{
  "bibcode": "2019GCN.23711....1O",
  "body": "M. Oeda,  K. L. Murata, R. Itoh, Y. Tachibana, S. Harita, K. Morita,\nK.Shiraishi, K. Iida, M. Niwano, R. Adachi, Y. Yatsu, and N. Kawai\n(TokyoTech)\nreport on behalf of the MITSuME collaboration:\n\nWe searched for the optical counterpart of GRB 190109B (B. Sbarufatti\net al.,GCN Circular #23648) with the optical three color (g', Rc, and\nIc) CCD cameras attached to the MITSuME 50 cm telescope of Akeno\nObservatory,Yamanashi, Japan.\n\nThe observation started on 11:57:03.81 UT. We did not find any new\npoint source within the enhanced XRT circle (A.P. Beardmore et al.,\nGCN Circular #23652) in all three bands. We obtained following 5 sigma\nlimits for the magnitudes.\n\nT0+[min]    MID-UT      T-EXP[sec]    g'       Rc        Ic\n-------------------------------------------------------------------------------------------------------\n0.913      11:57:33.81           60        >17.54     >17.26     >16.72\n0.913       12:31:59.3          3660      >19.29     >17.67     >17.12\n-------------------------------------------------------------------------------------------------------\nT0+ : Elapsed time after the burst\nT-EXP: Total Exposure time\nWe used UCAC-4 catalog for flux calibration.",
  "circularId": 23711,
  "createdOn": 1547550943000,
  "email": "oeda@hp.phys.titech.ac.jp",
  "subject": "GRB190109B: MITSuME Akeno optical upper limits",
  "submitter": "Motoki Oeda at Tokyo Inst. of Tech.  <oeda@hp.phys.titech.ac.jp>",
  "eventId": "GRB 190109B"
}