ALMA apply uvcont table

Applying Pipeline Continuum Subtraction

Starting in Cycle 5, ALMA pipeline-calibrated data will be delivered with a calibration table which describes the continuum subtraction the pipeline did. This CASA Guide describes how to apply this pipeline-determined continuum subtraction. The main benefit of using this pre-determined subtractionis that it will save time compared to repeating the hif_uvcontfit() and hif_uvcontsub() steps as described in XYZPQ. If you wish to revise the continuum subtraction you should instead use the steps described in IWIDJ.

This is a draft page describing how PI's can make use of the UVCONT table that is delivered with their data to uv subtract the data, saving time over doing the uvcont fitting themselves.

Here is a bulleted list:

• hello
  • that's great
• byebye
  • for now

casa --pipeline

os.system('ls -ltr')

STEP 1:

Restore the pipeline calibration as described [[1][here]]. Do not modify the cont.dat file! if you do, the procedure described here will not work as intended.

STEP 2:

Unpack the auxilliary calibration tables, which contain a description of the continuum subtraction.

cd ../../calibration/
gunzip -c (one auxcaltable) | tar xvf -

There will be one such table for each execution, with file names like (MOUS Name).session_2.auxcaltables.tgz, (MOUS Name).session 3.auxcaltables.tgz, etc.; repeat the above steps for each.

STEP 3:

Copy the auxilliary calibration tables into the working directory, and go back to the working directory:

cp *uvcontfit*uvcont.tbl ../calibrated/working

While here, take a look at the files called *auxcalapply*txt. There will be one file for each execution, with names like (Execution UID)_target.ms.auxcalapply.txt. These contain the applycal() statements with which, with minor modifications, you will apply the uv continuum subtraction as a calibration. You will use these in the following step. The contents will look something like this:

applycal(vis='/lustre/naasc/sciops/comm/amcnicho/pipeline/root/2013.1.00722.S_2017_09_13T14_30_33.955/SOUS_uid___A001_X145_X134/GOUS_uid___A001_X145_X135/MOUS_uid___A001_X145_X136/working/uid___A002_X9fddd8_Xc52_target.ms', field='', intent='', spw='17,19,21,23', antenna='0~35', gaintable='/lustre/naasc/sciops/comm/amcnicho/pipeline/root/2013.1.00722.S_2017_09_13T14_30_33.955/SOUS_uid___A001_X145_X134/GOUS_uid___A001_X145_X135/MOUS_uid___A001_X145_X136/working/uid___A002_X9fddd8_Xc52_target.ms.hif_uvcontfit.s27_3.SPT0346-52.uvcont.tbl', gainfield='', spwmap=[], interp='', calwt=False)

Looking ahead, the changes you will make to these statements will be to eliminate the long "full-path" prefix since you will be working with all required files in the "working" directory, which is where you will run the pipeline.

Finally, go back to the working directory

cd ../calibrated/working

STEP 4: