Systematic characterisation of the Herschel SPIRE Fourier Transform Spectrometer

Abstract

A systematic programme of calibration observations was carried out to monitor the performance of the SPIRE FTS instrument on board the Herschel Space Observatory. Observations of planets (including the prime point-source calibrator, Uranus), asteroids, line sources, dark sky, and cross-calibration sources were made in order to monitor repeatability and sensitivity, and to improve FTS calibration. We present a complete analysis of the full set of calibration observations and use them to assess the performance of the FTS. Particular care is taken to understand and separate out the effect of pointing uncertainties, including the position of the internal beam steering mirror for sparse observations in the early part of the mission. The repeatability of spectral line centre positions is <5km/s, for lines with signal-to-noise ratios >40, corresponding to <0.5-2.0% of a resolution element. For spectral line flux, the repeatability is better than 6%, which improves to 1-2% for spectra corrected for pointing offsets. The continuum repeatability is 4.4% for the SLW band and 13.6% for the SSW band, which reduces to ~1% once the data have been corrected for pointing offsets. Observations of dark sky were used to assess the sensitivity and the systematic offset in the continuum, both of which were found to be consistent across the FTS detector arrays. The average point-source calibrated sensitivity for the centre detectors is 0.20 and 0.21 Jy [1 sigma; 1 hour], for SLW and SSW. The average continuum offset is 0.40 Jy for the SLW band and 0.28 Jy for the SSW band.

arXiv comment41 pages, 37 figures, 32 tables. Accepted for publication in MNRAS

References in corpus (23)

• Herschel Space Observatory - An ESA facility for far-infrared and submillimetre astronomy
• The Herschel-SPIRE instrument and its in-flight performance
• IRIS: A new generation of IRAS maps
• The Far-Infrared Surveyor (FIS) for AKARI
• The Balloon-borne Large Aperture Submillimeter Telescope: BLAST
• Flux calibration of the Herschel-SPIRE photometer
• Absolute Calibration and Characterization of the Multiband Imaging Photometer for Spitzer. III. An Asteroid-based Calibration of MIPS at 160 microns
• A mid-infrared imaging catalogue of post-AGB stars
• Towards the automated reduction and calibration of SCUBA data from the James Clerk Maxwell Telescope
• Discovery of Time Variation of the Intensity of Molecular Lines in IRC+10216 in The Submillimeter and Far Infrared Domains
• An independent distance estimate to CW Leo
• Observing Extended Sources with the \Herschel SPIRE Fourier Transform Spectrometer
• Chemical Evolution of the Circumstellar Envelopes of Carbon-rich Post-AGB objects
• The Pointing System of the Herschel Space Observatory. Description, Calibration, Performance and Improvements
• Herschel-SPIRE FTS spectroscopy of the carbon-rich objects AFGL 2688, AFGL 618 and NGC 7027
• Herschel celestial calibration sources: Four large main-belt asteroids as prime flux calibrators for the far-IR/sub-mm range
• SPIRE Point Source Photometry
• ISOPHOT - Photometric Calibration of Point Sources
• Herschel SPIRE FTS Relative Spectral Response Calibration
• The molecular envelope of CRL 618: A new model based on Herschel/HIFI observations
• Relative pointing offset analysis of calibration targets with repeated observations with Herschel-SPIRE Fourier-Transform Spectrometer
• Herschel SPIRE FTS telescope model correction
• Herschel SPIRE Fourier Transform Spectrometer: Calibration of its Bright-source Mode

Cited by in corpus (15)

• Far-infrared Herschel SPIRE spectroscopy of lensed starbursts reveals physical conditions of ionised gas
• $\eta$ Carinae's Dusty Homunculus Nebula from Near-Infrared to Submillimeter Wavelengths: Mass, Composition, and Evidence for Fading Opacity
• HERUS: A CO Atlas from SPIRE Spectroscopy of local ULIRGs
• SPIRE Spectroscopy of Early Type Galaxies
• Herschel Spectroscopy of Early Type Galaxies
• Herschel spectroscopy of Massive Young Stellar Objects in the Magellanic Clouds
• Far-infrared/sub-millimetre properties of pre-stellar cores L1521E, L1521F and L1689B as revealed by the Herschel SPIRE instrument -- I. Central positions
• Eta Carinae & the Homunculus: Far Infrared, Sub-millimeter Spectral Lines
• Three-dimensional distribution of hydrogen fluoride gas toward NGC6334 I and I(N)
• Correcting the extended-source calibration for the Herschel-SPIRE Fourier-Transform Spectrometer
• The Herschel SPIRE Fourier Transform Spectrometer Spectral Feature Finder II. Estimating Radial Velocity of SPIRE Spectral Observation Sources
• The Herschel SPIRE Fourier Transform Spectrometer Spectral Feature Finder III. Line Identification and Off-Axis Spectra
• The Herschel SPIRE Fourier Transform Spectrometer Spectral Feature Finder I. The Spectral Feature Finder and Catalogue
• The Herschel SPIRE Fourier Transform Spectrometer Spectral Feature Finder IV. Neutral Carbon Detection in the SPIRE FTS Spectra
• Calibration of Herschel SPIRE FTS observations at different spectral resolutions