TITLE: GCN CIRCULAR NUMBER: 38802 SUBJECT: GRB 250103A: SVOM/VT optical counterpart confirmation DATE: 25/01/03 16:59:13 GMT FROM: Liping Xin at NAOC, SVOM <xlp@nao.cas.cn> 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, D. H. Zhao (NAOC), J. Zhang, L. J. Dan, G. Y. Zou, C. J. Wang, Y. F. Du, C. Huang (XIOPM), R.-Z. Li, J. X. Cao, D. F. Kong (GXU) and Y. Wang (PMO, CAS) 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: GRB 250103A (Wang et al., GCN 38786) was observed by on-board VT after the automatic slew of the platform. The VT conducted observations in VT_B (400nm-650nm) and VT_R (650nm-1000nm) channel simultaneously. With the X band downlinked data, the optical candidate reported (Li et al., GCN 38795) was detected in VT_B and VT_R band images. Its brightness was rising for 1.0 mag from 500 sec to 2000 sec after the burst and then decays. The magnitude was VT_B=21.8+/0.1 mag and VT_R=20.1+/0.1 mag in AB magnitude, at about 8000 seconds post the trigger. We confirm that this source is the optical counterpart of 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. View this GCN Circular online at https://gcn.nasa.gov/circulars/38802. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...