{
  "bibcode": "2022GCN.32320....1T",
  "body": "Y. Takamatsu, N. Ito, M. Niwano, Y. Imai, S. Sato, M. Tateda, N.\nHiguchi, T. Hattori, R. Hosokawa, K. L. Murata, M. Sasada, Y. Yatsu,\nand N. Kawai (Tokyo Tech) report on behalf of the MITSuME\ncollaboration:\n\nWe observed the field of GRB 220701A (P. A. Evans et al. GCN Circular\n#32306 & #32308, B. O'Connor et al. GCN Circular #32309, S. R. Oates\net al. GCN Circular #32310, Y.-D. Hu et al. GCN Circular #32311, R.\nStrausbaugh et al. GCN Circular #32313, J. D. Gropp et al. GCN\nCircular #32314, WeiKang Zheng et al. GCN Circular #32315, S. Belkin\net al. GCN Circular #32317, Alan M. Watson et al. GCN Circular #32318)\nwith the optical three color (g', Rc, and Ic) CCD cameras attached to\nthe MITSuME 50 cm telescope Akeno.\n\nThe observation with a series of 60 sec exposures started at\n2022-07-01 19:37:09 UT (884 minutes after the Swift/BAT trigger). We\nstacked the images with good conditions. We did not detect any\nuncatalogued sources within the enhanced Swift/BAT error region (Evans\net al. GCN Circular #32306). We obtained the 5-sigma limits of the\nstacked images as follows.\n\nT0+[days] | MID-UT | T-EXP[sec] | 5-sigma limits\n------------------------------------------------------------------------------------------------\n0.6 | 2022-07-01 14:31:19 | 9060 | g'>19.4, Rc>20.1, Ic>20.9\n------------------------------------------------------------------------------------------------\nT0+ : Elapsed time after the burst\nT-EXP: Total Exposure time\n\nWe used 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,\nIssue 1, Pages 4-24; https://github.com/MNiwano/Eclaire).",
  "circularId": 32320,
  "createdOn": 1656916712000,
  "email": "takamatsu@hp.phys.titech.ac.jp",
  "subject": "GRB 220701A: MITSuME Akeno optical upper limits",
  "submitter": "Yutaka Takamatsu at Tokyotech  <takamatsu@hp.phys.titech.ac.jp>",
  "eventId": "GRB 220701A"
}