The Atacama Large MillimeterSubmillimeter Array Current Status

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The Atacama Large Millimeter/Submillimeter Array
Current Status

• Chris Wilson
• Canadian ALMA Project Scientist
• McMaster University

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ALMA Science Requirements

• High Fidelity Imaging
• Precise Imaging at 0.1 Resolution
• Routine Sub-mJy Continuum Sensitivity
• Routine mK Spectral Sensitivity
• Wideband Frequency Coverage
• Wide Field Imaging Mosaics
• Submillimeter Receiver System
• Full Polarization Capability

Highest priority for new ground-based facility in
the Long Range Plan!
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ALMA Specifications

• 54 12-m antennas, plus compact array of 12 7-m
  antennas at 5000 m site
• Surface accuracy 25 mm, 0.6 reference pointing
  in 9m/s wind, 2 absolute pointing all-sky
• Array configurations between 150m and 15km
  3 to 0.015 resolution at 300 GHz (1mm)
• 10 bands in 31-950 GHz 183 GHz WVR. Initially
• 86-116 GHz 3
• 125-169 GHz 4
• 211-275 GHz 6
• 275-373 GHz 7
• 385-500 GHz 8
• 602-720 GHz 9
• 787-950 GHz 10
• 8 GHz BW, dual polarization
• Correlator 4096 channels/IF (multi-IF), full
  Stokes

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ALMA Specifications(continued)

• Interferometry, mosaics, total-power observing
• Data rate 6Mb/s average peak 60Mb/s
• All data archived (raw images) pipeline to
  process
• During full operations, the estimated flow of
  int/SD data into archive 100 Tb per year.
• Project lifecycle online proposal tool, script
  generator, dynamic scheduling, raw data available
  plus a reference image with pipeline processing
  history, calibration data

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ALMA Median Sensitivity
(1 minute 75 Quartile opacities lgt1mm, 25 l
lt1mm)
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The ALMA Partnership

• ALMA is a global partnership in astronomy to
  deliver a truly transformational instrument
• North America (US, Canada, Taiwan)
• Europe (via ESO)
• East Asia (Japan, Taiwan)
• Located on the Chajnantor plain of the Chilean
  Andes at 5000 m
• ALMA will be operated as a single Observatory
  with scientific access via regional centers
• North American ALMA Science Center (NAASC) is in
  Charlottesville
• Total global budget for ALMA 1.3B (U.S.)

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Canadians and ALMA

• Construction contribution Band 3 (100 GHz)
  receivers, software
• Operations funding money and people
• Part of North American side of ALMA
• Compete for observing time in common North
  American pool through proposals to the common
  ALMA TAC
• Observing and user support through NAASC

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ALMA Sites

• Array Operations Site AOS 5000m Antennas,
  correlator, some (oxygenated) office space
• Operations Support Facility OSF 3000m Array
  operation, equipment maintenance, living quarters
• ALMA Test Facility ATF Socorro, VLA site
  prototype antennas, software development
• Santiago Central Offices SCO Administration,
  scientific support. Will be located near ESO,
  currently Las Condes
• Joint ALMA Observatory - JAO
• ALMA Regional Centers ARCs ARC nodes
  interfaces to astronomy community

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Approximate Schedule

• First fringes ATF Q2 2007
• First fringes Chile Q2 2009 (see later
  slides)
• AOS, OSF facilities Complete
• Antennas 15 now on site in
  assembly
• first 3 accepted by AIV 4th June 2009
• Front Ends 1 delivered, install Oct
  2008
• 2 - end 2008
• Correlator 1st quadrant being
  installed at AOS
• ACA correlator
  installed at AOS
• New 2-antenna
  correlator installed at OSF
• Call for Early Science end of 2010
• Early Science Q3 2011
• Full Operations 2013

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The push to the high site

• ALMA is pushing to achieve closure phase at the
  high site before the end of this year
• This target is the key driver for the entire
  project at the moment
• To achieve this requires all of the necessary
  infrastructure and equipment to be in place
• This activity is being masterminded by the ALMA
  AIV team, led by Joe McMullin
• The path to the high site involves first
  establishing fringes at the OSF in a two antenna
  interferometer

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ATF single dish results
Sgr B2 Spectrum97.9 GHz
Raster on Moon with Total Power detectors
simultaneously on 2 antennas
Not using production receivers, but verifying
software for control, tuning, correlator and data
reduction
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ATF Interferometric spectrum Orion - 101 GHz,
April 2008
Not using production receivers, but verifying
software for control, tuning, correlator and data
reduction
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Chajnantor Plateau looking north
V. Licancabur
Cº Chajnantor
Pampa La Bola
Center of Array
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Google-Earth view of site with antennas in the
most extended configuration baselines to 16km
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12m Array
Simulation (!)
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20th International Symposium on Space Terahertz
Technology
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Roads Foundations
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Foundations

• Foundations for the Compact Array
• nearly done.
• Power and fibres next.

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20th International Symposium on Space Terahertz
Technology
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AOS Technical Building
AOS Technical Building - completed 2008
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OSF
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OSF
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Four MELCO Antennas being tested
(non-interferometrically!)
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Two Vertex Antennas under test Nine more being
assembled
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How to carry a 12 m telescope
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Dishes measured by holography at 104 GHzUse
source on tower at 300m distance and correct for
the curved wavefront
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Initial Map amplitude and phase
20th International Symposium on Space Terahertz
Technology
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After adjustment
20th International Symposium on Space Terahertz
Technology
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Pointing Vertex Metrology
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Bands 3 (84-116 GHz), 6 (211-275 GHz), 7
(275-373 GHz), and 9 (602-720 GHz)
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20th International Symposium on Space Terahertz
Technology
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ALMA Band 3 (100 GHz)
being built at Herzberg Institute of
Astrophysics in Victoria B.C.
Lens
Feed Horn
OMT
Pol0 2SB Mixer Assembly
Pol1 2SB Mixer Assembly
ALMA Requirement
IF Amplifiers and Isolators
4 K Stage
15 K Stage
300 K Vacuum Flange
80 K Stage
ALMA Requirement
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First FE/BE under test at OSF
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20th International Symposium on Space Terahertz
Technology
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Correlator first quadrant being installed
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First Light!
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First astronomical fringes at OSF30 April 2009
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Next Steps

• August - central LO to high site
• October - Antennas to the high site
• December - Closure phase
• Start Science Verification
• 20 months later start Early Science

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For more info www.alma.cl

• The Atacama Large Millimeter/submillimeter Array
  (ALMA), an international astronomy facility, is a
  partnership of Europe, North America and East
  Asia in cooperation with the Republic of Chile.
  ALMA is funded in Europe by the European
  Organization for Astronomical Research in the
  Southern Hemisphere (ESO), in North America by
  the U.S. National Science Foundation (NSF) in
  cooperation with the National Research Council of
  Canada (NRC) and the National Science Council of
  Taiwan (NSC) and in East Asia by the National
  Institutes of Natural Sciences (NINS) of Japan in
  cooperation with the Academia Sinica (AS) in
  Taiwan. ALMA construction and operations are led
  on behalf of Europe by ESO, on behalf of North
  America by the National Radio Astronomy
  Observatory (NRAO), which is managed by
  Associated Universities, Inc. (AUI) and on behalf
  of East Asia by the National Astronomical
  Observatory of Japan (NAOJ). The Joint ALMA
  Observatory (JAO) provides the unified leadership
  and management of the construction, commissioning
  and operation of ALMA.

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end
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(1 minute 75 Quartile opacities lgt1mm, 25 l
lt1mm)
ALMA Median Sensitivity
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Leroy, 2008, , Birth and feedback of massive
stars
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Brogan, 2008, Birth and feedback of massive
stars
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Krumholz, 2008, , Birth and feedback of massive
stars