GCN Circular 46254
Subject
GRB 261113A: SVOM/VT optical decay slope
Event
Date
2026-11-13T19:00:06Z (a day ago)
From
Huali Li at at NAOC, SVOM <lhl@nao.cas.cn>
Via
Web form
H. L. Li, C. Wu, Y. L. Qiu, Y. N. Ma, L. P. Xin, L. J. Chen, Z. H. Yao, J. R. Xu, 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, A. Saccardi, S. Bisero (CEA/Irfu) report on behalf of the SVOM/VT team.
SVOM/VT performed observation with automatic slew on the field of GRB 261113A detected by SVOM/ECLAIRs (sb26111302, Saccardi et al., GCN 46244). Our observation started on 2026:11:13T14:33:08 UT, 126.0 seconds in the VT_B (400-650 nm) and VT_R (650-1000 nm) channels simultaneously .
With the limited X-band data available, the optical counterpart (Lin et al., GCN 46247; Lei et al., GCN 46248; Li et al., GCN 46249; Yin et al., GCN 46250; Wu et al., GCN 46252; Zhao et al., GCN 46253 ) was clearly detected in single frame of both channels. It shows a decay with a slope index of -0.8 over our 1.5-hour observation span. The following measurements are in AB magnitudes and are not corrected for Galactic extinction:
Mid time | Band | Exposure Time | Brightness
133 s VT_B 15 s 17.16 +/- 0.07 mag
133 s VT_R 15 s 16.27 +/- 0.06 mag
More observations are ongoing.
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.