ALMA Simulation Tests on Cygnus-A
This is a demonstration of the feasibility and is not meant to be
a rigorous test of the imaging capability of the strawperson
arrays. Here, 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. All images are shown
with logarithmic stretch in order to bring out the low level extended
features as well.
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.
A-Array Observations
Top: input image convolved to match the simulated A-array observations.
Middle: simulated 4 hr long track obseravations in the A-array.
Bottom: simulated 15 minute snap shot C-array observation is added to the
4 hr long track in the A-array
C-Array Observations
Top: input image convolved to match the simulated C-array observations.
Bottom: simulated 4 hr long track observation in the C-array
E-Array Snapshot Observations
Top: input image convolved to match the simulated E-array observations.
Bottom: simulated 10 minute long snapshot observation in the E-array
Created by M. Yun (July 28, 2000)