{
  "bibcode": "2002GCN..1339....1M",
  "body": "GRB020331: Optical Observations of Afterglow Candidate\n\nG. Monnelly, A. Dullighan, N. Butler, R. Vanderspek, G. Ricker (MIT)\n\nwrite:\n\nWe observed the HETE error circle of GRB020331 (Ricker et al., GCN\n#1315) with the Baade 6.5m telescope at Magellan on 2002 April 1.22 UT\nusing LDSS-2.  The observations took place 12.7 hours after the burst.\nSeven 90s R-band exposures were used to mosaic the entire HETE error\ncircle. The limiting magnitude was R = 23.5, with 0.6\" seeing.\n\nWe detect the afterglow candidate reported by Fox et. al. (GCN #1334)\nat R = 21.05 +/- 0.11.  In comparison to their finding chart, the OT\nis clearly separated in our image from the stellar object 3.9 arcsec\nto the southeast, and we detect the reference star at R = 18.52 +/-\n0.11.  Magnitudes are calibrated against star G020331 (R = 18.945)\nfrom the photometry of Henden et. al. (GCN #1319).\n\nFurther, Fox et. al. (GCN #1334) report a weak detection of the\ncandidate on Mar 31.78, in observations having a limiting magnitude\nof R ~ 19.5 mag.  If we take R = 19.5 as an upper limit on the magnitude\nat this epoch, then our observations constrain the power law decay\nindex to be steeper than alpha = 0.8.\n\nThis message may be cited.",
  "circularId": 1339,
  "createdOn": 1018286116000,
  "email": "grr@space.mit.edu",
  "subject": "GRB020331: Optical Observations of Afterglow Candidate",
  "submitter": "George Ricker at MIT  <grr@space.mit.edu>",
  "eventId": "GRB 020331"
}