{
  "bibcode": "2009GCN..9002....1Y",
  "body": "M. Yoshida, D. Kuroda, K. Yanagisawa, Y. Shimizu, S. Nagayama,\nH. Toda (OAO, NAOJ) and N. Kawai (Tokyo Tech) report on behalf\nof the MITSuME collaboration:\n\nWe observed the field of GRB 090313 (Mao et al. GCN 8980) with\nthe optical three-color (g', Rc and Ic) CCD camera attached to\nthe MITSuME 50cm telescope of Okayama Astrophysical Observatory.\nThe observation started on 2009-03-14 14:27:51 UT (29.34 hours\nafter the alert). We detected a point source at the position of\nthe X-ray - optical - IR afterglow (Chornock and Filippenko GCN\n8979; Mao et al. GCN 8991; Updike et al. GCN 8983; Vaalsta et al.\nGCN 8996; de Ugarte Postigo et al. GCN 8992, GCN 8999; Perley\nGCN 8997; Perley et al. GCN 9001) in Ic band. Photometric result\nis listed below. We used GSC2.3 catalog for flux calibration.\n\nMid-UT                Td           Exp.Time      Ic\n-------------------------------------------------------------\n2009-03-14 16:30:24   31.3775 hr   60sec x 171   19.3 +/- 0.2\n-------------------------------------------------------------\n\nOur result and previous reports (Vaalsta et al. GCN 8996; Perley\nGCN 8997; de Ugarte Postigo et al. GCN 8999) show that the\nafterglow maintained its brightness from 10 hours to 30 hours\nafter the burst. de Ugarte Postigo et al. (GCN 8999) and Perley\net al. (GCN 9001) reported steep decline of the I band magnitude\nof the object after our observation. Thus the break point of the\nlight curve may exist at around 31 hours after the burst.",
  "circularId": 9002,
  "createdOn": 1237197501000,
  "email": "yoshida@oao.nao.ac.jp",
  "subject": "GRB 090313: MITSuME Okayama observation",
  "submitter": "Michitoshi Yoshida at Okayama Astrophysical Obs  <yoshida@oao.nao.ac.jp>",
  "eventId": "GRB 090313"
}