TITLE:   GCN CIRCULAR
NUMBER:  39731
SUBJECT: EP250315a: Einstein Probe detection of an X-ray transient
DATE:    25/03/15 07:33:28 GMT
FROM:    EP Team at NAOC/CAS <ep_ta@bao.ac.cn>

J. Q. Peng (IHEP,CAS), M. Q. Huang (USTC), H. Sun, W. X. Wang, W. D. Zhang (NAO,CAS) report on behalf of the Einstein Probe 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 EP250315a. The transient triggered EP-WXT (ID: 01709132646) at 2025-03-15T06:02:47 (UTC). The WXT position of the source is R.A. = 203.020 deg, DEC = -9.531 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. = 203.0307 deg, DEC = -9.5316 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).