TITLE:   GCN CIRCULAR
NUMBER:  45982
SUBJECT: GRB 261017A: J band upper limit by the SYSU 80cm infrared telescope
DATE:    26/10/18 11:14:16 GMT
FROM:    Rui-Chen Gao <ayxzxn0100@gmail.com>

Zhi-Xiang Tan, Zhong-Nan Dong, Rui-Chen Gao, Jin-Ji Li, Jia-Qi Lin, Pu Lin, Yun Shi, Jing-Kai Sun, Hao-Nan Yang, Hao-Ran Zhang, P. H. Thomas Tam, Rong-Feng Shen, and Bin Ma (Sun Yat-sen University) report on behalf of the SYSU 80cm infrared telescope team:

We observed the field of GRB 261017A, detected by Fermi (Fermi GBM team, GCN 45973) and Swift (Siegel et al., GCN 45974), with the Sun Yat-sen University (SYSU) 80cm infrared telescope in the J band. The observations were carried out on 2026-10-17, from 20:13:49 to 20:43:33 UT, beginning 4.15 hr after the BAT trigger. A total of 86 frames of 20 s each were stacked, giving 1720 s on source.

We do not detect any new source within the enhanced Swift-XRT error circle (Beardmore et al., GCN 45977) in our stacked image. The 5-sigma limiting magnitude of the stack is J = 18.6 mag (Vega)

The SYSU 80cm infrared telescope is operated and managed by the Department of Astronomy, Sun Yat-sen University.