TITLE:   GCN CIRCULAR
NUMBER:  45649
SUBJECT: EP260920a: Einstein Probe detection of an X-ray transient
DATE:    26/09/20 01:22:23 GMT
FROM:    EP Team at NAOC/CAS <ep_ta@bao.ac.cn>

K. R. Ni (CCNU)，S. Q. Zheng，Jin-Rui Liu(BNU)，Tian-Yu Liu, G. J. Yang, B. B. Zhang and Z.-X. Ling (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 EP260920a. The transient triggered EP-WXT (ID: 01709318515) at 2026-09-20T00:06:04 (UTC). The WXT position of the source is R.A. = 26.557 deg, DEC = -13.967 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. = 26.5298 deg, DEC = -13.9825 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).