{
  "eventId": "GRB 260903A",
  "circularId": 45527,
  "submitter": "Alexander Moskvitin at SAO RAS <mosk@sao.ru>",
  "createdOn": 1788782340672,
  "submittedHow": "email",
  "body": "A. Moskvitin (SAO RAS), O. Spiridonova (SAO RAS), A. Pozanenko (IKI),\nA. Volnova (IKI), N. Pankov (IKI) report on behalf of GRB follow-up team\n\nWe observed the field of the GRB 260903A discovered by the SVOM\n(Brunet et al., GCNs 45499; 45517), and observed by EP (Li et al.,\nGCN 45510). Observations were carried out using the SAO RAS\nZeiss-1000 telescope and a new CCD photometer. A set of 18 x 300 sec.\nimages in Rc band obtained on September 5, 19:34:52--21:25:55 UT\n(t_mid - T0 = 2.32851 days).\n\nWe do not detect the OT (Li et al., GCN 45504; Saccardi et al.,\nGCN 45505; Malesani et al., GCN 45508; Russeil et al., GCN 45509;\nMoskvitin et al., GCN 45515; Bochenek and Perley, GCN 45516)\nin a stacked image. Details of the observation are the following.\n\nDate,      UTstart, t-T0,   Exp., Filter, Mag,     Err.,     UL\n                    (mid,d) (n*s)                          (3-sigma)\n\n2026-09-05 19:34:52 2.32851 18*300 Rc     n/d               24.1\n\nThe preliminary photometry (Vega) is based on nearby SDSS stars\n(Lupton 2005 transformation) and not corrected for Galactic extinction.\n",
  "subject": "GRB 260903A: SAO RAS optical upper limit"
}