[asac] Yun: dust emission from high-z galaxies

[Al Wootten]

The plot apparently caused the following message to bounce as too long.
I have placed the plot at:
http://www.cv.nrao.edu/~awootten/mmaimcal/asac/submmgal.cps
for easy retrieval. - Al

From: "Min S. Yun" <myun at bonito.astro.umass.edu>
X-Sender: myun at bonito
To: asac at nrao.edu
Subject: dust emission from high-z galaxies
Message-ID: <Pine.LNX.3.96.1010522150031.13166B-101000 at bonito>
MIME-Version: 1.0

To examine which ALMA band is best suited for studying dust
emission from high-z galaxies, I made the attached plot.
The expected flux density is derived using the observed 
SED of Arp220 in a flat universe with Ho=75.  Several ALMA
bands are shown (as labeled on top).  The 5 sigma detection
sensitivity (after 2 hrs of integration time) are shown 
in thick dashed red lines, assuming piece-wise analytic 
expressions of Tsys as given in Stephane's SSB-vs-DSB write-up.

This plot suggests Bands 6 & 7 are by far the best bands for
studying redshifted Arp220s out to z=10.  Band 4 is not too
bad, but it is not the most sensitive.  This plot offers
a confirmation of Stephane's claim that Band 4 is needed 
for photometric redshift determination of dusty galaxies --
the submm drop-off can be detected only in Band 4 for
galaxies at z of 10 or larger.  If few galaxies are at z>5, on the
other hand, Bands 6 & 7 offer all there is know.

Just as a clarification, FIR luminosity of Arp220 is
about 10^12 solar luminosity, which is a factor of 4 smaller
than the case Pierre considered in our write-up (which is
more typical of the submm population detected by SCUBA).
Therefore Band 4 is still a useful band for studying SCUBA sources
and might even be the work horse band if the weather condition
at Chajnantor is much worse than we think.


					-- Min
-----------

Min S. Yun				e-mail: myun at astro.umass.edu
Assistant Professor			phone:  (413) 545-2215
Astronomy Department			FAX:    (413) 545-4223
University of Massachusetts             http://www.astro.umass.edu/~myun
Amherst, MA 01003