TITLE: GCN CIRCULAR NUMBER: 37610 SUBJECT: EP240919a / GRB 240919A: SVOM/VT upper limit DATE: 24/09/26 04:01:58 GMT FROM: Liping Xin at NAOC, SVOM <xlp@nao.cas.cn> SVOM/VT commissioning team: Y. L. Qiu, L. P. Xin, H. L. Li, C. Wu, X. H. Han, 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 (NAOC), J. Zhang, L. J. Dan, G. Y. Zou, C. J. Wang, Y. F. Du, C. Huang (XIOPM) and Shaolin Xiong (IHEP). SVOM JSWG: Jian-Yan Wei (NAOC), Bertrand Cordier (CEA), Shuang-Nan Zhang (IHEP), Stéphane Basa (LAM), Jean-Luc Atteia (IRAP), Arnaud Claret (CEA), Zi-Gao Dai (USTC), Frédéric Daigne (IAP), Jin-Song Deng (NAOC), 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), Bing Zhang (UNLV) report on behalf of the SVOM team: During the commissioning phase of SVOM mission, we observed the field of the EP240919a (Liang et al., GCN 37561) which is also confirmed as GRB 240919A (Liang et al., GCN 37563; Rodi et al., GCN 37572; Wang et al., GCN 37574) with SVOM/VT telescope in ToO mode. The observation started at 2024-09-21T14:12:58 UT, about 47.5 hours after the burst, and the total exposure time was 6160 seconds. VT made the observations with two channels simultaneously, VT_B (400nm-650nm) and VT_R (650nm-1000nm). No any uncatalogued sources were detected in the 5.5 ks stacked images within the error circles of EP/FXT(Liang et al., GCN 37561) compared to DESI Legacy DR10 catalog, down to the following 3 sigma upper limit of VT_B=24.0 mag and VT_R=24.0 mag in AB magnitude. 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/37610. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...