{
  "bibcode": "2009GCN..9858....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 090831B (De Pasquale et al. GCN\n9851) with the optical three color (g', Rc and Ic) CCD camera\nattached to the MITSuME 50cm telescope of Okayama Astrophysical\nObservatory. The observation started on 2009-08-31 18:03:21 UT\n(2m 7s after the burst). We did not find any new point source\nin the BAT error circle reported by De Pasquale et al. (GCN 9851)\nin all the three bands.\n\nThree sigma upper limits of the OT are listed below. We used\nGSC2.3 catalog for flux calibration.\n\n#PDAY      MID-UT   T-EXP      g'     Rc      Ic\n--------------------------------------------------\n0.00505  18:09:49    540.0   >19.0   >18.8   >18.1\n0.03482  18:52:41   4200.0   >19.9   >19.7   >19.0\n--------------------------------------------------",
  "circularId": 9858,
  "createdOn": 1251797730000,
  "email": "yoshida@oao.nao.ac.jp",
  "subject": "GRB 090831B: MITSuME optical upper limits",
  "submitter": "Michitoshi Yoshida at Okayama Astrophysical Obs  <yoshida@oao.nao.ac.jp>",
  "eventId": "GRB 090831B"
}