TITLE:   GCN CIRCULAR
NUMBER:  38864
SUBJECT: EP250109a: EP-WXT detection of an X-ray transient
DATE:    25/01/09 09:20:17 GMT
FROM:    EP Team at NAOC/CAS <ep_ta@bao.ac.cn>

R.-Z. Li (YNAO, CAS), X.-L. Chen (YNU), K. Chatterjee (YNU), Y.-L. Hua (PMO, CAS), H. Sun and Y. Liu (NAO, CAS) report on behalf of the Einstein Probe team:

We report on the detection of an X-ray transient detected by EP-WXT, which triggered the on-board processing unit at 2025-01-09 06:17:58 (UTC) (trigger ID: 01709130082). The source position is R.A. = 88.806 deg, DEC = -12.500 deg (J2000) with an uncertainty of about 3 arcmin (radius, 90% C.L. statistical and systematic).

A follow-up observation on the X-ray transient was performed by the EP-FXT, which detected an uncatalogued X-ray source at R.A. = 88.8055 deg, DEC = -12.4966 deg (J2000) with an uncertainty of about 20 arcsec (radius, 90% C.L. statistical and systematic), consistent with the position of the WXT transient within the uncertainties.

More information will be updated when the telemetry data is received. Further observations are encouraged to explore the origin of the transient.

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).