The Herschel PACS photometer calibration - A time dependent flux calibration for the PACS chopped point-source photometry AOT mode

Abstract

We present a flux calibration scheme for the PACS chopped point-source photometry observing mode based on the photometry of five stellar standard sources. This mode was used for science observations only early in the mission. Later, it was only used for pointing and flux calibration measurements. Its calibration turns this type of observation into fully validated data products in the Herschel Science Archive. Systematic differences in calibration with regard to the principal photometer observation mode, the scan map, are derived and amount to 5-6%. An empirical method to calibrate out an apparent response drift during the first 300 Operational Days is presented. The relative photometric calibration accuracy (repeatability) is as good as 1% in the blue and green band and up to 5% in the red band. Like for the scan map mode, inconsistencies among the stellar calibration models become visible and amount to 2% for the five standard stars used. The absolute calibration accuracy is therefore mainly limited by the model uncertainty, which is 5% for all three bands.

arXiv comment20 pages, 7 pages of appendix, 11 figures, accepted to appear in Experimental Astronomy, Special Issue for Herschel Calibrations based on the "Herschel Calibration Workshop: Only the Best Data Products for the Legacy Archive", held at ESAC, 25 - 27 March 2013, http://herschel.esac.esa.int/CalibrationWorkshop5.shtml

References in corpus (7)

• Validation of the new Hipparcos reduction
• Herschel Space Observatory - An ESA facility for far-infrared and submillimetre astronomy
• The Photodetector Array Camera and Spectrometer (PACS) on the Herschel Space Observatory
• The Herschel-PACS photometer calibration: Point-source flux calibration for scan maps
• Herschel celestial calibration sources: Four large main-belt asteroids as prime flux calibrators for the far-IR/sub-mm range
• Structure of the outer layers of cool standard stars
• PACS photometer calibration block analysis

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• Herschel celestial calibration sources: Four large main-belt asteroids as prime flux calibrators for the far-IR/sub-mm range
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