TITLE: GCN CIRCULAR NUMBER: 44426 SUBJECT: EP260429a: EP-WXT detection of a fast X-ray transient DATE: 26/04/30 03:05:55 GMT FROM: EP Team at NAOC/CAS <ep_ta@bao.ac.cn> Y. Wang (PMO), Y. L. Wang (NAO, CAS; ICE, CSIC), C.C Jin (NAO, CAS) on behalf of the Einstein Probe (EP) team: We report on the detection of a fast X-ray transient by the Wide-field X-ray Telescope (WXT) on board the Einstein Probe (EP) mission, designated EP260429a. The WXT light curve shows a single pulse with a duration of about 250 s. The transient started at 2026-04-29 14:41:11 UTC. The WXT position of the source is R.A. = 240.629 deg, DEC = -9.588 deg (J2000) with an uncertainty of 1.9 arcmin in radius (90% C.L. statistical and systematic). The average WXT 0.5 - 4 keV spectrum can be fitted with an absorbed power law with a Galactic hydrogen column density of 4.31 (-0.08/+0.09) x 10^21 cm^-2 and a photon index of 1.44 (-0.04/+0.04). The derived average unabsorbed 0.5-4 keV flux is 3.96 (-0.32/+0.37) x 10^-9 erg/s/cm^2. Follow-up observation with the Follow-up X-ray Telescope on board EP has been scheduled. Further information will be updated when the telemetry data is received. 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/44426. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...