TITLE:   GCN CIRCULAR
NUMBER:  44594
SUBJECT: EP260512a: Einstein Probe detection of an X-ray transient
DATE:    26/05/13 04:03:17 GMT
FROM:    EP Team at NAOC/CAS <ep_ta@bao.ac.cn>

R. D. Liang, M. J. Liu (NAO, CAS), H. Z. Wu (HUST), H. Sun (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 EP260512a. The transient was detected at 2026-05-12 08:31:32 (UTC) with a duration of about 200s. The signal-to-noise ratio is below the on-board trigger threshold, and hence the transient was discovered by ground-based analysis. The WXT position of the source is R.A. = 223.899 deg, DEC = 28.432 deg (J2000) with an uncertainty of 2.6 arcmin in radius (90% C.L. statistical and systematic).

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).