{
  "submitter": "Alexander Moskvitin at SAO RAS <mosk@sao.ru>",
  "createdOn": 1792535590978,
  "circularId": 46001,
  "eventId": "GRB 261017A",
  "subject": "GRB 261017A: SAO RAS optical upper limit",
  "body": "A. Moskvitin (SAO), V. Vlasyuk (SAO), A. Volnova (IKI),\nN. Pankov (IKI) and A. Pozanenko (IKI) on behalf of the SAO GRB\nfollow-up team and the IKI-GRB-FuN report.\n\nWe observed the field of GRB 261017A detected by Fermi, Swift\nand Konus-Wind (The Fermi GBM team, GCN 45973; Siegel et al.,\nGCN 45974; Mukherjee et al., GCN 45976; Beardmore et al., GCN 45977;\nSbarrato et al., GCN 45979; Barthelmy et al., GCN 45985;\nRidnaia et al., GCN 45990) with the SAO RAS 0.5-m AS-500 (2)\ntelescope on 2026-10-18T00:50:15--2026-10-18T02:31:59.\n\nWe did not detect the OT possibly discovered by Swift/UVOT\n(Kuin et al., GCN 45988) or any source within the XRT enhanced error\ncircle (Beardmore et al., GCN 45977) in our stacked image\ndown to the following limiting magnitude.\n\nDate        UT start  t-T0      Exp,    Filter   UL\n                     (mid, d)   (n*s)\n2026-10-18  00:50:15  0.4000    88*60   R        21.2\n\nOur non-detection is in a good agreement with the other observations:\nFu et al., GCN 45978; Hagio et al., GCN 45980; Tan et al., GCN 45982;\nBao et al., GCN 45987; de Ugarte Postigo et al., GCN 45995).\n\nThis preliminary photometry (Vega) is based on nearby SDSS stars\n(Lupton 2005 transformation) and not corrected for Galactic extinction.\n",
  "submittedHow": "email"
}