Examples for imcontsub)

NRAO Home > CASA > CASA Cookbook and User Reference Manual

6.3.1 Examples for imcontsub)

The following uses the example images from NGC5921 (§ F.1).

First, we make a clean image without the uv-plane continuum subtraction:

  # First, run clearcal to clear the uvcontsub results from the
  # corrected column
  clearcal(’ngc5921.demo.src.split.ms’)

  # Now clean, keeping all the channels except first and last
  default(’clean’)
  vis = ’ngc5921.demo.src.split.ms’
  imagename = ’ngc5921.demo.nouvcontsub’
  mode = ’channel’
  nchan = 61
  start = 1
  width = 1
  imsize = [256,256]
  psfmode = ’clark’
  imagermode = ’’
  cell = [15.,15.]
  niter = 6000
  threshold=’8.0mJy’
  weighting = ’briggs’
  robust = 0.5
  mask = [108,108,148,148]
  interactive=False
  clean()

  # It will have made the image:
  # -----------------------------
  # ngc5921.demo.nouvcontsub.image

  # You can view this image
  viewer(’ngc5921.demo.nouvcontsub.image’)

You can clearly see continuum sources in the image which were removed previously in the script by the use of uvcontsub. Lets see if imcontsub can work as well.

Using the viewer, it looks like channels 0 through 4 and 50 through 60 are line-free. Then:

  default(’imcontsub’)
  imagename = ’ngc5921.demo.nouvcontsub.image’
  linefile  = ’ngc5921.demo.nouvcontsub.lineimage’
  contfile  = ’ngc5921.demo.nouvcontsub.contimage’
  fitorder  = 1
  chans      = ’0~4,50~60’
  stokes    = ’I’
  imcontsub()

This did not do too badly!

[next] [prev] [prev-tail] [front] [up]

More information about CASA may be found at the CASA web page

This code is available under the terms of the GNU General Public Lincense