{
  "bibcode": "2021GCN.29805....1M",
  "body": "K. L. Murata, R. Hosokawa, M. Niwano, N. Ito, H. Takamatsu, Y. Yatsu, and\nN.Kawai (TokyoTech) report on behalf of the MITSuME collaboration:\n\nWe observed the field of GRB 210410A (The Fermi GBM team et al. GCN\nCircular #29777, A. Melandri  et al. GCN Circular #29778, V. Lipunov et al.\nGCN Circular #29779, M. Jelinek et al. GCN Circular #29780, M. Arimoto et\nal. GCN Circular #29781, A. Ursi et al. GCN Circular #29782, Nat Butler et\nal. GCN Circular #29784, Nat Butler et al. GCN Circular #29786, Paul Kuin\net al. GCN Circular #29787, J. Wood et al. GCN Circular #29788, A. D'Ai  et\nal. GCN Circular #29790, A. Y. Lien et al. GCN Circular #29793, A. Ridnaia\net al. GCN Circular #29797, A. Ursi  et al. GCN Circular #29798) with the\noptical three color (g', Rc, and Ic) CCD cameras attached to the MITSuME 50\ncm telescope of Akeno Observatory, Yamanashi, Japan. The observation with a\nseries of 60 sec exposures started at 2021-04-10 13:35 (9.7 hours after the\nFermi/GBM trigger). We stacked the images with good conditions. We did not\ndetect the optical afterglow reported previously (Jelinek et al. GCN\nCircular #29780, Butler et al. GCN Circular #29784) in all three bands. We\nobtained the 5-sigma limits of the stacked images as follows.\n\nT0+[hour] MID-UT T-EXP[sec] 5-sigma limits\n------------------------------------------------------------------------------------------------\n10.0 14:00:15 1740 g'>19.3, Rc>19.6, Ic>19.0\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": 29805,
  "createdOn": 1618223370000,
  "email": "murata@u.phys.nagoya-u.ac.jp",
  "subject": "GRB 210410A: MITSuME Akeno optical upper limits",
  "submitter": "Katsuhiro L. Murata at Nagoya U  <murata@u.phys.nagoya-u.ac.jp>",
  "eventId": "GRB 210410A"
}