TITLE: GCN CIRCULAR NUMBER: 43425 SUBJECT: EP260116a: Xinglong optical upper limit DATE: 26/01/16 16:49:09 GMT FROM: Xinglong Observatory at National Astronomical Observatories (NAOC), Chinese Academy of Sciences (CAS) <xinglong@nao.cas.cn> Junjie-Jin (NAOC), Haiyang-Mu (NAOC), Sen-Liu (NAOC), Pengliang-Du (NAOC), Zhou-Fan (NAOC), Hong-Wu (NAOC) report: Following the detection of EP260116a by EP-WXT (GCN Circular 43424), we observed the field of EP260116a using the 2.16-m telescope at Xinglong Observatory, NAOC. We obtained 3x300s clear-band frames with a median time of 2026-01-16T15:26:52 hr after the EP trigger. No uncatalogued optical transient is detected in the stacked images within the 3 arcmin EP/WXT error circle (GCN Circular 43424), down to 5-sigma limiting magnitudes of N ~ 20.8, calibrated with Pan-STARRS sources in the field. Also there is no apparent brightening for the catalogued sources within the error circle. View this GCN Circular online at https://gcn.nasa.gov/circulars/43425. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...