{
  "bibcode": "2021GCN.29438....1B",
  "body": "S. Belkin (IKI), A. Pozanenko (IKI), E. Klunko (ISTP), N. Pankov (HSE) \nreport  on behalf of GRB IKI FuN:\n\nWe continued observation of the ZTF21aagwbjr/AT2021buv transient (Kool \net al., GCN 29405) at the redshift of 0.876 (Xu et al., GCN 29432) which \nis  an afterglow (Kennea et al., GCN 29413; Teja  et al., GCN 29414) of \n  GRB 210204A (Fermi GBM team, GCN 29390; Li et al., GCN 29392; Hurley \net al., GCN 29408; Waratkar et al., GCN 29410;  Frederiks et al., GCN \n29415). Images in R-filter were taken in AZT-33IK telescope of Sayan\nobservatory (Mondy) on Feb.7 and Feb.8.\n\nPreliminary photometry of the optical transient in combined images in \ntwo epochs is following\n\nDate       UT start  t-T0     Filter Exp.  OT    Err.  UL(3s) Telescope\n                       (mid, days)        (s)\n\n2021-02-07 13:43:58 3.32260  R      60*60 20.61 0.04  22.8  AZT-33IK\n2021-02-08 15:22:01 4.39035  R      59*60 20.92 0.05  22.7  AZT-33IK\n\nThe photometry does not contradict a possible jet-break suggested by \nRossi et al (GCN 29433).\n\nThe photometry is based on the nearby USNO-B1.0 stars\nUSNO-B1.0_id R2\n1014-0149033 15.43\n1014-0149115 17.00",
  "circularId": 29438,
  "createdOn": 1612874435000,
  "email": "apozanen@iki.rssi.ru",
  "subject": "GRB 210204A (ZTF21aagwbjr/AT2021buv): continued Mondy optical observations",
  "submitter": "Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>",
  "eventId": "GRB 210204A"
}