{
  "bibcode": "2002GCN..1589....1T",
  "body": "K. Torii (RIKEN), T. Kato (Kyoto Univ.), and H. Yamaoka (Kyushu Univ.)\nreport:\n\n In response to the GCN/HETE burst position notice, a part of the\nerror region of GRB 021004 (Shirasaki, et al., GCN 1565) was observed\nby the automated system at RIKEN. Starting at 12:09:27 UT (193-s after\nthe burst trigger), 30-s exposures were repeated with the 0.20-m\nreflector equipped with unfiltered CCD AP7p.\n\n Frequent passages of clouds significantly degraded the limiting\nmagnitudes of the data. The optical afterglow reported by Fox (GCN\n1564) is not visible in our early phase images. Comparison with the\nUSNO-A2.0 red magnitudes gave the following 3-sigma upper limits for\nthe afterglow. Further analyses for the full data set are in progress.\n\n----------------------------------------\nMean epoch     From GRB   Magnitude  \n----------------------------------------\n12:09:42 UT    208 s      > 13.6    \n12:10:21       247        > 13.6    \n12:11:00       286        > 13.6    \n12:11:40       326        > 14.2\n12:12:19       365        > 13.6\n----------------------------------------",
  "circularId": 1589,
  "createdOn": 1033895345000,
  "email": "torii@crab.riken.go.jp",
  "subject": "GRB 021004: Optical observations at RIKEN",
  "submitter": "Ken ichi Torii at RIKEN  <torii@crab.riken.go.jp>",
  "eventId": "GRB 021004"
}