{
  "circularId": 44963,
  "createdOn": 1781688790882,
  "submitter": "Alexander Moskvitin at SAO RAS <mosk@sao.ru>",
  "body": "A. Moskvitin (SAO RAS), O. Maslennikova (SAO RAS),\nV. Goranskij (SAI MSU, SAO RAS), A. Pozanenko (IKI), A. Volnova (IKI),\nN. Pankov (IKI) report on behalf of GRB follow-up team\n\nWe observed the field of GRB 260610B discovered by Fermi (The Fermi\nGBM team, GCN 44891; GCN 44901; Godwin and Meegan; GCN 44931),\nand also detected by SVOM (Yu et al., GCN 44944), with the Zeiss-1000 1-m\ntelescope of SAO RAS + CCD photometer in Rc band on June 14,\n15 and 16.\n\n\nThe OT (O'Neill et al., GCN 44903; Watson et al., GCN 44905;\nZhu et al., GCN 44909; Gillanders et al., GCN 44910; Akl et al.,\nGCN 44911; O'Neill et al., GCN 44914; Moskvitin et al., GCN 44918;\nJackson-Horne et al., GCN 44919; Izzo, GCN 44920; Li et al.,\nGCN 44921; Bochenek and Perley, GCN 44927; Moskvitin et al., GCN 44929;\nAkl et al., GCN 44930; Bochenek and Perley, GCN 44932; Pankov et al.,\nGCN 44946; Gillanders et al., GCN 44955; Angulo et al., GCN 44958;\nDimple et al., GCN 44959) is detected in our stacked images\nwith the following brightness:\n\nDate,      UTstart, t-T0,   Exp.,  Filter, Mag, Err., UL\n                    (mid,d) (n*s)                    (3-sigma)\n                   \n2026-06-14 23:15:23 4.56847 15*180 Rc      21.14 0.12 22.3\n2026-06-15 23:42:44 5.57617  8*180 Rc      20.98 0.17 21.8\n2026-06-16 20:30:40 6.44388  3*600 Rc      21.06 0.18 21.9\n\nThis preliminary photometry is based on nearby SDSS stars\n(using Lupton 2005 transformation equations) and not corrected\nfor Galactic extinction.\n \nAlthough we cannot directly confirm that the afterglow brightness has increased, we can observe a plateau in the afterglow light curve.",
  "eventId": "GRB 260610B",
  "format": "text/plain",
  "submittedHow": "web",
  "bibcode": "2026GCN.44963....1M",
  "subject": "GRB 260610B / AT2026owq: SAO RAS optical observations of possible re-brightening"
}