TITLE: GCN CIRCULAR NUMBER: 39402 SUBJECT: EP250220a: 1.6m Mephisto observations DATE: 25/02/21 09:36:39 GMT FROM: Brajesh Kumar at SWIFAR, YNU <brajesh@ynu.edu.cn> Helong Guo, Guowang Du, Xinlei Chen, Xiangkun Liu, Xiaotong Chen, Yiheng Xie, Brajesh Kumar, Yuan Fang, Edoardo P. Lagioia, Yu Pan, Xingzhu Zou, Xiaowei Liu (all SWIFAR, YNU) report on behalf of the Mephisto Team: The field of EP250220a detected by EP Team (Wang et al., GCN 39387) was observed with the 1.6m Multi-channel Photometric Survey Telescope (Mephisto) of Yunnan University located at Lijiang Observatory. Simultaneous uvgr band photometric observations were conducted starting from 13:08:36 2025-02-20 UT (~10.93 hr after the trigger) and 3 frames with 300s exposure times were taken. No reliable uncatalogued source was detected in our stacked images, consistent with Zhang et al. (GCN 39393) and Fan et al. (GCN 39400). The 3 sigma upper limits are listed below. Start_Time(UT) | Band | Exp(s)| LimMag (AB) --------------------|------|-------|------------ 2025-02-20T13:33:57 | u | 300*3 | >22.85 2025-02-20T13:08:36 | v | 300*3 | >22.85 2025-02-20T13:33:57 | g | 300*3 | >23.10 2025-02-20T13:08:36 | r | 300*3 | >23.04 ------------------------------------------------------------------------------------------------- Mephisto (Multi-channel Photometric Survey Telescope) is a 1.6-m wide-field multi-channel telescope, the first of its type in the world, capable of imaging the same field of view in three optical bands simultaneously. It provides real-time, high-quality colors of stellar objects. The on-site telescope assemblage and commissioning were carried out in September 2022. The first light in all three channels was achieved on 2023 December 21. ------------------------------------------------------------------------------------------------- View this GCN Circular online at https://gcn.nasa.gov/circulars/39402. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...