GCN Circular 41324
Subject
GRB 250812A: TRT likely optical counterpart detection
Event
Date
2025-08-12T09:35:34Z (9 days ago)
From
J. An <jiean0813@foxmail.com>
Via
Web form
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:
We 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.
In our stacked image, we detect an uncatalogued source within the SVOM/ECLAIRs error circle at coordinates:
R.A.(J2000) = 02:11:13.72 = 32.80715
Dec.(J2000) = -43:09:49.21 = -43.16367
with 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.
We suggest this is likely the optical counterpart of GRB 250812A.