GCN Circular 40916
Subject
GRB 250702F: TRT Optical Observation
Event
Date
2025-07-03T14:23:55Z (9 hours ago)
From
Zipei Zhu at NAOC <zpzhu@nao.cas.cn>
Via
Web form
J. An (NAOC), K. Noysena, K. Chanchaiworawit, S. Tinyanont (NARIT), S.Y. Fu (HUST), X. Liu, Z.P. Zhu, S.Q. Jiang, L.B. He, D. Xu (NAOC) report on behalf of a large collaboration:
We observed the field of GRB 250702F detected by Swift/BAT (Klingler et al., GCN 40894) and Fermi/GBM (Fermi GBM Team, GCN 40892), using the 0.7-m telescope of the Thai Robotic Telescope network (TRT), located at Fresno, California, U.S.A. (SRO). Observations started at 05:17:25 UTC on 2025-07-03, i.e., ~ 8.18 hr after the Swift/BAT trigger and several frames in the R & I band were obtained.
We clearly detect the optical afterglow (Jelinek et al., GCN 40895; Kumar et al., GCN 40896; Lipunov et al., GCN 40899; Martin-Carrillo et al., GCN 40900; Angulo et al., GCN 40907; Becerra et al., GCN 40911; Brivio et al., GCN 40913) in our images. Preliminary photometry shows that the source has R ~ 19.4 mag at 8.32 hr post-trigger and I ~ 18.6 mag at 8.61 hr post-trigger, calibrated with Pan-STARRS DR2 catalog and not corrected for Galactic extinction.