hifi h eterodyne i nstrument for the f ar i nfrared

HIFI: CASCA08, 23 May, 2008 1

HIFI Heterodyne Instrument for the

Far Infrared(The high resolution spectrometer for Herschel)

Michel Fich


Outline

Herschel- science - the mission

HIFI- the instrument- science- the Canadian HIFI team

• what comes after Herschel?


Herschel Main Scientific Objectives

Formation and evolution of galaxies and clusters in the early universe Star formation rates, bolometric luminosities, AGN structure Evolution of chemical elements

Formation of stars & planets and physics of the interstellar medium Tracers of structure, kinematics, chemistry in star forming regions Circulation/enrichment of the interstellar medium Astrochemistry – WATER Detailed studies of nearby resolvable galaxies

Cometary, planetary, and satellite atmospheres History of the solar system Pristine material in comets Water activity


Herschel: The Mission• facility-class far-infrared/submm space observatory

– 1/3 Guaranteed Time, 2/3 Open Time with annual calls for proposals

• 3.5 m Ritchey-Chrétien telescope that will passively cool to around 70K

• have an operational lifetime of at least three years

• incorporates an ISO-type liquid helium cryostat

• launched by an Ariane 5 in late late 2008 (with Planck)

• operate from an orbit around the L2 point in the Sun/Earth system located approximately 1.5 million km away from the Earth in the anti-sunward direction


Herschel: The Instruments

• SPIRE: simultaneously imaging at 250, 350, 500 μm with 322, 242, and 162 pixels in same 4'x4' FOV or low to medium resolution spectroscopy in 2'x2'

• PACS: spectroscopy with velocity resolution of 100-250 km/s and 1300-3000 km/s coverage or imaging with two 25x16 arrays at 80-130 and 130-210 μm simultaneously

• HIFI: very high spectral resolution heterodyne spectroscopy spanning 480-1250 and 1410-1910 GHz with wide and narrow band spectrometers operating in parallel


HIFI Design block diagram

Instrument Control Unit

f~1GHz f variable

HRS-vIF processorSub-band division

f~1GHz f variable

HRS-hIF processorSub-band division

f 4 GHz f 1 MHz

WBS-vIF processorSub-band division

f 4 GHz f 1 MHz

WBS-hIF processorSub-band division

fromtelescope

Common OpticsCalibration sourceChopper mechanism7 Mixer Assemblies each with 2 mixersIF amplifiers

FPU

ControlMixer biasAmplifier biasMechanism control

FCU

LOUHousingRadiator7 LO Assemblies with 7x2 LO chains and power amplifiers

LCUControlMultiplier biasPower amplifier

bias

LSUControlMaster oscillatorSynthesizerRef. distribution

spacecraftOBDH


HIFI Local Oscillator Source Unit (LSU)

• built by COMDEV• performing extremely well in tests

• the LSU dimensions are 265(H) x 424(L) x 286(W) mm.

The Canadian Hardware Contribution to HIFI


HIFI Core Science

Solar System:• Water in Giant Planets• Chemistry Martian atmosphere

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

Dense cores and star-formation:• Dynamics• Role of Water• Disks

ISM in the Milky Way:• Structure• Dynamics (pressure)• Composition (gradients)

Late stages of stellar evolution:• Winds• Shells• Asymmetries• Composition


Molecular Lines visible with HIFI

H2O 20 lines

O2 15 lines

HDO 40 lines

H218O 24 lines

CO 13 lines

OH 6 lines

OH+ 4 lines

Plus lines ofHD, HD+, H2D, 6LiH, 7LiH, CH, CH+, NH, NH+, NeH+, HF, SH, SH+, HCl, FeH, SiH, SiH+, CH2, NH2, NH3, … plus many lines from larger molecules


Science with HIFI – Water

SWAS result


HIFI Key Projects (Guaranteed Time)• water in star forming regions

– low mass: pre-stellar, Class 0, Class 1, outflows– intermediate mass: embedded (led by Doug Johnstone)– high mass: pre-stellar, hot cores, maps– disks– hydrides

• Ori B maps and spectral surveys– Ori KL, Ori-South (led by Rene Plume), bar maps

• warm ISM– PDRs, diffuse, shocks, low-UV, hydrides, C-clusters (Peter Martin on

team)• Solar System

– comets, mars, outer solar system• evolved stars• extragalactic

– galactic centre, star bursts, ultra-luminous, AGNs, Cen A, metal-poor


Canadian HIFI Steering Committee

• Michel Fich* (University of Waterloo) Canadian Lead Co-Investigator• Doug Johnstone* (NRC/HIA)• Peter Martin* (University of Toronto)• Henry Matthews (NRC/HIA/DAO/DRAO)• Bill McCutcheon (University of British Columbia)• Rene Plume* (University of Calgary)

* “Astronomy Co-Investigator” - member of the international HIFI Science Team


Canadian HIFI strategy is to maximize success rate on Open Time Proposals

•we expect a call for OT proposals due no sooner than May 2009

•Canadian staff and Science Team members available as a resource to all Canadian astronomers to help with proposals

•Canadian HIFI Workshop for potential users in 2009 (perhaps with CASCA meeting)

•observing assistance, data analysis advice and software support will be available

http://astro.uwaterloo.ca/HIFI

email: [email protected]

Herschel Meeting: 12:00 – 13:30 Friday, Esqumalt Room

http://astro.uwaterloo.ca/HIFI

mailto:[email protected]

What comes after Herschel?


• cold telescopes (SPICA)• larger telescopes (10 meter diameter)• Interferometers

Join the Far InfraRed Discipline Working Group

(FIRDWG) to learn more!

http://astro.uwaterloo.ca/~firdwgMeeting Thursday after the CASCA Business

Meeting

UofW Astro-lunch29 Nov. 2006

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The Far-IR Spatial Resolution Gap

~ 0.005 arcsecs with few K sensitivity

~ 10 arcsec with micro-K sensitivity

JWST


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Interferometers: Heterodyne vs. Direct Detection Heterodyne – detect the signals at each antenna and then

combine electronically

Direct Detection – combine beams, then detect signal

• sensitivity• resolution• technology challenges (cost and schedule)


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Based largely on the NASA-sponsored study of theSpace Infrared Interferometric Telescope (SPIRIT), a candidate Origins Probe mission

Based largely on the NASA-sponsored study of theSpace Infrared Interferometric Telescope (SPIRIT), a candidate Origins Probe mission

Dave LeisawitzNASA

hifi h eterodyne i nstrument for the f ar i nfrared

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