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ESO Seminar, 25 May 20061 Science With ALMA T. L. Wilson European ALMA Project Scientist, and Interim JAO Project Scientist
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ESO Seminar, 25 May 20062 Bilateral ALMA + ALMA Compact Array (in lower right)
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ESO Seminar, 25 May 20063 ALMA Location Chajntantor Plateau at 5000m in northern Chile
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ESO Seminar, 25 May 20064 ALMA Science Drivers Key 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
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ESO Seminar, 25 May 20065 Simulation of a protostellar disk Jupiter-mass protoplanet around 0.5 solar mass star Orbital radius: 5 AU Maximum baseline: 10 km f = 850 GHz 8 hour integration 150 Light years 300 Light years
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ESO Seminar, 25 May 20066 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
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ESO Seminar, 25 May 20067 Visible InfraredmmUV Wavelength Intensity Add dust
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ESO Seminar, 25 May 20068 A Next Generation Millimeter Telescope A major step in astronomy a mm/submm equivalent of VLT, HST, JWST, EVLA Capable of seeing star-forming galaxies across the Universe Capable of seeing star-forming regions across the Galaxy These Objectives Require: An angular resolution of 0.1” at 3 mm A collecting area of about 6,000 sq m An array of antennas to obtain arc sec or better angular resolution A site which is high, dry, large, flat since water vapor absorbs mm/sub-mm signals A high Andean plateau is ideal
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ESO Seminar, 25 May 20069 Summary of Requirements Frequency30 to 950 GHz (initially only 84-720 GHz) Bandwidth8 GHz, fully tunable Spectral resolution3.15 kHz (0.01 km/s) at 100 GHz Angular resolution1.4 ” to 0.015 ” at 300 GHz Dynamic range10000:1 (spectral); 50000:1 (imaging) Flux sensitivity0.2 mJy in 1 min at 345 GHz (median conditions) Bilateral Antenna Complement50 to 64 antennas of 12-m diameter ACA12 x 7-m & 4 x 12-m diameter antennas PolarizationAll cross products simultaneously
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ESO Seminar, 25 May 200610 Back End & Correlator Front-End Digitizer Clock Local Oscillator ANTENNA Data Encoder 12*10Gb/s 12 Optical Transmitters 12->1 DWD Optical Mux Digitizer 8* 4Gs/s -3bit ADC 8* 250 MHz, 48bit out IF-Processing (8 * 2-4GHz sub-bands) Fiber Patch-Panel From 270 stations to 64 DTS Inputs Optical De-Mux & Amplifier Digital De-Formatter Correlator Technical Building Tunable Filter Bank Fiber
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ESO Seminar, 25 May 200611 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)
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ESO Seminar, 25 May 200612 The ALMA FOV is 25” at 1 mm ALMA Receiver Bands
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ESO Seminar, 25 May 200613 Sensitivity with 6 antennas Bands 3, 6, 7 and 9 are in bilateral ALMA
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ESO Seminar, 25 May 200614 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 sensitivity Higher angular resolution to image the sources measured by Herschel Follow up to sources discovered with PACS or SPIRE in longer wavelength dust emission Also, surveys in CO to determine redshifts
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ESO Seminar, 25 May 200615 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
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ESO Seminar, 25 May 200616 Scientific Areas High Redshift Galaxies and Cosmology Active Galactic Nuclei & Star Formation in Galaxies Star and Planet Formation Water in the Universe Astrochemistry in Hot Cores and Envelopes of Evolved Stars Solar System
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ESO Seminar, 25 May 200617 High Redshift Sources and AGN’s High star formation rates, >>20 solar masses per year Most of the radiation emitted by stars is absorbed by dust and re-radiated in the 3 micrometer to 1 mm wavelength range The luminous IR galaxies trace regions where the concentration of galaxies is largest, and trace the formation of large scale structures.
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ESO Seminar, 25 May 200618 AGN’s: Herschel & ALMA Measure 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
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ESO Seminar, 25 May 200619 Image of the redshift z=6.4 source in CO line emission The CO emission was shown to be extended
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ESO Seminar, 25 May 200620 CO Lines Observable with ALMA Receivers as a Function of Redshift
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ESO Seminar, 25 May 200621 Normalized integrated CO line intensity With a number of CO line measurements one can determine physical parameters of a source
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ESO Seminar, 25 May 200622 NGC6240-An AGN Case Study
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ESO Seminar, 25 May 200623 Nearby Galaxies Investigate star formation in other types of galaxies At 10 Mpc, 0.1” is equivalent to 4.8 pc Compare to models, in regard to the influence of nearby surroundings, metallicity, mergers
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ESO Seminar, 25 May 200624 IC10-A Nearby Blue Dwarf Galaxy D=0.7 Mpc; Total size of the image is 10’
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ESO Seminar, 25 May 200625 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
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ESO Seminar, 25 May 200626 Star Formation in our Galaxy We can study different stages of star formation in individual sources We believe that the basic physical laws are understood but the relative importance of various effects is not known The study of low mass star formation will allow us to understand how our solar system formed In this study we group ‘protostars’ and ‘debris disks’
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ESO Seminar, 25 May 200627 Sketch of Protostar Development
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ESO Seminar, 25 May 200628 450/850 micrometer images of Fomalhaut. The contours are 13 and 2 mJy/beam. Below are deconvolved images (data from JCMT and SCUBA)
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ESO Seminar, 25 May 200629 Dust Spectra and Herschel Bolometer Bands
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ESO Seminar, 25 May 200630 Orion KL Spectrum from Ground
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ESO Seminar, 25 May 200631 Orion KL: The Classical Hot Core Source Within a 20” region there are a variety of physical conditions
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ESO Seminar, 25 May 200632 Heerschel HIFI Water Lines This transition in ALMA band 5 (a maser line)
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ESO Seminar, 25 May 200633 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 LMC In 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
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ESO Seminar, 25 May 200634 Sample spectra from IRC+10216 (R Leo), a nearby carbon star
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ESO Seminar, 25 May 200635 Images of some molecules in IRC10216, a nearby carbon star
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ESO Seminar, 25 May 200636 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 planets Follow 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
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ESO Seminar, 25 May 200637 A Comparison of analysis schemes
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ESO Seminar, 25 May 200638 Conclusions Overall, Herschel is best suited for surveys, while ALMA a follow up instrument ALMA has a small FOV, but high angular resolution and sensitivity Higher angular resolution to image the sources measured or detected by Herschel Also follow ups to PACS or SPIRE surveys in CO or in longer wavelength dust emission Need common set of sources In 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
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