The part of the spectrum to be under consideration for the procedure is
chosen to include all lines to be modeled and is extended on both sides
in order to collect sufficient background. The parameter dlam,
units Å, gives the range below the lowest and above the highest line.
The value of for each line is limited by the range indicated by
dsig. The unit system for
can either be Å or km/s depending
(only for Gaussian line profiles) on the parameter sigunit (0/I). The
wavelengths must be in units Å, but the x-axis can be plotted in units keV
depending on the parameter ikev (0/I). The four parameters are to be
written on the same input line of the parameter file in the order
dsig, sigunit, dlam, ikev.