Split Continuum and Spectral line imaging

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Split Continuum and Spectral line imaging

To image the spectral line, we simply remove in the plane the continuum defined before and image the resulting spectral line data:
uv_baseline
uv_map
clean (and optionally uv_restore)

The last step is to add back to this image the deconvolved continuum one:
define image my_clean * real /like clean /global
map_combine my_clean ADD clean continuum
where the last command is equivalent to the following loop:
let my_clean% clean% ! Set its header
for i 1 to clean%dim[3]
let my_clean[i] clean[i]+continuum
next
Because the Fourier Transform is a linear operation, we end up with a combined data set that properly includes all the emission, line and continuum, deconvolved in a (well almost...) 9 optimal way.

Further analysis of the spatial variations of the continuum emission (including variations of its spectral index) can be done on this combined image that contains all the information, see Sec.

Note that we used in this example commands uv_filter and uv_baseline with their default behaviour provided by uv_preview: the user could specify more adapted values using the command options and/or control variables if needed.