{
  "bibcode": "2002GCN..1378....1T",
  "body": "K. Torii (RIKEN), T. Kato (Kyoto U.), H. Yamaoka (Kyushu U.), and\nA. Yoshida (Aoyama Gakuin U., RIKEN) report:\n\n Based on the GCN alert notice, the GRB 020124 (Ricker, et al. GCN\n1220) was observed at RIKEN with the 0.25m f/3.4 hyperboloid\nastro-camera equipped with unfiltered cooled CCD AP7p. The field of\nview was 50'x50' which covered the HETE's entire error region of 12'\nradius (GCN 1220).  The observation started at 2002/1/24 12:43 UT (122\nminutes after the burst) and 126 frames of 20-s exposure were acquired\nby 13:47 UT. The central time of all the exposures were 2002/1/24\n13:15 UT. \n\n PSF photometry was applied to each frame and then stacked to yield\n3.0-sigma detection of the optical afterglow at the position reported\nby Price et al. (GCN 1221). By using 21 nearby comparison stars from\nthe Henden's field photometry (GCN 1251), we derive the afterglow's\nmagnitude as R=18.5 mag. The 1-sigma error range is estimated to be\nbetween R=18.2 and R=18.9.\n\n This message may be cited.",
  "circularId": 1378,
  "createdOn": 1019219567000,
  "email": "torii@crab.riken.go.jp",
  "subject": "GRB 020124: Optical observations",
  "submitter": "Ken ichi Torii at RIKEN  <torii@crab.riken.go.jp>",
  "eventId": "GRB 020124"
}