{
  "bibcode": "2011GCN.11820....1S",
  "body": "B. Sbarufatti (INAF-OAB/IASFPA) reports on behalf of the Swift-XRT team:\n\nSwift performed a second target of opportunity observation of\nGRB 110319B on March 23, 2011.\n\nThe XRT began observing the field at 2011-03-23 17:57:33 UT, that is\nT+340 ks ( 3.9 days) (Cummings, GCN Circ. 11813).\nUsing 4.9 ks of Photon Counting mode data we find that the source\nreported previously (Sbarufatti, GCN Circ. 11814) has faded down to\na 3-sigma upper limit of 0.002 counts/s.\nAssuming a power law decay starting from the first source detection\nthe upper limit is consistent with a decay index steeper than\nalpha = 0.6.\n\nThe fading nature of the source confirms its afterglow origin.\n\nThis circular is an official product of the Swift-XRT team.",
  "circularId": 11820,
  "createdOn": 1300984262000,
  "email": "boris.sbarufatti@brera.inaf.it",
  "subject": "GRB 110319B Swift-XRT afterglow confirmation",
  "submitter": "Boris Sbarufatti at INAF-OAB/IASFPA  <boris.sbarufatti@brera.inaf.it>",
  "eventId": "GRB 110319B"
}