{
  "bibcode": "2015GCN.18431....1K",
  "body": "D. Kuroda, K. Yanagisawa, Y. Shimizu, H. Toda (OAO, NAOJ),\nS. Nagayama (NAOJ), M. Yoshida (Hiroshima), K. Ohta (Kyoto)\nand N. Kawai(Tokyo Tech)\nreport on behalf of MITSuME and OISTER collaboration:\n\nWe observed the field of GRB 151021A (Melandri et al., GCNC 18425)\nwith the optical three color (g', Rc and Ic) CCD camera attached\nto the MITSuME 50cm telescope of Okayama Astrophysical Observatory.\n\nThe observation started on 2015-10-21 09:35:46 UT (8.1 h after\nthe burst). We could not detect the previously reported afterglow\n(de Ugarte Postigo et al., GCNC 18426; Lipunov et al., GCNC 18427)\nin all the three bands.\n\nThree sigma upper limits of the OT are listed below.\nWe used GSC2.3 catalog for flux calibration.\n\n#T0+[day]  MID-UT    T-EXP[sec]   g'    Rc     Ic\n-----------------------------------------------------\n0.37964    10:35:52    6180.0   >19.5  >19.7  >19.1\n-----------------------------------------------------\nT0+ : Elapsed time after the burst [day]\nT-EXP: Total Exposure time [sec]",
  "circularId": 18431,
  "createdOn": 1445437447000,
  "email": "dikuroda@oao.nao.ac.jp",
  "subject": "GRB 151021A: MITSuME Okayama upper limits",
  "submitter": "Daisuke Kuroda at OAO/NAOJ  <dikuroda@oao.nao.ac.jp>",
  "eventId": "GRB 151021A"
}