General information
EP260725a is an Einstein Probe X-ray transient detected by EP-WXT on 2026-07-25 02:45:59 UTC and followed up by EP-FXT about 15 hours later. The updated FXT position is consistent with the known RS CVn-type variable star ZTF J222816.62+504629.8.
Wavelength coverage
- X-ray: EP-WXT detected the transient and EP-FXT performed follow-up, detecting an X-ray source within the WXT error circle with an updated 10 arcsec position.
No observations are mentioned in optical, infrared, radio, gamma-ray, neutrino, or gravitational-wave bands.
Lightcurve and spectrum
- EP-WXT peak flux was reported as ~1 x 10^-10 erg cm^-2 s^-1 in 0.5-4 keV.
- The average WXT 0.5-4 keV spectrum was fit with an absorbed power-law model using fixed Galactic NH = 7.0 x 10^20 cm^-2 and photon index 3.5 (-1.7/+2.2).
- The WXT average unabsorbed 0.5-4 keV flux was 2.0(-0.8/+2.4) x 10^-11 erg cm^-2 s^-1.
- EP-FXT measured an average unabsorbed 0.5-10 keV flux of about 1.2 x 10^-12 erg cm^-2 s^-1.
- The corresponding EP-WXT X-ray luminosity was estimated as approximately 1.1 x 10^34 erg/s.
Redshift
What’s special vs typical