{
  "body": "L.B. He (NAOC), K. Noysena, K. Chanchaiworawit, S. Tinyanont (NARIT), S.Y. Fu (HUST),  J. An, X. Liu, Z.P. Zhu, S.Q. Jiang, D. Xu (NAOC) report on behalf of a large collaboration:\n\nWe observed the field of GRB 250812A (Xin et al., GCN 41322), using the 0.7-m telescope of the Thai Robotic Telescope network (TRT), located at Cerro Tololo Inter-American Observatory, Chile. Observations started at 04:32:00 UTC on 2025-08-12, i.e., ~1.8 hr after the SVOM/ECLAIRs trigger and a series of frames in the r band were obtained. \n\nIn our stacked image, we detect an uncatalogued source within the SVOM/ECLAIRs error circle at coordinates:\n\nR.A.(J2000) = 02:11:13.72 = 32.80715\nDec.(J2000) =  -43:09:49.21 = -43.16367\n\nwith an uncertainty of ~0.5 arcsec. We measure a preliminary magnitude of r ~ 18.8, calibrated with Legacy catalog and not corrected for Galactic extinction.\n\nWe suggest this is likely the optical counterpart of GRB 250812A.",
  "format": "text/plain",
  "circularId": 41324,
  "createdOn": 1754991334146,
  "submittedHow": "web",
  "eventId": "GRB 250812A",
  "submitter": "J. An <jiean0813@foxmail.com>",
  "subject": "GRB 250812A: TRT likely optical counterpart detection",
  "bibcode": "2025GCN.41324....1H"
}