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Science With ALMA. T. L. Wilson European ALMA Project Scientist, and Interim JAO Project Scientist. Bilateral ALMA + ALMA Compact Array (in lower right). Location Chajntantor Plateau at 5000m in northern Chile. ALMA. ALMA Science Drivers. Key drivers: Detect the Milky Way at z=3 - PowerPoint PPT Presentation
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ESO Seminar, 25 May 2006 1
Science With ALMA
T. L. WilsonEuropean ALMA Project Scientist,
and
Interim JAO Project Scientist
ESO Seminar, 25 May 2006 2
Bilateral ALMA + ALMA Compact Array (in lower right)
ESO Seminar, 25 May 2006 3
ALMALocation
Chajntantor Plateau at5000m in northern Chile
ESO Seminar, 25 May 2006 4
ALMA Science DriversKey drivers:
Detect the Milky Way at z=3 Measure dust broadband emission and spectral line radiation
from atoms and molecules in high-z galaxies to obtain detailed morphology and kinematics
Protostars and planet formation:Angular resolution of an AU at 150 pc (nearest molecular cloud); 10milli arc seconds
High Fidelity Images in Spectral Lines and Continuum
ESO Seminar, 25 May 2006 5
Simulation of a protostellar disk
Jupiter-mass protoplanet around 0.5 solar mass star Orbital radius: 5 AU
Maximum baseline: 10 kmf = 850 GHz8 hour integration
150 Light years
300Light years
ESO Seminar, 25 May 2006 6
Sizes of the SPIRE and PACS beam sizes on the HDF north Field
This
shows the
limits of
Herschel
angular
resolution.
Herschel
measurements
need
follow ups
with higher
angular
resolution
imaging
ESO Seminar, 25 May 2006 7
Visible Infrared mmUV
Wavelength
Inte
nsit
y
Add dust
ESO Seminar, 25 May 2006 8
A Next Generation Millimeter Telescope
A major step in astronomy a mm/submm equivalent of VLT, HST, JWST, EVLACapable of seeing star-forming galaxies across the UniverseCapable of seeing star-forming regions across the Galaxy
These Objectives Require:An angular resolution of 0.1” at 3 mmA collecting area of about 6,000 sq mAn array of antennas to obtain arc sec or better angular resolutionA site which is high, dry, large, flat since water vapor absorbs mm/sub-mm signals
A high Andean plateau is ideal
ESO Seminar, 25 May 2006 9
Summary of Requirements
Frequency 30 to 950 GHz (initially only 84-720 GHz)
Bandwidth 8 GHz, fully tunable
Spectral resolution 3.15 kHz (0.01 km/s) at 100 GHz
Angular resolution 1.4” to 0.015” at 300 GHz
Dynamic range 10000:1 (spectral); 50000:1 (imaging)
Flux sensitivity 0.2 mJy in 1 min at 345 GHz (median conditions)
Bilateral Antenna Complement 50 to 64 antennas of 12-m diameter
ACA 12 x 7-m & 4 x 12-m diameter antennas
Polarization All cross products simultaneously
ESO Seminar, 25 May 2006 10
Back End & Correlator
Front-End
DigitizerClock
Local Oscillator
ANTENNA
Data Encoder12*10Gb/s
12 Optical Transmitters
12->1 DWD Optical Mux
Digitizer8* 4Gs/s -3bit ADC
8* 250 MHz, 48bit out
IF-Processing(8 * 2-4GHz sub-bands)
Fiber Patch-PanelFrom 270 stations to 64 DTS Inputs
Optical De-Mux& Amplifier
Digital De-Formatter
Correlator
Technical Building
Tunable Filter Bank
Fiber
ESO Seminar, 25 May 2006 11
Correlator Set Up: Four IF Bands of 2 GHz Each Can be Analyzed by 32 Filters, 16 in Each Polarization
2 GHz wide IF
Region analyzed by a single spectrometer
Spectrometer is a recycling correlator: # of channels x total bandwidth=(128)x(2 GHz)
(we show ½ of the filters)
ESO Seminar, 25 May 2006 12
The ALMAFOV is 25”at 1 mm
ALMA ReceiverBands
ESO Seminar, 25 May 2006 13
Sensitivity
with 6
antennas
Bands 3, 6, 7 and 9 are in bilateral ALMA
ESO Seminar, 25 May 2006 14
Herschel and ALMA Science: The Cool Universe
Herschel is best suited for surveys, ALMA a follow-up instrument
ALMA has a small Field Of View (FOV), but high angular resolution and sensitivityHigher angular resolution to image the sources measured by HerschelFollow up to sources discovered with PACS or SPIRE in longer wavelength dust emission Also, surveys in CO to determine redshifts
ESO Seminar, 25 May 2006 15
Herschel and ALMA Science Topics
Solar System:• Water in Giant Planets• Atmospheric chemistry• Water activity and composition of comets
ISM in Galaxies:• Normal galaxies• Physical properties of star-forming ISM
Dense cores and star-formation:• Temperature, density
structure• Dust properties• Stellar IMF
ISM in the Milky Way:• Structure• Dynamics (pressure)• Composition (gradients)
Late stages of stellar evolution:• Winds• Shells• Asymmetries• Composition
ESO Seminar, 25 May 2006 16
Scientific Areas
High Redshift Galaxies and CosmologyActive Galactic Nuclei & Star Formation in GalaxiesStar and Planet FormationWater in the UniverseAstrochemistry in Hot Cores and Envelopes of Evolved StarsSolar System
ESO Seminar, 25 May 2006 17
High Redshift Sources and AGN’s
High star formation rates, >>20 solar masses per yearMost of the radiation emitted by stars is absorbed by dust and re-radiated in the 3 micrometer to 1 mm wavelength rangeThe luminous IR galaxies trace regions where the concentration of galaxies is largest, and trace the formation of large scale structures.
ESO Seminar, 25 May 2006 18
AGN’s: Herschel & ALMAMeasure 1000’s of sources with PACS and SPIRE, then follow up with longer wavelength continuum data with ALMA
ALMA spectral line measurements of CO and other species
Herschel will sample the regime where most of the luminosity is radiated
High resolution images with ALMA allow a better determination of the size of emission sources ALMA would provide high resolution images to refine models. Separate star formation and accretion in AGN’s
Could also make imaging survey of sources found with PLANCK
ESO Seminar, 25 May 2006 19
Image of the redshift z=6.4 source in CO line emission
The CO emissionwas shown to beextended
ESO Seminar, 25 May 2006 20
CO Lines Observable with ALMA Receivers as a Function of Redshift
ESO Seminar, 25 May 2006 21
Normalized integrated CO line intensity
With a number of CO linemeasurementsone can determinephysical parametersof a source
ESO Seminar, 25 May 2006 22
NGC6240-An AGN Case Study
NICMOS 1.6 micronNICMOS 1.6 micron
CO J=2-10.7” resolutionIRAM Interferometer
2”, 960 pc
CO J=2-10.7” resolutionIRAM Interferometer
2”, 960 pc
CO J=2-10.7” resolutionIRAM Interferometer
2”, 960 pc
ESO Seminar, 25 May 2006 23
Nearby Galaxies
Investigate star formation in other types of galaxiesAt 10 Mpc, 0.1” is equivalent to 4.8 pc
Compare to models, in regard to the influence of nearby surroundings, metallicity, mergers
ESO Seminar, 25 May 2006 24
IC10-A Nearby Blue Dwarf Galaxy
D=0.7 Mpc;
Total size of the image is 10’
ESO Seminar, 25 May 2006 25
Boxes
show
FOV
of
Bolometers.
The FOV
of ALMA
at 3 mm
is the
circle
in the
lower
left
Smallest
box is
the integral
field
spectrometer
In PACS
ESO Seminar, 25 May 2006 26
Star Formation in our Galaxy
We can study different stages of star formation in individual sourcesWe believe that the basic physical laws are understood but the relative importance of various effects is not knownThe study of low mass star formation will allow us to understand how our solar system formedIn this study we group ‘protostars’ and ‘debris disks’
ESO Seminar, 25 May 2006 27
Sketch of Protostar Development
ESO Seminar, 25 May 2006 28
450/850 micrometerimages of Fomalhaut.The contours are13 and 2 mJy/beam. Below are deconvolvedimages (data from JCMT and SCUBA)
ESO Seminar, 25 May 2006 29
Dust Spectra and Herschel Bolometer Bands
ESO Seminar, 25 May 2006 30
Orion KL Spectrum from Ground
ESO Seminar, 25 May 2006 31
Orion KL: The Classical Hot Core Source
Within a
20” region
there are
a variety
of physical
conditions
ESO Seminar, 25 May 2006 32
Heerschel HIFI Water Lines
This transition inALMA band 5 (a maser line)
ESO Seminar, 25 May 2006 33
Main Sequence & Evolved Stars
In broadband continuum, ALMA should be able to detect high mass stars in our Galaxy, and evolved stars even in the LMCIn evolved stars such as IRC+10216, ALMA will be able to image molecular and dust emission
Herschel can be used to search for water vapor in the envelopes of such stars
ESO Seminar, 25 May 2006 34
Sample spectra from IRC+10216(R Leo), a nearbycarbonstar
ESO Seminar, 25 May 2006 35
Images of some molecules in IRC10216, a nearby carbon star
ESO Seminar, 25 May 2006 36
Solar System Objects
Herschel can easily measure outer planets, and moons of these planets, as well as Trans Neptune Objects
Highly accurate photometry Water on the giant planetsFollow up would be HDO, to determine D/H ratio
ALMA and Herschel might be used to measure a common source at a common wavelength to set up a system of amplitude calibrators
ALMA provides high resolution image, but also records the total flux density
ESO Seminar, 25 May 2006 37
A Comparison of
analysis schemes
ESO Seminar, 25 May 2006 38
Conclusions
Overall, Herschel is best suited for surveys, while ALMA a follow up instrument
ALMA has a small FOV, but high angular resolution and sensitivityHigher angular resolution to image the sources measured or detected by HerschelAlso follow ups to PACS or SPIRE surveys in CO or in longer wavelength dust emission
Need common set of sourcesIn combining results we need well established calibrations In analyzing the results, really need a much more sophisticated system For planets, comets and asteroids can image in spectral lines and continuum