GCN 44186: EP260402a/GRB 260402A: Einstein Probe detection of an X-ray transient

2026-04-02T14:16:37.632Z | rev 0 | event: GRB 260402A
Y. Q. Zhao (USTC,PRIC), C. L. Guo, J. W. Hu, C. Jin (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 EP260402a. The transient triggered EP-WXT (ID: 01709259488) at 2026-04-02T10:30:41 (UTC). The WXT position of the source is R.A. = 170.994 deg, DEC = 63.604 deg (J2000) with an uncertainty of 3 arcmin in radius (90% C.L. statistical and systematic). EP260402a is temporally and spatially consistent with GRB 260402A (GCN #44181).

A follow-up observation with the Follow-up X-ray Telescope (FXT) was performed automatically triggered by SVOM GRB detection, began at 2026-04-02T12:55:33Z. Within the WXT error circle, an uncatalogued X-ray source was detected at R.A. = 170.9607 deg, DEC = 63.6128 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).