TITLE: GCN CIRCULAR NUMBER: 44032 SUBJECT: EP260316a: Xinglong optical upper limit DATE: 26/03/16 17:46:14 GMT FROM: Xinglong Observatory at National Astronomical Observatories (NAOC), Chinese Academy of Sciences (CAS) <xinglong@nao.cas.cn> Junbo-Zhang (NAOC), Junjie-Jin (NAOC), Haiyang-Mu (NAOC), Feng-Xiao (NAOC), Yuguang-Sun (NAOC), Jie-Zheng (NAOC), Dong-Xu (NAOC), Zhou-Fan (NAOC), Hong-Wu (NAOC) report on behalf of a large collaboration: Following the detection of EP260316a by EP-WXT (Jiang et al., GCN 44027), we observed the field of EP260316a using the 2.16-m telescope at Xinglong Observatory, NAOC. We obtained 6x300s clear-band frames with a median time of 2026-03-16 16:18:40 (UT), 3.76 hr after the EP trigger. No uncatalogued optical transient is detected in the stacked images within the 3 arcmin EP/WXT error circle (Jiang et al., GCN 44027), down to 3-sigma limiting magnitudes of g ~22.00 mag, calibrated with Pan-STARRS sources in the field. Also there is no apparent brightening for the catalogued sources within the error circle. We also detected no optical transient candidate with a median time of 2026-03-16T16:37:50.536 (UT) with the 0.8-m Telescope in Xinglong, Hebei, China. The upper limit is ～19.9 mag in the g-band. View this GCN Circular online at https://gcn.nasa.gov/circulars/44032. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...