Title  CO nucleus outgassing of 29P/Schwassmann-Wachmann 1 
Pi     D. Bockelee-Morvan
Time   

1. Name of program and authors 
   CO nucleus outgassing of 29P/Schwassmann-Wachmann 1 
   Authors: D. Bockelee-Morvan, N. Biver, J. Crovisier, J. Boissier 
 
2. One short paragraph with science goal(s) 
  Comet 29P/Schwassmann-Wachmann 1 is an unusual comet  
   which orbits on an almost circular orbit at ~6 AU from the Sun. 
   It shows a well developed dusty coma and recurrent outbursts. 
   CO is the only detected parent molecule (through millimeter 
   observations), and likely one of the main drivers of this activity.  
   Maps of the CO J(2-1) line profiles show that its brightness distribution 
   is more extended than expected. This can be due to gas temperature 
   variations in the coma. Diffuse production in the coma by icy grains is 
   also not excluded. Interferometric maps will unravel CO outgassing from 
   the nucleus and the kinematics of the inner coma. 
 
3. Number of sources  
   1 
    
4. Coordinates: 
 
4.1. Rough RA and DEC  
    DEC about 0 
 
4.2. Moving target: yes 
 
4.3. Time critical: no 
 
4.4. Scheduling constraints:  
 
5. Spatial scales: 
 
5.1. Angular resolution (arcsec): 
       
     Compact configuration (1 arcsec at 230 GHz to 3 arsec at 115 GHz) 
     
 
5.2. Range of spatial scales/FOV (arcsec): 
  
5.3. Required pointing accuracy: (arcsec) 
     0.5" 
 
6. Observational setup 
 
6.1. Single dish total power data: beneficial 
 
     Observing modes for single dish total power:  
     frequency switch 
 
6.2. Stand-alone ACA: no 
 
6.3. Cross-correlation of 7m ACA and 12m baseline-ALMA antennas:  
     beneficial 
 
6.4. Subarrays of 12m baseline-ALMA antennas: no 
 
 
7. Frequencies: 
 
7.1. Receiver band: 3, 6 
 
7.2. Lines and Frequencies (GHz):  
      
     CO (2-1) 230 GHz 
     CO (1-0) 115 GHz 
 
7.3. Spectral resolution (km/s): < 0.05 km/s 
 
7.4. Bandwidth or spectral coverage (km/s or GHz): 
     20 km/s 
 
8. Continuum flux density:  
 
9. Line intensity 
 
9.1. Typical value (K or Jy):  
1 K km/s with 1" resolution over 1 km/s for CO2-1 
0.5 K km/s with 3" resolution over 1 km/s for CO(1-0) 
      
 
9.2. Required rms per channel (K or Jy):  
      
 
9.3. Spectral dynamic range: 
 
9.4. Calibration requirements: absolute      (10%) 
                               repeatability (10%) 
                               relative      (10%) 
 
10. Polarization: no  
 
 
11. Integration time for each observing mode/receiver setting (hr): 
    230 GHz: 7h 
    115 GHz: 7h 
 
12. Total integration time for program (hr):  
    14 hr 
 
13. Comments on observing strategy :  
     
 
 
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Review v2.0:
 
Review of 4.3.1-4.3.9

These projects have all been updated to v2.0 and a new, timely project
on D/H has been added.

One issue that all projects share is their use of the ACA in
crosscorrelation with the ALMA-12m antennas. Are the common baselines
really essential, or would *simultaneous* (but standalone) ACA
observations also work? This might be much easier on the system
(slewing times; correlator; ...). Fully standalone (and therefore
separate in time) ACA observations for comets obviously make little
sense (...although, one could think of cases where some large-scale
monitoring could be useful). 

Comment: the integration times do not seem to be worked out in much
detail, although the total times listed seem of the correct
magnitude. This may be the best that is currently feasible. (cf. v1.1
where more detailed estimates are given).