Removing a Spectrum's Continuum using
rvsao.contpars
contpars is an IRAF pset which sets the parameters to be used to
fit the continuum of spectra prior to cross-correlation or an emission
line search. A pset is basically a free-standing parameter file which can
be used by several tasks. In this case, the same parameters are used for both
xcsao and emsao.
A similar pset, contsum, is used by
sumspec. The parameters are used by one
subroutine, icsubcon, which is called by all three of the above
tasks.
Remove continuum for line search (ICSUBCON)
The IRAF curve fitting subroutines may be used interactively by setting
c_interactive to yes.
In this case, a
graph of the fit and the spectrum is displayed,
and the result may be examined or refit after individual pixels are removed.
Aq command is needed to exit from the interactive graph.
A function, spline1, spline3, legendre, or chebyshev, which
is specified by c_function
of order order
is used for the continuum fit.
The portion of the spectra to be fit is the image section specified by
sample, averaged in groups of
naverage pixels.
Points outside of limits
s_low_reject and
s_high_reject, specified in
standard deviations of the fit, are eliminated through
niterate iterations, with
grow pixels rejected on each
side of the rejected point at each iteration.
If emsao.contsub_plot
or xcsao.contsub_plot
is yes, the spectrum is plotted with the continuum removed.
[rvsao]
[xcsao]
[emsao]