New Windows on Star Formation in the Cosmos October 1113, 2004 U' of Maryland The Dusty and Molecula

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New Windows on Star Formation in the
CosmosOctober 11-13, 2004U. of MarylandThe
Dusty and Molecular UniverseA prelude to
HERSCHEL and ALMA27 - 29 October 2004, Paris
ALMA UpdateAl Wootten NRAO
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U. Of Md.
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Dusty04http//aramis.obspm.fr/DUSTY04/plan.html
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Dusty04Herschel Schedule
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HIFI
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PACS
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SPIRE
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ALMA Current Definition

• 64 moveable 12-m antennas 100-m class
  telescope
• Baselines from 15m to 15km
• Angular resolution 40 mas at 100 GHz (5mas at
  900GHz)
• Strong implications for atmospheric phase
  correction scheme
• Receivers low-noise, wide-band (8GHz),
  dual-polarisation, SSB
• Many spectral lines per band
• Digital correlator, gt8192 spectral channels, 4
  Stokes
• very high spectral resolution (up to 15kHz)
• Short spacing data provided by 12-m antennas in
  single-dish mode
• Critical for objects bigger than the primary beam
• Requirements for star formation and high-z
  studies are remarkably similar!

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Summary of detailed requirements

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Management JAO Staffing

• Joint Alma Office (JAO) in Chile
• Director Massimo Tarenghi
• Project Manager Tony Beasley
• Project Engineer Rick Murowinski
• Project Scientist Vacant
• Project Controller Richard Simon (interim)
• Logistics Officer Charlotte Hermant

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Agreement (2/2)
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Primary Scientific Requirements

• ALMA will be a flexible observatory supporting a
  wide range of scientific investigations in
  extragalactic, galactic and planetary astronomy.
• ALMA should be easy to use
  (i.e. you do not need to be an expert in
  aperture synthesis to produce images).
• Three scientific requirements drive the science
  planning. These are the Primary Scientific
  Requirements.

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Primary Scientific Requirements

• The ability to detect spectral line emission from
  CO or CII in a normal galaxy like the Milky Way
  at a redshift of 3, in less than 24 hours of
  observation.
• The ability to image the gas kinematics in
  protostars and protoplanetary disks around young
  Sun-like stars at a distance of 150 pc, enabling
  one to study their physical, chemical and
  magnetic field structures and to detect the gaps
  created by planets undergoing formation in the
  disks. (see John Richers talk)
• The ability to provide precise images at an
  angular resolution of 0.1. Here the term
  precise images means representing to within the
  noise level the sky brightness at all points
  where the brightness is greater than 0.1 of the
  peak image brightness. This requirement applies
  to all sources visible to ALMA that transit at an
  elevation greater than 20.

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Detecting normal galaxies at z3

• CO emission now detected in 25 zgt2 objects.
• To date only in luminous AGN and/or
  gravitationally lensed. Normal galaxies are 20 to
  30 times fainter.
• Current millimeter interferometers have
  collecting areas between 500 and 1000 m2.

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Detecting normal galaxies at z3

• ALMA sensitivity depends on
• Atmospheric transparency
  Chajnantor plateau at
  5000m
  altitude is superior to all
  existing mm
  observatories.
• Noise performance of receivers can be reduced by
  factor 2 (approaching quantum limit). Also gain
  v2 because ALMA will simultaneously measure both
  states of polarization.
• Collecting area remaining factor of 7 to 10 can
  only be gained by increasing collecting area to
  gt7000 m2.

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Detecting normal galaxies at z3

• At z3, the 10 kpc molecular disk of the Milky
  Way will be much smaller than the primary beam ?
  single observation.
• Flux density sensitivity in image from an
  interferometric array with 2 simultaneously
  sampled polarizations and 95 quantum efficiency
  is
• Aperture efficiencies 0.45ltealt0.75
• can be achieved (25 µm antenna
  surface
  accuracy).
• Tsys depends on band, atmosphere,
  for 115 GHz, Tsys 67 K
  obtainable.

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Detecting normal galaxies at z3

• Total CO luminosity of Milky Way Lco(1-0)
  3.7x108 K km s-1pc2 (Solomon Rivolo 1989).
• COBE found slightly higher luminosities in
  higher transitions (Bennett et al 1994) ? adopt
  Lco 5x108 K km s-1pc2.
• At z3 ? observe (3-2) or (4-3) transition in
  the 84-116 GHz atmospheric band ? need to
  correct, but also higher TCMB providing higher
  background levels for CO excitation.
• Different models predict brighter or fainter
  higher-order transitions. Few measurements of CO
  rotational transitions exist for distant quasars
  and ULIRGs, but these are dominated by central
  regions.
• ? Assume Lco(3-2) / Lco(1-0) 1.

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Detecting normal galaxies at z3

• For ?CDM cosmology, ?v300 km/s, the expected
  peak CO(3-2) flux density is 36 µJy.
• Require 5s detection in 12h on source (16h total
  time).
• ? ND27300 m2.
• Achievable with N64 antennas of D12m diameter.

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Precise 0.1 resolution images

• 0.1 resolution needed to complement
  contemporary facilities JWST, eVLA, AO with
  8-10m telescopes,
• High angular resolution and sensitivity
  complementary.
• High fidelity images require a sufficiently
  large number of baselines to fill gt50 of the
  uv-plane.
• Short tracking (lt2 hours) to reduce atmospheric
  variations
• ? requires ND gt 560 for a maximum baseline of 3
  km.
• Achievable with 64 12m antennas.

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Precise 0.1 resolution images

• Array cannot measure smallest spatial
  frequencies (ltD).
• Solve by having four antennas optimized for
  total power measurements (nutating
  secondaries).
• Remaining gap in uv-plane filled in by
  Atacama Compact Array (ACA) 12
  antennas 7m diameter.

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Design Reference Science Plan

• 128 projects full list available from
  http//www.alma.nrao.edu
• Use ALMA sensitivity calculator
• http//www.eso.org/projects/alma/science/bin/sensi
  tivity.html
• Total time 3-4 years of ALMA observing.

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Design Reference Science Plan
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Molecular line studies of submm galaxies

• gt50 of the FIR/submm background are submm
  galaxies.
• Trace heavily obscured star-forming galaxies.
• Optical/near-IR identification very difficult.
• Optical spectroscopy ltzgt2.4.
• Confirmation needed
  with CO spectroscopy.

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Molecular line studies of submm galaxies

• ALMA will provide 0.1 images of submm sources
  found in bolometer surveys (LABOCA/APEX,
  SCUBA-2/JCMT) or with ALMA itself.
• 3 frequency settings will cover the entire
  84-116 GHz band ? at least one CO line. (1h per
  source)
• Confirm with observation of high/lower order CO
  line. (1h per source)

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Molecular line studies of submm galaxies

• Follow-up with ALMA
• High resolution CO imaging to determine
  morphology (mergers?), derive rotation curves ?
  Mdyn, density, temperature, ... (1h per source)
• Observe sources in HCN to trace dense regions of
  star-formation. (10h per source, 20 sources)
• Total 12h per source, 170h for sample of 50
  sources.

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Millimeter VLBI Imaging the Galactic center
black hole (Falcke 2000)
Kerr
R_g 3 uas
Schwarzschild
0.6 mm VLBI 16uas res
1.3 mm VLBI 33 uas res
Model opt. thin synch
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Enabling technology III Wideband spectroscopy
Redshifts for obscured/faint sources 8 - 32 GHz
spectrometers on ALMA, LMT, GBT (Min Yun 04,
Harris 04) L_FIR 1e13 L_sun
ALMA
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Andre
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ALMA Level 0 Requirements

• Image gas kinematics in protostars and
  protoplanetary disks around Sun-like stars at
  140pc distance, enabling one to study their
  physical, chemical and magnetic field structures
  and to detect the gaps created by planets
  undergoing formation in the disk.
• Provide precise images at 0.1 arcsec resolution.
  Precise means representing within the noise level
  the sky brightness at all points where the
  brightness is greater than 0.1 of the peak image
  brightness. This applies to all objects
  transiting at gt20 degree elevation.

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• Good match to weather statistics and science

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Frequency band capabilities

• Band 3 84-116GHz. FOV 60 arcsec
• Continuum ff/dust separation, optically-thin
  dust, dust emissivity index, grain size
• SiO maser, low excitation lines CO 1-0 (5.5K), CS
  2-1, HCO 1-0, N2H
• Band 6 211-275GHz. FOV 25 arcsec
• Dust SED
• Medium excitation lines CO 2-1 (16K), HCN 3-2,
• Band 7 275-373GHz. FOV 18 arcsec
• Continuum most sensitive band for dust.
• Wave plate at 345GHz for precision polarimetry
• Medium-high excitation lines CO 3-2 (33K), HCN
  4-3, N2D,
• Band 9 602-720GHz. FOV 9 arcsec
• Towards peak of dust SED, away from Rayleigh
  Jeans hence T(dust)
• High excitation lines e.g. CO 6-5 (115K), HCN 8-7
  in compact regions

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Diffraction limited imaging needs phase correction

• Water fluctuations typically 500m-1000m above
  site
• Correct by Fast Switching of antennas to QSO,
  plus Water Vapor Radiometry

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Star Forming Regions are complex

• Such as DR21 at roughly 3 Kpc (Marston et al.
  IRAC)

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Serpens at 3mm and 100 microns (Testi priv.comm)
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Fundamental steps forward with Herschel

• PACS Maps of star forming regions in continuum
  and OI 63 micron line
• SPIRE Maps on the large scale (eg of galactic
  plane, see Molinari HIGAL poster)
• HIFI Water and detailed kinematics of star
  forming regions

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Initial Conditions Pre-collapse Cores

• Strong chemical gradients and clumpiness
• Indicates depletion and chemical evolution
• ALMA mosaic at 3mm 100 pointings plus
  single-dish data needed
• ALMA can resolve 15AU scales in nearby cores, or
  study cores at 1000AU scales out to 10kpc

L1498 Tafalla et al.
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Core dynamics infall
Small-scale
Extended 0.1 - 0.3 pc
Walsh et al
Di Francesco et al (2001)
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Starless Core Chemistry probing the depletion
zones

• Complete CNO depletion within 2500AU?
• ALMA can study this region, in objects as far as
  the GC, in H2D

CS, CO, HCO
NH3, N2H
H2D D2H
2,500AU
8,000AU
372GHz line
15,000AU
Walmsley et al. 2004 Caselli et al 2003
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Role of Magnetic Fields?
(Figure by A. Chrysostomou)
(Crutcher et al)
L1544 Ward-Thompson et al 2000
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Star formation in crowded environments

• ALMA can resolve 15AU scales at Taurus
• Clump mass function down to 0.1 Jupiter masses
• Onset of multiplicity
• BD formation
• Internal structure of clumps
• Turbulence on AU scales

Bate 2002
Protostars and Clumps in Perseus Hatchell et al
2005.
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Molecular Outflows
Chandler Richer 1999
170AU resolution

• Origin of flows down to 1.5AU scales
• 10 mas resolution at 345 GHz
• 24 hours gives 5K rms at 20 km/s resolution
• Resolve magnetosphere X or disk winds?
• Flow rotation?
• Proper motions
• 0.2 arcsec per year for 100km/s at 100pc
• Resolve the cooling length
• Resolve multiple outflow regions

Beuther et al, 2002
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Spatially-resolved Spectral Surveys
8GHz bandwidth
Kuan et al 2004
Schilke et al
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Hot Core chemistry around low mass protostars
Looney et al, 2000

• 300AU sized molecular structures around
  protostellar candidates
• Different chemical signatures

Kuan et al 2004
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Circumstellar Disks Structure and Evolution
Dutrey et al
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Disk around young stars

• Current arrays have done about 20 sources...
  (e.g. IRAM PdB Survey)
• ALMA sensitivity 50 times better ...
• ALMA could do hundreds of sources in continuum,
  to a much better level, and at much higher
  angular resolution

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Zooming on inner disks

• Nice, circularly symmetric, Keplerian disks dont
  really exist
• E.g. AB Aur 1.3 mm image at 0.6 resolution
  spiral density enhancements 100 AU from the
  star (black IR from Fukagawa et al 2004, White
  mm from Piétu et al 2004)
• Are such phenomena common? Long-lived ?

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Stellar Masses (and more)

• From the (Keplerian) rotation curve, measured
  from CO (Simon et al 2000)
• Temperature from CO isotopes (Dartois et al 2003)
• A sample of 40 sources, in CO and its isotopes at
  0.2 resolution requires 2600 hours of ALMA !

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Transition Disks ?

• ALMA can image the débris disks around (young)
  stars
• But also perhaps unveil the transition stage
  between proto-planetary disks and débris disks
• Small disks just being found e.g. BP Tau (Dutrey
  et al 2003)
• But studies will require long integration time
  even with ALMA (gtgt 10 hours / object)

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Long term schedule

• Proper motions can be measured with ALMA
• Clumps in debris disks (? evidence for planets
  ?)
• Orbital motions of proto-stellar condensations in
  massive star forming regions
• ?Plan in advance and for the long term...

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Imaging Protoplanetary Disks

• Protoplanetary disk at 140pc, with Jupiter mass
  planet at 5AU
• ALMA simulation
• 428GHz, bandwidth 8GHz
• total integration time 4h
• max. baseline 10km
• Contrast reduced at higher frequency as optical
  depth increases
• Will push ALMA to its limits

Wolf, Gueth, Henning, Kley 2002, ApJ 566, L97
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Direct detection of proto-Jovian planets?

• See Sebastian Wolfs talk

Wolf et al 2004
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Debris disk spectroscopy with Spitzer
Rieke et al 2004
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Debris Disk imaging with ALMA
Fomalhaut (Greaves et al)
Vega (Holland et al)

• Wyatt (2004) model dust trapped in resonances by
  migrating planets in disk
• ALMA will revolutionise studies of the large cold
  grains in other planetary systems

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Star Formation at the Galactic Centre
Pierce-Price, Richer, et al 2000
SCUBA 850 micron Pierce-Price et al 2000

• ALMA could map one square degree at 350GHz in 180
  hours to
• 0.7mJy sensitivity
• This is 0.15 solar masses at 20K
• confusion limited unless resolution high
• 1 arcsec beam (8500AU) would give
• ?T0.6K at 1 km/s resolution
• Possible lines in 2x4GHz passband
• USB SiO 8-7, H13CO 4-3, H13CN 4-3, CO 3-2
• LSB CH3CN, CH3OH
• Or
• USB HCN 4-3, HCO 4-3
• LSB H13CN 4-3, CS 7-6, CO 3-2

SCUBA 450 micron
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Final Remarks

• ALMAs unique role will be imaging down to few AU
  scales in nearby star forming regions with a
  sensitivity of a few Kelvin
• Protostellar and protoplanetary disks
• Accretion, rotation and outflow deep in the
  potential well
• Chemistry and dust properties at high spatial
  resolution
• Will require excellent operation on long
  baselines
• Study star formation across the Galaxy
• Modest resolution observations (0.5 arcsec or so)
  will be important too
• Good brightness sensitivity
• ALMA has a narrow field of view
• Need surveys with single dishes to feed ALMA
• Many targets extended over several primary beams
• Need high-quality short spacing data to make
  precise images and for flux ratio experiments

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Site Road Construction 1

• Road Construction
• There are 42Km of road being constructed between
  Highway 23 outside San Pedro de Atacama to the
  AOS via the OSF giving ALMA its own private road
  network.
• Initial construction started in 2003 and the road
  was opened in time for the Ground Breaking
  ceremony in November.
• Commencing in June 2004 the final construction is
  now taking place to consolidate the existing road
  and make it suitable for the main construction
  and operations phases.

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GPS track on site image
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Site Road Construction 2
Right of Way
Concession
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Site Road Construction 3
To AOS
OSF Site
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Site Road Construction 4
View West Road at 18Km
View East
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Site ALMA Camp 1

• ALMA Camp
• The permanent ALMA camp at the OSF is currently
  being used by members of the site IPT. Further
  expansion is planned over the following year to
  allow accommodation of all ALMA staff during the
  main integration phase.
• The camp will also be used during the operations
  phase and it is planned to augment the facilities
  with a Residence building housing about 100
  visiting staff and observers.
• At the same time a Contractors camp is being
  built nearby to house the contractors workforce
  during the construction phase.

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Site ALMA Camp 2
Inner Court
ALMA Camp General View
Typical Office
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ALMA Board at ALMA Camp Grill
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Site OSF 1

• Operations Support Facility
• The OSF is the main facility for operations and
  maintenance of the array. Situated at 2900m it
  will offer a modern, comfortable and safe
  environment from which both scientific
  observation and routine maintenance can be
  conducted.
• The design of the OSF encompasses workshop
  facilities, integration facilities and
  maintenance areas for both the current baseline
  ALMA and the enhanced design to include the
  contribution of Japan. In addition the array
  operations centre and associated observing
  facilities are all contained within the same
  campus.

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Visitors Center
Residence Area
OSF Camps and Technical Facilities
Access Road to Visitors Center
Contractors Camp
ALMA Camp
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Site AOS 1

• Array Operation Site
• The AOS complex houses the Correlator and Local
  Oscillator equipment together with limited
  workshop facilities and emergency overnight
  accommodation. It is not intended to have any
  staff permanently stationed at the AOS and all
  operations will be conducted remotely from the
  AOS.
• The layout of the array foundations has been
  completed with a total of 216 pads. The original
  compliment of 256 pads has been reduced with no
  compromise to the ALMA science.

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Site AOS Building 1
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