ALMA

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ALMAs Roots in Three Scientific VisionsPaul
Vanden BoutNRAOThe Dusty Molecular Universe
Paris 28/10/04
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LSA (1988)
ALMA
MMA (1982)
LMSA (19??)
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The Millimeter Array

• MMA thinking was heavily influenced by the
  experience of the Very Large Array rapid
  high-quality imaging at 230 GHz was the central
  performance characteristic of the MMA.
• The very first concept to be proposed (by F.
  Owen, 1982) was to build a 15 x 10m array at the
  VLA site at a cost of 36M.
• The MMA proposal (1992) was for a 40 x 8m array
  at a site to be chosen following a study cost
  120M
• The site study led NRAO to find the present ALMA
  site and to an interest in the submillimeter.

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The Large Southern Array

• The first concept for what became the Large
  Southern Array was a 10 x 8m array to be located
  near Paranal part of long term planning for
  SEST cost 50M.
• The proposal (1991) for the LST itself was a 50 x
  16m array at a cost of 250M. The huge
  collecting area of 10000 m2 was needed (D.
  Downes) to gain sensitivity needed to observe
  unlensed high-z CO galaxies. (F10214 had just
  been detected in CO.)
• The LST was to work at 230 GHz and below and be
  located at a more modest elevation (3500m) than
  the present ALMA site in Chile.

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Merger of MMA and LSA26 June 1997

• Elements of the Agreement
• a big array 64x12m antennas
• a high (submm) Chilean site
• 5050 deal between North America and
  Europe (Japan as possibility)
• ESO and NRAO to do the job (no new
  international treaty organization like ESO or
  observatory like Gemini).

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The Large Millimeter Submillimeter Array

• The first vision in Japan for the LMA was to
  expand the Nobeyama Interferometer to 30
  antennas.
• Delayed by SUBARU, this plan was expanded to
  50x10m antennas and submillimeter capability.
  The Large Millimeter Submillimeter Array (LMSA)
  was to operate to 950 GHz
• Following extensive site testing in Chile, the
  10m ASTI telescope was installed at Pampa la Bola
  near the ALMA site.
• Plans for the LMSA evolved, following the
  European-North American partnership for ALMA, to
  joining ALMA with a contribution from Japan that
  added capabilities in brightness sensitivity (a
  compact array) and frequency coverage (additional
  receiver bands).
• The combination is known as Enhanced ALMA.

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Enhanced ALMA

• 64x12m antennas in a large array
• 12x7m 4x12m antenna compact array
• 7 receiver bands, 84 950 GHz
• Powerful correlators for both arrays
• Spatial frequency coverage from 12m single dish
  through compact array to 14km extent of the
  largest configuration of the large array.
• Excellent site

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ALMA Observers
Astronomers will see ALMA like a space mission,
their point of contact from proposal submission
to data analysis being an ALMA regional science
center.

• In Europe, these functions will be conducted at
  ESO and several national institutes.
• In Japan at the NAOJ.
• In North America these functions will be located
  at NRAO, Charlottesville VA.

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When?

• Interim operations are scheduled to begin in
  mid-2007 with 8 antennas
• Full operations are to begin in 2012.
• Antennas added to the array in sets of 8.
• Expect the level of support to begin modestly and
  grow, as the array is commissioned, de-bugged,
  and experience is gained in operations.
• Start to plan your science!

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The Atacama Large Millimeter Array
ALMA A World Array