TITLE:   GCN CIRCULAR
NUMBER:  43327
SUBJECT: EP260105a: Einstein Probe detection of an X-ray transient
DATE:    26/01/05 06:17:04 GMT
FROM:    EP Team at NAOC/CAS <ep_ta@bao.ac.cn>

H. Zhou (PMO, CAS), Z. C. Zou (NJU), D. Y. Li, 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 EP260105a. The transient triggered EP-WXT (ID: 01709250995) at 2026-01-05T05:50:30 (UTC). The WXT position of the source is R.A. = 181.036 deg, DEC = 22.723 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. = 181.0158 deg, DEC = 22.7089 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).