TITLE: GCN CIRCULAR NUMBER: 41257 SUBJECT: EP250802a: EP-FXT follow-up observation DATE: 25/08/07 08:39:07 GMT FROM: EP Team at NAOC/CAS <ep_ta@bao.ac.cn> Y.-H. I. Yin (NJU), X. Mao, T. Zhao, C. C. Jin (NAO, CAS) on behalf of the Einstein Probe (EP) team: EP-FXT performed a follow-up observation of EP250802a (GCN 41221) at 2025-08-04T04:10:31 (UTC), about 42 hours after the WXT detection, with an exposure time of 1.5 ks. The source was also followed by several optical telescopes (GCN 41222, GCN 41223, GCN 41224, GCN 41227). Three uncatalogued sources are detected within the WXT error circle, among which Source 1 is spatially consistent with a known star TYC 2158-1481-1. Preliminary analysis on these sources are automatically conducted, and the details are listed as follows. Source 1: EPF_J201319.4+244937 RA (J2000): 303.3308 Dec (J2000): 24.8268 Flux: 4.63 x 10^-13 erg/s/cm^2 (observed, 0.5-10 keV) Flux_err: 1.25 x 10^-13 erg/s/cm^2 (1 sigma) Note: This source is spatially consistent with the a known star TYC 2158-1481-1. Source 2: EPF_J201330.2+244901 RA (J2000): 303.3759 Dec (J2000): 24.8168 Flux: 2.21 x 10^-13 erg/s/cm^2 (observed, 0.5-10 keV) Flux_err: 6.99 x 10^-14 erg/s/cm^2 (1 sigma) Source 3: EPF_J201318.2+245121 RA (J2000): 303.3260 Dec (J2000): 24.8559 Flux: 3.56 x 10^-13 erg/s/cm^2 (observed, 0.5-10 keV) Flux_err: 9.84 x 10^-14 erg/s/cm^2 (1 sigma) Launched on January 9, 2024, EP is a space X-ray observatory to monitor the soft X-ray sky with X-ray follow-up capability (Yuan et al. 2022, Handbook of X-ray and Gamma-ray Astrophysics). View this GCN Circular online at https://gcn.nasa.gov/circulars/41257. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...