GREAT: the SOFIA high-frequency heterodyne instrument

Abstract

We describe the design and construction of GREAT, the German REceiver for Astronomy at Terahertz frequencies operated on the Stratospheric Observatory for Infrared Astronomy (SOFIA). GREAT is a modular dual-color heterodyne instrument for highresolution far-infrared (FIR) spectroscopy. Selected for SOFIA's Early Science demonstration, the instrument has successfully performed three Short and more than a dozen Basic Science flights since first light was recorded on its April 1, 2011 commissioning flight. We report on the in-flight performance and operation of the receiver that - in various flight configurations, with three different detector channels - observed in several science-defined frequency windows between 1.25 and 2.5 THz. The receiver optics was verified to be diffraction-limited as designed, with nominal efficiencies; receiver sensitivities are state-of-the-art, with excellent system stability. The modular design allows for the continuous integration of latest technologies; we briefly discuss additional channels under development and ongoing improvements for Cycle 1 observations. GREAT is a principal investigator instrument, developed by a consortium of four German research institutes, available to the SOFIA users on a collaborative basis.

References in corpus (5)

• Herschel Space Observatory - An ESA facility for far-infrared and submillimetre astronomy
• Early Science with SOFIA, the Stratospheric Observatory for Infrared Astronomy
• High-resolution wide-band Fast Fourier Transform spectrometers
• GREAT/SOFIA atmospheric calibration
• Terahertz hot electron bolometer waveguide mixers for GREAT

Cited by in corpus (106)

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• HII Region Driven Galactic Bubbles and Their Relationship to the Galactic Magnetic Field
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• High-resolution absorption spectroscopy of the OH 2Pi 3/2 ground state line
• The Strength of the Sheared Magnetic Field in the Galactic's Circum-Nuclear Disk
• Nature of shocks revealed by SOFIA OI observations in the Cepheus E protostellar outflow
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• Low Frequency Carbon Radio Recombination Lines II: The Diffuse Interstellar Medium
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• First detection of [13CII] in the Large Magellanic Cloud
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• The Dense Warm Ionized Medium in the Inner Galaxy
• L1599B: Cloud Envelope and C+ Emission in a Region of Moderately Enhanced Radiation Field
• Anatomy of the massive star-forming region S106: The OI 63 micron line observed with GREAT/SOFIA as a versatile diagnostic tool for the evolution of massive stars
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• Unveiling the remarkable photodissociation region of M8
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• High Resolution Observations of HI in the IC 63 Reflection Nebula
• [CII] gas in IC 342
• Atomic oxygen abundance toward Sagittarius B2
• SOFIA observations of CO(12-11) emission along the L1157 bipolar outflow
• Disentangling emission from star-forming regions in the Magellanic Clouds: Linking [OIII]88 micron and 24 micron
• Star Formation Triggered by the expanding bubble S111
• Physical conditions in the gas phases of the giant HII region LMC-N11: II. Origin of [CII] and fraction of CO-dark gas
• Velocity-resolved high-J CO emission from massive star-forming clumps
• SOFIA FIFI-LS spectroscopy of DR21 Main: energetics of the spatially-resolved outflow from a high-mass protostar
• GREAT [CII] and CO observations of the BD+40°4124 region
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• Hydrogen in diffuse molecular clouds in the Milky Way: Atomic column densities and molecular fraction along prominent lines of sight