Science With ALMA

T. L. Wilson

European ALMA Project Scientist, and Interim JAO Project Scientist

ESO Seminar, 25 May 2006 1

Bilateral ALMA + ALMA Compact Array (in lower right)

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Location

Chajntantor Plateau at 5000m in northern Chile

ALMA ESO Seminar, 25 May 2006 3

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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150 Light years

Simulation of a protostellar disk

Jupiter-mass protoplanet around 0.5 solar mass star Orbital radius: 5 AU

300 Light years

Maximum baseline: 10 km f = 850 GHz 8 hour integration

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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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UV Visible Infrared

Add dust

mm

Wavelength ESO Seminar, 25 May 2006 7

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 ESO Seminar, 25 May 2006 8

Frequency Bandwidth Spectral resolution Angular resolution Dynamic range Flux sensitivity

Summary of Requirements

30 to 950 GHz (initially only 84-720 GHz) 8 GHz, fully tunable 3.15 kHz (0.01 km/s) at 100 GHz 1.4

” to 0.015

” at 300 GHz 10000:1 (spectral); 50000:1 (imaging) 0.2 mJy in 1 min at 345 GHz (median conditions) Bilateral Antenna Complement 50 to 64 antennas of 12-m diameter ACA Polarization 12 x 7-m & 4 x 12-m diameter antennas

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Back End & Correlator

ANTENNA Front-End Technical Building Correlator Tunable Filter Bank IF-Processing (8 * 2-4GHz sub-bands) Local Oscillator Digital De-Formatter Digitizer 8* 4Gs/s -3bit ADC 8* 250 MHz, 48bit out Digitizer Clock Optical De-Mux & Amplifier Data Encoder 12*10Gb/s 12 Optical Transmitters 12->1 DWD Optical Mux Fiber Patch-Panel From 270 stations to 64 DTS Inputs

Fiber ESO Seminar, 25 May 2006 10

Correlator Set Up: Four IF Bands of 2 GHz Each Can be Analyzed by 32 Filters, 16 in Each Polarization

Region analyzed by a single spectrometer

2 GHz wide IF Spectrometer is a recycling correlator: # of channels x total bandwidth=(128)x(2 GHz) (we show ½ of the filters)

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The ALMA FOV is 25” at 1 mm ALMA Receiver Bands

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Sensitivity with 6 antennas

ESO Seminar, 25 May 2006

Bands 3, 6, 7 and 9 are in bilateral ALMA

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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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Herschel and ALMA Science Topics

• •

ISM in Galaxies: Normal galaxies Physical properties of star-forming ISM ISM in the

• • •

Milky Way: Structure Dynamics (pressure) Composition (gradients) Dense cores and

• • •

star-formation: Temperature, density structure Dust properties Stellar IMF Late stages of stellar

• • • •

evolution: Winds Shells Asymmetries Composition ESO Seminar, 25 May 2006

• • •

Solar System: Water in Giant Planets Atmospheric chemistry Water activity and composition of comets 15

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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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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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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Image of the redshift z=6.4 source in CO line emission

The CO emission was shown to be extended

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CO Lines Observable with ALMA Receivers as a Function of Redshift

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Normalized integrated CO line intensity

With a number of CO line measurements one can determine physical parameters of a source

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NGC6240-An AGN Case Study

CO J=2-1 0.7” resolution

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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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D=0.7 Mpc; Total size of the image is 10’

IC10-A Nearby Blue Dwarf Galaxy

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Boxes show FOV of Bolometers.

The FOV of ALMA at 3 mm is the circle in the lower left

ESO Seminar, 25 May 2006

Smallest box is the integral field spectrometer In PACS

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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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Sketch of Protostar Development

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ESO Seminar, 25 May 2006

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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Dust Spectra and Herschel Bolometer Bands

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Orion KL Spectrum from Ground

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Within a 20” region there are a variety of physical conditions

Orion KL: The Classical Hot Core Source

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Heerschel HIFI Water Lines

ESO Seminar, 25 May 2006

This transition in ALMA band 5 (a maser line)

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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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Sample spectra from IRC+10216 (R Leo), a nearby carbon star

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Images of some molecules in IRC10216, a nearby carbon star

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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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A Comparison of analysis schemes

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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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