GCN Circular 40392
Subject
GRB 250506A: SVOM/VT optical upper limit
Date
2025-05-08T07:22:50Z (10 days ago)
Edited On
2025-05-08T13:19:19Z (10 days ago)
From
SVOM_group <svomgroup@bao.ac.cn>
Edited By
Judith Racusin at NASA/GSFC <judith.racusin@nasa.gov> on behalf of SVOM_group <svomgroup@bao.ac.cn>
Via
Web form
L. Lan(NAOC), C. W. Wang(IHEP), R. C. Chen(NJU), W. J. Tan(IHEP), L. P. Xin, Y. L. Qiu, H. L. Li, C. Wu, Z. H. Yao, Y. N. Ma, X. H. Han, Y. Xu, J. Wang, P. P. Zhang, W. J. Xie, Y. J. Xiao, H. B. Cai, J. T. Palmerio (CEA), J. S. Deng, J. Y. Wei (NAOC) report on behalf of the SVOM/VT instrument team.
SVOM/VT performed ToO observations on the GRB 250506A (Fermi GBM team, GCN 40355; Wang et al., GCN 40358) in the VT_B (400nm-650nm) and VT_R (650nm-1000nm) channels simultaneously. The observation started at 13.69 hours after the SVOM trigger.
No uncatalogued sources are detected in single or stacked images at the improved MXT position (Maggi et al., GCN Circ. 40364), the position of FXT (Zhang et al., GCN 40365) and XRT (Burrows et al., GCN 40378), compared to the Legacy survey.
The 3 sigma upper limits are derived below:
Mid_time | Band | Exposure Time (second) | Upper limit (AB)
15.64 hour | VT_B | 100*63 | 23.7
15.64 hour | VT_R | 100*73 | 23.6
This results are consistent with the report by Postigo et al. (GCN 40359), Liu et al. (GCN 40360), Ferro et al. (GCN 40363), Xin et al. (GCN 40366), Liu et al. (GCN 40373), Ducoin et al. (GCN 40382) and Oates et al. (GCN 40387).
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.