GCN Circular 46046
Subject
GRB 261026A: SVOM/VT optical observations
Event
Date
2026-10-26T15:16:38Z (6 days ago)
From
Huali Li at at NAOC, SVOM <lhl@nao.cas.cn>
Via
Web form
H. L. Li, C. Wu, Y. N. Ma, 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), C. W. Wang (IHEP) report on behalf of the SVOM/VT team.
SVOM/VT performed an automatic slew toward the position of GRB 261026A, triggered by SVOM/ECLAIRs (sb26102601, Goto et al., GCN 46030) and also detected by SVOM/GRM (Goto et al., GCN 46030). The observation started at 2026-10-26T06:20:29 UTC, about 10.8 minutes post trigger in VT_B (400nm-650nm) and VT_R (650nm-1000nm) channels simultaneously.
The optical counterpart (Dornic et al., GCN 46033; Zheng et al., GCN 46034; Wu et al., GCN 46035; Mohan et al., GCN 46041) was clearly detected in both channels, showing a power-law temporal decay index of -0.6 during our observation. The following measurements are in AB magnitudes and are not corrected for Galactic extinction:
Mid time | Band | Exposure Time | Brightness
677 s VT_B 50 s 19.0 +/- 0.1
677 s VT_R 50 s 18.6 +/- 0.1
5.74 h VT_B 100 s 20.95 +/- 0.15
5.74 h VT_R 100 s 20.52 +/- 0.13
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.