Difference between revisions of "Sky temperature maps"

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<span style="color:Red">NOTE: Text in red to be removed when filling the contents</span>
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{{DISPLAYTITLE:2015 Sky temperature and polarization maps}}
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==Product description==
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==General description==
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<span style="color:Red">A general description of the product, including e.g. figures related to the contents (e.g. maps, tables), and some explanation of its scientific meaning. If there are scientific warnings about the use of the product (User’s caveats), they should also be given here, or at least references to other explanatory documents (papers etc).</span>
 
  
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Sky maps give the best estimate of the signal from the sky (unpolarised) after removal, as far as possible, of known systematic effects and of the dipole signals induced by the motion of the solar system in the CMB and of the Planck satellite in the solar system.  In particular, they include the Zodiacal light emission (Zodi for short) and also the scattering from the far-side lobes of the beams (FSL).  More on this below.
+
Sky maps give the best estimate of the intensity and polarization (Stokes Q and U components), if available, of the signal from the sky after removal, as far as possible, of known systematic effects (mostly instrumental, but including also the solar and earth-motion dipole, Galactic strylight and the Zodiacal light).  Sky maps are provided for the full Planck mission using all valid detectors in each frequency channel, and also for various subsets by splitting the mission in various time ranges or in subsets of the detectors in a given channel.  These products are useful for the study of source variability, but they are especially interesting for characterisation purposes (see also the [[HFI-Validation | data validation]] section).  The details of the start and end of the time ranges are given in the table below.
  
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Sky maps are provided for the nominal Planck mission and for the first two single surveys, the third one being covered only for a small part during the nominal mission (REF).  <span style="color:red">AMo: There is a table with table below that defines these coverage periods, but I believe that information should be in an earlier section that describes the mission and the events that interrupted it, the planet passages, the pointing, issues relating to timing, etc. That section should define a pointing period, and operational day, etc. There is some of that info in the HFI pre-processing section, but that may not be the best place for it.</span>For characterization purposes, are also provided maps covering the nominal survey but using only half of the available data.  These are the ''ringhalf_{1|2}'' maps, which are built using the first and second half of the stable pointing part of the data in each pointing period.
+
To help in further processing, there are also masks of the Galactic Plane and of point sources, each provided for several different depths.
  
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{| border="1" cellpadding="5" cellspacing="0" align="center" style="text-align:center"
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All sky maps are in Healpix format, with Nside of 1024 (LFI 30, 44 and 70) and 2048 (LFI 70 and HFI), in Galactic coordinates, and Nested ordering.
−
|+ '''Missions and sky survey coverage periods'''
+
 
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! width="80"| Name    !! Ini_OD  !! Ini_Ring !! Ini_ptgID  !!  End_OD !! End_ring !! End_ptgID
+
;WARNING: the Healpix convention for polarization is NOT the same as the IAU convention - see Section 8 in this page.
 +
 
 +
The signal is given in units of K<sub>cmb</sub> for 30-353 GHz, and of MJy/sr (for a constant <math>\nu F_\nu</math> energy distribution ) for 545 and 857 GHz.  For each frequency channel, the intensity and polarization maps are packaged into a ''BINTABLE'' extension of a FITS file together with a hit-count map (or hit map, for short, giving the number of observation samples that are cumulated in a pixel, all detectors combined) and with the variance and covariance maps. Additional information is given in the FITS file header.  The structure of the FITS file is given in the [[#FITS_file_structure | FITS file structure]] section below.
 +
 
 +
; R2.00 : this first release (Jan 2015) contains polarisation data for the 353 GHz channel only.
 +
; R2.01 : this second release (May 2015) adds polarisation data to the 100-217 GHz channels.
 +
; R2.02 : a full re-release to correct the Healpix bad pixel value in the maps which was altered during the preparation of the maps and not reset to the correct value (the valid pixels are unchanged). It also fixes some FITS keywords, and includes a full re-release of the Zodi correction maps, with the 100-217 GHz one now including the polarisation correction)
 +
 
 +
{| border="1" cellpadding="3" cellspacing="0" align="center" style="text-align:left" width=800px
 +
|+ '''Ranges for mission and surveys'''
 +
|- bgcolor="ffdead"  
 +
! Range || ODs || HFI rings || pointing-IDs || Comment
 +
|-
 +
|nominal mission || 91 - 563 || 240 - 14723 || 00004200 - 03180200 ||
 +
|-
 +
|full mission || 91 - 974 || 240 - 27005 || 00004200 - 05322620 || for HFI
 
|-
 
|-
−
! align="left" | Nominal 
+
|full mission || 91 - 1543 || n/a || 00004200 - 06511160 || for LFI
−
|   91   ||   240  ||   00004200   ||    563  ||  14724  || 03180200
 
 
|-
 
|-
−
! align="left" | HFI-Full
+
|Survey 1 || 91 - 270 || 240 - 5720 || 00004200 - 01059820 ||
−
|   91   ||   240   ||   00004200   ||    993  ||  27008  || 06344800
 
 
|-
 
|-
−
! align="left" | LFI-Full
+
|Survey 2 || 270 - 456 || 5721 - 11194 || 01059830 - 02114520 ||
−
|   91  ||   240  ||   00004200  ||  TBD  ||  TBD    ||   TBD
 
 
|-
 
|-
−
! align="left" | SCAN1   
+
|Survey 3 || 456 - 636 || 11195 - 16691 || 02114530 - 03193660 ||
−
|   91  ||   240  ||   00004200  ||   270  ||  5720  ||  01059820
 
 
|-
 
|-
−
! align="left" | SCAN2   
+
|Survey 4 || 636 - 807 || 16692 - 21720 || 03193670 - 04243900 ||
−
|   270  ||   5721  ||   01059830  ||   456  ||  11194  ||  02114520
 
 
|-
 
|-
−
! align="left" | SCAN3
+
|Survey 5 || 807 - 974 || 21721 - 27005 || 05267180 - 05322590 || end of mission for HFI
−
|   456  || 11195  ||   02114530  ||   636  ||  16691  ||  03193660
 
 
|-
 
|-
−
! align="left" | SCAN4 
+
|Survey 5 || 807 - 993 || n/a || 05267180 - 06344800 || end of survey for LFI
−
|   636  || 16692  ||  03193670  ||    807  || 21720  || 04243900
 
 
|-
 
|-
−
! align="left" | SCAN5   
+
|Survey 6 || 993 - 1177 || n/a || 06344810 - 06398120 || LFI only
−
|   807   || 21721  ||   95000020  ||   993  || 27008  || 06344800
+
|-
 +
|Survey 7 || 1177 - 1358 || n/a || 06398130 - 06456410 || LFI only
 +
|-
 +
|Survey 8 || 1358 - 1543 || n/a || 06456420 - 06511160 || LFI only
 +
|-
 +
|Survey 9 || 1543 - 1604 || n/a || 06511170 - 06533320 || LFI only Not in this delivery
 +
|-
 +
|HFI mission-half-1 || 91 - 531 || 240 - 13471 || 00004200 - 03155580 ||
 +
|-
 +
|HFI mission-half-2 || 531 - 974 || 13472 - 27005 || 03155590 - 05322590 ||
 +
|-
 +
|LFI Year 1 || 91 - 456 || n/a || 00004200 - 02114520 ||
 +
|-
 +
|LFI Year 2 || 456 - 807 || n/a || 02114530 - 04243900 ||
 +
|-
 +
|LFI Year 3 || 807 - 1177 || n/a || 05267180 - 06398120 ||
 +
|-
 +
|LFI Year 4 || 1177 - 1543 || n/a || 06398130 - 06511160 ||
 
|-
 
|-
−
! align="left" | SCAN6   
 
−
|  993  ||  ----  ||  06344810  ||    993  ||  ----  ||  TBD 
 
 
|}
 
|}
  
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All sky maps are in Healpix format, with Nside of 2048 for HFI and of  1024 for LFI, in Galactic coordinates, and Nested ordering. The signal is given in units of K<sub>cmb</sub> for 33-353 GHz, and of MJy/sr (for a constant $\nu F_\nu$ energy distribution ) for 545 and 857 GHz. Each sky map is packaged into a ''BINTABLE'' extension of a FITS file together with a hit-count map (or hit map, for short) and a variance map, and additional information is given in the FITS file header.  The structure of the FITS file is given in the [[#Format | FITS file structure]] section below.
+
==Production process==
 +
 
 +
Sky maps are produced by combining appropriately the data of all working detectors in a frequency channel over some period of the mission. They give the best estimate of the signal from the sky (unpolarised) after removal, as far as possible, of known systematic effects and of the dipole signals induced by the motion of the solar system in the CMB and of the Planck satellite in the solar system. In particular, they include the Zodiacal light emission (Zodi for short) and also the scattering from the far-side lobes of the beams (FSL). More on this below.
 +
 
 +
=== HFI processing ===
 +
 
 +
The mapmaking and calibration process is described in detail in the [[Map-making_LFI | Map-making]] section and in the {{PlanckPapers|planck2014-a09}} paper, where detailed references are found.  In brief it consists of:
 +
 
 +
; binning the TOI data onto ''rings'' : Healpix rings (HPRs) are used here, each ring containing the combined data of one pointing period.
 +
; flux calibration : at 100-353 GHz, the flux calibration factors are determined by correlating the signal with the orbital dipole, which is determined very accurately from the Planck satellite orbital parameters provided by Flight Dynamics.  This provides a single gain factor per bolometer.  At 545 and 857 GHz the gain is determined from the observation of Uranus and Neptune (but not Jupiter which is too bright) and comparison to recent models made explicitly for this mission.  A single gain is applied to all rings at these frequencies.
 +
; destriping : in order to remove low-frequency noise, an offset per ring is determined by minimizing the differences between HPRs at their crossings, and removed.
 +
; Zodiacal light correction : a Zodiacal light model is used to build HPRs of the the Zodi emission, which is subtracted from the calibrated HPRs.
 +
; projection onto the map : the offset-corrected, flux-calibrated, and Zodi-cleaned HPRs are projected onto Healpix maps, with the data of each bolometer weighted by a factor of 1/NET of that bolometer.
 +
 
 +
These steps are followed by some post-processing which is designed to prepare the maps for the component separation work.  This post processing consists of:
 +
 
 +
; Dust bandpass leakage correction : the Q and U maps are corrected for the intensity-to-polarisation leakage caused by the foregrounds having a non-CMB spectrum, and as a consequence of the non-identical bandpasses on the different detectors (bandpass mismatch, or BPM). This correction is determined using the ''ground'' method as described in Section 7.3 of {{PlanckPapers|planck2014-a09}}. These correction maps can be found in the Planck Legacy Archive as ''HFI_CorrMap_???-dustleak-ground_2048_R2.0?_{coverage}.fits''. The correction is applied by subtracting the correction map from the corresponding input map.  This correction is not applied to the nominal mission maps in order to maintain compatibility with the PR1 products.
 +
; Far Side Lobe calibration correction : the 100-217 maps are multiplied by factors of 1.00087, 1.00046, and 1.00043, respectively, to compensate for the non-removal of the far-side lobes, and similarly the corresponding covariance maps have also been corrected by multiplication by the square of the factor.
 +
; Fill missing pixels : missing pixels are filled in with a value that is the mean of valid pixels within a given radius.  A radius of 1 deg is used for the full channel maps, and 1.5 deg is used for the detset maps.  This step is not applied to the single survey maps since they have large swaths of the sky that are not covered.
 +
 
 +
; Map zero-level : for the  100 to 857 GHz maps, the zero levels are set to their optimal levels for Galactic and CIB studies.  A procedure for adjusting them to astrophysical values is given in the HFI Mapmaking and Calibration paper {{PlanckPapers|planck2014-a09}}.
  
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===Types of maps ===
+
These maps provide the main mission products.  Together with signal maps, hit count, variance, and variance maps are also produced. The hit maps give the (integer) number of valid TOI-level samples that contribute to the signal of each pixel. All valid samples are counted in the same way, i.e., there is no weighting factor applied.  The variance maps project the white noise estimate, provided by the NETs, in the sky domain.
−
==== Full channel maps ====
 
  
−
Full channel maps are built using all the valid detectors of a frequency channel and cover the full mission (or the nominal mission for the 1st release).  For HFI, the 143-8 and 545-3 bolometers are rejected entirely as they are seriously affected by RTS noise.
+
Note that the nominal mission maps have not had the post-processing applied, which makes them more easily comparable to the PR1 products.
  
−
==== Single survey maps ====
+
=== LFI processing ===
 +
LFI maps were constructed with the Madam map-making code, version 3.7.4. The code is based on generalized destriping technique, where the correlated noise component is modeled as a sequence of constant offset,  called baselines. A noise filter was used to constrain the baseline solution allowing the use of 0.25 s and 1 second baselines for the 30 and 44, 70 GHz respectively.
  
−
Single survey maps are built using all valid detectors of a frequency channel, but cover separately the different sky surveys. The single sky surveys are defined in terms of the direction of the satellite's spin axis:  the first survey covers from the beginning of the science observations (the First Light Survey) to the time when the spin axis has rotated by 180 degrees (to the nearest pointing period), the following ones covers from 180 to 360, and so on. In the case of the nominal mission, the process stops at the third survey, which is incomplete.  In the case of the full mission the 4th survey was interrupted shortly before completing the 180 degree rotation (see LINK), in order to begin observing with a different scanning law.  The HFI mission ended slightly before the natural end of the 5th survey, the LFI mission continued to the XXX survey. The coverage of each of these periods in terms of ring number, pointingID, and OD, is given in the table below. Note that the OD numbers are only to indicate during which OD the period boundary occurs.
+
Radiometers were combined according to the horn-uniform weighting scheme to minimize systematics. The used weights are listed in [[Map-making LFI#Map-making|Map-making]]. The flagged samples were excluded from the analysis by setting their weights to <math>C_{w}^{-1}</math> = 0. The galaxy region was masked out in the destriping phase, to reduce error arising from strong signal gradients. The polarization component was included in the analysis...  
  
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==== Half-ring maps ====
+
; Dipole and Far Side Lobe correction : input timelines are cleaned by 4pi convolved dipole and Galactic Straylight obtained as convolution of the 4pi in band far sidelobes and Galactic Simulation as explained in Section 7.4 of {{PlanckPapers|planck2014-a03||Planck-2015-A03}}.
  
−
Half-ring maps are built using only the first or the second half of the stable pointing period data.  There are thus two half-ring maps per frequency channel named ''ringhalf_1'' and ''ringhalf_2'' respectively. These maps are built for characterization purposes in order to perform null tests. In particular, the difference between the two half-ring maps at a given frequency give a good estimate of the high frequency noise in the data.
+
Beam effects on the LFI maps are described in Section 7.1 of {{PlanckPapers|planck2014-a03||Planck-2015-A03}}. Scaling of the maps due to beam effects is taken into account in the LFI's beam functions (as provided in the RIMO, give reference) which should be used for analysis of diffuse components. To compute the flux densities of compact sources, correction must be made for beam effects (see Table 8 of {{PlanckPapers|planck2014-a03||Planck-2015-A03}})."
  
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=== Caveats and known issues ===
+
; Bandpass leakage correction : '''as opposed to the HFI, the LFI high resolution maps have not been corrected for bandpass leakage. Only low resolution (nside 256) maps are provided with the bandpass correction'''. The correction maps (LFI_CorrMap_0??-BPassCorr_*.fits) can be found in the Planck Legacy Archive. Further details about the procedure used to generate the bandpass correction maps can be found in Section 11 of {{PlanckPapers|planck2014-a03}}.
−
==== Map zero-level ====
+
 
 +
; Map zero-level : for the 30, 44 and 70 GHz, maps are corrected for zero level monopole by applying an offset correction, see LFI Calibration paper {{PlanckPapers|planck2014-a06||Planck-2015-A06}}. Note that the offset applied is indicated in the header as a comment keyword.
 +
 
 +
A detailed description of the map-making procedure is given in {{PlanckPapers|planck2013-p02}}, {{PlanckPapers|planck2014-a03||Planck-2015-A03}}, {{PlanckPapers|planck2014-a07||Planck-2015-A07}} and in section [[Map-making LFI#Map-making|Map-making]].
 +
 
 +
==Types of maps ==
 +
 
 +
=== Full mission, full channel maps (6 HFI, 4 LFI)===
 +
 
 +
Full channel maps are built using all the valid detectors of a frequency channel and cover the either the full or the nominal mission.  For HFI, the 143-8 and 545-3 bolometers are rejected entirely as they are seriously affected by RTS noise.  HFI provides the Q and U components for the 100, 143, 217 and 353 GHz channels only. LFI provides the I, Q and U maps for all the channels. Reminder: HFI Q and U maps are corrected for bandpass leakage but LFI Q and U maps are not. The I, Q and U maps are displayed in the figures below. The color range is set using a histogram equalisation scheme (from HEALPIX) that is useful for these non-Gaussian data fields. For visualization purposes, the Q and U maps shown here have been smoothed with a 1 degree Gaussian kernel, otherwise they look like noise to the naked eye.
 +
The 70 GHz full map is available also at <math>N_{side}</math> 2048.
 +
 
 +
<center>
 +
<gallery style="padding:0 0 0 0;" perrow=3 widths=260px heights=160px>
 +
File: SkyMap30e.png| '''Full mission I, 30 GHz'''
 +
File: SkyMap44e.png | '''Full mission I, 44 GHz'''
 +
File: SkyMap70e.png | '''Full mission I, 70 GHz'''
 +
File: SkyMap100e.png | '''Full mission I, 100 GHz'''
 +
File: SkyMap143e.png | '''Full mission I, 143 GHz'''
 +
File: SkyMap217e.png | '''Full mission I, 217 GHz'''
 +
File: SkyMap353e.png | '''Full mission I, 353 GHz'''
 +
File: SkyMap545e.png | '''Full mission I, 545 GHz'''
 +
File: SkyMap857e.png | '''Full mission I, 857 GHz'''
 +
</gallery>
 +
</center>
 +
<br>
 +
<center>
 +
<gallery style="padding:0 0 0 0;" perrow=3 widths=260px heights=160px>
 +
File: LFI_SkyMap_030_1024_R2.01_full_Qb_sm1deg.png| '''Full mission Q, 30 GHz'''
 +
File: LFI_SkyMap_044_1024_R2.01_full_Qb_sm1deg.png | '''Full mission Q, 44 GHz'''
 +
File: LFI_SkyMap_070_1024_R2.01_full_Qb_sm1deg.png | '''Full mission Q, 70 GHz'''
 +
File: HFI_Skymap_100_full_bplcorrected_sm1deg_Qb.png | '''Full mission Q, 100 GHz'''
 +
File: HFI_Skymap_143_full_bplcorrected_sm1deg_Qb.png | '''Full mission Q, 143 GHz'''
 +
File: HFI_Skymap_217_full_bplcorrected_sm1deg_Qb.png | '''Full mission Q, 217 GHz'''
 +
File: HFI_Skymap_353_full_bplcorrected_sm1deg_Qb.png | '''Full mission Q, 353 GHz'''
 +
</gallery>
 +
</center>
 +
<br>
 +
<center>
 +
<gallery style="padding:0 0 0 0;" perrow=3 widths=260px heights=160px>
 +
File: LFI_SkyMap_030_1024_R2.01_full_Ub_sm1deg.png| '''Full mission U, 30 GHz'''
 +
File: LFI_SkyMap_044_1024_R2.01_full_Ub_sm1deg.png | '''Full mission U, 44 GHz'''
 +
File: LFI_SkyMap_070_1024_R2.01_full_Ub_sm1deg.png | '''Full mission U, 70 GHz'''
 +
File: HFI_Skymap_100_full_bplcorrected_sm1deg_Ub.png | '''Full mission U, 100 GHz'''
 +
File: HFI_Skymap_143_full_bplcorrected_sm1deg_Ub.png | '''Full mission U, 143 GHz'''
 +
File: HFI_Skymap_217_full_bplcorrected_sm1deg_Ub.png | '''Full mission U, 217 GHz'''
 +
File: HFI_Skymap_353_full_bplcorrected_sm1deg_Ub.png | '''Full mission U, 353 GHz'''
 +
</gallery>
 +
 
 +
</center>
 +
 
 +
 
 +
=== Nominal mission, full channel maps (6 HFI)===
 +
 
 +
These maps are similar to the ones above, but cover the nominal mission only.  They are meant primarily to be compared to the PR1 products in order to see the level of improvements in the processing.  Because of this, they are produced in Temperature only, and have not had the post-processing applied.
 +
 
 +
=== Single survey, full channel maps (30 HFI, 35 LFI)===
 +
 
 +
Single survey maps are built using all valid detectors of a frequency channel; they cover separately the different sky surveys.  The surveys are defined as the times over which the satellite spin axis rotates but 180 degrees, which, due to the position of the detectors in the focal plane does not cover the full sky, but a fraction between ~80 and 90% depending on detector position.  During adjacent surveys the sky is scanned in opposite directions. More precisely it is the ecliptic equator that is scanned in opposite directions.  While these are useful to investigate variable sources, they are also used to study the systematics of the time-response of the detectors as they scan bright sources, like the Galactic Plane, in different directions during different survey.  Note that the HFI and LFI missions cover 5 and 8 surveys, respectively, and in case of HFI the last survey in incomplete.
 +
The 70 GHz surveys maps are available also at <math>N_{side}</math> 2048.
 +
Note LFI provide a special surveys maps combination used in the low l analysis. This maps, available at the three LFI frequency 30, 44 and 70 GHz, was built using the combination of survey 1, 3, 5, 6, 7 and 8.
  
−
* not corrected for HFI; estimates are ??? determined from ????
+
=== Year maps, full channel maps (12 HFI, 16 LFI)===
−
* corrected for LFI (values?)
 
  
−
==== The Zodiacal light and the Far-Side Lobes ====
+
These maps are built using the data of surveys 1+2, surveys 3+4, and so forth.  They are used to study long-term systematic effects.
 +
The 70 GHz years maps are available also at <math>N_{side}</math> 2048.
  
−
<span style="color:red">Insert here how these are seen in the differences of the single survey maps </span>
+
===Half-mission maps, full channel maps (12 HFI, 12 LFI)===
  
−
==== Artifacts near caustics of the scanning strategy ====
+
For HFI, the half mission is defined after eliminating those rings discarded for all bolometers. There are 347 such rings, may of which are during the 5th survey when the ''End-of-Life'' tests were performed.  The remaining 26419 rings are divided in half (up to the odd ring) to define the two halves of the mission.  This exercise is done for the full mission only.
  
−
TBW if still an issue??
+
For LFI instead of the half-mission the following year combination has been created: Year 1+2, Year 1+3, Year 2+4, Year 3+4,
  
−
==Production process==
+
===Full mission, single detector maps (18 HFI, 22 LFI)===
−
<span style="color:Red">Description of the Pipeline used to generate the product. In particular any limitations and approximations used in the data processing should be listed. Avoiding detailed descriptions of methods and referring to other parts of the ES and/or the relevant Planck papers for the details. References however should be quite detailed (i.e. it is not enough to direct the user to a paper, but the relevant section in the paper should be provided).</span>
 
−
Sky maps are produced by combining appropriately the data of all working detectors in a frequency channel over some period of the mission. They give the best estimate of the signal from the sky (unpolarised) after removal, as far as possible, of known systematic effects and of the dipole signals induced by the motion of the solar system in the CMB and of the Planck satellite in the solar system.  In particular, they include the Zodiacal light emission (Zodi for short) and also the scattering from the far-side lobes of the beams (FSL).  More on this below.
 
−
=== HFI processing ===
 
  
−
The inputs to the mapmaking are TOIs of signal that have been cleaned (as far as possible) of instrumental effects and calibrated in absorbed watts. While the processing involved is described in detail in the [[TOI processing|TOI processing]] section, we give a very brief summary here for convenience. That pipeline performs the following operations:
+
IN case of HFI these maps are built only for the SWBs (non polarized) and contain only temperature data, of course. They are not built for the polarisation sensitive detectors because they are not fixed on the sky as the polarisation component depends on the position angle at the time of observation.  Instead, we provide maps built by ''quads'' of polarisation-sensitive detectors (see next section), which have different polarisation angles and that can be used to built I, Q, and U maps
  
−
; demodulation: this is performed around a variable level which is determined from the valid input data (a validity flag from a previous version of the processing is used for this purpose), and the data are converted to engineering units (V) using known conversion coefficients.
+
{| border="1" cellpadding="3" cellspacing="0" align="center" style="text-align:left" width=600px
−
; despiking: using the demodulated data converted to V (by the transfer function) the glitches are identified and fitted with templates.  A glitch flag is produced that identifies the strongest part of the glitches, and a timeline of glitch tails is produced from the template fits, and subtracted from the demodulated timeline from step 1.  Finally, the flagged ranges are replaced with data from an average over the pointing period (TBC)
+
|+ '''HFI Temperature sensitive bolometers'''
−
; dark template removal: the two dark bolometers are demodulated and despiked as above; the resulting timelines are then smoothed and used as an indicator of the overall temperature variations of the bolometer plate.  Where the variations are consistent with each other, they are combined and removed from the bolometer signal timelines using appropriate coupling coefficients.  The few percent of the data where they are not consistent are flagged on the timelines.
+
|- bgcolor="ffdead" 
−
; conversion to absorbed power: the timeline is converted to watts of absorbed power using the bolometer function.  This includes a non-linearity correction; removal of the 4K cooler lines: the electromagnetic interference of the 4K cooler with the bolometer readout wires induces some sharp lines in the signal power spectra at frequencies of the 4K cooler's fundamental and its multiples, folded by the signal modulations.  Fourier coefficients of the relevant lines are determined on a per-ring basis, and then removed from the data. The quality of the removal depends on the bolometer.
+
!Frequency || Detector names
−
<!-- at this point a timeline in W and a glitch flag are stored to disk. The final two steps are: -->
+
|-
−
; deconvolution by the time transfer function: this is done to correct for the non-instantaneous time response of the bolometers. The function itself is modeled using 4 parameters which are adjusted primarily on the planet data and also from comparisons of the  northward and southward scans of the Galactic Plane.  It is then removed using Fourier techniques, which has the side-effect of increasing the noise at high frequencies.
+
|143 GHz || 143-5, 6, 7
−
; jump correction: removes some (relatively rare: 0.3 jumps per bolometer per pointing period, on average) jumps in the signal baseline.  The jumps are detected characterized on smoothed TOIs, and corrected by adding a constant to part of the signal timeline. The origin of the jumps is not known.
+
|-
 +
|217 GHz || 217-1, 2, 3, 4
 +
|-
 +
|353 GHz || 353-1, 2, 7, 8
 +
|-
 +
|545 GHz || 545-1, 2, 4
 +
|-
 +
|857 GHz || 857-1, 2 , 3, 4
 +
|}
  
−
The results of this processing are a timeline of signal (in absorbed watts) and a ''valid data'' flag timeline for each of the 50 valid bolometers processed; these timelines contain the full sky signal, i.e., including the solar and orbital dipoles, the Zodiacal light, and contributions from the Far-Side lobes. The dipoles are necessary for the flux calibration and are removed at the mapmaking stage.  The remaining two bolometers (143-8 and 535-3) show semi-random jumps in the signal level, typically jumping over 2-5 different ''pseudo-baseline'' levels, a behavior known as ''Random Telegraphic Signal'', so that these are commonly called the RTS bolometers.  Finally, ring-level statistics of different types (mean, median, rms, kurtosis, etc.) are determined on a per-ring basis for all timelines, and a selection based on these statistics is used to discard anomalous rings, which are recorded in a ring-level flag for each valid bolometer timeline. 
+
The 143-8 and 353-3 bolometer data are affected by strong RTS (random telegraphic signal) noise.  They have not been used in the data processing, and are not delivered.  For a figure showing the focal plane layout, see [[Detector_pointing#Introduction_and_Summary | this Introduction]] of the Detector Pointing chapter.
  
−
Throughout this processing, bright planets (Mars, Jupiter, Saturn, Uranus) and bright asteroids are masked in the timeline in order to avoid ringing effects in the processing.  Since they move on the sky, the portion of the sky masked during one survey is observed during one, and no hole is left in the final map.  In parallel, the planet data are processed in a similar way, but with different parameters for the despiking step, and without the final jump correction step.  These results are processed separately to determine the beam shapes and the focal plane geometry.
+
In case of LFI, all the 22 Radiometers maps are available, those, obviously, are only in temperature.
  
 +
===Full mission, detector set or detector pairs maps (8 HFI, 8 LFI)===
  
−
The pointing is determined starting from the AHF produced by MOC, which gives the direction and orientation of the LOS of a fiducial position in the focal plane at frequencies of 8Hz during stable pointing and 4 Hz during maneuvers (TBC for details, reference). This is interpolated to the times of data observation (ref to method), corrected for the wobble and other time-dependent offsets determined from the observed positions of a large number of sources around the sky, and finally converted to the LOS of each detector using the quaternions in the IMO (which are determined from observations of bright planets - see the Focal plane reconstruction pipeline).  
+
The objective here is to build independent temperature (I) and polarisation (Q and U) maps with the two pairs of polarisation sensitive detectors of each channel where they are available, i.e. in the 44-353 GHz channels.  The table below indicates which detectors were used to built each detector set (detset).
  
  
−
The mapmaking pipeline is described in detail in the [[Map-making_LFI | Map-making]] section, and a brief summary is given here for convenience.
+
{| border="1" cellpadding="3" cellspacing="0" align="center" style="text-align:left" width=600px
 +
|+ '''Definition of HFI Detector Sets'''
 +
|- bgcolor="ffdead" 
 +
!Frequency || DetSet1 || DetSet2
 +
|-
 +
|100 GHz || 100-1a/b  & 100-4a/b || 100-2a/b & 100-3a/b
 +
|-
 +
|143 GHz || 143-1a/b 1 & 43-3a/b || 143-2a/b & 143-4a/b
 +
|-
 +
|217 GHz || 217-5a/b & 217-7a/b || 217-6a/b & 217-8a/b
 +
|-
 +
|353 GHz || 353-3a/b & 353-5a/b || 353-4a/b & 353-6a/b
 +
|}
  
−
The cleaned TOIs of signal of each detector, together with their flags, produced by the [[TOI processing|TOI processing]] pipeline, and the TOIs of pointing (quaternions), described in [[Pointing&Beams | Detectors pointing and beams]], are the inputs to the mapmaking step. 
+
{| border="1" cellpadding="3" cellspacing="0" align="center" style="text-align:left" width=600px
 +
|+ '''Definition of LFI Detector Pairs'''
 +
|- bgcolor="ffdead" 
 +
!Frequency || Horn Pair || Comment
 +
|-
 +
|44 GHz || 24 || This maps is only in temperature
 +
|-
 +
|44 GHz || 25  & 26 ||
 +
|-
 +
|70 GHz || 18 & 23 || Available also at <math>N_{side}</math> = 2048
 +
|-
 +
|70 GHz || 19 & 22 || Available also at <math>N_{side}</math> = 2048
 +
|-
 +
|70 GHz || 20 & 21 || Available also at <math>N_{side}</math> = 2048
 +
|}
  
−
The input signal TOIs are expressed in Watts from the sky absorbed by the bolometer, and their associated flags are used to samples or full rings to discard. Are discarded periods of unstable pointing and pointing maneuvers in general, glitched data, transits over bright planets (since they move, the ''hole'' flagged during one survey is covered during another sky survey), and some full rings are discarded if their noise properties differ significantly from the nominal value and the few rings of duration longer than 90 min, since the pointing is not sufficiently stable over such long periods (details in [[TOI_processing#Discarded_rings| Discarded rings]] section). The preparation of input pointing TOIs is described in [[Pointing&Beams | Detectors pointing and beams]].  In brief, the STR (StarTracker) pointing produced by Flight Dynamics is interpolated to the detector sampling frequency in order to obtain a tuple of pointing quaternions for each sample and corrected for certain known effects. The angular offset between the STR line of sight and that of each bolometer is reflected in the Focal Plane Geometry, which is determined from the observation of bright planets. Also, the STR pointing timeline is corrected for slowly varying offsets between the STR and the HFI focal plane using observations of all planets and of other (fixed) bright sources.
 
  
−
Using the pointing TOIs, the signal TOIs are first used to build Healpix rings using the nearest grid point method; each ring containing the combined data of one pointing period. These are then calibrated in brightness, cleaned of the dipole signals, and projected onto Healpix maps as explained in the following sections.
+
===Half-ring maps (64 HFI, 62 LFI)===
  
−
The cleaned TOIs must be calibrated in astrophysical units.  At 100-353 GHz, the flux calibration gains are determined for each pointing period (or ring) from the solar-motion dipole after removal of the small dipole induced by the motion of the Planck satellite in the solar system. The solar-motion dipole from WMAP (REF) is used for this purpose.  This gain by ring is then smoothed with a window of width 50 rings, which reveals an apparent variation of ~1-2% on a scale of 100s to 1000s of rings for the 100-217 GHz channels, and is applied to the Watt data.  At 353GHz, where the solar motion dipole is weaker compared to the signal, no gain variation is detected, and a single fixed gain is applied to all rings. At 545 and 857 GHz the gain is determined from the observation of Uranus and Neptune (Jupiter is not used because its brightness produced some non-linearity in the bolometer response) and comparison to recent models (REF) made explicitly for this mission.  A single gain is applied to all rings at these frequencies.
+
These maps are similar to the ones above, but are built using only the first or the second half of each ring (or pointing period).   The HFI provides half-ring maps for the full mission only, and for the full channel, the detsets, and the single bolometers. The LFI provides half-rings maps for the channel full mission (70 GHz also at <math>N_{side}</math> 2048), for the radiometer full mission and the horn pairs full mission.
−
Prior to projecting the Healpix rings (HPRs) onto a map, a destriping approach is used to remove low-frequency noise.  The noise is  modelled as the sum of a white noise component and a constant, or ''offset'', per pointing period which represents the low frequency 1/f noise. The offsets are determined by minimizing the differences between  HPRs at their crossings.  After subtracting these offsets, calibrated data are projected onto Healpix maps, with the data of each bolometer weighted by a factor of 1/NET of that bolometer, and accounting for the slight different band transmission profiles of the bolometers in each band.  
+
<!----
 +
===Masks===
  
−
These maps provide the main mission products.  A second, reduced, set of maps, cleaned of the Zodiacal emission of the FSL leakage is also produced for the nominal mission and the two single surveys, but not for the half-rings (since the contribution would be the same for the two halves of each ring).  For this purpose, the the Zodiacal emission and the FSL contamination, which are not fixed on the sky, are modeled separately at HPR-level, and subtracted from the signal HPR before projecting them onto the maps.  
+
Masks are provided of the Galactic Plane and of the point sources.  For the Galactic Plane, eight masks are given covering different fractions of the sky, and for the points sources two masks are given, at the 5 and 10 sigma level, for each Planck HFI and LFI frequency channel. These are generic masks, specific masks applicable to other products are delivered with the products themselves.
 +
--->
  
−
Together with signal maps, hit count and variance maps are also produced. The hit maps give the (integer) number of valid TOI-level samples that contribute to the signal of each pixel. All valid samples are counted in the same way, i.e., there is no weighting factor applied.  The variance maps project the white noise estimate, provided by the NETs, in the sky domain.
+
=== The Zodiacal light correction maps ===
  
−
=== LFI processing ===
+
The Zodiacal light signal depends on the location of the observer relative to the Zodiacal light bands, and thus it is not a fixed pattern on the sky but depends on the period of observation. The maps presented here are the difference between the uncorrected (and not delivered) and the corrected maps. 
 +
 
 +
Note that while the Zodiacal light model that is subtracted at ring level (see [[Map-making#Zodiacal_light_correction | here]]) is not polarised, the corrections are not null and Q and U.  This is suspected to come from some combination of leakage due to bandpass differences and beam mismatch, and maybe other effects. These leakages are typically of order a few %, at max, of the maximum zodi intensity at I for each channel. They range from ~150 nK at 100 GHz to ~5 uK at 353 GHz.
 +
 
 +
=== Caveats and known issues ===
  
−
LFI processing is covered in Sect. 4.5
+
; HFI polarization 100-217 GHz : at low multipoles, despite the progress that has been made to control the systematic effects present in the maps, polarization data between 100-217 GHz are still contaminated by systematic residuals. Figure 10 of {{PlanckPapers|planck2014-a09}} shows the EE power spectra from the half-difference maps at 100, 143, and 217 GHz and compared to the noise power spectrum from FFP8 simulations. he half-ring differences are compatible with noise while, at multipoles typically lower than 50, detector-set and half-mission differences are dominated by excess power which is larger than the EE CMB signal. The Planck Collaboration has used the range ell>30 to carry out component separation ({{PlanckPapers|planck2014-a11}}), as data at ell<30 is not considered usable for cosmological analyses. The origin of the excess power will be explored in a forthcoming publication.
 +
  
 
==Inputs==
 
==Inputs==
−
<span style="color:Red">A list (and brief description to the extent possible) of the input data used to generate this product (down to file names), as well as any external ancillary data sets which were used.</span>
+
=== HFI inputs ===
  
−
=== HFI inputs ===
+
The HFI mapmaking takes as input:
 +
* the cleaned TOIs of signal of each detector, together with their flags, produced by the [[TOI processing|TOI processing]] pipeline;
 +
* the TOIs of pointing (quaternions), described in [[Detector_pointing|Detector pointing]];
 +
* bolometer-level characterization data, from the DPC's internal IMO (not distributed);
 +
* Planck orbit data, used to compute and remove the Earth's dipole;
 +
* Planck solar dipole information, used to calibrate the CMB channels;
 +
* Planet models used to calibrate the Galactic channels.
  
 
=== LFI inputs ===
 
=== LFI inputs ===
 +
 +
The Madam mapmaker takes as input:
 +
 +
* the calibrated timelines (for details see [[TOI processing LFI|TOI Processing]]);
 +
* the detector pointings (for details see [[Detector_pointing|Detector pointing]]);
 +
* the noise information in the form of 3-parameter (white noise level, &sigma;, slope, and knee frequency, <i>f</i><sub>knee</sub>) noise model (for details see  [[The RIMO|RIMO]])
  
 
==Related products==
 
==Related products==
−
<span style="color:Red">A description of other products that are related and share some commonalities with the product being described here. E.g. if the description is of a generic product (e.g. frequency maps), all the products falling into that type should be listed and referenced.</span>
+
=== Masks ===
  
−
see section [[Map-making LFI#Inputs|Input test]].
+
This section presents the masks of the point sources and of the Galactic plane. These are ''general purpose'' masks.  Other masks specific to certain products are packaged with the products.
−
link to PLA example {{PLAMaps|type=TYPE|inst=LFI|freq=44|link=LFI 44 GHz frequency maps}}
 
  
−
{{PLAMaps|type=TYPE|inst=LFI|freq=044|link=LFI 44 GHz frequency maps}}
+
====Point source masks====
  
−
==Format==
+
For HFI and LFI two sets of masks are provided: 
−
<span style="color:Red">A detailed description of the data format of each file, including header keywords for fits files, extension names, column names, formats….</span>
+
* Intensity masks, which removes sources detected with SNR > 5.
−
===File names===
+
* Polarisation masks, which remove sources which have polarisation detection significance of 99.97 % or greater at the position of a source detected in intensity.  They were derived from the polarisation maps with dust ground bandpass mismatch leakage correction applied. The cut around each source has a radius of 3σ (width) of the beam ~ 1.27 FWHM (for LFI the cut around each source has a radius of 32 arcmin at 30GHz, 27 arcmin at 44 GHz and 13 arcmin at 70 GHz).
−
The FITS filenames are of the form ''{H|L}FI_SkyMap_fff_nnnn_R1.nn_{type}_{coverage}_{type}.fits'', where ''fff'' are three digits to indicate the Planck frequency band, and ''nnnn'' is the Healpix Nside of the map, ''coverage'' indicates which part of the mission is covered, and the optional ''type'' indicates the subset of input data used.  A full list of products, by their names, is given in the [[#List of products | List of products]] below.  
 
  
−
The list of products containing sky maps are given below, grouped by type
+
Both sets are found in the files ''HFI_Mask_PointSrc_2048_R2.00.fits'' and  ''LFI_Mask_PointSrc_2048_R2.00.fits'' in which the first extension contains the Intensity masks, and the second contains the Polarisation masks.
  
−
<span style="color:red">Outstanding: link to archive objects / LFI to fill in their products</span>
+
====Galactic plane masks====
  
−
; Full channel maps :
+
Eight masks are provided giving 20, 40, 60, 70, 80, 90, 97, and 99% sky coverage derived from the 353 GHz map, after CMB subtraction. They are independent of frequency channel. Three versions of these are given: not apodized, and apodized by 2 and 5 deg.  The filenames are ''HFI_Mask_GalPlane-apoN_2048_R2.00.fits'', where N = 0, 2, 5.
−
LFI maps ….
 
−
HFI_SkyMap_100_2048_R1.nn_nominal.fits
 
−
HFI_SkyMap_143_2048_R1.nn_nominal.fits
 
−
HFI_SkyMap_217_2048_R1.nn_nominal.fits
 
−
  HFI_SkyMap_353_2048_R1.nn_nominal.fits
 
−
HFI_SkyMap_545_2048_R1.nn_nominal.fits
 
−
HFI_SkyMap_857_2048_R1.nn_nominal.fits
 
  
−
; Single survey maps :
+
The masks are shows below. The 8 GalPlane masks are combined (added together) and shown in a single figure for each of the three apodization.  While the result is quite clear for the case of no apodization, it is less so for the apodized case.  The point source masks are shown separately for the Intensity case.
−
  LFI maps ….
+
 
−
  HFI_SkyMap_100_2048_R1.nn_survey_1.fits
+
<center>
−
  HFI_SkyMap_143_2048_R1.nn_survey_1.fits
+
<gallery perrow=3 widths=260px heights=160px >
−
  HFI_SkyMap_217_2048_R1.nn_survey_1.fits
+
File: GalPlaneMask_apo0.png |  '''Galactic Plane masks, no apod'''
−
HFI_SkyMap_353_2048_R1.nn_survey_1.fits
+
File: GalPlaneMask_apo2.png |  '''Galactic Plane masks, apod 2 deg'''
−
HFI_SkyMap_545_2048_R1.nn_survey_1.fits
+
File: GalPlaneMask_apo5.png |  '''Galactic Plane masks, apod 5 deg'''
−
HFI_SkyMap_857_2048_R1.nn_survey_1.fits
+
File: PointSrcMask_100.png | '''PointSource mask 100 GHz'''
−
HFI_SkyMap_100_2048_R1.nn_survey_2.fits
+
File: PointSrcMask_143.png  | '''PointSource mask 143 GHz'''
−
HFI_SkyMap_143_2048_R1.nn_survey_2.fits
+
File: PointSrcMask_217.png | '''PointSource mask 217 GHz'''
−
HFI_SkyMap_217_2048_R1.nn_survey_2.fits
+
File: PointSrcMask_353.png  | '''PointSource mask 343 GHz'''
−
HFI_SkyMap_353_2048_R1.nn_survey_2.fits
+
File: PointSrcMask_545.png  | '''PointSource mask 545 GHz'''
−
HFI_SkyMap_545_2048_R1.nn_survey_2.fits
+
File: PointSrcMask_857.png | '''PointSource mask 857 GHz'''
−
HFI_SkyMap_857_2048_R1.nn_survey_2.fits
+
</gallery>
 +
</center>
 +
 
 +
== File names ==
 +
The FITS filenames are of the form ''{H|L}FI_SkyMap_fff{-tag}_Nside_R2.nn_{coverage}-{type}.fits'', where ''fff'' are three digits to indicate the Planck frequency band, ''tag'' indicates the single detector or the detset,  ''Nside'' is the Healpix Nside of the map, ''coverage'' indicates which part of the mission is covered (full, half mission, survey, year, ...) , and the optional ''type'' indicates the subset of input data used.  The table below lists the products by type, with the appropriate unix wildcards that form the full filename.
 +
 
 +
{| class="wikitable" align="center" style="text-align"left" border="1" cellpadding="15" cellspacing="20"  width=880px
 +
|+ '''HFI FITS filenames'''
 +
|- bgcolor="ffdead"
 +
! Coverage  ||  filename  ||  half-ring filename
 +
|-
 +
| Full chan, full mission ||HFI_SkyMap_???_2048_R2.??_full.fits ||HFI_SkyMap_???_2048_R2.??_full-ringhalf-?.fits
 +
|-
 +
| Full channel, nominal mission ||HFI_SkyMap_???_2048_R2.??_nominal.fits || n/a
 +
|-
 +
| Full channel, single survey || HFI_SkyMap_???_2048_R2.??_survey-?.fits || n/a
 +
|-
 +
| Full channel, single year || HFI_SkyMap_???_2048_R2.??_year-?.fits || n/a
 +
|-
 +
| Full channel, half mission || HFI_SkyMap_???_2048_R2.??_halfmission*-?.fits || n/a
 +
|-
 +
| Det-set, full mission || HFI_SkyMap_???-ds?_2048_R2.??_full.fits || HFI_SkyMap_???-ds?_2048_R2.??_full-ringhalf-?.fits
 +
|-
 +
|Single SWB, full mission || HFI_SkyMap_???-?_2048_R2.??_full.fits || HFI_SkyMap_???-?_2048_R2.??_full-ringhalf-?.fits
 +
|}
  
 +
{| class="wikitable"  align="center" style="text-align"left" border="1" cellpadding="15" cellspacing="20"  width=1000px
 +
|+ '''LFI FITS filenames'''
 +
|- bgcolor="ffdead"
 +
! Coverage  ||  filename  ||  half-ring filename || Comment
 +
|-
 +
| Full channel, full mission ||LFI_SkyMap_???_1024_R2.??_full.fits ||LFI_SkyMap_???_1024_R2.??_full-ringhalf-?.fits || Available also at Nside = 2048
 +
|-
 +
| Full channel, single survey || LFI_SkyMap_???_1024_R2.??_survey-?.fits || n/a || Available also at Nside = 2048
 +
|-
 +
| Full channel, survey combination || LFI_SkyMap_???_1024_R2.??_survey-1-3-5-6-7-8.fits || n/a || n/a
 +
|-
 +
| Full channel, single year || LFI_SkyMap_???_1024_R2.??_year-?.fits  || n/a || Available also at Nside = 2048
 +
|-
 +
| Full channel, year combination || LFI_SkyMap_???_1024_R2.??_year?-?.fits || n/a || n/a
 +
|-
 +
| Horn pair, full mission || LFI_SkyMap_???-??-??_1024_R2.??_full.fits || LFI_SkyMap_???_??-??_1024_R2.??_full-ringhalf-?.fits || Available also at Nside = 2048
 +
|-
 +
| Single radiometer, full mission || LFI_SkyMap_???-???_1024_R2.??_full.fits || LFI_SkyMap_???-???_1024_R2.??_full-ringhalf-?.fits || n/a
 +
|}
  
−
; Half-ring maps :
 
−
LFI maps ….
 
−
HFI_SkyMap_100_2048_R1.nn_nominal_ringhalf_1.fits
 
−
HFI_SkyMap_143_2048_R1.nn_nominal_ringhalf_1.fits
 
−
HFI_SkyMap_217_2048_R1.nn_nominal_ringhalf_1.fits
 
−
HFI_SkyMap_353_2048_R1.nn_nominal_ringhalf_1.fits
 
−
HFI_SkyMap_545_2048_R1.nn_nominal_ringhalf_1.fits
 
−
HFI_SkyMap_857_2048_R1.nn_nominal_ringhalf_1.fits
 
−
HFI_SkyMap_100_2048_R1.nn_nominal_ringhalf_2.fits
 
−
HFI_SkyMap_143_2048_R1.nn_nominal_ringhalf_2.fits
 
−
HFI_SkyMap_217_2048_R1.nn_nominal_ringhalf_2.fits
 
−
HFI_SkyMap_353_2048_R1.nn_nominal_ringhalf_2.fits
 
−
HFI_SkyMap_545_2048_R1.nn_nominal_ringhalf_2.fits
 
−
HFI_SkyMap_857_2048_R1.nn_nominal_ringhalf_2.fits
 
  
−
; Zodi and Far-side-lobes corrected maps :
 
−
HFI_SkyMap_100_2048_R1.nn_nominal_ZodiCorrected.fits
 
−
HFI_SkyMap_143_2048_R1.nn_nominal_ZodiCorrected.fits
 
−
HFI_SkyMap_217_2048_R1.nn_nominal_ZodiCorrected.fits
 
−
HFI_SkyMap_353_2048_R1.nn_nominal_ZodiCorrected.fits
 
−
HFI_SkyMap_545_2048_R1.nn_nominal_ZodiCorrected.fits
 
−
HFI_SkyMap_857_2048_R1.nn_nominal_ZodiCorrected.fits
 
  
−
HFI_SkyMap_100_2048_R1.nn_survey_1_ZodiCorrected.fits
+
For the benefit of users who are only looking for the frequency maps with no additional information, we also provide a file combining the 9 frequency maps as separate columns in a single extension. The 9 columns in this file contain the intensity maps ONLY and no other information (hit maps and variance maps) is provided.
−
HFI_SkyMap_143_2048_R1.nn_survey_1_ZodiCorrected.fits
 
−
HFI_SkyMap_217_2048_R1.nn_survey_1_ZodiCorrected.fits
 
−
HFI_SkyMap_353_2048_R1.nn_survey_1_ZodiCorrected.fits
 
−
HFI_SkyMap_545_2048_R1.nn_survey_1_ZodiCorrected.fits
 
−
HFI_SkyMap_857_2048_R1.nn_survey_1_ZodiCorrected.fits
 
−
HFI_SkyMap_100_2048_R1.nn_survey_2_ZodiCorrected.fits
 
−
HFI_SkyMap_143_2048_R1.nn_survey_2_ZodiCorrected.fits
 
−
HFI_SkyMap_217_2048_R1.nn_survey_2_ZodiCorrected.fits
 
−
HFI_SkyMap_353_2048_R1.nn_survey_2_ZodiCorrected.fits
 
−
HFI_SkyMap_545_2048_R1.nn_survey_2_ZodiCorrected.fits
 
−
HFI_SkyMap_857_2048_R1.nn_survey_2_ZodiCorrected.fits
 
  
−
=== Detector-set maps ===
+
<!---
−
<span style="color:Red">NOT FOR 1st RELEASE … put detset table elsewhere ????</span>
+
{| class="wikitable"  align="center" style="text-align:center" border="1" cellpadding="3" cellspacing="0"  width=500px
 +
|+ '''FITS filenames'''
 +
|- bgcolor="ffdead"
 +
! Frequency || Full channel maps
 +
|-
 +
| '''30GHz''' || {{PLASingleFile|fileType=map|name=LFI_SkyMap_030_1024_R1.10_nominal.fits|link=LFI_SkyMap_030_1024_R1.10_nominal.fits}}
 +
|-
 +
| '''44GHz''' || {{PLASingleFile|fileType=map|name=LFI_SkyMap_044_1024_R1.10_nominal.fits|link=LFI_SkyMap_044_1024_R1.10_nominal.fits}}
 +
|-
 +
| '''70GHz''' || {{PLASingleFile|fileType=map|name=LFI_SkyMap_070_1024_R1.10_nominal.fits|link=LFI_SkyMap_070_1024_R1.10_nominal.fits}}
 +
|-
 +
| '''70GHz''' || {{PLASingleFile|fileType=map|name=LFI_SkyMap_070_2048_R1.10_nominal.fits|link=LFI_SkyMap_070_2048_R1.10_nominal.fits}}
 +
|-
 +
| '''100GHz''' ||  {{PLASingleFile|fileType=map|name=HFI_SkyMap_100_2048_R1.10_nominal.fits|link=HFI_SkyMap_100_2048_R1.10_nominal.fits}}
 +
|-
 +
| '''143GHz''' || {{PLASingleFile|fileType=map|name=HFI_SkyMap_143_2048_R1.10_nominal.fits|link=HFI_SkyMap_143_2048_R1.10_nominal.fits}}
 +
|-
 +
| '''217GHz''' ||  {{PLASingleFile|fileType=map|name=HFI_SkyMap_217_2048_R1.10_nominal.fits|link=HFI_SkyMap_217_2048_R1.10_nominal.fits}}
 +
|-
 +
| '''353GHz''' || {{PLASingleFile|fileType=map|name=HFI_SkyMap_353_2048_R1.10_nominal.fits|link=HFI_SkyMap_353_2048_R1.10_nominal.fits}}
 +
|-
 +
| '''545GHz''' || {{PLASingleFile|fileType=map|name=HFI_SkyMap_545_2048_R1.10_nominal.fits|link=HFI_SkyMap_545_2048_R1.10_nominal.fits}}
 +
|-
 +
| '''857GHz''' || {{PLASingleFile|fileType=map|name=HFI_SkyMap_857_2048_R1.10_nominal.fits|link=HFI_SkyMap_857_2048_R1.10_nominal.fits}}
 +
|- bgcolor="ffdead"
 +
! Frequency ||  Full channel, Zodi-corrected maps
 +
|-
 +
| '''100GHz''' ||  {{PLASingleFile|fileType=map|name=HFI_SkyMap_100_2048_R1.10_nominal_ZodiCorrected.fits|link=HFI_SkyMap_100_2048_R1.10_nominal_ZodiCorrected.fits}}
 +
|-
 +
| '''143GHz''' || {{PLASingleFile|fileType=map|name=HFI_SkyMap_143_2048_R1.10_nominal_ZodiCorrected.fits|link=HFI_SkyMap_143_2048_R1.10_nominal_ZodiCorrected.fits}}
 +
|-
 +
| '''217GHz''' ||  {{PLASingleFile|fileType=map|name=HFI_SkyMap_217_2048_R1.10_nominal_ZodiCorrected.fits|link=HFI_SkyMap_217_2048_R1.10_nominal_ZodiCorrected.fits}}
 +
|-
 +
| '''353GHz''' || {{PLASingleFile|fileType=map|name=HFI_SkyMap_353_2048_R1.10_nominal_ZodiCorrected.fits|link=HFI_SkyMap_353_2048_R1.10_nominal_ZodiCorrected.fits}}
 +
|-
 +
| '''545GHz''' || {{PLASingleFile|fileType=map|name=HFI_SkyMap_545_2048_R1.10_nominal_ZodiCorrected.fits|link=HFI_SkyMap_545_2048_R1.10_nominal_ZodiCorrected.fits}}
 +
|-
 +
| '''857GHz''' || {{PLASingleFile|fileType=map|name=HFI_SkyMap_857_2048_R1.10_nominal_ZodiCorrected.fits|link=HFI_SkyMap_857_2048_R1.10_nominal_ZodiCorrected.fits}}
 +
|- bgcolor="ffdead"
 +
! Frequency ||  Combined frequency maps
 +
|-
 +
| '''All''' ||  {{PLASingleFile|fileType=file|name=COM_MapSet_I-allFreqs_R1.10_nominal.fits|link=COM_MapSet_I-allFreqs_R1.10_nominal.fits}}
 +
|}
  
−
Detector-set (detset) maps are built for the full (or nominal) mission using a minimal set of detectors.  This concept is applicable to polarization maps, which are built using two PSB pairs at the proper orientations.  The HFI polarized channels are designed to provide two detsets (or quads) each, namely:
 
  
−
{| class="wikitable"  align="center" style="text-align:center" border="1" cellpadding="5" cellspacing="0"  
+
{| class="wikitable"  align="center" style="text-align:center" border="1" cellpadding="3" cellspacing="0" width=850px
−
|+ '''HFI detector sets or quads'''
+
|+ '''FITS filenames'''
−
| '''100–ds1:''' 100-1a,100-1b,100-4a,100-4b || '''100–ds2:''' 100-2a,100-2b,100-3a,100-3b
+
|- bgcolor="ffdead"
 +
! Frequency ||  Survey 1 maps || Survey 2 maps
 
|-
 
|-
−
| '''143–ds1:''' 143-1a,143-1b,143-3a,143-3b || '''143–ds2:''' 143-2a,143-2b,143-4a,143-4b
+
| '''30GHz''' || {{PLASingleFile|fileType=map|name=LFI_SkyMap_030_1024_R1.10_survey_1.fits|link=LFI_SkyMap_030_1024_R1.10_survey_1.fits}} ||
 +
{{PLASingleFile|fileType=map|name=LFI_SkyMap_030_1024_R1.10_survey_2.fits|link=LFI_SkyMap_030_1024_R1.10_survey_2.fits}}
 
|-
 
|-
−
| '''217–ds1:''' 217-5a,217-5b,217-7a,217-7b || '''217–ds2:''' 217-6a,217-6b,217-8a,217-8b
+
| '''44GHz''' || {{PLASingleFile|fileType=map|name=LFI_SkyMap_044_1024_R1.10_survey_1.fits|link=LFI_SkyMap_044_1024_R1.10_survey_1.fits}} ||
 +
{{PLASingleFile|fileType=map|name=LFI_SkyMap_044_1024_R1.10_survey_2.fits|link=LFI_SkyMap_044_1024_R1.10_survey_2.fits}}
 
|-
 
|-
−
| '''353–ds1:''' 353-5a,353-5b,353-3a,353-3b || '''353–ds2:''' 353-6a,353-6b,353-4a,353-4b
+
| '''70GHz''' || {{PLASingleFile|fileType=map|name=LFI_SkyMap_070_1024_R1.10_survey_1.fits|link=LFI_SkyMap_070_1024_R1.10_survey_1.fits}} ||
 +
{{PLASingleFile|fileType=map|name=LFI_SkyMap_070_1024_R1.10_survey_2.fits|link=LFI_SkyMap_070_1024_R1.10_survey_2.fits}}
 +
|-
 +
| '''70GHz''' || {{PLASingleFile|fileType=map|name=LFI_SkyMap_070_2048_R1.10_survey_1.fits|link=LFI_SkyMap_070_2048_R1.10_survey_1.fits}} ||
 +
{{PLASingleFile|fileType=map|name=LFI_SkyMap_070_2048_R1.10_survey_2.fits|link=LFI_SkyMap_070_2048_R1.10_survey_2.fits}}
 +
|-
 +
| '''100GHz''' || {{PLASingleFile|fileType=map|name=HFI_SkyMap_100_2048_R1.10_survey_1.fits|link=HFI_SkyMap_100_2048_R1.10_survey_1.fits}} ||
 +
{{PLASingleFile|fileType=map|name=HFI_SkyMap_100_2048_R1.10_survey_2.fits|link=HFI_SkyMap_100_2048_R1.10_survey_2.fits}}
 +
|-
 +
| '''143GHz''' || {{PLASingleFile|fileType=map|name=HFI_SkyMap_143_2048_R1.10_survey_1.fits|link=HFI_SkyMap_143_2048_R1.10_survey_1.fits}} ||
 +
{{PLASingleFile|fileType=map|name=HFI_SkyMap_143_2048_R1.10_survey_2.fits|link=HFI_SkyMap_143_2048_R1.10_survey_2.fits}}
 +
|-
 +
| '''217GHz''' || {{PLASingleFile|fileType=map|name=HFI_SkyMap_217_2048_R1.10_survey_1.fits|link=HFI_SkyMap_217_2048_R1.10_survey_1.fits}} ||
 +
{{PLASingleFile|fileType=map|name=HFI_SkyMap_217_2048_R1.10_survey_2.fits|link=HFI_SkyMap_217_2048_R1.10_survey_2.fits}}
 +
|-
 +
| '''353GHz''' || {{PLASingleFile|fileType=map|name=HFI_SkyMap_353_2048_R1.10_survey_1.fits|link=HFI_SkyMap_353_2048_R1.10_survey_1.fits}} ||
 +
{{PLASingleFile|fileType=map|name=HFI_SkyMap_353_2048_R1.10_survey_2.fits|link=HFI_SkyMap_353_2048_R1.10_survey_2.fits}}
 +
|-
 +
| '''545GHz''' || {{PLASingleFile|fileType=map|name=HFI_SkyMap_545_2048_R1.10_survey_1.fits|link=HFI_SkyMap_545_2048_R1.10_survey_1.fits}} ||
 +
{{PLASingleFile|fileType=map|name=HFI_SkyMap_545_2048_R1.10_survey_2.fits|link=HFI_SkyMap_545_2048_R1.10_survey_2.fits}}
 +
|-
 +
| '''857GHz''' || {{PLASingleFile|fileType=map|name=HFI_SkyMap_857_2048_R1.10_survey_1.fits|link=HFI_SkyMap_857_2048_R1.10_survey_1.fits}} ||
 +
{{PLASingleFile|fileType=map|name=HFI_SkyMap_857_2048_R1.10_survey_2.fits|link=HFI_SkyMap_857_2048_R1.10_survey_2.fits}}
 +
|- bgcolor="ffdead"
 +
! Frequency ||  Survey 1 Zodi-corrected maps || Survey 2 Zodi-corrected maps
 +
|-
 +
| '''100GHz''' || {{PLASingleFile|fileType=map|name=HFI_SkyMap_100_2048_R1.10_survey_1_ZodiCorrected.fits|link=HFI_SkyMap_100_2048_R1.10_survey_1_ZodiCorrected.fits}} ||
 +
{{PLASingleFile|fileType=map|name=HFI_SkyMap_100_2048_R1.10_survey_2_ZodiCorrected.fits|link=HFI_SkyMap_100_2048_R1.10_survey_2_ZodiCorrected.fits}}
 +
|-
 +
| '''143GHz''' || {{PLASingleFile|fileType=map|name=HFI_SkyMap_143_2048_R1.10_survey_1_ZodiCorrected.fits|link=HFI_SkyMap_143_2048_R1.10_survey_1_ZodiCorrected.fits}} ||
 +
{{PLASingleFile|fileType=map|name=HFI_SkyMap_143_2048_R1.10_survey_2_ZodiCorrected.fits|link=HFI_SkyMap_143_2048_R1.10_survey_2_ZodiCorrected.fits}}
 +
|-
 +
| '''217GHz''' || {{PLASingleFile|fileType=map|name=HFI_SkyMap_217_2048_R1.10_survey_1_ZodiCorrected.fits|link=HFI_SkyMap_217_2048_R1.10_survey_1_ZodiCorrected.fits}} ||
 +
{{PLASingleFile|fileType=map|name=HFI_SkyMap_217_2048_R1.10_survey_2_ZodiCorrected.fits|link=HFI_SkyMap_217_2048_R1.10_survey_2_ZodiCorrected.fits}}
 +
|-
 +
| '''353GHz''' || {{PLASingleFile|fileType=map|name=HFI_SkyMap_353_2048_R1.10_survey_1_ZodiCorrected.fits|link=HFI_SkyMap_353_2048_R1.10_survey_1_ZodiCorrected.fits}} ||
 +
{{PLASingleFile|fileType=map|name=HFI_SkyMap_353_2048_R1.10_survey_2_ZodiCorrected.fits|link=HFI_SkyMap_353_2048_R1.10_survey_2_ZodiCorrected.fits}}
 +
|-
 +
| '''545GHz''' || {{PLASingleFile|fileType=map|name=HFI_SkyMap_545_2048_R1.10_survey_1_ZodiCorrected.fits|link=HFI_SkyMap_545_2048_R1.10_survey_1_ZodiCorrected.fits}} ||
 +
{{PLASingleFile|fileType=map|name=HFI_SkyMap_545_2048_R1.10_survey_2_ZodiCorrected.fits|link=HFI_SkyMap_545_2048_R1.10_survey_2_ZodiCorrected.fits}}
 +
|-
 +
| '''857GHz''' || {{PLASingleFile|fileType=map|name=HFI_SkyMap_857_2048_R1.10_survey_1_ZodiCorrected.fits|link=HFI_SkyMap_857_2048_R1.10_survey_1_ZodiCorrected.fits}} ||
 +
{{PLASingleFile|fileType=map|name=HFI_SkyMap_857_2048_R1.10_survey_2_ZodiCorrected.fits|link=HFI_SkyMap_857_2048_R1.10_survey_2_ZodiCorrected.fits}}
 +
|- bgcolor="ffdead"
 +
! Frequency ||  Half-ring 1 maps ||Half-ring 2 maps
 +
|-
 +
| '''30GHz''' || {{PLASingleFile|fileType=map|name=LFI_SkyMap_030_1024_R1.10_nominal_ringhalf_1.fits|link=LFI_SkyMap_030_1024_R1.10_nominal_ringhalf_1.fits}} ||
 +
{{PLASingleFile|fileType=map|name=LFI_SkyMap_030_1024_R1.10_nominal_ringhalf_2.fits|link=LFI_SkyMap_030_1024_R1.10_nominal_ringhalf_2.fits}}
 +
|-
 +
| '''44GHz''' || {{PLASingleFile|fileType=map|name=LFI_SkyMap_044_1024_R1.10_nominal_ringhalf_1.fits|link=LFI_SkyMap_044_1024_R1.10_nominal_ringhalf_1.fits}} ||
 +
{{PLASingleFile|fileType=map|name=LFI_SkyMap_044_1024_R1.10_nominal_ringhalf_2.fits|link=LFI_SkyMap_044_1024_R1.10_nominal_ringhalf_2.fits}}
 +
|-
 +
| '''70GHz''' || {{PLASingleFile|fileType=map|name=LFI_SkyMap_070_1024_R1.10_nominal_ringhalf_1.fits|link=LFI_SkyMap_070_1024_R1.10_nominal_ringhalf_1.fits}} ||
 +
{{PLASingleFile|fileType=map|name=LFI_SkyMap_070_1024_R1.10_nominal_ringhalf_2.fits|link=LFI_SkyMap_070_1024_R1.10_nominal_ringhalf_2.fits}}
 +
|-
 +
| '''70GHz''' || {{PLASingleFile|fileType=map|name=LFI_SkyMap_070_2048_R1.10_nominal_ringhalf_1.fits|link=LFI_SkyMap_070_2048_R1.10_nominal_ringhalf_1.fits}} ||
 +
{{PLASingleFile|fileType=map|name=LFI_SkyMap_070_2048_R1.10_nominal_ringhalf_2.fits|link=LFI_SkyMap_070_2048_R1.10_nominal_ringhalf_2.fits}}
 +
|-
 +
| '''100GHz''' ||  {{PLASingleFile|fileType=map|name=HFI_SkyMap_100_2048_R1.10_nominal_ringhalf_1.fits|link=HFI_SkyMap_100_2048_R1.10_nominal_ringhalf_1.fits}} ||
 +
{{PLASingleFile|fileType=map|name=HFI_SkyMap_100_2048_R1.10_nominal_ringhalf_2.fits|link=HFI_SkyMap_100_2048_R1.10_nominal_ringhalf_2.fits}}
 +
|-
 +
| '''143GHz''' ||  {{PLASingleFile|fileType=map|name=HFI_SkyMap_143_2048_R1.10_nominal_ringhalf_1.fits|link=HFI_SkyMap_143_2048_R1.10_nominal_ringhalf_1.fits}} ||
 +
{{PLASingleFile|fileType=map|name=HFI_SkyMap_143_2048_R1.10_nominal_ringhalf_2.fits|link=HFI_SkyMap_143_2048_R1.10_nominal_ringhalf_2.fits}}
 +
|-
 +
| '''217GHz''' ||  {{PLASingleFile|fileType=map|name=HFI_SkyMap_217_2048_R1.10_nominal_ringhalf_1.fits|link=HFI_SkyMap_217_2048_R1.10_nominal_ringhalf_1.fits}} ||
 +
{{PLASingleFile|fileType=map|name=HFI_SkyMap_217_2048_R1.10_nominal_ringhalf_2.fits|link=HFI_SkyMap_217_2048_R1.10_nominal_ringhalf_2.fits}}
 +
|-
 +
| '''353GHz''' ||  {{PLASingleFile|fileType=map|name=HFI_SkyMap_353_2048_R1.10_nominal_ringhalf_1.fits|link=HFI_SkyMap_353_2048_R1.10_nominal_ringhalf_1.fits}} ||
 +
{{PLASingleFile|fileType=map|name=HFI_SkyMap_353_2048_R1.10_nominal_ringhalf_2.fits|link=HFI_SkyMap_353_2048_R1.10_nominal_ringhalf_2.fits}}
 +
|-
 +
| '''545GHz''' ||  {{PLASingleFile|fileType=map|name=HFI_SkyMap_545_2048_R1.10_nominal_ringhalf_1.fits|link=HFI_SkyMap_545_2048_R1.10_nominal_ringhalf_1.fits}} ||
 +
{{PLASingleFile|fileType=map|name=HFI_SkyMap_545_2048_R1.10_nominal_ringhalf_2.fits|link=HFI_SkyMap_545_2048_R1.10_nominal_ringhalf_2.fits}}
 +
|-
 +
| '''857GHz''' ||  {{PLASingleFile|fileType=map|name=HFI_SkyMap_857_2048_R1.10_nominal_ringhalf_1.fits|link=HFI_SkyMap_857_2048_R1.10_nominal_ringhalf_1.fits}} ||
 +
{{PLASingleFile|fileType=map|name=HFI_SkyMap_857_2048_R1.10_nominal_ringhalf_2.fits|link=HFI_SkyMap_857_2048_R1.10_nominal_ringhalf_2.fits}}
 
|}
 
|}
 +
--->
  
−
The LFI Detector-set maps are built using pairs of horns in the same scanning row, namely:
+
== FITS file structure ==
  
−
{| class="wikitable" align="center" style="text-align:center" border="1" cellpadding="5" cellspacing="0"  
+
The FITS files for the sky maps contain a minimal primary header with no data, and a ''BINTABLE'' extension (EXTENSION 1, EXTNAME = ''FREQ-MAP'') containing the data.  The structure is shows schematically in the figure below.  The ''FREQ-MAP'' extension contains a 3- or a 10-column table that contain the signal, hit-count and variance maps, all in Healpix format.  The 3-column case is for intensity only maps, the 10-column case is for polarisation. The number of rows is the number of map pixels, which is Npix = 12 <math>N_{side}</math><sup>2</sup> for Healpix maps, where <math>N_{side}</math> = 1024 or 2048 for most the maps presented in this chapter.
−
|+ '''LFI Couple Horn sets'''
+
 
−
| '''18_23:''' 18M,18S,23M,23S
+
[[File:FITS_FreqMap.png | 550px | center | thumb | '''FITS file structure''']]
 +
 
 +
Note that file sizes are ~0.6 GB for I-only maps and ~1.9 GB for I,Q,U maps at <math>N_{side}</math> 2048 and ~0.14 GB for I-only maps and ~0.45 GB for I,Q,U maps at <math>N_{side}</math> 1024 .
 +
 
 +
Keywords indicate the coordinate system (GALACTIC), the Healpix ordering scheme (NESTED), the units (K_cmb or MJy/sr) of each column, and of course the frequency channel (FREQ). Where polarisation Q and U maps are provided, the ''COSMO'' polarisation convention (used in HEALPIX) is adopted, and it is specified in the ''POLCCONV'' keyword (see [[Sky_temperature_maps#Polarization_convention_used_in_the_Planck_project|this section]]. The COMMENT fields give a one-line summary of the product, and some other information useful for traceability within the DPCs. The original filename is also given in the ''FILENAME'' keyword. The ''BAD_DATA'' keyword gives the value used by Healpix to indicate pixels for which no signal is present (these will also have a hit-count value of 0). The main parameters are summarised below:
 +
 
 +
 
 +
{| border="1" cellpadding="3" cellspacing="0" align="center" style="text-align:left" width=800px
 +
|+ '''Sky map file data structure'''
 +
|- bgcolor="ffdead" 
 +
!colspan="4" | 1. EXTNAME = 'FREQ-MAP' : Data columns
 +
|- bgcolor="ffdead" 
 +
! Column Name || Data Type || Units || Description
 
|-
 
|-
−
| '''19_22:''' 19M,19S,22M,22S
+
|I_STOKES || Real*4 || K_cmb or MJy/sr || The Stokes I map
 
|-
 
|-
−
| '''20_21:''' 20M,20S,21M,21S
+
|Q_STOKES || Real*4 || K_cmb or MJy/sr || The Stokes Q map (optional)
 
|-
 
|-
−
| '''24:''' 24M,24S
+
|U_STOKES || Real*4 || K_cmb or MJy/sr || The Stokes U map (optional)
 
|-
 
|-
−
| '''25_26:''' 25M,25S,26M,26S
+
|HITS || Int*4 || none || The hit-count map
 +
|-
 +
|II_COV || Real*4 || K_cmb<sup>2</sup> or (MJy/sr)<sup>2</sup> || The II variance map
 +
|-
 +
|IQ_COV || Real*4 || K_cmb<sup>2</sup> or (MJy/sr)<sup>2</sup> || The IQ variance map (optional)
 +
|-
 +
|IU_COV || Real*4 || K_cmb<sup>2</sup> or (MJy/sr)<sup>2</sup> || The IQ variance map (optional)
 +
|-
 +
|QQ_COV || Real*4 || K_cmb<sup>2</sup> or (MJy/sr)<sup>2</sup> || The QQ variance map (optional)
 +
|-
 +
|QU_COV || Real*4 || K_cmb<sup>2</sup> or (MJy/sr)<sup>2</sup> || The QU variance map (optional)
 +
|-
 +
|UU_COV || Real*4 || K_cmb<sup>2</sup> or (MJy/sr)<sup>2</sup> || The UU variance map (optional)
 +
|-
 +
|- bgcolor="ffdead" 
 +
! Keyword || Data Type || Value || Description
 +
|-
 +
|PIXTYPE ||  string || HEALPIX ||
 +
|-
 +
|COORDSYS ||  string || GALACTIC ||Coordinate system
 +
|-
 +
|ORDERING || string || NESTED  || Healpix ordering
 +
|-
 +
|POLCCONV || String || COSMO  || Polarization convention
 +
|-
 +
|NSIDE  ||  Int || 1024 or 2048 || Healpix <math>N_{side}</math>
 +
|-
 +
|FIRSTPIX ||  Int*4 ||                  0 || First pixel number
 +
|-
 +
|LASTPIX ||  Int*4 || 12 <math>N_{side}</math><sup>2</sup> – 1 || Last pixel number
 +
|-
 +
|FREQ ||    string ||                nnn || The frequency channel 
 
|}
 
|}
  
−
===Extensions===
 
−
[[File:FITS_FreqMap.png | 500px  | right | thumb | '''FITS file structure''']]
 
  
−
The FITS files for the sky maps contain a simple primary header with no data, and ''BINTABLE'' extension (EXTENSION 1, EXTNAME = 'FREQ-MAP') containing the data.   The structure is shows schematically in the figure at right.   The primary header has the form
+
The same structure applies to all ''SkyMap'' products, independent of whether they are full channel, survey of half-ring.  The distinction between the types of maps is present in the FITS filename (and in the traceability comment fields).
 +
 
 +
==Polarization convention used in the Planck project==
 +
 
 +
The Planck collaboration used the COSMO convention for the polarization angle (as usually used in space based CMB missions), whereas other astronomical fields usually use the IAU convention. In the following document we report the difference between these two conventions, and the consequence if it is NOT taken into account correctly in the analysis.
 +
 
 +
[[File:conventions.png|thumb|center|400px|'''Figure 1. COSMO convention (left) and IAU convention (right). The versor <math>\hat{z}</math> points outwards the pointing direction in COSMO, and inwards in IAU. The bottom panel refers to the plane tangent to the sphere.''']]
  
−
;-----------------------------------------------------------------------------
+
Changing the orientation convention is equivalent to a transformation <math>\psi'=\pi-\psi</math> of the polarization angle (Figure 1). The consequence of this transformation is the inversion of the Stokes parameter <math>U</math>.
−
; EXTENSION 0:
+
The components of the polarization tensor in the helicity basis <math>\epsilon^{\pm}=1/\sqrt{2}(\hat{x}\pm i\hat{y})</math> are:
−
; - Header
 
−
;-----------------------------------------------------------------------------
 
−
MRDFITS: Null image, NAXIS=0
 
−
SIMPLE  =                    T /Dummy Created by MWRFITS v1.11                 
 
−
BITPIX  =                    8 /Dummy primary header created by MWRFITS       
 
−
NAXIS  =                    0 /No data is associated with this header         
 
−
EXTEND  =                    T /Extensions may (will!) be present             
 
−
END 
 
−
The ''FREQ-MAP'' BINTABLE extension contains the data.  The table contains 3 columns of that contain the signal, variance, and hit-count maps in Healpix format.  the number of rows is 50331648 for HFI and 12582912 for LFI, corresponding to the number of pixels in a Healpix map of Nside= 2048 and 1024, respectively (N.B: Npix = 12 Nside^2).  The 3 columns are ''I_STOKES'' for the intensity (or temperature) signal, ''II_COV'' for the variance, and ''HIT'' for the hit-count.
 
−
The exact order of the columns in the figure is indicative only, and the details can be found in the keywords.  Keywords also indicate the coordinate system (GALACTIC), the Healpix ordering scheme (NESTED), the units (K_cmb or MJy/sr) of each column, and of course the frequency channel (FREQ). The COMMENT fields give a one-line summary of the product, and some other information useful for traceability within the DPCs. The original filename is also given in the ''FILENAME'' keyword as is the md5 checksum for the extension. The ''BAD_DATA'' keyword gives the value used by Healpix to indicate pixels for which no signal is present (these will also have a hit-count value of 0).                                                                         
 
−
===Keywords===
 
−
A typical header for the data extension of an intensity only map is:
 
  
−
;-----------------------------------------------------------------------------
+
<math>
−
; EXTENSION 1: FREQ-MAP
+
   (Q+iU)(\hat{n}) = \sum _{\ell m}a_{2,lm}{}_{2}Y_{\ell }^{m}(\hat{n})
−
; - Header
+
   \\(Q-iU)(\hat{n}) = \sum _{\ell m}a_{-2,lm}{}_{2}Y_{\ell }^{m}(\hat{n})
−
;-----------------------------------------------------------------------------
+
</math>
−
MRDFITS: Binary table.  3 columns by  1 rows.
 
−
XTENSION= 'BINTABLE'          /Written by IDL:  Thu Jan 31 11:03:21 2013     
 
−
BITPIX  =                    8 /                                               
 
−
NAXIS   =                   2 /Binary table                                   
 
−
NAXIS1  =            603979776 /Number of bytes per row                       
 
−
NAXIS2  =                    1 /Number of rows                                 
 
−
PCOUNT  =                    0 /Random parameter count                         
 
−
GCOUNT  =                    1 /Group count                                   
 
−
TFIELDS =                    3 /Number of columns                             
 
−
COMMENT                                                                       
 
−
COMMENT  *** End of mandatory fields ***                                       
 
−
COMMENT                                                                       
 
−
EXTVER  =                    1 /Extension version                             
 
−
DATE    = '2013-01-31'        /Creation date                                 
 
−
COMMENT                                                                       
 
−
COMMENT  *** Column names ***                                                 
 
−
COMMENT                                                                       
 
−
TTYPE1  = 'I_STOKES'          /                                               
 
−
TTYPE2  = 'HITS    '          /                                               
 
−
TTYPE3  = 'II_COV  '          /                                               
 
−
COMMENT                                                                       
 
−
COMMENT  *** Column formats ***                                               
 
−
COMMENT                                                                       
 
−
TFORM1  = '50331648E'          /                                               
 
−
TFORM2  = '50331648J'          /                                               
 
−
TFORM3  = '50331648E'          /                                               
 
−
COMMENT                                                                       
 
−
COMMENT  *** Column units ***                                                 
 
−
COMMENT                                                                       
 
−
TUNIT1  = 'K_CMB  '          /                                               
 
−
TUNIT2  = '        '          /                                               
 
−
TUNIT3  = 'K_CMB^2'          /                                               
 
−
COMMENT                                                                       
 
−
COMMENT  *** Planck params ***                                                 
 
−
COMMENT                                                                       
 
−
EXTNAME = 'FREQ-MAP'          / Extension name                               
 
−
COORSYS = 'GALACTIC'          / Coordinate system                             
 
−
ORDERING= 'NESTED  '          / Healpix ordering                             
 
−
NSIDE   =                2048 / Healpix Nside                                 
 
−
FIRSTPIX=                    0 / First pixel # (0 based)                      
 
−
LASTPIX =            50331647 / Last pixel # (0 based)                        
 
−
FILENAME= 'HFI_SkyMap_217_2048_R1.10_nominal_ZodiCorrected.fits' / FITS filename
 
−
CHECKSUM= '3aIB6Z993aGA3Y99'  / HDU checksum created 2013-01-31T10:03:22     
 
−
BAD_DATA=        -1.63750E+30 / bad pixel value                               
 
−
FREQ    = '217    '          / reference frequency                           
 
−
PROCVER = 'DX9_Delta'          / Product version                               
 
−
COMMENT                                                                       
 
−
COMMENT ------------------------------------------------------------------------
 
−
COMMENT Full channel sky map: nominal mission, corrected for Zodi & FSL       
 
−
COMMENT ------------------------------------------------------------------------
 
−
COMMENT Link to description in Planck Explanatory Supplement:                 
 
−
COMMENT http://www.sciops.esa.int/wikiSI/planckpla/index.php?title=           
 
−
COMMENT Frequency_Maps&instance=Planck_PLA_ES                                 
 
−
COMMENT ------------------------------------------------------------------------
 
−
COMMENT HFI-DMC objects:                                                       
 
−
COMMENT in-group: MAP_v53_noZodi_2048_GALACTIC_0240_27008/                     
 
−
COMMENT Creation date  - object name                                           
 
−
COMMENT 13-01-03 18:33 - 217GHz_W_TauDeconv_nominal_I                         
 
−
COMMENT 13-01-03 18:33 - 217GHz_W_TauDeconv_nominal_H                         
 
−
COMMENT 13-01-03 18:33 - 217GHz_W_TauDeconv_nominal_II                         
 
−
COMMENT ------------------------------------------------------------------------
 
−
END                                                                           
 
  
−
The same structure applies to all ''SkyMap'' products, independent of whether they are full channel, survey of half-ring.  The distinction between the types of maps is present in the FITS filename (and in the traceability comment fields). 
+
where  <math>{}_{2}Y_{\ell }^{m}(\hat{n})</math> are the spin weighted spherical harmonic functions.
 +
The <math>E</math> and <math>B</math> modes can be defined as:
 +
<math>
 +
  E(\hat{n}) = \sum_{\ell m}a_{E,\ell m}Y_{\ell }^{m}(\hat{n})
 +
  \\B(\hat{n}) = \sum_{\ell m}a_{B,\ell m}Y_{\ell }^{m}(\hat{n})
 +
</math>
  
−
===Numerical Format===
+
where the coefficients <math>a_{E,\ell m}</math> and <math>a_{B,\ell m}</math> are derived from linear combinations of the <math>a_{2,\ell m}</math> , <math>a_{-2,\ell m}</math> defined implicitly in the first equation (<math>Q\pm iU</math>).
  
−
<span style="color:Red">TBW</span>
+
[[File:test_gradient.jpg|thumb|center|400px|]]
 +
[[File:test_curl.jpg|thumb|center|400px|'''Figure 2. Error on Planck-LFI 70 GHz <math>EE</math> (top) and <math>BB</math> (bottom) spectra, in case of wrong choice of the coordinate system convention (IAU instead of COSMO).''']]
  
 +
The effect of the sign inversion of <math>U</math> on the polarization spectra is a non trivial mixing of <math>E</math> and <math>B</math> modes.
  
 +
An example of the typical error on <math>EE</math> and <math>BB</math> auto-spectra in case of a wrong choice of the polarization basis is shown in Figure 2.
  
−
---- '''A comment from E. Keihänen: '''
+
BE CAREFUL about the polarization convention you are using. If the IAU convention is used in computing the power spectra, the sign of the <math>U</math> component of the Planck maps must be inverted before computing <math>E</math> and <math>B</math> modes.
  
−
Here is a list of things that should go into this section:
+
=== Note on the convention used by the Planck Catalogue of Compact Sources (PCCS) ===
−
Insert a table of maps delivered:
+
For continuity with other compact sources catolgues, the Catalogue of Compact Sources provided by Planck follows the IAU convention, and the polarization angles are defined on an interval of [-90&deg;,90&deg;]. To switch to the COSMO convention, the polarization angles listed in the catalogue have to be shifted by 90&deg; and multiplied by -1.
−
*file name
 
−
*radiometers included
 
−
*PID/OD range
 
−
*resolution
 
−
*(-polarization included or not)
 
−
*sky coverage
 
−
*baseline length
 
−
*-reference to input toi objects)
 
−
Explain the format of the files, what is in what column, in what units.
 
−
Information common for all LFImaps:
 
−
*LFI maps were constructed with the Madam map-making code (version 3.7.4).
 
−
Maps are in Healpix format, in nested pixeling scheme, in K_cmb units, and in galactic coordinate system.
 
−
*Unobserved pixels are marked by the special value -1.6375e30.
 
  
−
EK's comment ends ------
+
== References ==
 +
<References />
  
  
  
  
−
[[Category:Mission science products]]
+
[[Category:Mission products|002]]

Latest revision as of 06:51, 27 May 2016

General description[edit]

Sky maps give the best estimate of the intensity and polarization (Stokes Q and U components), if available, of the signal from the sky after removal, as far as possible, of known systematic effects (mostly instrumental, but including also the solar and earth-motion dipole, Galactic strylight and the Zodiacal light). Sky maps are provided for the full Planck mission using all valid detectors in each frequency channel, and also for various subsets by splitting the mission in various time ranges or in subsets of the detectors in a given channel. These products are useful for the study of source variability, but they are especially interesting for characterisation purposes (see also the data validation section). The details of the start and end of the time ranges are given in the table below.

To help in further processing, there are also masks of the Galactic Plane and of point sources, each provided for several different depths.

All sky maps are in Healpix format, with Nside of 1024 (LFI 30, 44 and 70) and 2048 (LFI 70 and HFI), in Galactic coordinates, and Nested ordering.

WARNING
the Healpix convention for polarization is NOT the same as the IAU convention - see Section 8 in this page.

The signal is given in units of Kcmb for 30-353 GHz, and of MJy/sr (for a constant [math]\nu F_\nu[/math] energy distribution ) for 545 and 857 GHz. For each frequency channel, the intensity and polarization maps are packaged into a BINTABLE extension of a FITS file together with a hit-count map (or hit map, for short, giving the number of observation samples that are cumulated in a pixel, all detectors combined) and with the variance and covariance maps. Additional information is given in the FITS file header. The structure of the FITS file is given in the FITS file structure section below.

R2.00 
this first release (Jan 2015) contains polarisation data for the 353 GHz channel only.
R2.01 
this second release (May 2015) adds polarisation data to the 100-217 GHz channels.
R2.02 
a full re-release to correct the Healpix bad pixel value in the maps which was altered during the preparation of the maps and not reset to the correct value (the valid pixels are unchanged). It also fixes some FITS keywords, and includes a full re-release of the Zodi correction maps, with the 100-217 GHz one now including the polarisation correction)
Ranges for mission and surveys
Range ODs HFI rings pointing-IDs Comment
nominal mission 91 - 563 240 - 14723 00004200 - 03180200
full mission 91 - 974 240 - 27005 00004200 - 05322620 for HFI
full mission 91 - 1543 n/a 00004200 - 06511160 for LFI
Survey 1 91 - 270 240 - 5720 00004200 - 01059820
Survey 2 270 - 456 5721 - 11194 01059830 - 02114520
Survey 3 456 - 636 11195 - 16691 02114530 - 03193660
Survey 4 636 - 807 16692 - 21720 03193670 - 04243900
Survey 5 807 - 974 21721 - 27005 05267180 - 05322590 end of mission for HFI
Survey 5 807 - 993 n/a 05267180 - 06344800 end of survey for LFI
Survey 6 993 - 1177 n/a 06344810 - 06398120 LFI only
Survey 7 1177 - 1358 n/a 06398130 - 06456410 LFI only
Survey 8 1358 - 1543 n/a 06456420 - 06511160 LFI only
Survey 9 1543 - 1604 n/a 06511170 - 06533320 LFI only Not in this delivery
HFI mission-half-1 91 - 531 240 - 13471 00004200 - 03155580
HFI mission-half-2 531 - 974 13472 - 27005 03155590 - 05322590
LFI Year 1 91 - 456 n/a 00004200 - 02114520
LFI Year 2 456 - 807 n/a 02114530 - 04243900
LFI Year 3 807 - 1177 n/a 05267180 - 06398120
LFI Year 4 1177 - 1543 n/a 06398130 - 06511160

Production process[edit]

Sky maps are produced by combining appropriately the data of all working detectors in a frequency channel over some period of the mission. They give the best estimate of the signal from the sky (unpolarised) after removal, as far as possible, of known systematic effects and of the dipole signals induced by the motion of the solar system in the CMB and of the Planck satellite in the solar system. In particular, they include the Zodiacal light emission (Zodi for short) and also the scattering from the far-side lobes of the beams (FSL). More on this below.

HFI processing[edit]

The mapmaking and calibration process is described in detail in the Map-making section and in the Planck-2015-A08[1] paper, where detailed references are found. In brief it consists of:

binning the TOI data onto rings 
Healpix rings (HPRs) are used here, each ring containing the combined data of one pointing period.
flux calibration 
at 100-353 GHz, the flux calibration factors are determined by correlating the signal with the orbital dipole, which is determined very accurately from the Planck satellite orbital parameters provided by Flight Dynamics. This provides a single gain factor per bolometer. At 545 and 857 GHz the gain is determined from the observation of Uranus and Neptune (but not Jupiter which is too bright) and comparison to recent models made explicitly for this mission. A single gain is applied to all rings at these frequencies.
destriping 
in order to remove low-frequency noise, an offset per ring is determined by minimizing the differences between HPRs at their crossings, and removed.
Zodiacal light correction 
a Zodiacal light model is used to build HPRs of the the Zodi emission, which is subtracted from the calibrated HPRs.
projection onto the map 
the offset-corrected, flux-calibrated, and Zodi-cleaned HPRs are projected onto Healpix maps, with the data of each bolometer weighted by a factor of 1/NET of that bolometer.

These steps are followed by some post-processing which is designed to prepare the maps for the component separation work. This post processing consists of:

Dust bandpass leakage correction 
the Q and U maps are corrected for the intensity-to-polarisation leakage caused by the foregrounds having a non-CMB spectrum, and as a consequence of the non-identical bandpasses on the different detectors (bandpass mismatch, or BPM). This correction is determined using the ground method as described in Section 7.3 of Planck-2015-A08[1]. These correction maps can be found in the Planck Legacy Archive as HFI_CorrMap_???-dustleak-ground_2048_R2.0?_{coverage}.fits. The correction is applied by subtracting the correction map from the corresponding input map. This correction is not applied to the nominal mission maps in order to maintain compatibility with the PR1 products.
Far Side Lobe calibration correction 
the 100-217 maps are multiplied by factors of 1.00087, 1.00046, and 1.00043, respectively, to compensate for the non-removal of the far-side lobes, and similarly the corresponding covariance maps have also been corrected by multiplication by the square of the factor.
Fill missing pixels 
missing pixels are filled in with a value that is the mean of valid pixels within a given radius. A radius of 1 deg is used for the full channel maps, and 1.5 deg is used for the detset maps. This step is not applied to the single survey maps since they have large swaths of the sky that are not covered.
Map zero-level 
for the 100 to 857 GHz maps, the zero levels are set to their optimal levels for Galactic and CIB studies. A procedure for adjusting them to astrophysical values is given in the HFI Mapmaking and Calibration paper Planck-2015-A08[1].

These maps provide the main mission products. Together with signal maps, hit count, variance, and variance maps are also produced. The hit maps give the (integer) number of valid TOI-level samples that contribute to the signal of each pixel. All valid samples are counted in the same way, i.e., there is no weighting factor applied. The variance maps project the white noise estimate, provided by the NETs, in the sky domain.

Note that the nominal mission maps have not had the post-processing applied, which makes them more easily comparable to the PR1 products.

LFI processing[edit]

LFI maps were constructed with the Madam map-making code, version 3.7.4. The code is based on generalized destriping technique, where the correlated noise component is modeled as a sequence of constant offset, called baselines. A noise filter was used to constrain the baseline solution allowing the use of 0.25 s and 1 second baselines for the 30 and 44, 70 GHz respectively.

Radiometers were combined according to the horn-uniform weighting scheme to minimize systematics. The used weights are listed in Map-making. The flagged samples were excluded from the analysis by setting their weights to [math]C_{w}^{-1}[/math] = 0. The galaxy region was masked out in the destriping phase, to reduce error arising from strong signal gradients. The polarization component was included in the analysis...

Dipole and Far Side Lobe correction 
input timelines are cleaned by 4pi convolved dipole and Galactic Straylight obtained as convolution of the 4pi in band far sidelobes and Galactic Simulation as explained in Section 7.4 of Planck-2015-A03[2].

Beam effects on the LFI maps are described in Section 7.1 of Planck-2015-A03[2]. Scaling of the maps due to beam effects is taken into account in the LFI's beam functions (as provided in the RIMO, give reference) which should be used for analysis of diffuse components. To compute the flux densities of compact sources, correction must be made for beam effects (see Table 8 of Planck-2015-A03[2])."

Bandpass leakage correction 
as opposed to the HFI, the LFI high resolution maps have not been corrected for bandpass leakage. Only low resolution (nside 256) maps are provided with the bandpass correction. The correction maps (LFI_CorrMap_0??-BPassCorr_*.fits) can be found in the Planck Legacy Archive. Further details about the procedure used to generate the bandpass correction maps can be found in Section 11 of Planck-2015-A02[2].
Map zero-level 
for the 30, 44 and 70 GHz, maps are corrected for zero level monopole by applying an offset correction, see LFI Calibration paper Planck-2015-A06[3]. Note that the offset applied is indicated in the header as a comment keyword.

A detailed description of the map-making procedure is given in Planck-2013-II[4], Planck-2015-A03[2], Planck-2015-A07[5] and in section Map-making.

Types of maps[edit]

Full mission, full channel maps (6 HFI, 4 LFI)[edit]

Full channel maps are built using all the valid detectors of a frequency channel and cover the either the full or the nominal mission. For HFI, the 143-8 and 545-3 bolometers are rejected entirely as they are seriously affected by RTS noise. HFI provides the Q and U components for the 100, 143, 217 and 353 GHz channels only. LFI provides the I, Q and U maps for all the channels. Reminder: HFI Q and U maps are corrected for bandpass leakage but LFI Q and U maps are not. The I, Q and U maps are displayed in the figures below. The color range is set using a histogram equalisation scheme (from HEALPIX) that is useful for these non-Gaussian data fields. For visualization purposes, the Q and U maps shown here have been smoothed with a 1 degree Gaussian kernel, otherwise they look like noise to the naked eye. The 70 GHz full map is available also at [math]N_{side}[/math] 2048.

  • Full mission I, 30 GHz

  • Full mission I, 44 GHz

  • Full mission I, 70 GHz

  • Full mission I, 100 GHz

  • Full mission I, 143 GHz

  • Full mission I, 217 GHz

  • Full mission I, 353 GHz

  • Full mission I, 545 GHz

  • Full mission I, 857 GHz


  • Full mission Q, 30 GHz

  • Full mission Q, 44 GHz

  • Full mission Q, 70 GHz

  • Full mission Q, 100 GHz

  • Full mission Q, 143 GHz

  • Full mission Q, 217 GHz

  • Full mission Q, 353 GHz


  • Full mission U, 30 GHz

  • Full mission U, 44 GHz

  • Full mission U, 70 GHz

  • Full mission U, 100 GHz

  • Full mission U, 143 GHz

  • Full mission U, 217 GHz

  • Full mission U, 353 GHz


Nominal mission, full channel maps (6 HFI)[edit]

These maps are similar to the ones above, but cover the nominal mission only. They are meant primarily to be compared to the PR1 products in order to see the level of improvements in the processing. Because of this, they are produced in Temperature only, and have not had the post-processing applied.

Single survey, full channel maps (30 HFI, 35 LFI)[edit]

Single survey maps are built using all valid detectors of a frequency channel; they cover separately the different sky surveys. The surveys are defined as the times over which the satellite spin axis rotates but 180 degrees, which, due to the position of the detectors in the focal plane does not cover the full sky, but a fraction between ~80 and 90% depending on detector position. During adjacent surveys the sky is scanned in opposite directions. More precisely it is the ecliptic equator that is scanned in opposite directions. While these are useful to investigate variable sources, they are also used to study the systematics of the time-response of the detectors as they scan bright sources, like the Galactic Plane, in different directions during different survey. Note that the HFI and LFI missions cover 5 and 8 surveys, respectively, and in case of HFI the last survey in incomplete. The 70 GHz surveys maps are available also at [math]N_{side}[/math] 2048. Note LFI provide a special surveys maps combination used in the low l analysis. This maps, available at the three LFI frequency 30, 44 and 70 GHz, was built using the combination of survey 1, 3, 5, 6, 7 and 8.

Year maps, full channel maps (12 HFI, 16 LFI)[edit]

These maps are built using the data of surveys 1+2, surveys 3+4, and so forth. They are used to study long-term systematic effects. The 70 GHz years maps are available also at [math]N_{side}[/math] 2048.

Half-mission maps, full channel maps (12 HFI, 12 LFI)[edit]

For HFI, the half mission is defined after eliminating those rings discarded for all bolometers. There are 347 such rings, may of which are during the 5th survey when the End-of-Life tests were performed. The remaining 26419 rings are divided in half (up to the odd ring) to define the two halves of the mission. This exercise is done for the full mission only.

For LFI instead of the half-mission the following year combination has been created: Year 1+2, Year 1+3, Year 2+4, Year 3+4,

Full mission, single detector maps (18 HFI, 22 LFI)[edit]

IN case of HFI these maps are built only for the SWBs (non polarized) and contain only temperature data, of course. They are not built for the polarisation sensitive detectors because they are not fixed on the sky as the polarisation component depends on the position angle at the time of observation. Instead, we provide maps built by quads of polarisation-sensitive detectors (see next section), which have different polarisation angles and that can be used to built I, Q, and U maps

HFI Temperature sensitive bolometers
Frequency Detector names
143 GHz 143-5, 6, 7
217 GHz 217-1, 2, 3, 4
353 GHz 353-1, 2, 7, 8
545 GHz 545-1, 2, 4
857 GHz 857-1, 2 , 3, 4

The 143-8 and 353-3 bolometer data are affected by strong RTS (random telegraphic signal) noise. They have not been used in the data processing, and are not delivered. For a figure showing the focal plane layout, see this Introduction of the Detector Pointing chapter.

In case of LFI, all the 22 Radiometers maps are available, those, obviously, are only in temperature.

Full mission, detector set or detector pairs maps (8 HFI, 8 LFI)[edit]

The objective here is to build independent temperature (I) and polarisation (Q and U) maps with the two pairs of polarisation sensitive detectors of each channel where they are available, i.e. in the 44-353 GHz channels. The table below indicates which detectors were used to built each detector set (detset).


Definition of HFI Detector Sets
Frequency DetSet1 DetSet2
100 GHz 100-1a/b & 100-4a/b 100-2a/b & 100-3a/b
143 GHz 143-1a/b 1 & 43-3a/b 143-2a/b & 143-4a/b
217 GHz 217-5a/b & 217-7a/b 217-6a/b & 217-8a/b
353 GHz 353-3a/b & 353-5a/b 353-4a/b & 353-6a/b
Definition of LFI Detector Pairs
Frequency Horn Pair Comment
44 GHz 24 This maps is only in temperature
44 GHz 25 & 26
70 GHz 18 & 23 Available also at [math]N_{side}[/math] = 2048
70 GHz 19 & 22 Available also at [math]N_{side}[/math] = 2048
70 GHz 20 & 21 Available also at [math]N_{side}[/math] = 2048


Half-ring maps (64 HFI, 62 LFI)[edit]

These maps are similar to the ones above, but are built using only the first or the second half of each ring (or pointing period). The HFI provides half-ring maps for the full mission only, and for the full channel, the detsets, and the single bolometers. The LFI provides half-rings maps for the channel full mission (70 GHz also at [math]N_{side}[/math] 2048), for the radiometer full mission and the horn pairs full mission.

The Zodiacal light correction maps[edit]

The Zodiacal light signal depends on the location of the observer relative to the Zodiacal light bands, and thus it is not a fixed pattern on the sky but depends on the period of observation. The maps presented here are the difference between the uncorrected (and not delivered) and the corrected maps.

Note that while the Zodiacal light model that is subtracted at ring level (see here) is not polarised, the corrections are not null and Q and U. This is suspected to come from some combination of leakage due to bandpass differences and beam mismatch, and maybe other effects. These leakages are typically of order a few %, at max, of the maximum zodi intensity at I for each channel. They range from ~150 nK at 100 GHz to ~5 uK at 353 GHz.

Caveats and known issues[edit]

HFI polarization 100-217 GHz 
at low multipoles, despite the progress that has been made to control the systematic effects present in the maps, polarization data between 100-217 GHz are still contaminated by systematic residuals. Figure 10 of Planck-2015-A08[1] shows the EE power spectra from the half-difference maps at 100, 143, and 217 GHz and compared to the noise power spectrum from FFP8 simulations. he half-ring differences are compatible with noise while, at multipoles typically lower than 50, detector-set and half-mission differences are dominated by excess power which is larger than the EE CMB signal. The Planck Collaboration has used the range ell>30 to carry out component separation (Planck-2015-A09[6]), as data at ell<30 is not considered usable for cosmological analyses. The origin of the excess power will be explored in a forthcoming publication.


Inputs[edit]

HFI inputs[edit]

The HFI mapmaking takes as input:

  • the cleaned TOIs of signal of each detector, together with their flags, produced by the TOI processing pipeline;
  • the TOIs of pointing (quaternions), described in Detector pointing;
  • bolometer-level characterization data, from the DPC's internal IMO (not distributed);
  • Planck orbit data, used to compute and remove the Earth's dipole;
  • Planck solar dipole information, used to calibrate the CMB channels;
  • Planet models used to calibrate the Galactic channels.

LFI inputs[edit]

The Madam mapmaker takes as input:

  • the calibrated timelines (for details see TOI Processing);
  • the detector pointings (for details see Detector pointing);
  • the noise information in the form of 3-parameter (white noise level, σ, slope, and knee frequency, fknee) noise model (for details see RIMO)

Related products[edit]

Masks[edit]

This section presents the masks of the point sources and of the Galactic plane. These are general purpose masks. Other masks specific to certain products are packaged with the products.

Point source masks[edit]

For HFI and LFI two sets of masks are provided:

  • Intensity masks, which removes sources detected with SNR > 5.
  • Polarisation masks, which remove sources which have polarisation detection significance of 99.97 % or greater at the position of a source detected in intensity. They were derived from the polarisation maps with dust ground bandpass mismatch leakage correction applied. The cut around each source has a radius of 3σ (width) of the beam ~ 1.27 FWHM (for LFI the cut around each source has a radius of 32 arcmin at 30GHz, 27 arcmin at 44 GHz and 13 arcmin at 70 GHz).

Both sets are found in the files HFI_Mask_PointSrc_2048_R2.00.fits and LFI_Mask_PointSrc_2048_R2.00.fits in which the first extension contains the Intensity masks, and the second contains the Polarisation masks.

Galactic plane masks[edit]

Eight masks are provided giving 20, 40, 60, 70, 80, 90, 97, and 99% sky coverage derived from the 353 GHz map, after CMB subtraction. They are independent of frequency channel. Three versions of these are given: not apodized, and apodized by 2 and 5 deg. The filenames are HFI_Mask_GalPlane-apoN_2048_R2.00.fits, where N = 0, 2, 5.

The masks are shows below. The 8 GalPlane masks are combined (added together) and shown in a single figure for each of the three apodization. While the result is quite clear for the case of no apodization, it is less so for the apodized case. The point source masks are shown separately for the Intensity case.

  • Galactic Plane masks, no apod

  • Galactic Plane masks, apod 2 deg

  • Galactic Plane masks, apod 5 deg

  • PointSource mask 100 GHz

  • PointSource mask 143 GHz

  • PointSource mask 217 GHz

  • PointSource mask 343 GHz

  • PointSource mask 545 GHz

  • PointSource mask 857 GHz

File names[edit]

The FITS filenames are of the form {H|L}FI_SkyMap_fff{-tag}_Nside_R2.nn_{coverage}-{type}.fits, where fff are three digits to indicate the Planck frequency band, tag indicates the single detector or the detset, Nside is the Healpix Nside of the map, coverage indicates which part of the mission is covered (full, half mission, survey, year, ...) , and the optional type indicates the subset of input data used. The table below lists the products by type, with the appropriate unix wildcards that form the full filename.

HFI FITS filenames
Coverage filename half-ring filename
Full chan, full mission HFI_SkyMap_???_2048_R2.??_full.fits HFI_SkyMap_???_2048_R2.??_full-ringhalf-?.fits
Full channel, nominal mission HFI_SkyMap_???_2048_R2.??_nominal.fits n/a
Full channel, single survey HFI_SkyMap_???_2048_R2.??_survey-?.fits n/a
Full channel, single year HFI_SkyMap_???_2048_R2.??_year-?.fits n/a
Full channel, half mission HFI_SkyMap_???_2048_R2.??_halfmission*-?.fits n/a
Det-set, full mission HFI_SkyMap_???-ds?_2048_R2.??_full.fits HFI_SkyMap_???-ds?_2048_R2.??_full-ringhalf-?.fits
Single SWB, full mission HFI_SkyMap_???-?_2048_R2.??_full.fits HFI_SkyMap_???-?_2048_R2.??_full-ringhalf-?.fits
LFI FITS filenames
Coverage filename half-ring filename Comment
Full channel, full mission LFI_SkyMap_???_1024_R2.??_full.fits LFI_SkyMap_???_1024_R2.??_full-ringhalf-?.fits Available also at Nside = 2048
Full channel, single survey LFI_SkyMap_???_1024_R2.??_survey-?.fits n/a Available also at Nside = 2048
Full channel, survey combination LFI_SkyMap_???_1024_R2.??_survey-1-3-5-6-7-8.fits n/a n/a
Full channel, single year LFI_SkyMap_???_1024_R2.??_year-?.fits n/a Available also at Nside = 2048
Full channel, year combination LFI_SkyMap_???_1024_R2.??_year?-?.fits n/a n/a
Horn pair, full mission LFI_SkyMap_???-??-??_1024_R2.??_full.fits LFI_SkyMap_???_??-??_1024_R2.??_full-ringhalf-?.fits Available also at Nside = 2048
Single radiometer, full mission LFI_SkyMap_???-???_1024_R2.??_full.fits LFI_SkyMap_???-???_1024_R2.??_full-ringhalf-?.fits n/a


For the benefit of users who are only looking for the frequency maps with no additional information, we also provide a file combining the 9 frequency maps as separate columns in a single extension. The 9 columns in this file contain the intensity maps ONLY and no other information (hit maps and variance maps) is provided.


FITS file structure[edit]

The FITS files for the sky maps contain a minimal primary header with no data, and a BINTABLE extension (EXTENSION 1, EXTNAME = FREQ-MAP) containing the data. The structure is shows schematically in the figure below. The FREQ-MAP extension contains a 3- or a 10-column table that contain the signal, hit-count and variance maps, all in Healpix format. The 3-column case is for intensity only maps, the 10-column case is for polarisation. The number of rows is the number of map pixels, which is Npix = 12 [math]N_{side}[/math]2 for Healpix maps, where [math]N_{side}[/math] = 1024 or 2048 for most the maps presented in this chapter.

FITS file structure

Note that file sizes are ~0.6 GB for I-only maps and ~1.9 GB for I,Q,U maps at [math]N_{side}[/math] 2048 and ~0.14 GB for I-only maps and ~0.45 GB for I,Q,U maps at [math]N_{side}[/math] 1024 .

Keywords indicate the coordinate system (GALACTIC), the Healpix ordering scheme (NESTED), the units (K_cmb or MJy/sr) of each column, and of course the frequency channel (FREQ). Where polarisation Q and U maps are provided, the COSMO polarisation convention (used in HEALPIX) is adopted, and it is specified in the POLCCONV keyword (see this section. The COMMENT fields give a one-line summary of the product, and some other information useful for traceability within the DPCs. The original filename is also given in the FILENAME keyword. The BAD_DATA keyword gives the value used by Healpix to indicate pixels for which no signal is present (these will also have a hit-count value of 0). The main parameters are summarised below:


Sky map file data structure
1. EXTNAME = 'FREQ-MAP' : Data columns
Column Name Data Type Units Description
I_STOKES Real*4 K_cmb or MJy/sr The Stokes I map
Q_STOKES Real*4 K_cmb or MJy/sr The Stokes Q map (optional)
U_STOKES Real*4 K_cmb or MJy/sr The Stokes U map (optional)
HITS Int*4 none The hit-count map
II_COV Real*4 K_cmb2 or (MJy/sr)2 The II variance map
IQ_COV Real*4 K_cmb2 or (MJy/sr)2 The IQ variance map (optional)
IU_COV Real*4 K_cmb2 or (MJy/sr)2 The IQ variance map (optional)
QQ_COV Real*4 K_cmb2 or (MJy/sr)2 The QQ variance map (optional)
QU_COV Real*4 K_cmb2 or (MJy/sr)2 The QU variance map (optional)
UU_COV Real*4 K_cmb2 or (MJy/sr)2 The UU variance map (optional)
Keyword Data Type Value Description
PIXTYPE string HEALPIX
COORDSYS string GALACTIC Coordinate system
ORDERING string NESTED Healpix ordering
POLCCONV String COSMO Polarization convention
NSIDE Int 1024 or 2048 Healpix [math]N_{side}[/math]
FIRSTPIX Int*4 0 First pixel number
LASTPIX Int*4 12 [math]N_{side}[/math]2 – 1 Last pixel number
FREQ string nnn The frequency channel


The same structure applies to all SkyMap products, independent of whether they are full channel, survey of half-ring. The distinction between the types of maps is present in the FITS filename (and in the traceability comment fields).

Polarization convention used in the Planck project[edit]

The Planck collaboration used the COSMO convention for the polarization angle (as usually used in space based CMB missions), whereas other astronomical fields usually use the IAU convention. In the following document we report the difference between these two conventions, and the consequence if it is NOT taken into account correctly in the analysis.

Figure 1. COSMO convention (left) and IAU convention (right). The versor [math]\hat{z}[/math] points outwards the pointing direction in COSMO, and inwards in IAU. The bottom panel refers to the plane tangent to the sphere.

Changing the orientation convention is equivalent to a transformation [math]\psi'=\pi-\psi[/math] of the polarization angle (Figure 1). The consequence of this transformation is the inversion of the Stokes parameter [math]U[/math]. The components of the polarization tensor in the helicity basis [math]\epsilon^{\pm}=1/\sqrt{2}(\hat{x}\pm i\hat{y})[/math] are:

[math] (Q+iU)(\hat{n}) = \sum _{\ell m}a_{2,lm}{}_{2}Y_{\ell }^{m}(\hat{n}) \\(Q-iU)(\hat{n}) = \sum _{\ell m}a_{-2,lm}{}_{2}Y_{\ell }^{m}(\hat{n}) [/math]

where [math]{}_{2}Y_{\ell }^{m}(\hat{n})[/math] are the spin weighted spherical harmonic functions. The [math]E[/math] and [math]B[/math] modes can be defined as: [math] E(\hat{n}) = \sum_{\ell m}a_{E,\ell m}Y_{\ell }^{m}(\hat{n}) \\B(\hat{n}) = \sum_{\ell m}a_{B,\ell m}Y_{\ell }^{m}(\hat{n}) [/math]

where the coefficients [math]a_{E,\ell m}[/math] and [math]a_{B,\ell m}[/math] are derived from linear combinations of the [math]a_{2,\ell m}[/math] , [math]a_{-2,\ell m}[/math] defined implicitly in the first equation ([math]Q\pm iU[/math]).

Test gradient.jpg
Figure 2. Error on Planck-LFI 70 GHz [math]EE[/math] (top) and [math]BB[/math] (bottom) spectra, in case of wrong choice of the coordinate system convention (IAU instead of COSMO).

The effect of the sign inversion of [math]U[/math] on the polarization spectra is a non trivial mixing of [math]E[/math] and [math]B[/math] modes.

An example of the typical error on [math]EE[/math] and [math]BB[/math] auto-spectra in case of a wrong choice of the polarization basis is shown in Figure 2.

BE CAREFUL about the polarization convention you are using. If the IAU convention is used in computing the power spectra, the sign of the [math]U[/math] component of the Planck maps must be inverted before computing [math]E[/math] and [math]B[/math] modes.

Note on the convention used by the Planck Catalogue of Compact Sources (PCCS)[edit]

For continuity with other compact sources catolgues, the Catalogue of Compact Sources provided by Planck follows the IAU convention, and the polarization angles are defined on an interval of [-90°,90°]. To switch to the COSMO convention, the polarization angles listed in the catalogue have to be shifted by 90° and multiplied by -1.

References[edit]

  1. ↑ 1.01.11.21.3 Planck 2015 results. VIII. High Frequency Instrument data processing: Calibration and maps, Planck Collaboration, 2016, A&A, 594, A8.
  2. ↑ 2.02.12.22.32.4 Planck 2015 results. II. LFI processing, Planck Collaboration, 2016, A&A, 594, A2.
  3. ↑ Planck 2015 results. V. LFI calibration, Planck Collaboration, 2016, A&A, 594, A5.
  4. ↑ Planck 2013 results. II. Low Frequency Instrument data processing, Planck Collaboration, 2014, A&A, 571, A2.
  5. ↑ Planck 2015 results. VI. LFI mapmaking, Planck Collaboration, 2016, A&A, 594, A6.
  6. ↑ Planck 2015 results. XI. Diffuse component separation: CMB maps, Planck Collaboration, 2016, A&A, 594, A9.

(Planck) Low Frequency Instrument

(Planck) High Frequency Instrument

Flexible Image Transfer Specification

Cosmic Microwave background

Noise Equivalent Temperature

reduced IMO

random telegraphic signal

Data Processing Center

Full-Width-at-Half-Maximum

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