TITLE:   GCN CIRCULAR
NUMBER:  37728
SUBJECT: GRB 241006A:  SVOM/VT follow-up and optical upper limit 
DATE:    24/10/07 11:21:07 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), D. Turpin (CEA), Z. P. Jin, H. Zhou (PMO)

SVOM JSWG: Jian-Yan Wei (NAOC), Bertrand Cordier (CEA), Shuang-Nan Zhang (IHEP), Stéphane Basa (LAM), Arnaud Claret (CEA), Zi-Gao Dai (USTC), Frédéric Daigne (IAP), Jin-Song Deng (NAOC), Olivier Godet (IRAP), 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), Shao-Lin Xiong (IHEP), Bing Zhang (UNLV)

report on behalf of the SVOM team:

During the commissioning phase of SVOM mission, we observed the GRB 241006A detected by Swift/BAT (Gupta et al. GCN 37722) with SVOM/VT telescope in ToO mode. The observation started at 2024-10-07T03:15:07 UT, approximately 5.38 hours after the burst, with a total exposure time of 5220 seconds. The VT telescope conducted observations simultaneously in two channels: VT_B (400nm-650nm) and VT_R (650nm-1000nm).

Preliminary analysis shows that, no any source was detected within the error circles of XRT (Beardmore et al., GCN 37724) with the 3 sigma limit magnitudes of about 24.0 mag for VT_B and 23.8 mag for VT_R in the AB magnitude system, after stacking the images for both bands separately.

More observations with inferred wavelengths are encouraged to investigate the nature of the burst. 

The SpaceVariable 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.

