TITLE: GCN CIRCULAR NUMBER: 41683 SUBJECT: EP250903a: SVOM/VT optical confirmation DATE: 25/09/03 20:50:43 GMT FROM: Liping Xin at NAOC, SVOM <xlp@nao.cas.cn> L. P. Xin, H. L. Li, Y. N. Ma, Y. L. Qiu, C. Wu, Z. H. Yao, Y. Xu, J. Wang, P. P. Zhang, W. J. Xie, Y. J. Xiao, H. B. Cai, L. Lan, J. S. Deng, J. Y. Wei (NAOC), J. Palmerio (CEA) report on behalf of the SVOM/VT team. SVOM performed a Target of Opportunity observations of EP250903a detected by EP/WXT (Zhao et al., GCN 41674). The observations was started from 2025-09-03T15:01:54 UTC, 58 min after the EP trigger time, in VT_B (400-650 nm) and VT_R (650-1000nm) bands simultaneously. . The optical source reported (Levan et al., GCN 41680) was clear detected in VT stacked images. The brightness was VT_B=22.1+/-0.1 and VT_R=21.5+/-0.1 mag at the mid time of 1.1 hours after the trigger. Our photometry is not corrected for Galactic extinction. 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/41683. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...