{
  "body": "Y.Y. Shi (GXU), C. Wu, L.P. Xin (NAOC), A. Saccardi, D. Turpin (CEA/Irfu), Clara Plasse (HKU), Donghua Zhao (NAOC), report on behalf of the SVOM mission team:\n\n\nWe observed the field of GRB 260818A (SVOM burst-id sb26081801) detected by SVOM (Yin et al., GCN 45391) with the LCO 1m telescope at Teide Observatory and South African Astronomical Observatory equipped with the Sinistro instrument.\n\nOur observation started on 2026-08-18 at 01:46:28.00 UT (about 41.87 min after the trigger) and we obtained 6x200 s exposures in the SDSS r and 3x200 s exposures in the PS1 zs filter.\n\nNo credible uncatalogued source was detected in our stacked frames in the ECLAIRs localization region as also reported by SVOM/COLIBRÍ (Ducoin et al., GCN 45393). \n\nWe measure the following upper limits calibrated against the DESI Legacy Imaging Surveys DR10 catalog, and not corrected for Galactic extinction:\n\nr > 21.8 AB (5-sigma, mid-time 1.01 hr after the trigger),\nz > 20.5 AB (5-sigma, mid-time 1.14 hr after the trigger).\n\nThis project is funded by the SVOM collaboration.\n",
  "eventType": [
    "GRB",
    "Optical Transient"
  ],
  "format": "text/plain",
  "submittedHow": "web",
  "createdOn": 1787065710035,
  "subject": "GRB 260818A: LCO optical upper limits",
  "submitter": "SVOM_group <svomgroup@bao.ac.cn>",
  "circularId": 45395,
  "eventId": "GRB 260818A"
}