The effects of source redshift can be allowed for by specifying the redshift on the command line (Z=value) in any of the applications (currently SFIT,SERROR,SPLOT and SFLUX) for which it is supported. This value is stored as a global parameter and will be used for subsequent runs of any of these programs until explicitly overridden. The user is always warned when any non-zero value of redshift is in use.
The spectral model is assumed to apply in the SOURCE frame, and
the resulting spectrum is then redshifted before folding through
the instrument response for comparison with the data. SPLOT
corrects for redshift of the model to plot the spectrum which is
observed at Earth, and SFLUX, similarly, gives the Earth-based
flux.
Absorption:-
The AG (galactic absorption) model component represents absorption
occurring along the sight-line within our own galaxy. This component
is therefore NOT redshifted. The AB (intrinsic absorption model), on
the other hand IS redshifted, since it represents absorption local
to the source.