{
  "bibcode": "2013GCN.15241....1V",
  "body": "A. Volnova (IKI),  V. Nevskiy (ISON),  I. Molotov (KIAM), Yu. Krugly(IA \nKhNU), I. Slyusarev (IA KhNU), A. Pozanenko (IKI)  report on behalf of \nlarger collaboration:\n\nAfter the refined analysis of the ISON-Kislovodsk observations (Volnova \net al., GCN 15171) of GRB 130903A field (Mereghetti et al., GCN 15169) \nin the coordinates of OT reported by Tanga et al. (GCN 15177) we found a \nfaint source with a R magnitude 20.40 � 0.3. Photometry is  based on the \n  stars reported below.\n\nWe also observed the field of the field with AZT-8 (0.7m) telescope of \nInstitute of Astronomy, Kharkiv National University starting on Sep. 03 \n(UT) 01:38:52. We took 11 frames with exposures of 120 seconds in R \nfilter. On the stacked image within 1.5 arcmin of error circle \nlocalization (Mereghetti et al., GCN 15169) we do not detect any\nsource.\n\nPhotometry of combined image is the following\n\nT_start, T0+,    Exp.,  Filter, UL (3 sigma)\n(UT) mid (d)     (s)\n\n01:38:52 0.03579 11*120 R       >20.0\n\nand based on SDSS stars, R (gri -> R transformations by Lupton 2005):\n\n# SDSS R Err_R\n1 J052835.34-000624.7 15.543 0.013\n2 J052817.12-000749.0 14.650 0.012\n3 J052841.64-000642.3 14.233 0.013",
  "circularId": 15241,
  "createdOn": 1379790478000,
  "email": "apozanen@iki.rssi.ru",
  "subject": "GRB 130903A: optical observations",
  "submitter": "Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>",
  "eventId": "GRB 130903A"
}