Difference: PacsCalibrationWeb (126 vs. 127)

Revision 1272015-12-10 - KatrinaExter

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META TOPICPARENT name="WebHome"

PACS instrument and calibration web pages

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Photometer map-makers

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  • Four fundamentally different map-makers are offered in HIPE 13 with interactive pipeline scripts, starting from Level 1. These map-makers are used in different ways to generate standard products ("SPG" product) provided by the Herschel Science Archive: high-pass filtering is applied to generate Level2 products, while Unimap and JScanam are used to create Level2.5 products. Level3 products are mosaics of Level2.5 products that belong to the same sky field and to the same observing program.
    • Highpass filtering branch, where the bolometer timelines are high-pass filtered to remove the 1/f noise, but at the expense of extended emission. It provides optimum sensitivity to point-sources
    • MADmap, a GLS (generalised least square) map-maker, that allows one to preserve extended emission at all scales. MADMap is not used anymore in the SPG processing, but it is still available as an interactive script.
    • Unimap, a light (memory-wise) GLS map-maker from Lorenzo Piazzo ('La Sapienza' University of Rome) under a free Matlab runtime environment, with advanced pre-processing (drift correction, jump detection) and post-processing stages (bright sources). The runUnimap task is used to invoke the Unimap Matlab routine on the users's computer.
    • JScanam, a Java-version of the IDL Scanamorphos map-maker, an IDL map-maker from Hélène Roussel (IAP) with an advanced and powerful destriper for PACS maps.
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  • Four fundamentally different map-makers are offered in HIPE 13 with interactive pipeline scripts, starting from Level 1. These map-makers are used in different ways to generate standard products ("SPG" product) provided by the Herschel Science Archive. High-pass filtering is applied to generate Level2 products, while Level2.5 products are generated by combining pairs of observations acquired in the scan plus cross-scan mode, using the Unimap, JScanam, and High-pass filtering mappers. Level3 products are mosaics of Unimap and Jscanam Level2.5 products that belong to the same sky field and to the same observing program.

    JScanam, Unimap and MadMap mappers all clean the dataset of systematic effects and remove the correlated 1/f noise while preserving the sky signal over large spatial scales. They are suited for analysing both point sources and extended emission.

    • Highpass filtering branch, where the bolometer timelines are high-pass filtered to remove the 1/f noise, but at the expense of extended emission. It provides optimum sensitivity for point-sources
    • JScanam, a Java-version of the IDL Scanamorphos map-maker, an IDL map-maker from Hélène Roussel (IAP), with an advanced and powerful destriper for PACS maps
    • Unimap, a light (memory-wise) GLS (generalised least square) map-maker from Lorenzo Piazzo ('La Sapienza' University of Rome) running under a free Matlab runtime environment, with advanced pre-processing (drift correction, jump detection) and post-processing stages (bright sources). The runUnimap task is used to invoke the Unimap Matlab routine on the users's computer
    • MADmap, a GLS (generalised least square) map-maker, a GLS map-maker that is not used anymore in the SPG processing, but it is still available as an interactive script
 
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  • If you are using data with SPG v 12 or reducing data with HIPE 12, remember that the optical field distortion in not applied at level 1. As a result, external map-makers starting from level 1 have a systematic flux overestimate of 6-7% in the red channel and a lower underestimate (~2%) in the blue channel of the flux scale.
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  • If you are using data with SPG v 12 or lower, or reducing data with HIPE 12 or lower, remember that the optical field distortion in not applied at level 1. As a result, external map-makers starting from level 1 have a systematic flux overestimate of 6-7% in the red channel and a lower underestimate (~2%) in the blue channel of the flux scale. From HIPE 13/SPG 13 onwards, this has been corrected.
 
 
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