TITLE: GCN CIRCULAR NUMBER: 39477 SUBJECT: EP250225a: GSP optical upper limit DATE: 25/02/26 05:25:33 GMT FROM: Wenxiong Li <liwenxiong1992@gmail.com> W. X. Li, S. J. Xue (NAOC), M. Andrews, J. Farah, D. A. Howell, M. Newsome, E. Padilla Gonzalez, C. McCully, and G. Terreran (Las Cumbres Observatory), on behalf of a larger collaboration, report: Following the detection of the fast X-ray transient EP250225a by the Einstein Probe (Jiang et al., GCN 39475) with the Sinistro instrument mounted on the 1-m telescope of the LCO, we initiated observations of the fast X-ray transient location starting on 2025 Feb 26th at 04:50:50 UT (~15 hours after the EP/WXT trigger) in the r band. These observations were conducted using the 1-meter telescope at the Las Cumbres Observatory node located at the Cerro Tololo Inter-American Observatory in Chile. No new optical source was detected in the co-added images within the EP/WXT error box down to ~21.5 mag. These observations were taken as part of the Global Supernova Project. View this GCN Circular online at https://gcn.nasa.gov/circulars/39477. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...