Dust and Gas distribution in multiple-systems
    =============================================
    Authors: A.Dutrey, M.Saito

   2. Science Goals: Mapping the dust and gas distribution around
  multiple systems in order to estimate the frequency of CB ring and 
inner disks or binary system, the mass distribution, possible streamers 
flowing from the outer disk to the inner disks. Selected samples in clusters
and in loose association such as Taurus.

It is needed to detect low brightness dusty disks, or very small
disks.  Disks larger than 20 AU should be resolved. The angular
separation of the stars range from 3" (450 AU) to 0.05" (8 AU). Inner
disks in the closer binaries may be truncated to only 2 AU or so. Such
inner disks, at 50 K, will have a flux around 75 microJy at 345 K. For
the outer disks, the brightness may be low,
e.g. 50 mK or so (corresponding to 45 microJy/beam at 345 GHz and 0.1" 
resolution).

  A secondary goal: Detect CO in these disks (kinematics) at the 
sensitivity limit provided by the main goal (the continuum).

  3. Number of sources: 20 objects per region

  4. Coordinates:
     4.1 20 sources in Taurus, 20 sources in Rho Oph.
         (RA=04, DEC=+25)
         (RA=16:30, DEC=-24)
     4.2 Moving target: no
     4.3 Time critical: no

  5.  Spatial scales:
    5.1. Angular resolution: 0.1-0.05 arcsec (depending on separation)
    5.2. Range of spatial scales/FOV: up to 5-10 arcsec
    5.3. Single dish: in some sources
    5.4. ACA: In some sources
    5.5. Subarrays: no

  6. Frequencies:
    6.1. Receiver band: band 7 (best for continuum, not too bad for C18O =
3-2 line)
    6.2. Lines: CO/13CO/C18O lines (depending on line opacity in cloud)
         Frequency: 345 GHz
         Note: 2 tunings required. We shall spend 1/3 time on 12CO,
         2/3 on 13CO and C18O.
    6.3. Spectral resolution (km/s): <=0.2 km/s
    6.4. Spectral coverage (km/s or GHz): ~ 40 km/s

  7. Continuum flux density:
    7.1. Typical value: 5-200 mJy (warning: expected low flux density 
for CB rings)
    7.2. Continuum peak value: 1--10 mJy/beam
    7.3. Required continuum rms: 15 microJy/beam
    7.4. Dynamic range in image: Low in general, but may be high in some regions

  8. Line intensity: sensitivity limited by continuum goals
    8.1. Typical value: (C18O 2-1)
    8.2. Required rms per channel: in brightness, 2.7 K in 0.2 km/s at 
0.1".
    Better sensitivity by smoothing to 0.5 km/s and slightly in angular 
resolution.
    8.3. Spectral dynamic range: Low.

  9. Polarization: YES in continuum

  10. Integration time per setting:
      3 hrs / pointing (1hr on 12CO, 2hr on 13CO and C18O)

  11. Total integration time for program:  120h
       20 x 3h=60h Taurus
       20 x 3h=60h Ophiucus

  Note: In some cases (Rho.Oph.) many targets in small area, may
  be more efficient to do a mosaic.

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Review Phil Myers: Good program to study structure of young binaries
and small disks, taking advantage of ALMA resolution.