GCN Circular 43930
Subject
EP260306a: Einstein Probe detection of an X-ray transient
Event
Date
2026-03-06T02:47:52Z (6 days ago)
Edited On
2026-03-06T14:05:53Z (5 days ago)
From
EP Team at NAOC/CAS <ep_ta@bao.ac.cn>
Edited By
Judith Racusin at NASA/GSFC <judith.racusin@nasa.gov> on behalf of EP Team at NAOC/CAS <ep_ta@bao.ac.cn>
Via
Web form
G.L. Huang, Z.X. Li (IHEP), H. Zhou (PMO, CAS) 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 EP260306a. The transient triggered EP-WXT (ID: 01709258759) at 2026-03-06T01:29:20 (UTC).
The WXT position of the source is R.A. = 145.955 deg, DEC = 15.685 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. = 145.9478 deg, DEC = 15.6963 deg (J2000) with an uncertainty of 20 arcsec in radius (90% C.L. statistical and systematic).
The location of the reported optical counterpart (GCN 43929) is consistent with the location of the uncatalogued X-ray source detected by FXT.
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).