Title  Imaging Molecular material in the vicinity of an AGN
Pi     E. Schinnerer
Time   64 hrs


1. Name of program and authors
1.5.1: Name -- Imaging Molecular material in the vicinity of an AGN
       Authors: E. Schinnerer

2. Science goal: Molecular gas has been detected within a radius of
   10pc of a Seyfert nucleus (correspinding to 0.12'' at a distance of
   17 Mpc). Here we propose to map the CO(2-1) line emission at 0.06"
   resolution in a sample of 2 nearby AGN in order to resolve their
   nuclear molecular reservoir. Finding more molecular gas within a
   few pc of the BH is essential to understand the actual process of
   feeding the AGN.  These data will also allow us to test dynamical
   models of the gas flow which include the presence of
   BH. Ultimately, this method will allow measuring BH masses using
   the molecular line emission due to the high spectral resolution
   provided by ALMA.

3. Number of sources: 2

4. Coordinates:

  4.1. N1068, N1097

  4.2. Moving target: no

  4.3. Time critical: no

5. Spatial scales:


  5.1. Angular resolution: 0.06"

  5.2. Range of spatial scales/FOV: 0.06" to 25"

  5.3. Required pointing accuracy: ~ 1"

6. Observational setup

  6.1. Single dish total power data: no

  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


7. Frequencies:

  7.1. Receiver band: Band 6 -- 220 GHz  in Configuration AB

  7.2. Lines and Frequencies (GHz): CO(2-1) @ 230 GHz

  7.3. Spectral resolution (km/s): 5 km/s

  7.4. Bandwidth or spectral coverage (km/s or GHz):  ~ 1200 km/s


8. Continuum flux density:

  8.1. Typical value (Jy):

  8.2. Required continuum rms (Jy or K):

  8.3. Dynamic range within image:

     (from 7.1 and 7.2, but also indicate whether, e.g., weak objects
     next to bright objects)

  8.4. Calibration requirements: absolute      ( 5% )
                                 repeatability ( 5% )
                                 relative      ( 5% )


9. Line intensity:

  9.1. Typical value (K or Jy): <= 1 mJy/beam at 230 GHz

  9.2. Required rms per channel (K or Jy): 0.2 mJy/beam

  9.3. Spectral dynamic range: 5 - 10

  9.4. Calibration requirements: absolute      ( 5% )
                                 repeatability ( 5% )
                                 relative      ( 5% )


10. Polarization: no 

  10.1. Required Stokes parameters:

  10.2. Total polarized flux density (Jy):

  10.3. Required polarization rms and/or dynamic range:

  10.4. Polarization fidelity:

  10.5. Required calibration accuracy:


11. Integration time for each observing mode/receiver setting (hr):
    2 track (+/- 4hr) at 230  x 2 sources x 2 configurations


12. Total integration time for program (hr): 64 hr


13. Comments on observing strategy : (optional)

    (e.g. line surveys, Target of Opportunity, Sun, ...):

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Revised version of drsp1_1.5.1.txt.

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Comments:


revised to go to 0.06" resolution
--> The requested resolution is already 0.06", abstract has been clarified

The abstract proposes to map CO(2-1) line emission in 6 AGN, but the
proposal seems to be for two sources only.  That seems sufficient.
--> Abstract corrected to 2 sources.

proposal looks ok


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Previous comments:


Review Jean Turner: Science case is good; the behavior of molecular
gas near AGN is of great interest for many reasons, kinematics, star
formation triggering, AGN fueling. This will certainly be something
done early on by ALMA.  The high resolution is justified. Scope is
reasonable: one can learn much from studies of a single nearby system.

This is high resolution for CO(2-1). While 0.02" is justified by the
sizescales of the source -- this corresponds to 1-2 pc at these
distances -- there is not a lot of power in this beam. 20K gas will be
detectable only at 3 sigma. Possibilities: higher J CO lines, since
one might expect warm gas in these regions, and lower resolution.  The
Doppler shifting will give you the resolution better than the beam if
you have the signal to noise; in theory 0.1" at 20:1 signal to noise
would give you roughly equivalent Doppler positional information to
.02", and the 1 sigma sensitivity would be 0.24 K rather than
6K. Could do CO(3-2) also.

==>recommend 0.1" resolution

Also, dust continuum will be very useful for tracing gas distribution.
Integration time in the proposal checks out, but see comments above
regarding beamsize.
            
Reply Schinnerer: I changed the required resolution to 0.06" (~ 5pc at
17Mpc distance). Spatially resolving the nuclear molecular gas reservoir 
around an AGN is important, especially with respect of a possible flaring 
of the molecular gas layer in z-direction, or a complicated structure 
(e.g. warping of the molecular disk). This information cannot easily be 
recovered from the Doppler positional information alone.
A resolution of 0.06" will still allow to (at least) partially resolve
a possible central reservoir of molecular gas with a diameter of ~ 20pc
while providing a 1 sigma line sensitivity of about 1.34 K. This
sensitivity should be sufficient to detect warmer molecular clouds (T
=> 20 K) close to the AGN with reasonable S/N of ~ 10. This appears to
be a good compromise between sensitivity and resolution requirements. I 
agree that higher J-transitions might be a good alternative. However, 
since there are no good estimates yet for CO(3-2) line intensities close 
to an AGN, time estimates based on CO(2-1) appear more reliable at the 
moment.