General information
EP260703a is a fast X-ray transient detected by EP-WXT at R.A. 274.7265 deg, Dec. -62.6004 deg, with a 2.7 arcmin 90% confidence error radius. The transient began at 2026-07-03T03:13:57 UTC, lasted about 50 s, and had no known X-ray source in the WXT error circle.
Wavelength coverage
- X-ray: EP-WXT detected the transient in 0.5-4 keV, and EP-FXT later performed a follow-up observation in 0.5-10 keV.
No observations are mentioned in gamma-ray, optical/UV, infrared, radio, neutrino, or gravitational-wave bands.
Lightcurve and spectrum
- Duration: about 50 s from the EP-WXT detection.
- Peak 0.5-4 keV flux: approximately 2 x 10^-9 erg cm^-2 s^-1.
- Average WXT 0.5-4 keV spectrum: absorbed power-law model with Galactic NH fixed at 5.56 x 10^20 cm^-2 and photon index 0.22 (-1.17/+1.08).
- Average unabsorbed 0.5-4 keV flux: 1.46 (-0.81/+2.22) x 10^-9 erg cm^-2 s^-1.
- EP-FXT follow-up started 11.17 hours after the WXT detection, with 6.1 ks exposure, and found no significant X-ray source within the WXT error circle.
- EP-FXT 0.5-10 keV upper limit: about 7.6e-14 erg cm^-2 s^-1 at 90% confidence.
Redshift
What’s special vs typical
- The transient was short-lived and bright in soft X-rays, with no known X-ray source in the localization region.
- The rapid non-detection by EP-FXT suggests no reported persistent X-ray counterpart at 11.17 hours after the WXT event.