{
  "bibcode": "2022GCN.31837....1P",
  "body": "N. Pankov (HSE), A. Zhornichenko (KIAM), A. Pozanenko (IKI), V. \nAgletdinov (KIAM), S. Belkin (IKI), Sh. Ehgamberdiev (UBAI) report on \nbehalf of IKI-GRB-FuN:\n\nWe observed the field of  GRB 220403B  (Klingler  et al., GCN 31820) \nwith Kitab RC-36  telescope in Clear filter.  Observation started on \nApril, 03  (UT) 21:23:55 and ended on April, 04 (UT) 00:00:11. We \nclearly detect the optical afterglow (Klingler  et al., GCN  31820; \nJelinek  et al., GCN 31821; Zhu  et al., GCN 31823; Rossi  et al., GCN \n31826; see also early upper limits in Lipunov et al., GCN 31825; Grossan \n  et al., GCN 31830) in the combined images of an initial part of \nobservations and do not detect it in the final part.\nPreliminary photometry of the  combined images is following\n\n  Date,      UT start, t-T0,   Exp.,  Filter, OT,    Err,  UL(3 sigma)\n                     (mid, days)\n\n2022-04-03  21:23:55 0.05178   40*60  CR      19.24  0.19   20.2\n2022-04-03  22:30:39 0.10640   87*60  CR      n/d    n/d    20.5\n\nThe photometry is based on nearby USNO-B1.0 stars, R2 magnitude\nUSNO-B1.0_id R2\n1791-0003982 16.77\n1791-0003984 17.83",
  "circularId": 31837,
  "createdOn": 1649193870000,
  "email": "apozanen@iki.rssi.ru",
  "subject": "GRB 220403B: Kitab optical observations",
  "submitter": "Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>",
  "eventId": "GRB 220403B"
}