GCN Circular 44141
Subject
EP260329a: Einstein Probe detection of an X-ray transient
Event
Date
2026-03-29T11:35:22Z (6 days ago)
From
EP Team at NAOC/CAS <ep_ta@bao.ac.cn>
Via
Web form
Guojiong Yang (NAO, CAS), F.-F Song(YNAO, CAS), Wei Chen, Yuan Liu (NAO, CAS) on behalf of the Einstein Probe (EP) team:
We report on the detection of an X-ray transient by the Wide-field X-ray Telescope (WXT) on board the Einstein Probe (EP) mission, designated EP260329a. The transient triggered EP-WXT (ID: 01709259198) at 2026-03-29T03:30:40 (UTC). The WXT position of the source is R.A. = 5.459 deg, DEC = 82.513 deg (J2000) with an uncertainty of 3.2 arcmin in radius (90% C.L. statistical and systematic).
The WXT 0.5-4 keV spectrum can be described by an absorbed power law. Since the hydrogen column density is not well constrained by the current data, it was fixed at the Galactic value 0.1 x 10^22 cm^-2. The best-fit photon index is 2.23 (-0.69/+2.26). The derived 0.5-4 keV flux is 1.43 (-0.33/+0.40) x 10^-10 erg cm^-2 s^-1.
A follow-up observation with the Follow-up X-ray Telescope (FXT) is 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).