GCN Circular 40154
Subject
EP250416a: Einstein Probe detection of an X-ray transient
Date
2025-04-17T03:08:20Z (7 days ago)
From
EP Team at NAOC/CAS <ep_ta@bao.ac.cn>
Via
Web form
G.Y. Zhao (SYSU), C. Zhou (HUST), X.L. Chen, K. Chatterjee (YNU), H. Zhou (PMO, CAS) and C.C. Jin (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 EP250416a. The transient triggered EP-WXT (ID: 01709135021) at 2025-04-16T17:53:59 (UTC). The WXT position of the source is R.A. = 256.402 deg, DEC = 25.768 deg (J2000) with an uncertainty of 3 arcmin in radius (90% C.L. statistical and systematic).
A follow-up observation with the Follow-up X-ray Telescope (FXT) was performed automatically. Within the WXT error circle, an uncatalogued X-ray source was detected at R.A. = 256.4228 deg, DEC = 25.7755 deg (J2000) with an uncertainty of 20 arcsec in radius (90% C.L. statistical and systematic).
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).