Issue |
A&A
Volume 518, July-August 2010
Herschel: the first science highlights
|
|
---|---|---|
Article Number | L4 | |
Number of page(s) | 6 | |
Section | Letters | |
DOI | https://doi.org/10.1051/0004-6361/201014605 | |
Published online | 16 July 2010 |
Letter to the Editor
In-flight calibration of the Herschel-SPIRE instrument*
1
Space Science and Technology Department, Rutherford Appleton Laboratory, Chilton,
Didcot, Oxon, UK e-mail: bruce.swinyard@stfc.ac.uk
2
Cardiff University, The Parade, Cardiff, UK
3
LAM, Marseille, France
4
CEA Saclay, Gif-sur-Yvette, France
5
University College London, UK
6
Imperial College, London, UK
7
NASA JPL, Pasadena, California, USA
8
Cornell University, Ithaca, New York, USA
9
Department of Astronomy and Astrophysics, University of Toronto, Toronto, Canada
10
European Space Agency (ESA), European Space Astronomy Centre (ESAC), Villanueva de la Cañada,
Madrid, Spain
11
Blue Sky Spectroscopy Inc., Lethbridge, Canada
12
University of Colorado, Boulder, Colorado, USA
13
UK Astronomy Technology Centre, Blackford Hill, Edinburgh, UK
14
Institute of Astronomy, ETH Zurich, 8093 Zurich, Switzerland
15
Institute for Space Imaging Science, University of Lethbridge, Canada
16
Caltech, Pasadena, California, USA
17
NASA Herschel Science Centre, IPACS, Pasadena, California, USA
18
Astronomy Centre, Dept. of Physics & Astronomy, University of Sussex, UK
19
Department of Physics, Oxford University, Keble Road, Oxford, UK
20
Institut d'Astrophysique de Paris, Université Pierre & Marie Curie, 98 bis Boulevard Arago, Paris, France
21
SUPA, Institute for Astronomy, University of Edinburgh, Blackford Hill, Edinburgh, UK
Received:
31
March
2010
Accepted:
3
May
2010
SPIRE, the Spectral and Photometric Imaging REceiver, is the Herschel Space Observatory's submillimetre camera and spectrometer. It contains a three-band imaging photometer operating at 250, 350 and 500 μm, and an imaging Fourier-transform spectrometer (FTS) covering 194–671 μm (447-1550 GHz). In this paper we describe the initial approach taken to the absolute calibration of the SPIRE instrument using a combination of the emission from the Herschel telescope itself and the modelled continuum emission from solar system objects and other astronomical targets. We present the photometric, spectroscopic and spatial accuracy that is obtainable in data processed through the “standard” pipelines. The overall photometric accuracy at this stage of the mission is estimated as 15% for the photometer and between 15 and 50% for the spectrometer. However, there remain issues with the photometric accuracy of the spectra of low flux sources in the longest wavelength part of the SPIRE spectrometer band. The spectrometer wavelength accuracy is determined to be better than 1/10th of the line FWHM. The astrometric accuracy in SPIRE maps is found to be 2 arcsec when the latest calibration data are used. The photometric calibration of the SPIRE instrument is currently determined by a combination of uncertainties in the model spectra of the astronomical standards and the data processing methods employed for map and spectrum calibration. Improvements in processing techniques and a better understanding of the instrument performance will lead to the final calibration accuracy of SPIRE being determined only by uncertainties in the models of astronomical standards.
Key words: instrumentation: photometers / instrumentation: spectrographs / space vehicles: instruments
© ESO, 2010
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