{
  "bibcode": "2011GCN.12380....1P",
  "body": "A. Pozanenko (IKI), M. Andreev, A. Sergeev (Terskol Branch of Institute of \nAstronomy),  M. Ibrahimov (MAO) on behalf of larger GRB follow up \ncollaboration report:\n\nWe observed  the field of the Swift GRB 110921A (Baumgartner et al., GCN \n12373) with Zeiss-600 telescope of Mt. Terskol observatory and AZT-22 \ntelescope of Maidanak observatory on Sep. 21. Several images were taken in \nboth observatories in R filter. Within the enhanced XRT error box  (Goad et \nal., GCN 12379)  we do not  detect the candidate of optical counterpart of \nGRB 110921A (Xin et al., GCN 12377).  Preliminary photometry of a combined \nimage (Zeiss-600) and a single image of AZT-22 is based on the nearby USNO \nB1.0 stars:\n\nUT                 Filter,   Exposure, OT,        Upper Limit (3 sigma) \nTelescope\n(mid)                           (s)\n\nSep.21 16:50  R        1800       n/d           21.1 \nZeiss-600\nSep.21 17:48  R         300        n/d           21.2 \nAZT-22\n\nSince our photometry is somewhat deeper than photometry of the candidate \n(Xin et al., GCN 12377), we could suggest the candidate is a real afterglow \nof GRB 110921A.",
  "circularId": 12380,
  "createdOn": 1316637656000,
  "email": "apozanen@iki.rssi.ru",
  "subject": "GRB 110921A: optical observations in Mt. Terskol and Maidanak observatories",
  "submitter": "Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>",
  "eventId": "GRB 110921A"
}