{
  "bibcode": "2021GCN.29708....1P",
  "body": "A. Pozanenko (IKI), N. Pankov (HSE), E. Klunko (ISTP), S. Belkin (IKI) \nreport  on behalf of GRB IKI FuN:\n\nWe observed the field of short GRB 210323A (Gropp et al., GCN 29699) \nwith AZT-33IK telescope of Sayan observatory (Mondy) starting on \n2021-03-23 (UT) 22:05:05, i.e. 167 s after GRB trigger. We obtained 10 \nimages in R-filter. In the first image we detect an object (S/N = 4.2) \nin coordinates of (J2000) 21:11:47.35, 25:22:09.4 with uncertainty of \n0.6\" in each coordinate. The coordinates are in agreement with reported \nby NOT an afterglow candidate (Malesani  et al., GCN 29703)  and \nenhanced XRT position (Evans et al., GCN 29704). In the next two stacked \nimages the object is barely detected (S/N =1.8), while in rest stacked \nimages we do not detect the object.\n\nPreliminary photometry of the object and the field in  stacked images is \nfollowing\n\nDate       UT start   t-T0       Filter Exp.   OT   Err.  UL(3sigma)\n                       (mid, days)        (s)\n\n2021-03-23 22:05:05   0.00229    R      1*60  18.4  0.25      18.9\n2021-03-23 22:06:07   0.00333    R      2*60  19.2  S/N =1.8  19.0\n2021-03-23 22:08:06   0.00403    R      5*60  n/d   n/d       18.9\n\nThe photometry is based on the nearby USNO-B1.0 star\nUSNO-B1.0_id R2\n1153-0524625 14.44\n\nThe non-detection of the object in Nanshan/NEXT observations up to \ndeeper limiting magnitude of r~20.4 (Fu et al., GCN 29700) might be due \nto searching of the afterglow in a stacked image but non in early single \nimages.",
  "circularId": 29708,
  "createdOn": 1616588409000,
  "email": "apozanen@iki.rssi.ru",
  "subject": "GRB 210323A: Mondy optical observations, counterpart detection",
  "submitter": "Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>",
  "eventId": "GRB 210323A"
}