Title   Low Frequency Continuum Survey of Free-Free Emission in the LMC
Pi     J. Turner
Time   2400 hrs
1. Low Frequency Continuum Survey of Free-Free Emission in the LMC
J. Turner et al.

2. The goal is to measure and locate free-free emission from HII regions in 
star-forming regions of the Large Magellanic Cloud. The images will reveal at
high spatial resolution the youngest massive star-forming regions that are 
optically obscured, and will be able to map regions containing the ionization 
equivalent of 1 O9 star. These observations will allow an important extension 
of our current knowledge of Galactic star formation to these nearby HII regions
in a low metallicity setting. They include the giant HII region 30 Doradus. 
The submillimeter fluxes will be measured at 3 and 1mm, spectral regions which 
are relatively free of synchrotron and dust confusion, at resolutions comparable 
to the sizes of the HII regions themselves. These images will have the capability 
of imaging structure within HII complexes the size of Orion and of identifying
compact HII regions by their size.   

3. Number of sources: 2

4. Coordinates:

	4.1 6 fields in LMC 5:23, -69
		
	4.2 Moving target: no
	4.3 Time critical: no
	
5. Spatial scales:
	5.1 Angular resolution: 0.08" = .02 pc
	5.2 Range of spatial scales/FOV:  3'x3' fields to cover 50 pc regions: 
		require 144 point mosaics for each, using OTF if efficient for 
		these fields. Each field - 2250x2250 beams
		one additional 12' square field at 30 Doradus
	
	
6. Observational setup

6.1. Single dish total power data: no(?)

     Observing modes for single dish total power: 

     (e.g., nutator switch; frequency switch; position switch;
     on-the-fly mapping; and combinations of the above)

6.2. Stand-alone ACA: no

6.3. Cross-correlation of 7m ACA and 12m baseline-ALMA antennas: 
     no

6.4. Subarrays of 12m baseline-ALMA antennas: 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  mJy/beam
	7.2 Continuum peak value: 2800 mJy/beam (10^4K point source)
	7.3 Required continuum rms: ~0.05 mJy/beam to detect significant (>6 sigma) structure 
		around an O9 star in an HII region the size of Orion 
	7.4 Dynamic range in image:  50000:1 (worst case; unlikely to be an HII region
		with tau >>1 at 3mm! -- more likely 1000:1)
	
8. Line Intensity N/A
	
9. Polarization  N/A

10.  Integration time per setting: 4 minutes at 1mm, 1 minute at 3mm per setting, 
	144 settings (3'x3' mosaics) in each of 5 locations, 
	plus 2300 settings (12'x12') around 30 Dor field 
	Total integration time, without calibration, ~60 + 191 hours or ~10 days. 
	(N.B. This is dominated by the 30 Doradus field)
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Review v2.0:
 
1.8.4 Low frequency continuum survey of free-free emission in LMC
    Turner 250 hours

Again I don't quite see why all of this needs to be done as part of
the DRSP.  Why not start with one location and a 3'x3' mosaic, or only
do 30 Dor

MRH: The DRSP should reflect what will be attempted in the first 3
years of ALMA, not necessarily the first programs to be run (in which
case starting with one target would be prudent).