{
  "bibcode": "2015GCN.17567....1R",
  "body": "V. Rumyantsev (CrAO), E. Mazaeva (IKI),  A. Volnova (IKI), A. Pozanenko \n(IKI) report on  behalf of larger GRB follow-up collaboration:\n\nWe observed the field of the Swift GRB GRB 150222A (Bernardini et al., \nGCN 17486) with ZTSh telescope of CrAO observatory starting on\nFeb. 22 (UT) 23:19:54. We took several images in R-filter of 120 s \nexposure under non-optimal weather conditions and mean seeing of 4\". \nWithin enhanced  XRT position (Beardmore et al., GCN 17494) we detect a \nsource in coordinates (J2000) 13 15 08.74 -12 09 07.2 with uncertainty \nof 0.4 arcsec in both coordinates. The source position is coincident \nwith the optical afterglow candidate (Nicuesa Guelbenzu et al., GCNs \n17495, GCN 17506).  Photometry of the source in a combined image is \nfollowing\n\nDate       UT start,  t-t0     Filter   Exp.    OT   OT_err UL(3sigma)\n                       (mid, days)        (s)\n\n2015-02-22 23:19:54   0.2913   R        34*120  23.0 0.3    23.3\n\nThe photometry is based on USNO-B1.0  star 0778-0337957 (J2000) 13 15 \n05.41 -12 08 17.5 assuming R2=15.31\n\nTaking into account photometry of the source r' = 24.6+/-0.3 at ~0.42 \ndays reported by Nicuesa Guelbenzu et al. (GCN 17495) one could suggest \nthe source is the optical afterglow of GRB 150222A.\n\nThe source reported in GCN 17489 (Mazaeva et al) is clearly visible in \ncoordinates (J2000) 13 15 08.30 -12 08 57.5 with uncertainty of 0.4 \narcsec in both coordinates. A photometry of the source is R=22.12+/-0.12.",
  "circularId": 17567,
  "createdOn": 1426108385000,
  "email": "apozanen@iki.rssi.ru",
  "subject": "GRB 150222A: CrAO optical observation",
  "submitter": "Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>",
  "eventId": "GRB 150222A"
}