TITLE: GCN CIRCULAR NUMBER: 39124 SUBJECT: GRB 250129A: SVOM/C-GFT optical observations DATE: 25/02/02 11:25:12 GMT FROM: Chao Wu at NAOC <cwu@nao.cas.cn> 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), Yulei, Qiu(NAOC), Jing Wang(NAOC), Jianyan Wei (NAOC) report on behalf of the SVOM/C-GFT team: We observed the field of GRB 250129A detected by Swift/BAT (Beardmore et al., GCN 39066) with C-GFT. Our observations were started on 2025-01-30T17:51:44 UTC, ~37.11 hr after the trigger. A series of g, r and i band images were obtained with exposure time of 30s for each image. The optical counterpart (Beardmore et al., GCN 39066; Francile et al., GCN 39065; Lipunov et al., GCN 39070; Schneider et al., GCN 39071; Belkin et al., GCN 39072; Izzo et al., GCN 39073; Izzo et al., GCN 39074; Francile et al., GCN 39075; Ghosh et al., GCN 39077; Schneider et al., GCN 39078; Brivio et al.,GCN 39079; Siegel et al.,GCN 39085; Zheng et al., GCN 39090; Schlekat et al., GCN39091; Antier et al., GCN 39096; Odeh et al. GCN 39097; Ferroet al. GCN 39098; Bochenek et al., GCN 39099; Malesani et al., GCN 39100; Romanov et al., GCN 39101; Zheng et al., GCN 39102; Watson et al., GCN 39104;Vinko et al., GCN 39105; Akl et al., GCN 39106; Moskvitin et al., GCN 39107; Giovanni et al., GCN 39109; Schlekat et al., GCN 39110; Schlekat et al., GCN 39114 and Ror et al., GCN 39115) was clearly detected in stacked images of band g,r and i. The results are, (T-T0)_mid(hr) mag mag_err band ----------------------------------------- 37.73 20.08 0.22 g 37.83 19.74 0.16 r 37.92 19.32 0.11 i The photometry was calibrated with nearby Pan-STARRS1 stars. We thank the observation assistants Bowen Li and Yinghuai Hao 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. View this GCN Circular online at https://gcn.nasa.gov/circulars/39124. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...