{
  "bibcode": "2007GCN..6198....1W",
  "body": "J. Wren, W.T. Vestrand, P.R. Wozniak, R. White, J. Pergande\nof Los Alamos National Laboratory report:\n \nOur Raptor telescopes responded to Integral trigger 6146\n(Mereghetti et al., GCN 6189) at 01:53:16.10 UT, 26.1 s after\nthe trigger and 5.9 s after receiving the GCN packet.  We detected\noptical emission from the IR counterpart reported by Covino et al.\n(GCN 6190) and confirmed by Bloom et al. (GCN 6191).  Due to\ntwilight conditions we did not detect the optical counterpart while\nthe gamma-rays were still being detected by Integral (3-sigma\nlimiting magnitude R~15.5).  As the twilight period ended we detected\nthe counterpart at magnitude 17.8 +/- 0.2 in a 40 s image stack with\na mid-exposure time of 01:55:22.7 UT.  Subsequent image stacks show\nfading of the counterpart.  Our unfiltered magnitudes were calibrated\nusing the R-band magnitudes from the USNO B1.0 catalog.",
  "circularId": 6198,
  "createdOn": 1173672202000,
  "email": "jwren@nis.lanl.gov",
  "subject": "GRB 070311: RAPTOR Detection of Optical Emission",
  "submitter": "James Wren at LANL  <jwren@nis.lanl.gov>",
  "eventId": "GRB 070311"
}