{
  "bibcode": "2011GCN.12470....1F",
  "body": "W. Fong and E. Berger (Harvard) report:\n\n\"We re-imaged the field of GRB 111020A (GCN 12640) with GMOS on the\nGemini-South telescope on 2011 October 22.01 UT (mid-time of 1.7 days\npost-burst, and 23.1 hours after our initial observations; GCN 12467).  We\nobtained 11x180s exposures in i-band in 0.73\" seeing.\n\nWe still detect the two faint sources S1 and S2 from our previous GMOS\nobservation (GCN 12467), and neither source shows evidence for fading.\nDigital image subtraction of the two epochs using the ISIS package reveals\nno residuals inside or near the XRT error circle.  We therefore place a\nlimit on the optical afterglow of i~25 mag at 17.7 hours after the burst.\"",
  "circularId": 12470,
  "createdOn": 1319251664000,
  "email": "wfong@cfa.harvard.edu",
  "subject": "GRB 111020A: Gemini-South additional observations and limit on an optical afterglow",
  "submitter": "Wen-fai Fong at CFA  <wfong@cfa.harvard.edu>",
  "eventId": "GRB 111020A"
}