{
  "bibcode": "2007GCN..6430....1I",
  "body": "T. Ishimura, T. Shimokawabe, N. Vasquez, Y. Yatsu, Y. Kudou and\nN. Kawai (Tokyo Tech) report on behalf of the MITSuME collaboration:\n \nWe observed the field of GRB070520A (Romano et al., GCN 6423)\nwith the 3-color 50cm MITSuME Telescope at Akeno, Japan starting \nat 13:15:15 UT, 10 min after the trigger, under a clear, but windy\ncondition.\nIn the co-added images of Ic, Rc, and g' bands, we did not detect\nany new source in the XRT error circle.  The 3-sigma limiting\nmagnitudes based on USNO-B1.0 (I-band) and NOMAD (R-band,g'-band)\nstars are following.\n\nFilter   start time   end time    Exp(s)   Mag (3-sigma UL)  \n-----------------------------------------------------------\nIc       13:15:15    15:06:06     60s * 91         20.3    \nRc       13:15:15    15:06:06     60s * 91         21.2    \ng'       13:15:15    15:06:06     60s * 91         21.1    \n-----------------------------------------------------------",
  "circularId": 6430,
  "createdOn": 1179721191000,
  "email": "nkawai@hp.phys.titech.ac.jp",
  "subject": "GRB 070520A: MITSuME Akeno optical upper limits",
  "submitter": "Nobuyuki Kawai at Tokyo Tech  <nkawai@hp.phys.titech.ac.jp>",
  "eventId": "GRB 070520A"
}