[mmaimcal] Re: MMA HDF simulation

[Al Wootten]

Some of you were on an earlier email which Min sent around; I surmise
that there is a group working on the VLA Upgrade HDF simulation.  On the
off chance that you might also be interested in the MMA equivalent I have
included you in this message.

I'd like to get a first cut of HDF-MMA to present to the  Workshop on 
Submillimeter Space Astronomy in the Next Millennium where I have to give
an MMA talk on 8-9 Feb.  Bob will be presenting the MMA to the Radio Panel
of the Decadal Survey Committee on 18 Feb; he would like to show what the
MMA can do to that audience.  So here are some more musings. Discussion
welcome please!

Our HDF simulation is to be based upon  Blain's astroph9806062 graphs adopting
Model Peak-5 for galaxy evolution.  We will employ a flat Universe with
q=0.5.  We will show the same general area
as the HDF-S, with the ~800 galaxies randomly distributed, with coordinates
to emphasize one advantage of radio images over optical images.
The field will be about 4' x 4' at a continuum sensitivity of about .01 mJy.
We'll color code the galaxies according to their distance.  The
strawman D array for 48 12m antennas appears to have a diameter of about
130m which will provide a resolution of something like 1.5".  The image
will be about 512x512 with dots of this size scattered artfully about.
Blue z<1.5
Green 1.5<z<3
Red z>3
This is a medium deep mosaicked observation taking a few weeks at just over
one hundred pointings.  We have decided that best sensitivity is at 350 GHz(?).
The observations will be taken in spectral line mode but with coarse
resolution covering all 8 GHz centered on 339 GHz in the LSB.  In the
USB, the 4-12 GHz IF centers us at 355 GHz, again with 8 GHz coverage.
This results in the total band matched well to the atmospheric window.
The minimum frequency resolution per spectral channel is 31.25 MHz, or
27.2 km/s; 90% of the analog bandwidth will be usable for a total
spectral coverage of 12,500 km/s, though non-contiguous.  Up to J=8-7
CO at z=1.75, different transitions of CO will fall within the band for
different z.  For 25% of z-space, a transition of CO will fall within this
band for some transition.  Granted, J=8-7 isn't the most expected search
line, but lines of H2O or CI will also be shifted into the band for 
moderate redshifts.  Therefore, we will not only detect about 800 galaxies,
we'll get redshifts for some hefty percentage of them for free.  The optical
HDF is dominated by galaxies with z<1.7 though the submillimeter HDF would
be expected to have a somewhat different redshift distribution.  But we may
well also obtain redshifts for dozens if not hundreds of galaxies simultaneously
with the continuum observations.  We must determine what the sensitivity 
will be to line emission for these few hours per pointing integrations, 
and what fraction of galaxies we might measure line emission for.  This can 
be quite rough for the first cut.  Perhaps we should show this somehow on
the simulation--randomly pepper the percentage of galaxies for which we
expect CO detections with rainbow colors, to indicate spectral detection?

Here is my table of z coverage.  I'm having Pat make up a figure of this too,
showing z as abcissa with coverage color coded to lines.  
Each CO line is named on the y axis as in column 1.  The first CI is
492 GHz, the second 809 GHz.  The abcissa is z
which is given in the following table and on my sketch as two line segments, 
the lowest z from column 4 going to column 5, then another segment from
column 2 value to that in column 3.

   1          2        3                4          5
  Line     zlower            zrange   zupper
     3-2    0.00874 0.031611 0.022871 -0.03624 -0.01539
     4-3   0.344926  0.37542 0.030494 0.284952 0.312758
     5-4   0.681062 0.719176 0.038115 0.606098 0.640854
     6-5   1.017133 1.062867 0.045735 0.927182 0.968887
     7-6   1.353124 1.406477 0.053352 1.248191 1.296842
     8-7   1.689029 1.749997 0.060968 1.569116 1.624712
  CI       0.435239  0.46778 0.032541 0.371237 0.400911
  CI       1.359977 1.413484 0.053508 1.254738 1.303531
 
Comments or contributions welcome.

Clear skies,
Al