{
  "eventId": "GRB 250903A",
  "circularId": 41686,
  "body": "A. Saccardi (CEA/Irfu), L. P. Xin (NAOC), C. Wu (NAOC), B. Cordier (CEA/Irfu), report on behalf of the SVOM mission team:\n\nWe observed the field of the GRB 250903A detected by SVOM/ECLAIRs (Maiolino et al., GCN 41677) with the LCO 1m telescope at South African Astronomical Observatory equipped with the Sinistro instrument.\n\nOur observation started on 2025-09-03 at 23:25:00 UT (6.0 hr after the trigger) and we obtained 4x300 s exposures using the SDSS r filter. In the stacked image, we detected the optical afterglow (An et al., GCN 41679, Xin et al., GCN 41684, Pérez-Fournon et al. GCN 41685) within the errorbox of SVOM/MXT (Gotz et al., GCN 41681).\n\nWe derived the following magnitude r = 20.04 +/- 0.11 mag calibrated by the Guide Star Catalog, Version 2.3.2 (GSC2.3) (STScI, 2006) and not corrected for Galactic extinction.\n\nThis project is funded by the SVOM collaboration.",
  "subject": "GRB 250903A: LCO optical observation",
  "submittedHow": "web",
  "submitter": "SVOM_group <svomgroup@bao.ac.cn>",
  "format": "text/plain",
  "bibcode": "2025GCN.41686....1S",
  "createdOn": 1756950515243
}