GCN Circular 40429
Subject
EP250511a: Einstein Probe detection of an X-ray transient
Date
2025-05-11T12:09:26Z (18 hours ago)
From
EP Team at NAOC/CAS <ep_ta@bao.ac.cn>
Via
Web form
T. Y. Lian (NAO, CAS), A. Li (BNU), Y. L. Wang (NAO, CAS; ICE, CSIC-IEEC), 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 EP250511a. The transient triggered EP-WXT (ID: 01709175648) at 2025-05-11T07:59:59 (UTC). The WXT position of the source is R.A. = 202.096 deg, DEC = -2.725 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. = 202.1113 deg, DEC = -2.7023 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).