SPIRE: The Spectral and Photometric Imaging Receiver

1. SPIRE:The Spectral and Photometric Imaging Receiver Presentation to CASCA 2001 The SPIRE Team

2. 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)

3. 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 low-resolution spectroscopy, 80-210 m • Spectral and Photometric Imaging Receiver (SPIRE) • Imaging photometry and low-resolution spectroscopy, 200-670 m

4. 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

5. 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 Galaxies and Protostars PACS

6. 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

7. Beam steering mirror Dichroics and arrays Shutter 3He cooler 2-K cold stop M4 M6 M8 M3 M5 M9 M7 FIRST focal surface Offner relay Detector arraymodules SPIRE Photometer

8. Fore-optics shared with photometer Output port Telescope input port Output port Intensity beam dividers Calibrator input port Detector arraymodules Mirrormechanism SPIRE Spectrometer

9. 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

10. The SPIRE Consortium • PI: Matt Griffin, QMW, London • COUNTRIES: Canada, France, Italy, Spain, Sweden, UK, USA • CONSORTIUM INSTITUTES: • 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

11. 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

12. Shutter Subsystem • DESCRIPTION: • vane will cover SPIRE entrance aperture to block flux from cryostat • surface facing detectors will be coated with high-emissivity 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 (Courtesy COM DEV)