Difference between revisions of "Map-making"
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Zodiacal Emission is removed from the 353, 545 and 857 GHz channels. It is described in <span style="color:red">the HFI DPC Paper</span>, but a synopsis of the procedure is as follows: | Zodiacal Emission is removed from the 353, 545 and 857 GHz channels. It is described in <span style="color:red">the HFI DPC Paper</span>, but a synopsis of the procedure is as follows: | ||
* During each survey, a large fraction of the sky has observations which all fall within a week of each other. That is, during a single survey, most pixels are observed during a short, well-defined period. The contribution from Zodiacal Emission to the total brightness seen, then, is well defined. | * During each survey, a large fraction of the sky has observations which all fall within a week of each other. That is, during a single survey, most pixels are observed during a short, well-defined period. The contribution from Zodiacal Emission to the total brightness seen, then, is well defined. | ||
| − | * We use the the COBE model of the Zodiacal Light to make predictions for this emission for those pixels observed over a span of one week or less. | + | * We use the the COBE model of the Zodiacal Light to make predictions for this Zodiacal emission for those pixels observed over a span of one week or less, and use GRASP models of the beams to predict the emission from the Galaxy given our sidelobes. |
| − | * We fit the survey difference maps with these model templates to estimate the emissivity of each component at the Planck wavelengths. | + | * We fit the survey difference maps with these model templates to estimate the emissivity of each Zodi component and sidelobe at the Planck wavelengths. |
| − | * We reconstruct the full mission using the combination of the COBE geometric model with the emissivities determined above. | + | * We reconstruct each ring of the the full mission using the combination of the COBE geometric model with the emissivities determined above and the sidelobe models. |
* We remove the reconstruction above from each ring of data. | * We remove the reconstruction above from each ring of data. | ||
| − | * We then make maps as described in section | + | * We then make maps as described in section elsewhere in this section. |
== Far Sidelobe Correction == | == Far Sidelobe Correction == | ||
Revision as of 12:04, 18 October 2012
Contents
Introduction[edit]
Flux calibration[edit]
Noise properties[edit]
Zodi correction[edit]
Zodiacal Emission is removed from the 353, 545 and 857 GHz channels. It is described in the HFI DPC Paper, but a synopsis of the procedure is as follows:
- During each survey, a large fraction of the sky has observations which all fall within a week of each other. That is, during a single survey, most pixels are observed during a short, well-defined period. The contribution from Zodiacal Emission to the total brightness seen, then, is well defined.
- We use the the COBE model of the Zodiacal Light to make predictions for this Zodiacal emission for those pixels observed over a span of one week or less, and use GRASP models of the beams to predict the emission from the Galaxy given our sidelobes.
- We fit the survey difference maps with these model templates to estimate the emissivity of each Zodi component and sidelobe at the Planck wavelengths.
- We reconstruct each ring of the the full mission using the combination of the COBE geometric model with the emissivities determined above and the sidelobe models.
- We remove the reconstruction above from each ring of data.
- We then make maps as described in section elsewhere in this section.
Far Sidelobe Correction[edit]
CO Correction[edit]
Map validation[edit]
[LFI meaning]: absolute calibration refers to the 0th order calibration for each channel, 1 single number, while the relative calibration refers to the component of the calibration that varies pointing period by pointing period.
(Planck) High Frequency Instrument
Data Processing Center
