barb

 BARB N1 N2 N3 FILE METHOD -- Broadens spectra with user defined profile


 Parameters:
           
     N1   -- First spectrum to be broadened
     N2   -- Last spectrum to be broadened
     N3   -- First output spectrum
     FILE -- File with 2 columns, the first of velocities, and the second
             of the profile function at each velocity. Velocities in km/s.
             It should increase monotonically in X. Linear interpolation
             is used at the moment so a fine sampling is advisable.
             Empty lines or lines beginning with # will be ignored.
             The normalisation will be set by the maximum value. i.e.
             a max value = 1 will leave the continuum unchanged whereas
             0.5 will reduce it. This is to allow for sequences of models
             where the normalisation may vary in a defineable manner.

     METHOD- F = Fast crude method, which is only accurate if
                 the broadening covers many pixels, otherwise it
                 tends to underbroaden. It is only worth using
                 on spectra which are not on a velocity scale since
                 the time saving is otherwise small.

             S = Slow, accurate method which requires convolving the
                 broadening with the interpolating function for which
                 a truncated SIN(X)/X type interpolation is used.
                 BE WARNED: this can be VERY VERY slow see next.

     If the scale is uniform in velocity, then the routine need only 
     compute the blurring array once and the computation should not 
     be much affected by the METHOD used. Otherwise the blurring array 
     is recomputed for EVERY pixel assuming that the scale is locally 
     a velocity scale according to the dispersion at the pixel of interest. 
     This is the reason for the large difference in speeds between the
     two methods for non-uniform in velocity data. I recommend that for
     resonable accuracy and speed you rebin to a uniform velocity scale
     (vbin) with sinc function rebinning, and then use method S, otherwise
     it can take a VERY long time.

This command belongs to the classes: arithematic and manipulation .