X-Ray afterglow of SWIFT J1644+57: a Compton echoquestionMark

Swift, Chandra, and XMMNewtonhave found a weak but nearly constant Xraycomponent from the tidal disruption event Swift J1644+57 that appeared at virgul500days and was visible at least until virgul1400 days after the stellar capture, whichcannot be explained by standard tidal disruption theories. We suggest that thisXray afterglow component may result from the Thomson scattering between theprimary Xrays and its surrounding plasma, i.e., a Compton echo effect. Theproposed XMMNewton observation will allow us to test our theory and constrainthe size and geometry of the surrounding gas cloud. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]