1. Name: Structure of the ISM in irregular galaxies
	C. Wilson et al. 

   2. One short paragraph with science goal(s)

The structure of the ISM in low metallicity dwarf galaxies. Are the
molecular clouds smaller as well as less luminous in CO? Do they have
small CO cores surrounded by larger H2 envelopes? Are the physical
properties (density, temperature) very different
from gas at solar metallicities? What is the dust to gas ratio at lower
metallicities? What effect does the presence of a starburst have on the
ISM structure at low metallicity?  Besides understanding nearby dwarf
galaxies, the answers to these questions could be important for
interpreting ALMA observations of high-redshift galaxies with reduced
metallicities. 


   3. Number of sources 

	10, about half starburst and half non-starburst

   4. Coordinates:

      4.1. all over the sky (probably)

      4.2. Moving target: no

      4.3. Time critical: no 

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

   5. Spatial scales:

      5.1. Angular resolution (arcsec): 0.4"  (20 pc at 10 Mpc)

      5.2. Range of spatial scales/FOV (arcsec): single field (55")

      5.3. Single dish total power data: yes

      5.4. ACA: yes

      5.5. Subarrays: no


   6. Frequencies:

      6.1. Receiver band: Band 3

      6.2. Lines and Frequencies (GHz):
		CO 115.0 GHz (redshifted for 10 Mpc and Ho = 75)

      6.3. Spectral resolution (km/s): 2 km/s

      6.4. Bandwidth or spectral coverage (km/s or GHz): 300 km/s max


   8. Line intensity:

      8.1. Typical value (K or Jy): 1-4  K 

      8.2. Required rms per channel (K or Jy): 0.2 K

      8.3. Spectral dynamic range: 20

   9. Polarization:  no

   10. Integration time for each observing mode/receiver setting (hr): 
		7.3 hr per galaxy

CO 3-2 imaging:
---------------

   5. Spatial scales:

      5.1. Angular resolution (arcsec): 1"

      5.2. Range of spatial scales/FOV (arcsec): medium mosaic (19 fields)

      5.3. Single dish total power data: yes

      5.4. ACA: yes

      5.5. Subarrays: no


   6. Frequencies:

      6.1. Receiver band: Band 7

      6.2. Lines and Frequencies (GHz):
		CO 3-2 345 GHz (redshifted for 10 Mpc and Ho = 75)

      6.3. Spectral resolution (km/s): 2 km/s

      6.4. Bandwidth or spectral coverage (km/s or GHz): 300 km/s max

   8. Line intensity:

      8.1. Typical value (K or Jy): 0.5-2  K 

      8.2. Required rms per channel (K or Jy): 0.1 K

      8.3. Spectral dynamic range: 20


   9. Polarization:  no

   10. Integration time for each observing mode/receiver setting (hr): 
	90 sec hr x 19 fields  = 0.5 hours per galaxy

13CO 1-0 imaging:
-----------------

   5. Spatial scales:

      5.1. Angular resolution (arcsec): 1"

      5.2. Range of spatial scales/FOV (arcsec): single field

      5.3. Single dish total power data: yes

      5.4. ACA: yes

      5.5. Subarrays: no


   6. Frequencies:

      6.1. Receiver band: Band 3

      6.2. Lines and Frequencies (GHz):
		13CO 3-2 110 (redshifted for 10 Mpc and Ho = 75)

      6.3. Spectral resolution (km/s): 2 km/s

      6.4. Bandwidth or spectral coverage (km/s or GHz): 300 km/s max

   8. Line intensity:

      8.1. Typical value (K or Jy): 0.1-0.4  K 

      8.2. Required rms per channel (K or Jy): 0.02 K

      8.3. Spectral dynamic range: 20

   9. Polarization:  no

   10. Integration time for each observing mode/receiver setting (hr): 
						10 hr per galaxy


   11. Total integration time for program (hr): 10 x (7.3 + 10 + 0.5 ) = 
							180 hours

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

Have chosen 3 CO lines as a minimum estimate of what is needed to
constrain gas density and temperature in any way.

Will pick targets that are reasonably close, because gain
in resolution and sensitivity, but not so close that we have to mosaic
at 115 GHz. 10 Mpc seems like a reasonable estimate for a typical
distance. In some cases we might chose to image a piece of a galaxy
rather than the whole thing.

Get 110 GHz continuum sensitivity of 0.0019 mJy or 0.19 mK and
345 continuum sensitivity of 0.16 mJy or  10 mK for free. At 345 GHz,
this is equivalent to about 8e4 Msun (1 sigma) of gas and dust within 1" at
a distance of 10 pc (30 Msun/pc^2), so will only detect the biggest clouds.

Should also do 12CO J=1-0 simultaneously with 13CO J=1-0 
to get better sensitivity to large
extended structures; doesn't remove the need for higher resolution
12CO J=1-0 imaging in its own right ...


This project would take > 1/10 of the available time for this sub-theme!
(2 months = 1440 hours)

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

Review Chris Carilli: OK 
but 1440 hrs => cut down by factor 2 (do 5 galaxies not 10?)

Comment Ewine: requested time is 180 hrs rather than 1440 hrs, so OK;
no need to cut.