TITLE:   GCN CIRCULAR
NUMBER:  37820
SUBJECT: GRB 241017A: SVOM/VT follow-up and optical upper limit
DATE:    24/10/18 19:46:29 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, J. Wang, 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), H. Zhou (PMO)

SVOM JSWG: Jian-Yan Wei (NAOC), Bertrand Cordier (CEA), Shuang-Nan Zhang (IHEP), Stéphane Basa (LAM), Olivier Godet (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 GRB 241017A detected by SVOM/Eclairs (Le Provost et al, GCN 37799) with SVOM/VT telescope in ToO mode. The observation started at 2024-10-17T18:00:17 UT, about 14.0 hours after the burst, with a total exposure time of 4320 seconds. The VT telescope conducted observations simultaneously in two channels: VT_B (400nm-650nm) and VT_R (650nm-1000nm).

Analysis shows that, no any uncatalogued source was detected within the error circles of any of the three X-ray sources (Kennea et al., GCN 37811) with the 3 sigma limit magnitudes of about 23.9 mag for VT_B and 23.6 mag for VT_R in AB magnitude system, after stacking the images for both bands separately.

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.