General information
EP260628b is an EP-WXT X-ray transient detected starting 2026-06-28T10:04:53 UTC, lasting about 1000 s, at RA 327.606 deg and Dec -29.324 deg with a 2.6 arcmin 90% uncertainty radius. EP-FXT follow-up about one day later found two X-ray sources inside the WXT error region, but the association and event nature remain unclear.
Wavelength coverage
- X-ray: EP-WXT detected the transient in 0.5-4 keV, and EP-FXT observed the field in 0.5-10 keV about one day later, detecting two candidate X-ray sources within the WXT error circle.
No observations are mentioned in optical, infrared, radio, gamma-ray, neutrino, or gravitational-wave bands.
Lightcurve and spectrum
- The WXT transient started at 2026-06-28T10:04:53 UTC and lasted about 1000 s.
- The average WXT 0.5-4 keV spectrum is fit by an absorbed power-law model with fixed Galactic NH = 2.0 x 10^20 cm^-2 and photon index 1.40 +/- 0.46.
- The WXT unabsorbed 0.5-4 keV flux is 7.18(-1.80/+2.41) x 10^-11 erg cm^-2 s^-1.
- EP-FXT source EPF_J215025.7-291939 has photon index 3.09(-0.59/+0.59) and unabsorbed 0.5-10 keV flux 1.61(-0.30/+0.45) x 10^-13 erg cm^-2 s^-1.
- EP-FXT source EPF_J215025.3-291849 has photon index 2.61(-0.55/+0.60) and unabsorbed 0.5-10 keV flux 1.71(-0.38/+0.62) x 10^-13 erg cm^-2 s^-1.
Redshift
What’s special vs typical
- The event is notable as a short-duration soft-X-ray transient with two later uncataloged FXT sources inside the WXT localization, but the circular explicitly states that the association and nature remain unclear.