ALMA-IMF Telecon March 6, 2019

Agenda: https://github.com/ALMA-IMF/reduction/wiki/ALMA-IMF-Data-Reduction-Telecon,-March-6,-2019
Minutes:
Participating: Adam Ginsburg, Frederique Motte, Patricio Sanhueza, Brian Svoboda, Ana Lopez, Jordan Molet, Thomas Nony, Sylvain Bontemps, Fernando Olguin, Roberto,  Hongli Liu

1. General news and update

Mosaics in QA3 for imaging for a few months now. Some have been re-delivered. Others still in QA3: 5 SBs 12m array, 13 SBs 7m array

1. Brief discussion of status spreadsheet (see link in e-mail)
   • region status
2. Imaging status
   • Discussion of different scripts (Adam, Timea)
     1. https://github.com/ALMA-IMF/reduction/tree/master/reduction 
     2. E.g. https://github.com/ALMA-IMF/reduction/blob/master/reduction/continuum_imaging.py 
     3. Imaging scripts: suggested spectral averaging ~100 MHz?  Use maximum before bandwidth smearing becomes significant
   • What imaging results have been achieved?
     1. [Fernando] Some examples of imaging of G338 produced with the scripts: https://drive.google.com/open?id=1cJsCQqU-uhJQBSUOsouJ8BPIIUy3jr5V
     2. Roberto: in progress
     3. Adam: W51-E, See below
     4. Patricio: G327, See below
   • Is self-calibration necessary? If so, add that status to Continuum Imaging Results tab in spreadsheet
     1. Probably needed
     2. Andres Guzman working on selfcal of G10.62
   • Self-calibration process:
     1. Basic: tclean -> gaincal -> applycal -> tclean
     2. Difficulty w/mosaics?
        1. Look for pointings that do not contain bright emission to exclude from self-cal (LM - can solve on them but will not have a solution, only apply across from fields with ‘good’ solns)
        2. Potential problem with bright emission at edge of primary beam (maybe?)
     3. Are we concerned about astrometry?  Probably not yet.
   • Measuring image noise
     1. RMS in part of image where PB is “close to 1” in the pb-corrected map
     2. RMS of residual map?  I.e., take the RMS of the residual map in the area pb > 0.8 or some similar threshold
     3. Need comparison of different methods; enter these as different columns in the google spreadsheet
3. TP baseline issues (Patricio)
   • CASA can’t handle it.
   • Flag out EBs with ripples?
   • Roberto: removed EBs w/ugliest ripples, re-ran pipeline, result looked good.  However, not much difference before/after
4. Continuum subtraction (Jordan) - DELAYED til next week
5. Conclusion: will meet next week

W51 examples from Adam, lines excluded:
Left: Before: no selfcal ; Right: after 1 iter selfcal

G327 from Patricio B6 lines excluded, no selfcal (selfcal is needed):