TITLE: GCN CIRCULAR NUMBER: 38736 SUBJECT: EP241217A: J band upper limit by SYSU 80cm telescope DATE: 24/12/31 03:09:17 GMT FROM: lijj328@mail2.sysu.edu.cn Jin-Ji Li, Zhong-Nan Dong, Wei-Sen Huang, Jia-Qi Lin, Pu Lin, Hao-Nan Yang, Yan Yu, Hao-Ran Zhang, Rong-Feng Shen, Bin Ma (Sun Yat-sen University) report on behalf of the SYSU 80cm telescope team: We observed the field of the fast X-ray transient EP241217A (Zhou et al., GCN 38586), which was also detected by Swift-XRT (Williams et al., GCN 38596), using the Sun Yat-sen University 80cm telescope, with 130 × 20 s exposures in J band. Our observations began at 2024-12-18 17:51:36 UTC, 36.26 hours after the EP trigger. We did not detect any counterpart in the stacked images at the position of the optical afterglow (Levan et al., GCN 38587; Izzo et al., GCN 38588; Fan et al., GCN 38592; Jin et al., GCN 38607; Mohan et al., GCN 38612; Zhu et al., GCN 38613; Bochenek et al., GCN 38615; Liu et al., GCN 38636), down to a 5-sigma depth of J ~ 17.8 Vega magnitudes. View this GCN Circular online at https://gcn.nasa.gov/circulars/38736. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...