Title   Low Frequency Survey of Free-Free Emission in Nearby Starburst Galaxies
Pi     J. Turner
Time   43 hrs

1. Low Frequency Survey of Free-Free Emission in Nearby Starburst Galaxies
J. Turner et al.

2. The goal is to measure and locate free-free emission from HII
regions in starbursts in nearby galaxies. The images will reveal the
youngest massive star-forming regions that are optically obscured
within starburst complexes. Since free-free emission at cm-wavelengths
is confused with synchrotron up to 2cm, and emission from compact HII
regions is still rising into the millimeter, ALMA mm continuum fluxes
are more useful measures of the free-free flux than are VLA fluxes
(e.g., Meier et al. 2002). Comparison with high resolution Halpha and
optical multicolor HST images (which give ages for the visible star
clusters) will tell us about the spatial evolution of star formation
within starbursts. In the closest of the galaxies, we can trace the
internal stucture of individual HII regions, of particular interest
for the formation of SSCs. Comparison with SIRTF and ALMA observations
of gas and dust will allow the determination of the contributions of
the young HII regions to the total star formation budget, and an
estimate of star formation efficiency.  The submillimeter continuum
fluxes will be measured in a spectral region relatively free of
synchrotron and dust confusion at 3 and 1mm, at 0.15" resolution,
comparable to the sizes of the HII regions themselves. A small mosaic
is required to cover typical starburst regions, which are a few
hundred parsecs in size. Mapping at both 3 and 1 mm allows separation
of dust emission from the free-free emission.

3. Number of sources: 16

4. Coordinates:

	4.1	NGC253		00:47, -25:17 	 
		NGC1365  	03:31, -36:21	
		Circinus	14:13, -65:20	
		NGC4945		13:05, -49:28	
		M83		13:37, -29:52		
		NGC5253		13:40, -31:38	
		IIZw40		05:55, +03:23	
		He 2-10		08:36, -26:24
		NGC1808		05:08, -37:30
		NGC3256		10:27, -43:54
		NGC1097		02:46, -30:16
		NGC660		01:43, +13:38
		NGC1068		02:40, -00:13
		NGC3521		11:05, -00:02	
		NGC3627		11:20, +12:59
		NGC3628		11:20, +13:35
		
		
	4.2 Moving target: no
	4.3 Time critical: no
	
5. Spatial scales:

	5.1 Angular resolution: 0.15"  (to match sizes of HII regions =~1-3 pc)
	5.2 Range of spatial scales/FOV:  2'x2' fields: require  point mosaics. OTF
	mapping can be used if efficient for the size. 1500x1500 beam images.
	5.3 Single dish: yes
	5.4 ACA: yes
	5.5 Subarrays: no
	
6. Frequencies:
	
	6.1	Receiver band: Bands 3 and 6
	6.2	Continuum
	6.3	Spectral resolution N/A
	6.4 	Spectral coverage N/A
	
7. Continuum flux density

	7.1 Typical value 0
	7.2 Continuum peak value: 20 mJy
	7.3 Required continuum rms: 0.05 mJy/beam
	7.4 Dynamic range in image:  400:1 maximum
	
8. Line Intensity N/A
	
9. Polarization  N/A

10. Integration time per setting: 2 minutes per setting at 1mm, 1
minute at 3mm, 64 settings (2'x2' mosaic) at 1mm, 32 settings at 3mm,
in each field, total of 16 fields.  Total integration time, without
calibration, 43 hours w/o calib, slew, rampup.

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Review Chris Carilli: OK.

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Review v2.0:
 
Low-frequency survey of free-free...
Turner et al. 

The proposal reads well, and seems sound. I suggest updating `SIRTF'
to `Spitzer'. What role would eVLA have? I guess working at 7mm it
would help the separation of free-free and dust further?  Since it's
now more concrete than it was when DRSP1 was done, maybe a sentence
about it could be added?  Would adding (high-frequency/isotopic?) CO
maps of the same regions reveal anything useful about the dynamics in
the starburst regions?