Download SPIRE: The Spectral and Photometric Imaging Receiver

SPIRE:
The Spectral and Photometric
Imaging Receiver
Presentation to CASCA 2001
The SPIRE Team
CASCA 2001
Page 1 of 12
The Herschel Space Observatory
THE HERSCHEL MISSION:
• Herschel is a general purpose astronomical observatory to
carry out photometry and spectroscopy over the spectral
range 80 – 670 m
• Cornerstone ESA mission
UNIQUE FEATURES:
• Large (3.5m), cold (80K), low-emissivity (4%) telescope
• Access to poorly-explored spectral range with no atmospheric
interference
• Large amount of high-quality observing time
VITAL STATISTICS:
• Launch: April 2007 on Ariane 5; Lifetime: 4.25 years
• Orbit: around Sun-Earth L2 point
• Payload cooling: to 4K using onboard LHe (ISO cryostat
technology)
CASCA 2001
Page 2 of 12
The Herschel Spacecraft
PAYLOAD INSTRUMENTS:
• Heterodyne Instrument for
FIRST (HIFI)
 High-resolution
spectroscopy over selected
spectral bands
• Photoconductor Array
Camera and Spectrometer
(PACS)
 Imaging photometry and lowresolution spectroscopy,
80-210 m
• Spectral and Photometric
Imaging Receiver (SPIRE)
 Imaging photometry and lowresolution spectroscopy,
200-670 m
CASCA 2001
Page 3 of 12
SPIRE Science Objectives
PRIMARY OBJECTIVES:
• The main scientific goals of SPIRE are the investigation of the
statistics and physics of galaxy and structure formation at
high redshift and the study of the earliest stages of star
formation, while the protostar is still coupled to the interstellar
medium
• These studies require the capability to carry out large-area
deep photometric imaging surveys at far-infrared and
submillimetre wavelengths
• Survey observations will be followed up with spectroscopy of
selected sources
• SPIRE will exploit the unique advantages of Herschel and will
have unmatched sensitivity
SECONDARY OBJECTIVES:
• SPIRE will also be a powerful tool for many other
astrophysical studies: giant planets, comets, the galactic
interstellar medium, nearby galaxies, ultraluminous infrared
galaxies and active galactic nuclei
CASCA 2001
Page 4 of 12
Galaxies and Protostars
GALAXIES:
• emit primarily in the far infrared
due to reprocessing of stellar UV
by interstellar dust; redshifted
into submm for z~1-5
• determination of bolometric
luminosity (star formation rate)
requires that submm SED be
known
PROTOSTARS:
• cold cloud cores emit primarily in
the far infrared and submm
• bolometric luminosity and
temperature can be determined
from measurement of the thermal
continuum including the peak
CASCA 2001
Log (rest) (Hz)
12
13
14
15
16
13
Sanders & Mirabel
Ann. Rev. Astron.
Astrophys. 34, 749,1996
12
11
Log L
10
(L)
9
8
7
1000
100
10
1
0.1
rest (m)
PACS
Page 5 of 12
Instrument Summary
In order to carry out large-scale photometric surveys and follow-up
spectroscopy, SPIRE consists of two separate parts.
3-BAND IMAGING PHOTOMETER:
•  = 250, 350, 500 m; / ~ 3
• 4 x 8 arcmin field of view; diffraction-limited beams
IMAGING FOURIER TRANSFORM SPECTROMETER:
•  = 200-670 m; / = 20-1000 (variable)
• 2.6 arcmin field of view
• Mach-Zehnder configuration with novel broadband
beamsplitters
DESIGN FEATURES:
• feedhorn-coupled spider web bolometer detector arrays
• detector arrays cooled to 0.3 K by 3He fridge
• minimal use of mechanisms
• sensitivity limited by thermal emission from low-emissivity
telescope at 80 K
CASCA 2001
Page 6 of 12
SPIRE Photometer
Shutter
3He
cooler
Beam steering
mirror
2-K cold
stop
M4
Dichroics
and
arrays
M6
M8
M3 M5
Detector
array
modules
CASCA 2001
FIRST
focal
surface
M9
M7
Offner
relay
Page 7 of 12
SPIRE Spectrometer
Output
port
Detector
array
modules
CASCA 2001
Mirror
mechanism
Output
port
Telescope
input port
Intensity
beam
dividers
Fore-optics
shared with
photometer
Calibrator
input port
Page 8 of 12
Mach-Zehnder FTS
FEATURES:
 Access to two input ports, complementary output ports
 Optical amplification of 4
 Novel beamsplitters: high and uniform efficiency over broad
spectral range
 FTS of similar design is being built for use at the JCMT
CASCA 2001
Page 9 of 12
The SPIRE Consortium
PI: Matt Griffin, QMW, London
COUNTRIES: Canada, France, Italy, Spain, Sweden, UK, USA
CONSORTIUM INSTITUTES:
















CASCA 2001
Caltech/Jet Propulsion Laboratory, Pasadena, USA
CEA Service d’Astrophysique, Saclay, France
Imperial College, London, UK
Institut d’Astrophysique Spatiale, Orsay, France
Instituto de Astrofisica de Canarias, Tenerife, Spain
Istituto di Fisica dello Spazio Interplanetario, Rome, Italy
Laboratoire d’Astronomie Spatiale, Marseille, France
Mullard Space Science Laboratory, Surrey, UK
NASA Goddard Space Flight Center, Maryland, USA
Observatoire de Paris, Meudon, France
Queen Mary and Westfield College, London, UK
Rutherford Appleton Laboratory, Oxfordshire, UK
UK Astronomy Technology Centre, Edinburgh, UK
Stockholm Observatory, Sweden
Università di Padova, Italy
University of Saskatchewan, Canada
Page 10 of 12
Canadian Participation in SPIRE
AGREED WORK PACKAGES:
• shutter subsystem, ICC manpower
• other possibilities are under investigation
CANADIAN SPIRE TEAM:
• Principal Investigator:
 G.R. Davis, University of Saskatchewan
• Co-Investigators:





P.A. Feldman, HIA
M. Halpern, UBC
D.A. Naylor, University of Lethbridge
D. Scott, UBC
C.D. Wilson, McMaster University
• Project Manager:
 D.G. Peterson, CSA
• Instrumentation Scientist:
 J.K. Taylor, University of Saskatchewan
CASCA 2001
Page 11 of 12
Shutter Subsystem
DESCRIPTION:
• vane will cover SPIRE
entrance aperture to
block flux from cryostat
• surface facing detectors
will be coated with highemissivity material
• vane temperature will
be controllable between
5 and 20K to provide
known flux to detectors
(heater and temperature
monitor)
• 4-K actuator and
position sensor
• Industrial partner:
COM DEV
CASCA 2001
(Courtesy COM DEV)
Thermometer
Actuator
Heater
Thermometry
Position
Sensor
Page 12 of 12