{
  "format": "text/plain",
  "createdOn": 1788245811523,
  "submitter": "SVOM_group <svomgroup@bao.ac.cn>",
  "eventType": [
    "GRB",
    "Optical Transient"
  ],
  "subject": "GRB 260831B: LCO optical upper limits ",
  "circularId": 45482,
  "eventId": "GRB 260831B",
  "submittedHow": "web",
  "body": "Y.X. Guan (GXU), A. Saccardi, D. Turpin (CEA/Irfu), C. Wu, L.P. Xin (NAOC), C.Guepin (LUPM), C. Plasse (HKU) report on behalf of the SVOM mission team:\n \nWe observed the field of GRB 260831B (SVOM burst-id sb26083106 detected by SVOM (Godet et al., GCN 45477) with the LCO 1m telescope at Tenerife equipped with the Sinistro instrument.\n \nOur observation started on 2026-09-01 at 01:31:26 UT (about 6.92 hr after the trigger) and we obtained 3x200 s exposures in the SDSS r and 3x200 s exposures in the Pan-STARRS z filters.\n \nIn the stacked image, we do not detect any new source within the SVOM/ECLAIRs error box. We measure the following upper limit calibrated against the Pan-STARRS DR1 catalog, and not corrected for Galactic extinction:\n \nr >  21.5   AB (5-sigma, mid-time 7.22 hr after the trigger);\nz > 20.2   AB (5-sigma, mid-time 7.01 hr after the trigger).\n \nThis project is funded by the SVOM collaboration."
}