[alma-config] simulated imaging test

[Min Yun]

I have conducted a small set of imaging tests on Cygnus A model in
order to see if we have everything we need for imaging simulations
and all in correct format.  You can find my initial findings at:
www.aoc.nrao.edu/~myun/mma/imaging/sim.html.

This is a demonstration of the feasibility and is not meant to be 
a rigorous test of the imaging capability of the strawperson
arrays.  The same input model image was used for all different 
simulated observations. The comparison images are
constructed by convolving the input image with the synthesized 
Gaussian beams of the simulated observations -- as I discussed
in my earlier e-mail. All images are shown with logarithmic 
stretch in order to bring out the low level extended features.

I find little evidence for gridding/sampling effects in the simulated 
observation images. One practical issue I have come
across is that all model images needed to be scaled up by some 
factor (numbers of pixels per beam as well as the ratio in area
between the model and the reconstructed beam) because the unit of 
the input image is in "Jy/beam" rather than "Jy/pixel"
-- the simulated and reconstructed images are expected to be 
in "Jy/beam" unit as well. We may need to worry about any
error arising from computing the beam area in numbers of pixels 
during the comparison between the model and simulated image.

Please comment on what I have done here.  Any suggestions to improve
the process are welcome.



					-- Min