X-RAY AFTERGLOW of SWIFT J1644+57: A Compton ECHO?

K. S. Cheng, D. O. Chernyshov, V. A. Dogiel, Albert K.H. Kong, C. M. Ko

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Swift, Chandra, and XMM have found a weak but nearly constant X-ray component from Swift J1644+57 that appeared at ∼500 days and was visible at least until ∼1400 days after the stellar capture, which cannot be explained by standard tidal disruption theories. We suggest that this X-ray afterglow component may result from the Thomson scattering between the primary X-rays and its surrounding plasma, i.e., a Compton echo effect. Similar phenomena have also been observed from molecular clouds in our Galactic Center, which were caused by the past activity of Srg A∗. If this interpretation of Swift J1644+57 afterglow is correct, this is the first Compton Echo effect observed in the cosmological distances.

Original languageEnglish
Article numberL10
JournalAstrophysical Journal Letters
Issue number1
StatePublished - 1 Jan 2016


  • radiation mechanisms: non-thermal
  • X-rays: bursts


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