Figure 1 Sensitivity curves of EP/WXT as a function of integration time for X-ray sources with an assumed power-law photon spectral index of 2 (blue) and 3, respectively (bandpass: 0.5-4.keV; Galactic absorption column density of 3E20 atom/cm^2 is assumed). The shaded area denotes the detecting sensitivity of the ROSAT All-Sky Survey (RASS) in a similar band (0.1-2.4keV).