ALMA Science Workshop May 1415, 2004 Star and Planet Formation Breakout Session

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ALMA Science WorkshopMay 14-15, 2004Star and
Planet Formation Breakout Session

• Facilitators Doug Johnstone Debra Shepherd

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Science the DSRP
Detailed summary of representative
proposals Claire Chandler, DRSP 2.1.6, OTF
survey of large field James Di Francesco, DRSP
2.1.9, Envelope/disk structure David Wilner,
protoplanetary disks - gas and dust
continuum Science talks Yancy Shirley - Dust
continuum surveys bringing in the DRSP Derek
Lis - Deuteration and other fractionations
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Key issues from Science DSRP

• A significant number of star formation projects
  image large fields (gt 1000 pointings) and require
  ACA with total power. OTF mosaics easily push
  the data rate beyond 6/60 MB/s specs.
• Need for same uv coverage across mosaic ? must
  get through mosaic fast, before configuration
  changes significantly.
• Cant always assume ACA integration time 4 x
  ALMA. Some science requires same
  sensitivity/beam to get same mass sensitivity ?
  90 times more integration time on ACA than on
  ALMA. Some sources only need same sensitivity
  of the uv data in overlap region between ACA
  ALMA ? 4 x ALMA Needs more thought to determine
  impact on operations and determine how the ACA
  over-subscription will be handled.

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Missing science in DSRP

• Transition objects to debris disks with little
  gas dust. These will be closer, bigger will
  have low surface brightness in large scale
  structure. Very challenging to get ACA, TP data
  with high enough sensitivity. This will impact
  planned capabilities because it will put pressure
  on ACA observing time that already appears to be
  more over-subscribed than the ALMA array.
• Mosaic surveys with ACA only to get large scale
  structure in lesser known southern sources.
  Again, taxes an already severely over-subscribed
  ACA.
• Continuum modeling of SEDs and uv amplitudes.
  Needs wide range of frequency to get good SED,
  1-3 absolute calibration accuracy important
  across bands to constrain models.

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More Issues

• Will ALMA plans support early science proposals?
• Major problem supporting mosaics, since lack of
  OTF mosaic capabilities at early science will
  delay science return for star forming regions,
  the ALMA project should think more about how and
  when this will be implemented.
• If can't get through mosaic fast enough to get
  same uv coverage for all pointings, then relative
  calibration at different times must be extremely
  good. Issue if mosaic not finished will it
  take a year to get back to a configuration to
  finish a mosaic? BAD.
• If ALMA pipeline heuristics not well developed,
  need to guarantee one-on-one reduction/imaging
  support for non-expert users.

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Synergy with other projects

• ACA/TP over-subscription Single dish surveys
  critical for large mosaics to pinpoint
  interesting regions for ALMA. Minimize ACA/TP
  time. JCMT/SCUBA-2 may be critical.
• Need FIR - NIR - submm to get accurate SEDs.
• JCMT/SCUBA2 SMA at submm,
• VLT at near-IR,
• Need eVLA to characterized ionized gas at cm
  wavelengths
• Since high mass cores will be optically thick
  in dust emission with ALMA, eVLA at 43 GHz will
  be critical to see optically thin dust emission -
  As Neal Evans mentioned, this is the critical
  type of source to relate galactic star formation
  properties to more distant star bursts.

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Questionnaire

• Not clear from list what of science support
  activities what are core functions and what are
  non core functions. Needs to be made clearer.
  
• Beyond core functions, highest priorities seem to
  be 1) getting face-to-face support for
  reduction/imaging and training for students and
  2) Software development of analysis tools.
• Band 10 is, of course, important. Very good that
  the Japanese will provide this. Some people
  think Bands 2 5 are the next most important.
  Band 8 also important.
• Need to send back Questionnaire see how the
  statistics fall out.

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Comments on the importance and/or science case
for the ACA
It is absolutely critical to star and planet
formation projects Time required for ACA
observations needs to be looked at more
critically