{
  "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\nWe observed the field of the GRB 260509A (Götz et al., GCN 44504)\nwith the Shajn 2.6-meter telescope (ZTSh) of the Crimean Astrophysical\nObservatory (CrAO). We obtained  40*120 s exposures R filter\non 2026-05-15 19:45:59--21:09:48 UT (5.94218 days after trigger).\n\nWe did not detect the OT (O'Neill et al., GCN 44505; Saccardi et al.,\nGCN 44506; Wu et al., GCN 44507; Sánchez Álvarez et al., GCN 44509;\nZheng et al., GCN 44510; Kechin et al., GCN 44512; Belkin, GCN 44513;\nCorcoran et al., GCN 44514; Bochenek and Perley, GCN 44516; Moskvitin\nand Spiridonova, GCN 44563; Mo et al., GCN 44590; Li et al., GCN 44598)\ndown to the 3-sigma limiting magnitude of R_lim = 24.2.\n\nThis preliminary photometry is based on nearby stars from the USNO-B1\ncatalogue (R2 magnitudes) and is not corrected for the Galactic\nextinction.",
  "submitter": "Alexander Moskvitin at SAO RAS <mosk@sao.ru>",
  "createdOn": 1779112195136,
  "submittedHow": "web",
  "bibcode": "2026GCN.44662....1M",
  "eventId": "GRB 260509A",
  "format": "text/plain",
  "subject": "GRB 260509A: CrAO ZTSh optical upper limit",
  "circularId": 44662
}