TITLE: GCN CIRCULAR NUMBER: 41825 SUBJECT: GRB 250912A:SVOM/VT optical upper limit DATE: 25/09/13 06:18:59 GMT FROM: Huali Li at at NAOC, SVOM <lhl@nao.cas.cn> H. L. Li, L. P. Xin, Y. N. Ma, Z. H. Yao, Y. L. Qiu, C. Wu, 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, D. H. Zhao (NAOC), J. Palmerio (CEA) report on behalf of the SVOM/VT team. SVOM performed an automatic slew on the burst triggered by SVOM/ECLAIRs (Ducoin et al., GCN 41820). SVOM/VT began observing the field at 2025-09-12T21:10:17 UTC, 233 sec after T0, in the VT_B (400nm-650nm) and VT_R (650nm-1000nm) channels simultaneously. No uncatalogued sources were detected in our single or stacked images at the SVOM/MXT position (Ducoin et al., GCN 41820), compared to the Legacy survey. The 3 sigma limits are: mid-time | exposure time (s) | band | upper limit (AB) -----------|-------------------|------|----------------- 12.8 min | 18*50 | VT_B | 23.0 12.8 min | 18*50 | VT_R | 23.1 Our results are consistent with the reports (Lipunov et al., GCN 41822; Wu et al., GCN 41824). The Space Variable Objects Monitor (SVOM) is a China-France joint mission led by the Chinese National Space Administration (CNSA, China), National Center 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/41825. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...