Title    CO(6-5) emission from a small sample of Ultraluminous Infrared
Pi     K. Isaak
Time   65 hrs
1. Name: CO(6-5) emission from a small sample of Ultraluminous Infrared 
  Galaxies
 K. Isaak, C. Wilson et al.

   2. One short paragraph with science goal(s)

A study of the warm dense gas in a small sample of local ULIRGs. The aim
of this short project is to obtain a global measure of the warm, dense
molecular gas component in a small sample of starbursting/AGN galaxies.
The observations will complement existing CO(1-0) interferometer maps that
have been made as well as single-dish HCN(1-0) observations, and will
provide a clue as to the relative importance and physical extent of the
the warm molecular gas component. Observations such as these are central
to the interpretation of the results of studies of high-z galaxies where
mm interferometers are used to study redshifted CO(7-6), CO(6-5) and
CO(5-4). Very few, if any, local templates against which to compare line
ratios exist.


   3. Number of sources
       10, chosen from a list of well-studied local ULIRGs eg. Solomon et
       al., ApJ 1997, including such objects as Arp220.


   4. Coordinates:

      4.1. all over the sky (probably)

      4.2. Moving target: no

      4.3. Time critical: no


CO J=6-5 imaging:
----------------

   5. Spatial scales:

      5.1. Angular resolution (arcsec): 0.5

      5.2. Range of spatial scales/FOV (arcsec): 1-2 primary beams

      5.3. Single dish total power data: yes

      5.4. ACA: no

      5.5. Subarrays: no


   6. Frequencies:

      6.1. Receiver band: Band 9

      6.2. Lines and Frequencies (GHz):
		CO 690.0 GHz (redshifted to 684 GHz typically)

      6.3. Spectral resolution (km/s): 20 km/s

      6.4. Bandwidth or spectral coverage (km/s or GHz): ~800km/s


   8. Line intensity:

      8.1. Typical value (K or Jy): 1- 10 K

      8.2. Required rms per channel (K or Jy): 20 mK

      8.3. Spectral dynamic range: better than S/N 50 at the peak

   9. Polarization:  no

   10. Integration time for each observing mode/receiver setting (hr):
		average of 1 hour per field per galaxy; about half the
		galaxies need two fields total=15 hours

CO J=1-0 imaging:
----------------

to match the CO 6-5 data ...

   5. Spatial scales:

      5.1. Angular resolution (arcsec): 0.5

      5.2. Range of spatial scales/FOV (arcsec): 1 primary beam

      5.3. Single dish total power data: yes

      5.4. ACA: no

      5.5. Subarrays: no


   6. Frequencies:

      6.1. Receiver band: Band 3

      6.2. Lines and Frequencies (GHz):
		CO 115.3 GHz (redshifted to 114 GHz typically)

      6.3. Spectral resolution (km/s): 20 km/s

      6.4. Bandwidth or spectral coverage (km/s or GHz): ~800km/s


   8. Line intensity:

      8.1. Typical value (K or Jy): 1-10 K

      8.2. Required rms per channel (K or Jy): 40 mK

      8.3. Spectral dynamic range: S/N 25 or more at peak

   9. Polarization:  no

   10. Integration time for each observing mode/receiver setting (hr):
		average of 5 hours per galaxy = 50 hours


   11. Total integration time for program (hr): 10 x ( 300 minutes per
       source) = approx. 65 hrs

   12. Comments on observing strategy (e.g. line surveys, Target of
       Opportunity, Sun, ...): (optional)

The CO(6-5) line has been chosen to explore a strength of ALMA - high
sensitivity with large instantaneous bandwidth.

Sources will be chosen for which observations in the lower CO transitions
and HCN(1-0) already exist in order to make comparisons between different
gas components. A second selection criterion will be that sources
are sufficiently distant/small to be covered by one, or at most
two beams.

If we assume an average source size of 3", a main beam temperature in
CO(1-0) of 100mK as measured with the IRAM-30m (20" beam), a
CO(6-5)/CO(1-0) line ratio of 1, then we would expect a main beam
temperature of around 500mK in the primary beam (9"). The emission is
likely to be on a much smaller size scales than this, however.

If we make the simplifying assumption that the CO(1-0) emission is
uniformly distributed over a 3" x 3" extent, and that the CO(6-5) is
confined to small regions of say 1" x 1", then we arrive at a peak main
beam brightness of up to 10K per synthesized beam. 

About half of the sources will require more than one pointing to cover
either two nuclei in a closely interacting system, or simply that the
source is slightly larger than a single beam.

Note that most of the time is spent getting matching CO 1-0 data at
the same spatial and spectral resolution. If the 6-5/1-0 line ratio
is less than 1, will need more time in Band 9

*******************************************************************

Review Chris Carilli: OK.
--------------------------------------------------
Review v2.0:
 
CO(6-5) emission from a small sample of ULIRGS
Isaak, Wilson et al. 

Seems fine. What is the biggest program that the authors could forsee
in the 3-year period. This seems to be very modest. Is there a reason
beyond practical time requests not to cover more of the BGS ULIRGs
etc?