TITLE: GCN CIRCULAR NUMBER: 43620 SUBJECT: GRB 250204A: SVOM/VT optical candidate DATE: 26/02/05 02:02:27 GMT FROM: Huali Li at at NAOC, SVOM <lhl@nao.cas.cn> H.L. Li , C. Wu, Y.N. Ma, Z.H. Yao, Y. L. Qiu, L.P. Xin, X. H. Han, J. Wang, Y. Xu, P. P. Zhang, W. J. Xie, Y. J. Xiao, H. B. Cai, L. Lan, J. R. Xu, J. S. Deng, J. Y. Wei (NAOC), J. Palmerio (CEA/Irfu), M. Pillas (IAP), M. Dennefeld (IAP) report on behalf of the SVOM/VT team. SVOM/VT performed ToO observation to the field of GRB 260204A triggered by SVOM/ECLAIRs (sb26020403, Pillas et al., GCN 43613). The observation started at 2026-02-04T15:37:26UTC, i.e., 49 minutes post trigger in the VT_B (400nm-650nm) and VT_R (650nm-1000nm) channels simultaneously. An uncatalogued source was detected within the error box of ECLAIRs (Pillas et al., GCN 43613) and source 1 of Swift-XRT (https://www.swift.ac.uk/SVOM/SVOM_FIELD00057), compared to the Legacy survey catalog. The position is at R.A., Dec. = 205.106167, 1.930114 degrees, equivalent to: R.A. (J2000) = 13:40:25.48 Dec. (J2000) = +1:55:48.41 with an uncertainty of 0.5 arcsec. The measurements in AB magnitudes are given below: Mid_time Band Exposure Time Magnitude (AB) 1.23 hour VT_R 27*50 sec 20.5+/-0.1 mag 1.23 hour VT_B 26*50 sec 21.3+/-0.1 mag Our photometry was in AB magnitude and 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/43620. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...