[mmaimcal] ASAC Analysis of ACA/ALMA/SD simulations

[Al Wootten]

ALMA Atacama Compact Array Tiger Team

At today's meeting I agreed to distribute information about the location of
fits images showing the science which may be done with ALMA+ACA.  These can
be found in hyperlinks at the minutes of the 20 July tiger team telecon.
I provide them here in text form.

At the last ASAC meeting,
Ewine suggested that a team of Crutcher, Welch, Cox and Yun evaluate-that
is, make scientific measurements from-the simulated images to determine
their suitability for the science purposes of ALMA. Holdaway suggested that
this process could begin now, with the perfect images, for instance
convolving the model images with a clean beam and analyzing them. For
example, determining the arm interarm ratio of flux in M51. This way, when
simulated data come in the models will at least be understood in terms of
the science they are capable of delivering. This was thought a good idea.
Wootten will assemble and distribute the images.  Apparently, sending the
URL of the minutes was not a good way to do that; that is the reason for this
message.  ACA Tiger Team results may be read about at http://iram.fr/~alma

Excerpts from Teleconference, 20 July 2001 1415 UT

Draft Minutes

 Images were discussed. These include

M51 HST image

Holdaway can offer an M51 HST image. It is based on the model image in the
ALMA simulation library, but has been modified significantly. I have
eliminated the off-source noise by a combination of blanking and clipping,
and have played with the headers so the image is more amenable to radio
synthesis simulations. Last, I have regridded the image to 256 and 512
pixels square and clipped the negatives that resulted from the regridding.
These are quite clean for simulations.

Two versions of the images can be found at:

ftp://ftp.tuc.nrao.edu/mholdawa/

M51HA.MODEL256

M51HA.MODEL512

Cluster Image

Tatematsu's example is on Morita's WWW site
http://www.nro.nao.ac.jp/~morita/TEMP/CLUSTER.FITS
Protostellar Core image

Michiel's examples of a protostellar disk buried in a core include: 
HCO+ 1-0 http://www.cv.nrao.edu/~awootten/mmaimcal/hco+_1-0_60.fits
, HCO+ 4-3  "http://www.cv.nrao.edu/~awootten/mmaimcal/hco+_4-3_60.fits
and C18O 1-0 http://www.cv.nrao.edu/~awootten/mmaimcal/c18o_1-0_60.fits
fits images. One of the science cases involves
bright cores in extended weak halos such as these.

Debris Disk image
Lee Mundy will send this along soon.

Crutcher noted that one type of imaging problem was not included among
these-that with low contrast but structural detail on small scales.
Polarization work abounds with images such as these. Wootten suggested a
comet or the elliptical galaxy image discussed in Cambridge. Holdaway
suggested that the bright portions of the M51 image might be filtered so as
to leave a low contrast detailed image. It was generally agreed that this
was suitable.  This image is under investigation.

Crutcher brought up the evaluation process discussed at the ASAC meeting.
Ewine suggested that a team of Crutcher, Welch, Cox and Yun evaluate-that
is, make scientific measurements from-the simulated images to determine
their suitability for the science purposes of ALMA. Holdaway suggested that
this process could begin now, with the perfect images, for instance
convolving the model images with a clean beam and analyzing them. For
example, determining the arm interarm ratio of flux in M51. This way, when
simulated data come in the models will at least be understood in terms of
the science they are capable of delivering. This was thought a good idea.
Wootten will assemble and distribute the images.




Clear skies,
Al
+--------------------------------------------------------+
| Alwyn  Wootten   (http://www.cv.nrao.edu/~awootten/)	 |
| Project Scientist, Atacama Large Millimeter Array/US   |
| Astronomer, National Radio Astronomy Observatory       |        
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