General information
EP260430a is an X-ray transient detected by Einstein Probe/WXT on 2026-04-30 02:32:47 UTC with an uncatalogued X-ray source found by EP/FXT inside the WXT error region.
Wavelength coverage
- X-ray: EP-WXT detection and EP-FXT follow-up with spectral fits, flux estimates, and reported rapid decay (44436).
- Optical: MASTER-OAFA and LCO/SINISTRO report only upper limits; no new source in/near the EP/FXT uncertainty region (44428, 44432).
No observations were mentioned in radio, infrared, ultraviolet, gamma-ray, or high-energy neutrinos/GWs.
Lightcurve and spectrum
- FXT light curve: rapid decay reported (44436).
- WXT spectrum (0.5–4 keV): absorbed power law with fixed Galactic NH=0.3×10^21 cm^-2; photon index 0.84 (+0.19/-0.18); unabsorbed flux 4.63 (+2.54/-1.56)×10^-10 erg/s/cm^2 (44436).
- FXT spectrum (0.5–10 keV): absorbed power law with fixed Galactic NH=0.3×10^21 cm^-2; photon index 4.61 (+/-0.20); unabsorbed flux 1.27 (-0.16/+0.17)×10^-11 erg/s/cm^2 (44436).
- Optical limits: MASTER clear band reaching ~19.0 mag and LCO r > 22.1 (AB; not extinction-corrected) (44428, 44432).
Redshift
What’s special vs typical
The event shows a reported rapid X-ray decay and markedly different reported photon indices between WXT (hard; ~0.84) and FXT (very soft; ~4.61) fits, while contemporaneous optical searches found no counterpart down to r > 22.1 (44436, 44432).