{
  "bibcode": "2020GCN.27276....1P",
  "body": "A. Pozanenko (IKI), S. Belkin (IKI),  E. Klunko (ISTP), A. Kusakin \n(FAPHI),  I. Reva (FAPHI), V. Rumyantsev (CrAO), R. Ya. Inasaridze \n(AbAO), E. Mazaeva (IKI), A. Volnova (IKI) report on behalf of IKI-GRB-FuN:\n\nWe observed the field of GRB 200228B (Laha et al., GCN 27254; Fermi GBM \nTeam, GCN 27253) with AZT-33IK 1.5-m telescope of Sayan observatory \n(Mondy) starting on Feb. 28 (UT) 19:24:43. We detected an optical object \nnear the enhanced XRT position of the XRT afterglow (Evans et al., GCN \n27256). The object is absent in the Pan-STARRS DR1 catalog. The \ncoordinates of the object are (J2000) 16:48:10.88 +16:59:04.5 with \nuncertainty of 0.5 arcsec in both coordinates. Next we observed the \nfiled with Zeiss-1000 1-m telescope of Tien Shan Astronomical \nObservatory starting on Feb. 28 (UT) 23:08:56, Abastumani starting on \nFeb. 29 (UT) 01:38:45, Tien Shan Astronomical Observatory starting on \nFeb. 29 (UT) 23:08:56, and CrAO starting on Mar. 01 (UT) 00:58:28.\n\nPreliminary photometry of the object and the field is following.\n\nDate UT start       t-T0  Filter Exp. OT Err UL(3sigma)   telescope\n                         (mid, days) (s)\n2020-02-28 19:24:43 0.351  R 15*120 21.8  0.3  21.7 AZT-33IK\n2020-02-28 23:08:56 0.516  R 3480   n/d   n/d  22.3 Z-1000\n2020-02-29 01:38:45 0.616  R 46*60  n/d   n/d  21.8 AS-32\n2020-02-29 22:22:37 n/a    R 5040   n/a   n/a  n/a  Z-1000\n2020-03-01 00:58:28 1.594  R 31*120 22.05 0.09 23.8 ZTSh\n\n\nPhotometry is based on the USNO-B2.0 nearby stars.\nUSNO-B1.0    R2\n1069-0297786 18.42\n1069-0297719 18.25\n1069-0297797 14.78\n\nThe finding chart is available at \nhttp://193.232.11.154/GRB200228B/GRB200228B_AZT33IK_Z1000_ZTSh_FC.png \n(or \nhttp://grb.iki.rssi.ru/GRB200228B/GRB200228B_AZT33IK_Z1000_ZTSh_FC.png ).\n\nWe suggest this object is a candidate in the afterglow of GRB 200228B \nafter at least two epoch detections (see above), possible variability \nand absence of the bright object (R ~ 22) in the  Pan-STARRS DR1.\n\nWe did not detect any object at the position of NIR- candidate (Perley \nand  Cockeram, GCN 27271).",
  "circularId": 27276,
  "createdOn": 1583076079000,
  "email": "apozanen@iki.rssi.ru",
  "subject": "GRB 200228B: Mondy, TSHAO, AbAO and CrAO optical observations, afterglow candidate",
  "submitter": "Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>",
  "eventId": "GRB 200228B"
}