[alma-config] Size of model sources

[Adrian Webster]

Folks,

I have one suggestion to make, that comes from looking at Steven's recent
mapping simulations. The A-array maps of Cyg A only show the two bright hot
spots, one in each lobe, and this does not seem too sensible to me. Surely
we chose the various sources to give the sort of balance of structure on
various scales, across a wide range of scales, that might be met in practice
with ALMA. But only the small end of the scale has much effect in this case.

Should we not shrink the size of Cyg A, as might be done by moving it to
greater distance, so that the whole range of scale sizes gets sampled. What
I have in mind is scaling the source (and indeed any other source model) so
that the overall diameter (i.e. about 2 arcmin in the case of Cyg A) is
reduced to match roughly the diameter of the primary beam of the ALMA dishes
FWHM, at whatever observing frequency is adopted. I think this will give a
much more useful test of the different antenna configurations.

Cheers

Adrian

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Adrian Webster,
Institute for Astronomy,
Department of Physics and Astronomy,
University of Edinburgh,
Royal Observatory,
Blackford Hill,
Edinburgh EH9 3HJ,
Scotland.
asw at roe.ac.uk
tel: 0131-668-8391
fax: 0131-668-8416

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