GCN Circular 45610
Subject
GRB 260917B: SVOM/VT optical observations
Event
Date
2026-09-17T09:05:04Z (3 days ago)
From
Yinuo Ma <mayn@bao.ac.cn>
Via
Web form
Y. N. Ma, H. L. Li, L. P. Xin, Y. L. Qiu, C. Wu, Z. H. Yao, J. R. Xu, L. J. Chen, X. H. Han, Y. Xu, J. Wang, P. P. Zhang, W. J. Xie, Y. J. Xiao, H. B. Cai, J. S. Deng, J. Y. Wei (NAOC), J. Palmerio (CEA), K. Liu (USTC) report on behalf of the SVOM/VT team.
SVOM/VT performed an automatic slew on the burst GRB 260917B (sb26091701) triggered by SVOM/ECLAIRs (He et al., GCN 45606). SVOM/VT began observing the field at 2026-09-17T05:27:45 UTC, 1.59 hours after T0, in the VT_B (400nm-650nm) and VT_R (650nm-1000nm) channels simultaneously.
With X-band data available, the SVOM/COLIBRÍ optical candidate (Dornic et al., GCN 45607; Yin et al., GCN 45608) was detected in both VT_B and VT_R bands and showed a power law decay with the index of 1.0 during our observation. The AB magnitudes are:
mid time | exposure time | band | mag (AB)
-----------|----------------|------|------------
2.83 h | 22*100 s | VT_B | 22.7+/-0.2
2.85 h | 22*100 s | VT_R | 20.8+/-0.1
Our photometry was not corrected for Galactic extinction.
Given the red VT color (VT_B-VT_R~1.9) of this burst, it is likely at medium redshift (Wang et al., 2020).
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.