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ALMA-IMF Telecon March 13, 2019

3/13/2019

Minutes for ALMA-IMF telecon, March 13, 2019
Agenda: https://github.com/ALMA-IMF/reduction/wiki/ALMA-IMF-Data-Reduction-Telecon,-March-13,-2019

http://desktop.visio.renater.fr/scopia?ID=722288***2252&autojoin

Attendees: Adam Ginsburg, Roberto Galván,Hongli Liu, Patricio Sanhueza, Nichol Cunningham, Jonathan Braine, Fernando Olguin, Brian Svoboda, Thomas Nony

Imaging results:

Roberto: G333 some problems with antenna list for ‘best sensitivity image’. (continuum_imaging_template_3sigma.py, bsens images). Needs corrections.

We may want to spcetrally average the “best sensitivity” data to speed up continuum imaging
Adam: https://github.com/ALMA-IMF/notebooks/blob/master/W51_B6_quicklooks.ipynb
- Automultithresh is probably not a good options
Liu Hongli:
B3 7M+12M combination (what field?):

B6: only 12M. sidelobethreshold=2, noisethreshold=4.25 (from casaguide). negativethreshold=1000

Discussion of imaging parameter saving:
https://github.com/ALMA-IMF/reduction/pull/10/files

Masking and thresholding discussion:

Patricio: prefer interactive because you can mask regions, force flux to a small sub-region, then once sidelobes are removed, expand the mask
Experiment to-do: try re-cleaning an image using the final mask
Roberto: maybe, if one could save in the viewer in interactive cleaning the mask that one uses in each cycle, one could save the masks and together with the info of the niter one could put that in a script

This is what I used for line cleaning, some kind of auto-masking tclean. It worked quite well in IRDCs.
http://adsabs.harvard.edu/abs/2018ApJ...861...14C
(see also https://home.strw.leidenuniv.nl/~ycontreras/yclean.html -> https://home.strw.leidenuniv.nl/~ycontreras/yclean.py )

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ALMA-IMF Telecon March 6, 2019

3/6/2019

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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

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

Brief discussion of status spreadsheet (see link in e-mail)
- region status
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
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
Continuum subtraction (Jordan) - DELAYED til next week
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):

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ALMA-IMF Telecon March 13, 2019

ALMA-IMF Telecon March 6, 2019

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