TITLE: GCN CIRCULAR NUMBER: 37999 SUBJECT: GRB 241030B: SVOM/VT optical afterglow observations DATE: 24/10/31 08:29:09 GMT FROM: SVOM_group SVOM/VT commissioning team: Y. L. Qiu, H. L. Li, L. P. Xin, C. Wu, X. H. Han, J. Wang, W. J. Xie, H. B. Cai, Y. Xu, Y. J. Xiao, P. P. Zhang, J. S. Deng, L. Lan, X. M. Lu, R. S. Zhang, (NAOC), J. Zhang, L. J. Dan, G. Y. Zou, C. J. Wang, Y. F. Du, C. Huang (XIOPM), H. Zhou (PMO). SVOM JSWG: Jian-Yan Wei (NAOC), Bertrand Cordier (CEA), Shuang-Nan Zhang (IHEP), Stéphane Basa (LAM), Arnaud Claret (CEA), Zi-Gao Dai (USTC), Frédéric Daigne (IAP), Jin-Song Deng (NAOC), Olivier Godet (IRAP), Andrea Goldwurm (APC), Diego Götz (CEA), Xu-Hui Han (NAOC), Cyril Lachaud (APC), En-Wei Liang (GXU), Yu-Lei Qiu (NAOC), Susanna Vergani (Obs.Paris), Jing Wang (NAOC), Chao Wu (NAOC), Li-Ping Xin (NAOC), Shao-Lin Xiong (IHEP), Bing Zhang (UNLV) report on behalf of the SVOM team: VT started to observe the field of GRB 241030B (Fermi GBM team, GCN 37980; Klingler et al., GCN 37981; Evans, GCN 37983; Zhao et al., GCN 37984; Evans et al., GCN 37992; Mukherjee et.al, GCN 37996) after the automatic slew of the platform. The VT conducted observation in B band (400nm-650nm) channel. The optical counterpart (Fu et al., GCN 37985; Odeh et al., GCN 37986; Brivio et al., GCN 37991; Moskvitin et al., GCN 37987; Moskvitin et.al GCN 37995) was detected at 2024-10-30T18:39:52 in VT_B band image with a exposure time of 100s . The brightness was 19.47+-0.05 mag, at a mid time of 382 s after the burst. 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.