TITLE: GCN CIRCULAR NUMBER: 45250 SUBJECT: EP260728a: EP-FXT follow-up observation DATE: 26/07/29 07:40:29 GMT FROM: EP Team at NAOC/CAS <ep_ta@bao.ac.cn> G. J. Yang, J. W. Hu (NAO, CAS), H. Zhou (PMO), C. C. Jin (NAO, CAS) on behalf of the Einstein Probe (EP) team: EP-FXT performed a follow-up observation of the fast X-ray transient EP260728a (detected by EP-WXT, GCN 45248). The observation started at 2026-07-28 16:50:26 UTC, about 4 minutes after the WXT trigger, with an exposure time of 3.6 ks. The FXT telemetry data show that an uncatalogued source was detected within the WXT error circle at R.A. = 302.8576, DEC = -31.7138 (J2000) with an uncertainty of 10 arcsec (radius, 90% C.L. statistical and systematic). The 0.5-10 keV FXT spectrum can be fitted with an absorbed power law with a fixed Galactic hydrogen column density of 1.2 x 10^21 cm^-2. The best-fit photon index is 2.23 (-0.18/+0.18). The unabsorbed 0.5-10 keV flux is 1.22 (-0.12/+0.14) x 10^-12 erg cm^-2 s^-1. The uncertainties are at the 1 sigma confidence level for the above parameters. 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/45250. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...