TITLE:   GCN CIRCULAR
NUMBER:  46219
SUBJECT: GRB 261110A: SVOM/VT optical observations
DATE:    26/11/10 19:48:30 GMT
FROM:    Huali Li at at NAOC, SVOM <lhl@nao.cas.cn>

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, W. J. Tan (PKU), J. X. Cao (GXU) report on behalf of the SVOM/VT team.

SVOM/VT performed observation with automatic slew on the field of GRB 261110A detected by SVOM/ECLAIRs (sb26111002, Wang et al., GCN 46215). Our observation started on 2026-11-10T11:55:06 UT, 306 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 candidate from Xinglong 2.16m telescope (Chen et al., GCN 46218) was detected in both channels. It shows a shallow decay with the slope index of -0.13 over our 2-hour observation span. The following measurements are in AB magnitudes and are not corrected for Galactic extinction:

Mid time | Band | Exposure Time | Brightness
16.7 m     VT_B    20*70 s        22.3 +/- 0.2 mag
17.3 m     VT_R    21*70 s        22.0 +/- 0.2 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.