TITLE: GCN CIRCULAR NUMBER: 40936 SUBJECT: GRB 250702F: SVOM/VT optical observation DATE: 25/07/04 05:57:52 GMT FROM: SVOM_group <svomgroup@bao.ac.cn> Y.N. Ma, L. P. Xin, Y. L. Qiu, C. Wu, H. L. Li, Z. H. Yao, X. H. Han, Y. Xu, J. Wang, P. P. Zhang, W. J. Xie, Y. J. Xiao, H. B. Cai, L. Lan, J. S. Deng, J. Y. Wei (NAOC), J. Palmerio (CEA), Y. H. Cheng(YNU), J. X. Cao(GXU) report on behalf of the SVOM/VT team SVOM/VT performed a Target of Opportunity observation of GRB 250702F detected by Swift-BAT（Klingler et al., GCN 40894） and Fermi-GBM (Fermi GBM Team, GCN 40892). The observation began at 2025-07-03T15:11:40 UTC, 18.08 hours after the trigger, in the VT_B (400nm-650nm) and VT_R (650nm-1000nm) channels simultaneously. The optical afterglow (Klingler et al., GCN 40894; Jelinek et al., GCN 40895; Kumar et al., GCN 40896; Lipunov et al., GCN 40899; Martin-Carrillo et al., GCN 40900; de Ugarte Postigo et al., GCN 40901; Angulo et al., GCN 40907; Becerra et al., GCN 40911; Brivio et al., GCN 40913; An et al., GCN 40916; Dutton et al., GCN 40921; Odeh et al., GCN 40925; Moretti et al., GCN 40926; Siegel et al., GCN 40933) is detected using VT X-band data. The magnitudes in both channels are: start time (UT) | exposure time (s) | band | mag (AB) | mag err -----------------------|-------------------|------|----------|-------- 2025-07-03T17:25:09.50 | 30*70 | VT_B | 20.72 | 0.04 2025-07-03T17:25:09.50 | 30*70 | VT_R | 20.11 | 0.04 Our photometry was not corrected for Galactic extinction. The Space Variable Objects Monitor (SVOM) is a China-France joint mission led by the Chinese National Space Administration (CNSA, China), National Centre for Space Studies (CNES, France) and the Chinese Academy of Sciences (CAS, China), which is dedicated to observing gamma-ray bursts and other transient phenomena in the energetic universe. VT was jointly developed by Xi'an Institute of Optics and Precision Mechanics (XIOPM), CAS and National astronomical observatories (NAOC), CAS. View this GCN Circular online at https://gcn.nasa.gov/circulars/40936. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...