{
  "editedBy": "Vidushi Sharma at NASA GSFC/UMBC <vidushi.sharma@nasa.gov> on behalf of SVOM_group <svomgroup@bao.ac.cn>",
  "submitter": "SVOM_group <svomgroup@bao.ac.cn>",
  "body": "A. Saccardi, J. T. Palmerio (CEA/Irfu), C. Wu, L.P. Xin (NAOC), H. Yang, S. Guillot (IRAP) report on behalf of the SVOM mission team:\n\nWe observed the field of GRB 251222A (Yang et al., GCN 43188; Fermi GBM team, GCN 43186; Wang et al., GCN 43202; Guo et al., GCN 43201) with the LCO 1m telescope at South African Astronomical Observatory equipped with the Sinistro instrument.\n\nOur observation started at 2025-12-22T19:31:31 (about 2.43 hr after the trigger) and we obtained 3x200 s exposures in the SDSS r and 3x200 s exposures in the Pan-STARRS z filters. The optical counterpart reported by Palmerio et al. (GCN 43189) is clearly detected in our images.\n\nWe measure the following magnitudes, calibrated against the  Pan-STARRS1 catalog, and not corrected for Galactic extinction:\n\nr = 18.55 +/- 0.01 AB (mid-time of 3.04 hr after the trigger);\nz = 18.17 +/- 0.01 AB (mid-time of 2.59 hr after the trigger).\n\nThis result is consistent with the reports (An et al., GCN 43194; Durbak et al., GCN 43197, Li et al., GCN 43203).\n\nThis project is funded by the SVOM collaboration.\n",
  "bibcode": "2025GCN.43208....1S",
  "editedOn": 1766506828676,
  "submittedHow": "web",
  "format": "text/plain",
  "subject": "GRB 251222A / EP251222b: LCO  optical observations",
  "version": 2,
  "circularId": 43208,
  "createdOn": 1766474231627,
  "eventId": "GRB 251222A"
}