Title Low Frequency Spectral Survey aimed at Complex Organics
Pi     B. E. Turner
Time   35 hrs
1. Name of program and authors  

   Low Frequency Spectral Survey aimed at Complex Organics
   ========================================================
   B. E. Turner

   2. One short paragraph with science goal(s)
   The NRAO spectral line survey covers ~40 GHz in the 2mm band;
17,000 spectral lines are observed in seven sources.  Frequency
resolution is 0.78 MHz; sensitivity is generally 4 mK. Line emission
covering factors reach 0.52 for SgrB2N and 0.24 for Ori(KL).  The
confusion limit is reached in this survey.  Traditional methods of
line identification, based on specific search and identification of ~5
lines is unjustified in the face of such confusion.  Algorithms based
on binomial statistical analysis have been applied to asses the
probability that an apparent identification is not just due to chance.
Species 'identified' in the interstellar medium are shown to have
chances of misidentification of ~10% (e.g. glycol aldehyde; ethylene
glycol) while 75 other candidates have probabilities ~<0.001.  Many of
these candidates are quite complex and suggest active involvement of
grain surfaces in interstellar chemistry.  A sensitive ALMA survey is
proposed; the results will be used to 1) complement the current
survey, increasing the confidence in statistical identification of the
complex molecules selected by the 2mm survey.  2) Study the images
produced to determine whether statistically identified lines arise
from colocated regions.  3) Explore the astrochemistry of sources
beyond the reach of northern hemisphere observatories.

   3. Number of sources:  7
   
   4. Coordinates: 

      4.1. Rough RA and DEC   2 sources in Sgr, 
        2 sources in Orion, 1 source in Leo, 1 source in Aquila, NGC6334.  

      4.2. Moving target:  no  

      4.3. Time critical:  no   


   5. Spatial scales:

      5.1. Angular resolution (arcsec): 1.0"

      5.2. Range of spatial scales/FOV (arcsec):   Single field  1"/60"      
            
      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):Band scan, 86 GHz - 116 GHz requires 30 settings per source.
           
      6.3. Spectral resolution (km/s): 0.32

      6.4. Bandwidth or spectral coverage (km/s or GHz):30 GHz


   7. Continuum flux density:

      7.1. Typical value (Jy): ~2
                    
      7.2. Required continuum rms (Jy or K): N/A

      7.3. Dynamic range within image:   ~100                
          
   8. Line intensity:

      8.1. Typical value (K or Jy):  1.7 K
          
      8.2. Required rms per channel (K or Jy): 0.5 K

      8.3. Spectral dynamic range:   >5  weak lines   >1000 strong lines      

   9. Polarization:  no   

      9.1. Required Stokes
   
      9.2. Total polarized flux density (Jy)

      9.3. Required polarization rms and/or dynamic range

      9.4. Polarization fidelity


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

   11. Total integration time for program (hr): 7x30x10 min = 35 hr

   12. Comments on observing strategy (e.g. line surveys, Target of
       Opportunity, Sun, ...): line survey
This program could be executed more quickly with the availability of the
polyphase filter, by a factor of four.  These heavy molecules emit at
lower frequencies; Bands 1, 2 and 4 would be valuable complements to this
survey when available. 


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Review Lee Mundy: OK.
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Review v2.0:
 
ok