TITLE: GCN CIRCULAR NUMBER: 43821 SUBJECT: sb26021801: SVOM/VT optical upper limits DATE: 26/02/25 03:59:02 GMT FROM: Huali Li at at NAOC, SVOM <lhl@nao.cas.cn> H. L. Li, Y. N. Ma, L. P. Xin, Y. L. Qiu, C. Wu, Z. H. Yao, X. H. Han, Y. Xu, J. Wang, 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), W. J. TAN (IHEP) report on behalf of the SVOM/VT team. SVOM/VT performed ToO osbervation on the long faint X-ray transient sb26021801 reported by SVOM/Eclairs (Tan et al., GCN 43778). The observation started at about 7.75 hours after trigger in VT_B (400nm-650nm) and VT_R (650nm-1000nm) channel simultaneously. No credible sources are detected in single or stacked images within error box of SVOM/Eclairs (Tan et al., GCN 43778) with the 3 sigma limit magnitudes of VT_B ~ 23.8 mag and VT_R ~ 23.5 mag at 9.42 hours post trigger. Our non-detection is consistent with the reports from LCO (Wu et al., GCN 43792), COLIBRÍ (Fortin et al., GCN 43783), LAST (Konno et al., GCN 43784) and C-GFT (Wu et al, GCN 43819). 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/43821. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...