{
  "bibcode": "2021GCN.29577....1P",
  "body": "N.Pankov (HSE), S. Belkin (IKI),  A. Pozanenko (IKI), E. Klunko (ISTP) \nreport  on behalf of IKI GRB FuN:\n\nWe observed the field of GRB 210217A (Simpson  et al., GCN  29521) with \nAZT-33IK telescope of Sayan observatory (Mondy)  on 2021-02-19 and XX. \nWithin enhanced XRT position (Evans et al., GCN 29525) we do not detect \nafterglow (Simpson  et al., GCNs  29521,29555;  Zhu  et al., GCN  29523; \nZheng et al., GCN 29533; Shrestha et al., GCN  29535; Kumar et al., GCN \n29539). Preliminary photometry of the filed is following\n\nDate       UT start   t-T0       Filter Exp.    OT    Err.  UL(3sigma)\n                       (mid, days)        (s)\n\n2021-02-19 13:10:59   1.58579    R      2190   n/d   n/d   22.2\n2021-02-21 16:05:26   3.71250    R      3150   n/d   n/d   22.8\n2021-02-19+2021-02-21 2.65193    R      5850   n/d   n/d   22.9\n\nThe photometry is based on the nearby USNO-B1.0 star\nUSNO-B1.0_id R2\n1587-088041      17.94\n\nA light curve of afterglow of GRB 210217A (based on published \nphotometry) and upper limits can be found in\nhttp://grb.rssi.ru/GRB210217A/GRB210217A_LC.jpg\n\nUsing  upper   upper limit we may suggest a possible jet break of the \nlight curve we may suggest a jet break between 1.58 and 3.71 days after \npower law decay with index alpha of -0.48 (Shrestha et al., GCN 29535).",
  "circularId": 29577,
  "createdOn": 1614364521000,
  "email": "apozanen@iki.rssi.ru",
  "subject": "GRB 210217A: Mondy optical observations",
  "submitter": "Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>",
  "eventId": "GRB 210217A"
}