Title Disks in the sub-stellar regime 
Pi     L. Testi
Time   54 hrs

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1. Name of program and authors

Disks in the sub-stellar regime
  Authors: L.Testi


2. One short paragraph with science goal(s)

Detect dust continuum and molecular line
emission from a sample of young substellar systems. The
goal is to constrain the disks fraction, mass distribution, size
and gas content in the substellar regime. We need to detect dusty disks to a significative level (<=0.01 Mstar @ 10sig), and to
resolve disks if radius greater than 20 AU. A separate proposal
should address the dust emissivity in the detected sources.
Comparison with more massive TTs will be done using literature
data, observations from other ALMA programmes, and observations of 
TTs that will fall within the ALMA field of view (esp. in rho-Oph
and ONC).

      Secondary: Detect CO and isotopes in these disks at the sensitivity 
                 limit provided by the main goal (the continuum).



3. Number of sources 
   
   10-100 objects per region in Taurus, Cha I,
      rho-Oph and Orion Nebula Cluster.

4. Coordinates:

     4.1
         10 sources in Taurus   (RA=04, DEC=+25)
         20 sources in ChaI     (RA=11, DEC=-70)
         30 sources in Oph      (RA=16:30, DEC=-24)
         100 sources in ONC     (RA=05,  DEC=-05)
    4.2 Moving target: no
    4.3 Time critical: no


5. Spatial scales:

    5.1. Angular resolution: 0.2-0.1 arcsec (depending on distance)
    5.2. Range of spatial scales/FOV: up to 5-10 arcsec
    5.3. Required pointing accuracy: no critical constraints


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 and 7

7.2. Lines and Frequencies (GHz): 

     CO and main isotopes in bands 6 and 7, as allowed by the hardware.

7.3. Spectral resolution (km/s): <=0.2 km/s

7.4. Bandwidth or spectral coverage (km/s or GHz): >=40 km/s

8. Continuum flux density: 

8.1. Typical value (Jy):

     0.1-0.3 mJy

8.2. Required continuum rms (Jy or K):
     0.03 mJy/beam @ 230GHz; 0.25 mJy/beam @ 345GHz

8.3. Dynamic range within image:
      Low in general, but may be high in some regions
      (Ophiucus, ONC)

8.4. Calibration requirements: absolute      (  5% )
                               repeatability ( n/a )
                               relative      ( 1-3% )


9. Line intensity: sensitivity limited by continuum goals

9.1. Typical value (K or Jy):

     (take average value of set of objects)
     (optional: provide range of values for set of objects)

9.2. Required rms per channel (K or Jy):

9.3. Spectral dynamic range:

9.4. Calibration requirements: absolute      ( 5% )
                               repeatability ( n/a )
                               relative      ( 1-3% )


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):
        15min/obj @ Band6 = 40 hrs
         5min/obj @ Band7 = 14 hrs


12. Total integration time for program (hr):
      20min/obj = 54 hrs


13. Comments on observing strategy : (optional)

    (e.g. line surveys, Target of Opportunity, Sun, ...):
================================
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Review v2.0:
 
Disks in the sub-stellar regime
  Authors: L.Testi

Reviewer: John Bally

As with many other proposed disk programs, I advocate a pilot study
using a compact configuration of ALMA (roughly 1" resolution) to
identify the best candidates for high-resolution observations.  The
spectral-line contents of bright continuum detections should also be
explored in this mode to find the best gas tracers since it is NOT
obvious that in a disk, the usual lines such as CO are the best
tracers.

High angular resolution studies can then be done on the best
candidates.

While ONC is a great target, some closer clusters such as IC 348 or
NGC1333 should be considered.

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Reply: I do not want to go for Cepheus (not observable from
Chajnantor) or other barely observable northern sources like IC348 or
NGC1333. The principle of doing the observations of BD disks at low
angular resolution could be considered, although I do expect that this
project can be done at the 0.1 arcsec level, which may well be not so
oversuscribed and difficult to do... Having this resolution will help
in figuring out the size of these disks, a key to test ejection
scenarios.