TITLE:   GCN CIRCULAR
NUMBER:  35281
SUBJECT: GRB 231205B: Gaoyazi/GOT optical upper limit
DATE:    23/12/06 06:45:03 GMT
FROM:    Dong Xu at NAOC/CAS <dxu@nao.cas.cn>

S.Q. Jiang, S.Y. Fu, X. Liu, Z.P. Zhu, J. An, T.H. Lu, D. Xu (NAOC), L.F. Huo, M.M. Yang, S.W. Luo, Z. K. Feng (XJTS) report:

We observed the field of GRB 231205B detected by Swift (Evans et al., GCN 35269) using the GOT-0.5m telescope located at Gaoyazi, Xinjiang, China. Observations started at 16:46:51 UT on 2023-12-05, i.e., 172 s after the Swift/BAT trigger, and we obtained 5x3, 5x5, 5x10, 5x15, 5x20, 5x40, 10x60, 10x90, 10x120, 10x200 s frames with the Sloan r filter.

No optical counterpart is detected in our stacked image at the Enhanced XRT position (Osborne et al., GCN 35275), down to the following 3-sigma limiting magnitude of m(r)>21.2 @ 0.80 hr
calibrated with nearby PanSTARRS stars and the magnitude is not corrected for Galactic extinction.