Line_Moment — Image cube to line moment map analysis.

Usage: admit_recipe Line_Moment Your-Image-Cube [Your-Primary-Beam]



This ADMIT script makes a simple moment map from an ALMA interferometer data cube. The flow is:

  1. Ingest your cube into ADMIT (creates a CASA image if starts as FITS)
  2. Calculate statistics on cube for later use
  3. Calculate simple sum of all channels to decide where to make a spectrum
  4. Make a spectrum at the peak in the sum map from step #3
  5. Find segments with emission or absorption and try to ID the line(s)
  6. Cut out cubes for each line found; cube name is line name
  7. Calculate moment 0,1,2 maps for each line cube
  8. Make a spectrum at the peak in each moment map.


: image
Your CASA or FITS image. If the image file is not primary beam corrected, then input only this cube. Default cubes from clean are like this. The noise does not rise up at the edge of the field
: image, optional
Your CASA or FITS primary beam image. Cubes from the ALMA archive are often primary beam corrected. In these images, the noise rises out from the center of the imaged field. In this case, you need to input both the image file and the primary beam cube. Both are available to you from the archive.

Optional Keywords

  • numsigma in LineID_AT: typically use 6.0 to 8.0 for 4000 channels; 4.0 if you only have a few hundred channels 3.0 if you want to dig deep but then expect to get fake lines too. Default:6
  • minchan in LineID_AT: minimum width of line in # of channels to assume when searching for lines. Default:5
  • pad in Linecube_AT: this controls how many “extra” channels are added to either end of the line sub-cube to be cut from the input cube. It should generally be comparable to your line width. Default:50
  • cutoff in Moment_AT: number of sigma for cut levels in making moment maps: one value for each requested moment map. Must be a Python list: [1.0, 2.0,3.0] for example for moment 0, 1 and 2 maps. Default:[1.5,3,3]