TITLE: GCN CIRCULAR NUMBER: 37841 SUBJECT: GRB 241018A: SVOM/C-GFT optical observations DATE: 24/10/23 05:10:15 GMT FROM: Chao Wu at NAOC SVOM/C-GFT team: Chao WU (NAOC), Zhe Kang (CHO), Liping Xin(NAOC), Xuhui Han(NAOC), Pinpin Zhang (NAOC), Xiaomeng Lu (NAOC), Zhenwei Li (CHO), You Lv (CHO), Ruosong Zhang (NAOC), Yujie Xiao(NAOC) 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) We observed the field of GRB 241018A detected by SVOM (Atteia et al., GCN 37812 and Zheng et al. GCN 37831) on 2024-10-18T11:55:54 UT, 80 seconds after the trigger with C-GFT in the commissioning phase. A series of g, r and i band images were obtained with exposure time of 10s. In our refined processing, the optical counterpart reported by SVOM/VT (Qiu et al., GCN 37819, GCN 37826) and the NOT (Malesani et al., GCN 37821) was detected in our first sequence of coadded images of band g and r. The results are, (T-T0)_mid mag mag_err band ------------------------------------- 118 17.59 0.19 g 193 16.90 0.25 r The photometry was calibrated with nearby PS1 stars. We thank the observation assistant Guangsheng Zhang and Bowen Li at Jilin observatory for their excellent support. Chinese Ground Follow-up Telescope of SVOM mission is located at Jilin, Changchun Observatory, National Astronomical Observatories, CAS. It has FOV of 1.28 deg x 1.28 deg with a 4k*4k CMOS detector mounted on the primary focus of 1.2-meter-aperure telescope.