{
  "submittedHow": "web",
  "bibcode": "2026GCN.44652....1M",
  "createdOn": 1778975520090,
  "body": "A. Moskvitin (SAO RAS), A. Pozanenko (IKI), V. Rumyantsev (CrAO),\nN. Pankov (IKI), A. Volnova (IKI) report on behalf of IKI GRB-FuN.\n\n\nWe observed the field of the GRB 260515A (Brunet et al., GCN 44622;\nWang et al., GCN 44642; Frederiks et al., GCN 44647) with the Shajn\n2.6-meter telescope (ZTSh) of the Crimean Astrophysical Observatory\n(CrAO). We obtained  series of 120 s exposures in BVRI filters\nstarting on 2026-05-15  22:10:11 UT (about 3 hours after trigger).\n\n\nThe OT (He et al., GCN 44623; Saccardi et al., GCN 44624; Sosnovskij\net al., GCN 44625; He et al., GCN 44626; Wu et al., GCN 44628;\nMalesani et al., GCN 44629; Dennefeld et al., GCN 44633; Li et al.,\nGCN 44634; Antier et al., GCN 44643; Pérez-Fournon et al., GCN 44645;\nDimple et al., GCN 44646) is clearly detected in the stacked frames.\nDetails of the photometry is the following.\n\nStart_UT,  t_mid-T0, exp, filter, mag,   err,  UL(3 sigma)\n \n\n2026-05-15T22:54:33  4.79 15*120 B 21.53  0.04 23.9\n2026-05-15T22:56:41  4.75 13*120 V 21.30  0.05 23.7\n2026-05-15T22:10:11  3.12  5*120 R 20.56  0.04 23.4\n2026-05-15T22:20:40  3.29  5*120 R 20.57  0.04 23.4\n2026-05-15T22:31:09  3.46  5*120 R 20.65  0.04 23.5\n2026-05-15T22:41:44  3.66  6*120 R 20.64  0.03 23.6\n2026-05-15T22:56:41  4.26  7*120 R 20.87  0.03 23.7\n2026-05-15T23:58:56  5.35  8*120 R 21.03  0.04 23.4\n2026-05-15T23:00:57  4.89 15*120 I 20.75  0.05 22.8\n\n\nThis preliminary photometry is based on nearby SDSS stars\n(using Lupton 2005 transformation equations) and  not corrected for Galactic extinction.",
  "format": "text/plain",
  "submitter": "Alexander Moskvitin at SAO RAS <mosk@sao.ru>",
  "circularId": 44652,
  "eventId": "GRB 260515A",
  "subject": "GRB 260515A: CrAO ZTSh BVRI optical observations"
}