a thick disk to a thin disk. Swift continues to monitor this source in case the jet reactivates.