The current data have significant responses to data within 1.5 to 18 keV.
XSPEC> flux ! Calculate the current model flux over the default range.
XSPEC> flux 6.4 7.0 ! Calculate the current flux over 6.4 to 7 keV.
XSPEC> flux 1 10 ! The flux is calculated from 1.5 keV (the lower limit of the current response's sensitivity) to 10 keV.