TITLE:   GCN CIRCULAR
NUMBER:  45970
SUBJECT: EP261015b: J-band upper limit by the SYSU 80cm infrared telescope
DATE:    26/10/17 09:09:41 GMT
FROM:    Jianhong Cao at Sun Yat-sen University <caojh35@mail2.sysu.edu.cn>

Jian-Hong Cao, Jia-Qi Lin, Zhong-Nan Dong, Jin-Ji Li, Pu Lin, Yun Shi, Hao-Nan Yang, Rui-Chen Gao, Jing-Kai Sun, 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 EP261015b, detected by the Wide-field X-ray Telescope (WXT) on board Einstein Probe (Li et al., GCN 45958), using the Sun Yat-sen University (SYSU) 80cm infrared telescope. Our J-band observations were carried out on 2026 Oct 16 from 16:31 to 17:32 UTC, approximately 26.57–27.59 hours after the start of the WXT observation. We combined 150 exposures of 20 s each, yielding a total exposure time of 3000 s.

We do not detect any new source in the WXT localization in our stacked image, and obtain the following 5-sigma upper limit: J = 19.5 mag (Vega).

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