TITLE: GCN CIRCULAR NUMBER: 44528 SUBJECT: GRB 260510B: SVOM/VT optical upper limits DATE: 26/05/11 03:48:57 GMT FROM: Huali Li at at NAOC, SVOM <lhl@nao.cas.cn> H. L. Li, L. P. Xin, C. Wu, Y. L. Qiu, Y. N. Ma, Z. H. Yao, J. R. Xu, X. H. Han, J. Wang, Y. Xu, P. P. Zhang, W. J. Xie, Y. J. Xiao, H. B. Cai, L. Lan, J. S. Deng, J. Y. Wei (NAOC), J. Palmerio (CEA/Irfu) report on behalf of the SVOM/VT team. SVOM/VT performed automatic observations of GRB260510B triggered by SVOM/ECLAIRs (sb26051001, Saccardi et al., GCN 44515). The burst was also detected at sub-threshold level by Fermi-GBM (Palafox et al., GCN 44524). VT observations started at 2026-05-10T12:23:54 UTC, 274 seconds post trigger, in the VT_B (400-650 nm) and VT_R (650-1000 nm) channels simultaneously. No uncatalogued sources were detected within the error box of SVOM/ECLAIRs (Saccardi et al., GCN 44515), compared to the Legacy Survey. The following measurements are in the AB magnitude and are not corrected for Galactic extinction: Mid time | Band | Exposure Time | 3-sigma upper limit 23.3 min VT_B 45*50 sec > 23.0 mag 23.3 min VT_R 45*50 sec > 23.0 mag Our non-detection is consistent with the non-detections reported by LCO (Saccardi et al., GCN 44518) and GOTO (Ramsay et al., GCN 44522). 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/44528. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...