GCN Circular 46161
Subject
GRB 261104A: SVOM/VT optical upper limits
Event
Date
2026-11-05T16:20:26Z (a day ago)
From
Huali Li at at NAOC, SVOM <lhl@nao.cas.cn>
Via
Web form
H. L. Li, Y. N. Ma, C. Wu, L. P. Xin, Y. L. Qiu, Z. H. Yao, J. R. Xu, L. J. Chen, X. H. Han, J. Wang, Y. Xu, P. P. Zhang, W. J. Xie, Y. J. Xiao, H. B. Cai, J. S. Deng, J. Y. Wei (NAOC), J. T. Palmerio (CEA/Irfu), M. G. Bernardini (INAF/LUPM), M. Gnaoui (IAP) and R. Hamburg (USRA) report on behalf of the SVOM/VT team.
SVOM/VT performed an automatic slew on the burst GRB 261104A triggered by SVOM/ECLAIRs (sb26110402, Bernardini et al., GCN 46150). The observation started at 2026-11-04T21:31:59 UTC, about 0.92 hr in VT_B (400nm-650nm) and VT_R (650nm-1000nm) channels simultaneously.
No credible uncatalogued candidates were identified the stacked images within the ECLAIRs error box (Bernardini et al., GCN 46150), compared with the Legacy Survey.
Preliminary upper limits are estimated in AB magnitudes and are not corrected for Galactic extinction:
Mid time | Band | Exposure Time | 5-sigma upper limit
1.10 h VT_B 50*20 s > 22.5 mag
1.10 h VT_R 50*18 s > 22.5 mag
Our non-detection is consistent with the reports from LCO (Yin et al., GCN 46154).
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.