ALMA-IMF Core Working Group, February 11 2021

Connection:
https://univ-grenoble-alpes-fr.zoom.us/j/98634272360?pwd=YkQ1ZVM5K2l4UUFPTkViYVNZRDFXZz09

Attendees: Fred, Timea, Yohan, Sasha, Nathalie, Fabrice, Adam, Ant, Mélisse, Nichol, Thomas, Allison, Sylvain, Gemma, Tapas, Quang
Not attending: 

For memory:
Minutes from our last telecon
Activities of the Core Working Group
Members and their main interests


Agenda:

1. Catalog filtering, Yohan

• Filtering out free-free sources from our core catalog
  

    The 1mm-to-3mm flux ratio with “flux re-scaling” tells us something about the intensity distribution of our core and, possibly, about their prestellar/starless nature.

• Issues with the correction of continuum fluxes for line contamination
  

    In the Nature Astronomy paper, for W43-MM1 @ 1.3 mm, this correction was easier because the input images were cleaner/more restrictive:

• The best-sensitivity image used the SPW7 only ⇒ 1.9 GHz instead of 3.4 GHz (current bsens images)
  
• The line-free image used the few SPW7 channels without hot core lines ⇒ 65 MHz instead of 1.4 GHz (W43-MM2 cleanest 1.3 mm image)
  

Questions: 

• Nature of the large-diameter cores (Adam) to be investigated
  
• What is the difference when identifying free-free sources with their peak flux ratio?
  
• Check for any trend in the variation of the sizes with wavelengths and sensitivity
  

→ plot the re-scale factor in the case of the free-free and hot-core contamination

• Making aperture photometry or using the same structure observed at 1.3mm to measure the 3mm flux could help confirm the post-selection of free-free sources...
  

1. CMF results from the W43-MM2 & MM3 protocluster, Yohan

    CMFs vary depending on the different sub-regions taken.

1. General questions concerning the W43-MM2&3 dataset

• Cores name
  

Timea’s suggestion: ALMAIMF_184736.8-20054.3        (In RA-Dec)
Adam’s suggestion: ALMAIMF_G333.33333+00.3333    (In Galactic coordinates)
Yohan’s suggestion: ALMAIMF_281.86-02.66                      (In degrees)

• Yohan used his own continuum images to make the analysis
  

• The continuum image of MM2 in B3 differs by 20% in rms (Adam’s version is better than that of Yohan, 4 selfcal iterations instead of 1). [MM3 B3 5 versus 4 selfcal iterations]. 
  
• Band 6 images should be similar/the same. Only B6 is used as detection driver.
  
• Is it still OK? or shall we redo all the process? from stitching data, applying MnGseg, getsf and Gext2D, analyzing catalogs…
  

• Will the `pure-continuum’ image of MM1 or MM2-MM3 be compared to the cleanest image in the Data paper?