TITLE:   GCN CIRCULAR
NUMBER:  41246
SUBJECT: EP250806a: Einstein Probe detection of an X-ray transient
DATE:    25/08/06 10:21:46 GMT
FROM:    EP Team at NAOC/CAS <ep_ta@bao.ac.cn>

H.N. Yang, R. D. Liang (NAOC), Y. J. Zhang (THU), W. D. Zhang (NAOC) 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 EP250806a. The transient triggered EP-WXT (ID: 01709198415) at 2025-08-06T09:18:20 (UTC). The WXT position of the source is R.A. = 335.100 deg, DEC = -26.886 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. = 335.1046 deg, DEC = -26.8759 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).