GCN 43574: EP260131a: Einstein Probe detection of an X-ray transient

2026-01-31T04:36:37.533Z | rev 0 | event: EP260131a

H. C. Ding, T. Wu (AHNU), Q. Y. Wu, H. Sun (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 EP260131a. The transient triggered EP-WXT (ID: 01709254172) at 2026-01-31T03:31:25 (UTC). The WXT position of the source is R.A. = 149.921 deg, DEC = -3.291 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. = 149.9027 deg, DEC = -3.3094 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).