{
  "bibcode": "2021GCN.30936....1I",
  "body": "N. Ito, R. Hosokawa, K. L. Murata, Y. Imai, Y. Takamatsu, M. Niwano, R.\nNoto, S. Sato, M. Takaku, R. Yamaguchi, Y. Yatsu, and N. Kawai (Tokyo Tech)\nreport on behalf of the MITSuME collaboration:\n\nWe observed the field of Swift/BAT trigger 1078701 (Bernardini et al., GCN\n#30929) with the optical three color (g', Rc, and Ic) CCD cameras attached\nto the MITSuME 50 cm telescope Akeno. The observation with a series of 10\nsec exposures started at 2021-10-10 10:43:22 (46 seconds after Swift\ntrigger). We stacked the images with good conditions. We did not detect any\nuncatalogued sources within the BAT error region (Bernardini et al., GCN\n#30929). Also, we did not detect the possible optical counterpart reported\nby Mondy, CrAO, AbAO observations (N. Pankov et al., GCN #30932). We\nobtained the 5-sigma limits of the stacked images as follows.\n\nT0+[hour] MID-UT T-EXP[sec] 5-sigma limits\n------------------------------------------------------------------------------------------------\n1.3 2021-10-10 12:00:19 540 g'>17.4, Rc>17.5, Ic>16.3\n------------------------------------------------------------------------------------------------\nT0+ : Elapsed time after the burst\nT-EXP: Total Exposure time\n\nWe used PS1 catalog for flux calibration.\nThe magnitudes are expressed in the AB system.\nThe images were processed in real-time through the MITSuME GPU reduction\npipeline (Niwano et al. 2021, PASJ, Vol.73, Issue 1, Pages 4-24;\nhttps://github.com/MNiwano/Eclaire).",
  "circularId": 30936,
  "createdOn": 1634104861000,
  "email": "n.ito@hp.phys.titech.ac.jp",
  "subject": "Swift trigger 1078701: MITSuME Akeno optical upper limits",
  "submitter": "Naohiro Ito at Tokyo Tech  <n.ito@hp.phys.titech.ac.jp>"
}