General information
EP260526a is a fast X-ray transient detected by Einstein Probe WXT, with subsequent EP-FXT follow-up reporting an uncatalogued X-ray source within the WXT error circle. Optical follow-up observations reported only non-detections with limiting magnitudes.
Wavelength coverage
- X-ray: EP-WXT detected a ~140 s transient with a power-law spectrum and unabsorbed 0.5–4 keV flux 8.2 (+2.8/-2.2)×10^-10 erg/s/cm^2; EP-FXT later detected an uncatalogued source with unabsorbed 0.5–10 keV flux ~5.2 (+5.2/-2.7)×10^-14 erg/s/cm^2.
- Optical: Liverpool Telescope IO:O obtained g/r/i/z imaging ~3.8 hr after detection with no new sources; LCO 1m SINISTRO obtained r and z imaging ~1.4 days after detection with no new sources.
No observations are mentioned in radio, infrared, ultraviolet, gamma-ray, or neutrinos.
Lightcurve and spectrum
- WXT: event started at 2026-05-26T09:43:34 UTC and lasted ~140 s; absorbed power-law fit with photon index 1.98 (+0.78/-0.70) (Galactic NH fixed).
- FXT: absorbed power-law fit with photon index 1.8 (+1.5/-1.0) (Galactic NH fixed).
Redshift
What’s special vs typical
- EP-FXT reports an uncatalogued X-ray source detected within the original WXT error circle with 10 arcsec uncertainty.