{
  "bibcode": "2021GCN.29496....1M",
  "body": "K. L. Murata, R. Adachi, R. Hosokawa, M. Niwano, F. Ogawa, N. Nakamura, N.\nIto, S. Ogata, H. Takamatsu, H. Hara, Y. Yatsu, and N. Kawai (TokyoTech)\nreport on behalf of the MITSuME collaboration:\n\nWe observed the field of GRB 210212A (Troja et al. GCN #29487, Beardmore et\nal. GCN #29489, Palmer et al. GCN #29491, Kuin et al. GCN #29492, Hu et al.\nGCN #29494, Tohuvavohu et al. GCN #29495)  with the optical three color\n(g', Rc, and Ic) CCD cameras attached to the MITSuME 50 cm telescope of\nAkeno Observatory, Yamanashi, Japan. The observation with a series of 60\nsec exposures started at 2021-02-12 08:51:45 UT(4.43 hours after the Swift\nBAT trigger). We stacked the images with good conditions. We did not find\nany new point sources within the enhanced Swift XRT circle (Beardmore et\nal. GCN #29489) in all three bands.\nWe obtained the 5-sigma limits of the stacked images as follows.\n\nT0+[hour] MID-UT T-EXP[sec] 5-sigma limits\n------------------------------------------------------------------------------------------------\n8.6 13:05:08 5400 g'>18.6, Rc>18.5, Ic>17.8\n------------------------------------------------------------------------------------------------\nT0+ : Elapsed time after the burst\nT-EXP: Total Exposure time\nWe used the PS1 catalog for flux calibration. The magnitudes are expressed\nin the AB system. The images were processed in real-time through the\nMITSuME GPU reduction pipeline (Niwano et al. 2021, PASJ, Vol.73, Issue 1,\nPages 4-24; https://github.com/MNiwano/Eclaire).",
  "circularId": 29496,
  "createdOn": 1613149083000,
  "email": "murata@u.phys.nagoya-u.ac.jp",
  "subject": "GRB 210212A: MITSuME Akeno optical upper limits",
  "submitter": "Katsuhiro L. Murata at Nagoya U  <murata@u.phys.nagoya-u.ac.jp>",
  "eventId": "GRB 210212A"
}