Difference between revisions of "Sky temperature maps"

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{{DISPLAYTITLE:2015 Sky temperature and polarization maps}}
 
==General description==
 
==General description==
−
----------------------
 
  
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Sky maps give the best estimate of the intensity of the signal from the sky 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.  Sky maps are provided for the nominal Planck mission and also, separately,for the first two single surveys, the third one being covered only for a small part during the nominal mission. The details of the start and end times of each are given in [[HFI_detection_chain#Data_compression | this table]].
+
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.
  
−
For characterization purposes, are also provided maps covering the nominal survey but each one 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 in each pointing period. These maps are used extensively to investigate the (high frequency) noise properties the maps themselves and of other products described elsewhere (see e.g., the [[HFI-Validation | data validation]] section).
+
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 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
 +
|-
 +
|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==
 +
 
 +
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:
  
−
To help in further processing, there are also masks of the Galactic Plane and of point sources, each provided for several different depths.
+
; 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, as indicated below, in order to maintain compatibility with the PR1 products. We stress that the correction applies only to the Q and U maps contained in the files; the temperature maps are not affected, and thus all temperature-only maps (like the 545 and 857 GHz channel maps and the single SWB maps) are not affected.
 +
; 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.
  
−
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.
+
; 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}}.
  
−
===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
+
Note that the nominal mission maps have not had the post-processing applied, which makes them more easily comparable to the PR1 products.
−
: Full channel maps are built using all the valid detectors of a frequency channel and cover the nominal mission.  For HFI, the 143-8 and 545-3 bolometers are rejected entirely as they are seriously affected by RTS noise.  <span style="color:Red">  Images in the HFI-DPC paper (<cite>#planck2013-p03</cite>; can be copied here once produced with the final color scheme</span>).
 
  
−
; Single survey maps
+
=== LFI processing ===
−
: Single survey maps are built using all valid detectors of a frequency channel, but cover separately the different sky surveys.
+
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.
  
−
; Detector set or detector pairs maps
+
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...  
−
: These are maps built from a subset of the detectors in a frequency channel, typically our of two PSB pairs (i.e., four poloarisation-sensitive bolometers with different orientation on the sky), for HFI in order to extract a single temperature map. While none of these maps are part of the first Planck data release, the concept of ''detset'' is used, and thus it is worth mentioning it here. In particular, information by detector set is available at the [[Frequency_maps_angular_power_spectra | sky power spectrum]] level and in the [[The RIMO | RIMO]].
 
  
−
; 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.
 
  
−
; Masks
+
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}})."
−
: 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 frequency channel.
 
  
−
=== 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 : 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]].
  
−
==== Map zero-level ====
+
==Types of maps ==
  
−
For the  100 to 857 GHz maps, due to recent evolutions in the calibration scheme, the zero levels could not be set to their optimal levels especially for Galactic studies in time for the data release.  A recipe for adjusting these zero levels to astrophysical values is given in the HFI Calibration paper <cite>#planck2013-p03f</cite> .
+
=== Full mission, full channel maps (6 HFI, 7 LFI)===
  
−
For the 30, 44 and 70 GHz, maps are corrected for zero level monopole by applying an offset correction, see LFI Calibration paper <cite>#planck2013-p02b</cite> section 3.4 "Setting the zero levels in the maps". Note that the offset applied is indicated in the header as a comment keyword.
+
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. LFI Q and U maps at Nside 1024 and 2048 are not corrected for bandpass leakage (shown as BPL uncorr in the PLA archive), but LFI nside 256 have been corrected for bandpass leakage.  
  
−
==== The Zodiacal light and the Far-Side Lobes ====
+
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.
  
−
The figures below show the modeled Zodiacal light and Far Side Lobes projected onto the maps; they are simply the difference between the ''main product'' and the ''ZodiCorrected'' maps for the nominal mission.  The units are given in the figures.  The ''heat'' color table has been used in place of the standard Planck for clarity reasons.
 
  
−
<gallery perrow=3 widths=250px>
+
<center>
−
File: ZodiRes100.png  
+
<gallery style="padding:0 0 0 0;" perrow=3 widths=260px heights=160px>  
−
File: ZodiRes143.png  
+
File: SkyMap30e.png| '''Full mission I, 30 GHz'''
−
File: ZodiRes217.png  
+
File: SkyMap44e.png | '''Full mission I, 44 GHz'''
−
File: ZodiRes353.png  
+
File: SkyMap70e.png | '''Full mission I, 70 GHz'''
−
File: ZodiRes545.png  
+
File: SkyMap100e.png | '''Full mission I, 100 GHz'''
−
File: ZodiRes857.png  
+
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>
 
</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>
 +
 +
=== Full mission light maps, full channel maps (6 HFI, 7 LFI)===
 +
 +
These maps are based on the Full mission maps but contain fewer columns, IQU from 30 to 353 GHz, and I only at 545 and 857 GHz. These maps have been produced to reduce the transfer time of the most downloaded frequency full mission maps.
  
 +
=== Nominal mission, full channel maps (6 HFI)===
  
−
; Artifacts near caustics of the scanning strategy
+
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.
−
: TBW if still an issue??
 
  
−
==Production process==
+
=== 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.
 +
 
 +
=== Year maps, full channel maps (12 HFI, 16 LFI)===
 +
 
 +
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)===
  
−
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.
+
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.
  
−
=== HFI processing ===
+
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,
  
−
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:
+
===Full mission, single detector maps (18 HFI, 22 LFI)===
  
−
; 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.
+
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
−
; 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)
 
−
; 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.
 
−
; 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.
 
−
; 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.
 
−
; 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.
 
  
−
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. 
+
{| border="1" cellpadding="3" cellspacing="0" align="center" style="text-align:left" width=600px
 +
|+ '''HFI Temperature sensitive bolometers'''
 +
|- bgcolor="ffdead" 
 +
!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
 +
|}
  
−
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.
+
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.
  
 +
In case of LFI, all the 22 Radiometers maps are available, those, obviously, are only in temperature.
  
−
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).
+
===Full mission, detector set or detector pairs maps (8 HFI, 8 LFI)===
  
 +
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.
 
  
−
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 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 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.
+
{| 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
 +
|}
  
−
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.
 
  
−
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.
+
===Half-ring maps (64 HFI, 62 LFI)===
−
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.
 
  
−
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.
+
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.
 +
<!----
 +
===Masks===
  
−
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.
+
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.
 +
--->
  
−
=== LFI processing ===
+
=== The Zodiacal light correction maps ===
  
−
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 1 second baselines.
+
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.
  
−
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 $C_{w}^{-1}$ = 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, although only the temperature maps are released.  
+
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.
  
−
A detailed description of the map-making procedure is given in <cite>#planck2013-p02</cite>. See also section [[Map-making LFI#Map-making|Map-making]].
+
=== Caveats and known issues ===
 +
 
 +
; 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==
−
------------
 
−
 
 
=== HFI inputs ===
 
=== HFI inputs ===
  
−
* The cleaned TOIs of signal of each detector, together with their flags, produced by the [[TOI processing|TOI processing]] pipeline
+
The HFI mapmaking takes as input:
−
* The TOIs of pointing (quaternions), described in [[Pointing&Beams | Detectors pointing and beams]]
+
* the cleaned TOIs of signal of each detector, together with their flags, produced by the [[TOI processing|TOI processing]] pipeline;
−
* Bolometer-level characterization data, from the DPC's internal IMO (not distributed)
+
* the TOIs of pointing (quaternions), described in [[Detector_pointing|Detector pointing]];
−
* Planck orbit data used to compute and remove the earth dipole
+
* bolometer-level characterization data, from the DPC's internal IMO (not distributed);
−
* WMAP solar dipole information used to calibrate the CMB channels
+
* 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.
 
* Planet models used to calibrate the Galactic channels.
  
 
=== LFI inputs ===
 
=== LFI inputs ===
  
−
The Madam map-maker takes as an input:
+
The Madam mapmaker takes as input:
  
−
* The calibrated timelines (for details see [[TOI processing LFI|TOI Processing]])
+
* the calibrated timelines (for details see [[TOI processing LFI|TOI Processing]]);
−
* The detector pointings (for details see [[Pointing LFI|Detector pointing]])
+
* the detector pointings (for details see [[Detector_pointing|Detector pointing]]);
−
* The noise information in the form of three-parameter (white noise level ($\sigma$), slope, and knee frequency ($f_\mathrm{knee}$)) noise model (for details see  [[The RIMO|RIMO]])
+
* 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==
−
---------------------
 
−
 
 
=== Masks ===
 
=== Masks ===
  
−
Masks are provided of
+
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.
  
−
; the Galactic Plane
+
====Point source masks====
−
: 16 masks are provided giving 20, 40, 60, 70, 80, 90, 97, and 99% sky coverage in two different files, one for HFI at Nside=2048 and one for LFI at Nside=1024
 
  
−
; the point sources
+
For HFI and LFI two sets of masks are provided: 
−
: 18 masks are provided, 2 per frequency channel, each masking at the 5 and 10$\sigma$ level; 12 for HFI at Nside=2048 and 6 for LFI at Nside=1024
+
* 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).
  
−
The masks are apodized, in GALACTIC coordinates, and NESTED ordering. The table below give the filenames.
+
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.
  
−
{| class="wikitable"  align="center" style="text-align:center" border="1" cellpadding="5" cellspacing="0"
+
====Galactic plane masks====
−
|+ '''Generic Masks'''
 
−
! Galactic Plane || Point Sources
 
−
|-
 
−
| HFI_Mask_GalPlane_2048_R1.10.fits || HFI_Mask_PointSrc_2048_R1.10.fits
 
−
|-
 
−
| LFI_Mask_GalPlane_1024_R1.10.fits || LFI_Mask_PointSrc_1024_R1.10.fits
 
−
|}
 
  
−
The (HFI) masks are shows below in a single figure.  While this is quite clear for the Galactic Plane masks, it is less so for the point source masks, but it does give a clear perspective on how the latter are distributed over the sky.
+
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.
  
−
<gallery perrow=2 widths=400px>
+
<center>
−
File: HFI_GalPlaneMask.png |  '''Galactic Plane masks'''
+
<gallery perrow=3 widths=260px heights=160px >
−
File: HFI_PointSrcMask.png  | '''PointSource masks'''
+
File: GalPlaneMask_apo0.png |  '''Galactic Plane masks, no apod'''
 +
File: GalPlaneMask_apo2.png |  '''Galactic Plane masks, apod 2 deg'''
 +
File: GalPlaneMask_apo5.png |  '''Galactic Plane masks, apod 5 deg'''
 +
File: PointSrcMask_100.png  | '''PointSource mask 100 GHz'''
 +
File: PointSrcMask_143.png  | '''PointSource mask 143 GHz'''
 +
File: PointSrcMask_217.png  | '''PointSource mask 217 GHz'''
 +
File: PointSrcMask_353.png  | '''PointSource mask 343 GHz'''
 +
File: PointSrcMask_545.png  | '''PointSource mask 545 GHz'''
 +
File: PointSrcMask_857.png  | '''PointSource mask 857 GHz'''
 
</gallery>
 
</gallery>
 +
</center>
  
 
== File names ==
 
== 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.
  
−
The FITS filenames are of the form ''{H|L}FI_SkyMap_fff_nnnn_R1.nn_{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.
+
{| class="wikitable"  align="center" style="text-align"left" border="1" cellpadding="15" cellspacing="20" width=880px
−
+
|+ '''HFI FITS filenames'''
−
The list of products containing sky maps are given below, grouped by type
+
|- bgcolor="ffdead"
−
 
+
! Coverage  || filename  ||  half-ring filename
−
{| class="wikitable"  align="center" style="text-align:center" border="1" cellpadding="5" cellspacing="0"  
+
|-
−
|+ '''Full channel maps'''
+
| Full chan, full mission ||HFI_SkyMap_???_2048_R2.??_full.fits ||HFI_SkyMap_???_2048_R2.??_full-ringhalf-?.fits
−
! Frequency || FITS file name
+
|-
 +
| Full channel, nominal mission ||HFI_SkyMap_???_2048_R2.??_nominal.fits || n/a
 
|-
 
|-
−
| '''30GHz''' || {{PLAMaps|type=FULL|inst=LFI|freq=30|link=LFI_SkyMap_030_1024_R1.10_nominal.fits}}
+
| Full channel, single survey || HFI_SkyMap_???_2048_R2.??_survey-?.fits || n/a
 
|-
 
|-
−
| '''44GHz''' || {{PLAMaps|type=FULL|inst=LFI|freq=44|link=LFI_SkyMap_044_1024_R1.10_nominal.fits}}
+
| Full channel, single year || HFI_SkyMap_???_2048_R2.??_year-?.fits || n/a
 
|-
 
|-
−
| '''70GHz''' || {{PLAMaps|type=FULL|inst=LFI|freq=70|link=LFI_SkyMap_070_1024_R1.10_nominal.fits}}
+
| Full channel, half mission || HFI_SkyMap_???_2048_R2.??_halfmission*-?.fits || n/a
 
|-
 
|-
−
| '''100GHz''' || {{PLAMaps|type=FULL|inst=HFI|freq=100|link= HFI_SkyMap_100_2048_R1.10_nominal.fits}}
+
| Det-set, full mission || HFI_SkyMap_???-ds?_2048_R2.??_full.fits || HFI_SkyMap_???-ds?_2048_R2.??_full-ringhalf-?.fits
 
|-
 
|-
−
| '''143GHz''' || {{PLAMaps|type=FULL|inst=HFI|freq=143|link= HFI_SkyMap_143_2048_R1.10_nominal.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
 
|-
 
|-
−
| '''217GHz''' || {{PLAMaps|type=FULL|inst=HFI|freq=217|link= HFI_SkyMap_217_2048_R1.10_nominal.fits}}
+
| Full channel, full mission ||LFI_SkyMap_???_1024_R2.??_full.fits ||LFI_SkyMap_???_1024_R2.??_full-ringhalf-?.fits || Available also at Nside = 2048
 
|-
 
|-
−
| '''353GHz''' || {{PLAMaps|type=FULL|inst=HFI|freq=353|link= HFI_SkyMap_353_2048_R1.10_nominal.fits}}
+
| Full channel, single survey || LFI_SkyMap_???_1024_R2.??_survey-?.fits || n/a || Available also at Nside = 2048
 
|-
 
|-
−
| '''545GHz''' || {{PLAMaps|type=FULL|inst=HFI|freq=545|link= HFI_SkyMap_545_2048_R1.10_nominal.fits}}
+
| Full channel, survey combination || LFI_SkyMap_???_1024_R2.??_survey-1-3-5-6-7-8.fits || n/a || n/a
 
|-
 
|-
−
| '''857GHz''' || {{PLAMaps|type=FULL|inst=HFI|freq=857|link= HFI_SkyMap_857_2048_R1.10_nominal.fits}}
+
| 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
 
|}
 
|}
  
  
−
{| class="wikitable"  align="center" style="text-align:center" border="1" cellpadding="5" cellspacing="0"  
+
 
−
|+ '''Single survey maps'''
+
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.
−
! Frequency || Survey 1 FITS file name || Survey 2 FITS file name
+
 
 +
<!---
 +
{| 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}}
 
|-
 
|-
−
| '''30GHz''' || {{PLAMaps|type=SURVEY|inst=LFI|freq=30|link=LFI_SkyMap_030_1024_R1.10_survey_1.fits}} || {{PLAMaps|type=SURVEY|inst=LFI|freq=30|link=LFI_SkyMap_030_1024_R1.10_survey_2.fits}}
+
| '''44GHz''' || {{PLASingleFile|fileType=map|name=LFI_SkyMap_044_1024_R1.10_nominal.fits|link=LFI_SkyMap_044_1024_R1.10_nominal.fits}}
 
|-
 
|-
−
| '''44GHz''' || {{PLAMaps|type=SURVEY|inst=LFI|freq=44|link=LFI_SkyMap_044_1024_R1.10_survey_1.fits}} || {{PLAMaps|type=SURVEY|inst=LFI|freq=44|link=LFI_SkyMap_044_1024_R1.10_survey_2.fits}}
+
| '''70GHz''' || {{PLASingleFile|fileType=map|name=LFI_SkyMap_070_1024_R1.10_nominal.fits|link=LFI_SkyMap_070_1024_R1.10_nominal.fits}}
 
|-
 
|-
−
| '''70GHz''' || {{PLAMaps|type=SURVEY|inst=LFI|freq=70|link=LFI_SkyMap_070_1024_R1.10_survey_1.fits}} || {{PLAMaps|type=SURVEY|inst=LFI|freq=70|link=LFI_SkyMap_070_1024_R1.10_survey_2.fits}}
+
| '''70GHz''' || {{PLASingleFile|fileType=map|name=LFI_SkyMap_070_2048_R1.10_nominal.fits|link=LFI_SkyMap_070_2048_R1.10_nominal.fits}}
 
|-
 
|-
−
| '''100GHz''' || {{PLAMaps|type=SURVEY|inst=HFI|freq=100|link= HFI_SkyMap_100_2048_R1.10_survey_1.fits}} || {{PLAMaps|type=SURVEY|inst=HFI|freq=100|link= HFI_SkyMap_100_2048_R1.10_survey_2.fits}}
+
| '''100GHz''' || {{PLASingleFile|fileType=map|name=HFI_SkyMap_100_2048_R1.10_nominal.fits|link=HFI_SkyMap_100_2048_R1.10_nominal.fits}}
 
|-
 
|-
−
| '''143GHz''' || {{PLAMaps|type=SURVEY|inst=HFI|freq=143|link= HFI_SkyMap_143_2048_R1.10_survey_1.fits}} || {{PLAMaps|type=SURVEY|inst=HFI|freq=143|link= HFI_SkyMap_143_2048_R1.10_survey_2.fits}}
+
| '''143GHz''' || {{PLASingleFile|fileType=map|name=HFI_SkyMap_143_2048_R1.10_nominal.fits|link=HFI_SkyMap_143_2048_R1.10_nominal.fits}}
 
|-
 
|-
−
| '''217GHz''' || {{PLAMaps|type=SURVEY|inst=HFI|freq=217|link= HFI_SkyMap_217_2048_R1.10_survey_1.fits}} || {{PLAMaps|type=SURVEY|inst=HFI|freq=217|link= HFI_SkyMap_217_2048_R1.10_survey_2.fits}}
+
| '''217GHz''' || {{PLASingleFile|fileType=map|name=HFI_SkyMap_217_2048_R1.10_nominal.fits|link=HFI_SkyMap_217_2048_R1.10_nominal.fits}}
 
|-
 
|-
−
| '''353GHz''' || {{PLAMaps|type=SURVEY|inst=HFI|freq=353|link= HFI_SkyMap_353_2048_R1.10_survey_1.fits}} || {{PLAMaps|type=SURVEY|inst=HFI|freq=353|link= HFI_SkyMap_353_2048_R1.10_survey_2.fits}}
+
| '''353GHz''' || {{PLASingleFile|fileType=map|name=HFI_SkyMap_353_2048_R1.10_nominal.fits|link=HFI_SkyMap_353_2048_R1.10_nominal.fits}}
 
|-
 
|-
−
| '''545GHz''' || {{PLAMaps|type=SURVEY|inst=HFI|freq=545|link= HFI_SkyMap_545_2048_R1.10_survey_1.fits}} || {{PLAMaps|type=SURVEY|inst=HFI|freq=545|link= HFI_SkyMap_545_2048_R1.10_survey_2.fits}}
+
| '''545GHz''' || {{PLASingleFile|fileType=map|name=HFI_SkyMap_545_2048_R1.10_nominal.fits|link=HFI_SkyMap_545_2048_R1.10_nominal.fits}}
 
|-
 
|-
−
| '''857GHz''' || {{PLAMaps|type=SURVEY|inst=HFI|freq=857|link= HFI_SkyMap_857_2048_R1.10_survey_1.fits}} || {{PLAMaps|type=SURVEY|inst=HFI|freq=857|link= HFI_SkyMap_857_2048_R1.10_survey_2.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}}  
 
|}
 
|}
  
  
−
{| 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
−
|+ '''Half-ring maps'''
+
|+ '''FITS filenames'''
−
! Frequency || Half-ring 1 FITS file name || Half-ring 2 FITS file name
+
|- bgcolor="ffdead"
 +
! Frequency || Survey 1 maps || Survey 2 maps
 +
|-
 +
| '''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}}
 +
|-
 +
| '''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}}
 
|-
 
|-
−
| '''30GHz''' || {{PLAMaps|type=SURVEY|inst=LFI|freq=30|link=LFI_SkyMap_030_1024_R1.10_nominal_ringhalf_1.fits}} || {{PLAMaps|type=SURVEY|inst=LFI|freq=30|link=LFI_SkyMap_030_1024_R1.10_nominal_ringhalf_2.fits}}
+
| '''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}}
 
|-
 
|-
−
| '''44GHz''' || {{PLAMaps|type=SURVEY|inst=LFI|freq=44|link=LFI_SkyMap_044_1024_R1.10_nominal_ringhalf_1.fits}} || {{PLAMaps|type=SURVEY|inst=LFI|freq=44|link=LFI_SkyMap_044_1024_R1.10_nominal_ringhalf_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}}
 
|-
 
|-
−
| '''70GHz''' || {{PLAMaps|type=SURVEY|inst=LFI|freq=70|link=LFI_SkyMap_070_1024_R1.10_nominal_ringhalf_1.fits}} || {{PLAMaps|type=SURVEY|inst=LFI|freq=70|link=LFI_SkyMap_070_1024_R1.10_nominal_ringhalf_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}}
 
|-
 
|-
−
| '''100GHz''' || {{PLAMaps|type=SURVEY|inst=HFI|freq=100|link=HFI_SkyMap_100_2048_R1.nn_nominal_ringhalf_1.fits}} || {{PLAMaps|type=SURVEY|inst=HFI|freq=100|link=HFI_SkyMap_100_2048_R1.nn_nominal_ringhalf_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}}
 
|-
 
|-
−
| '''143GHz''' || {{PLAMaps|type=SURVEY|inst=HFI|freq=143|link=HFI_SkyMap_143_2048_R1.nn_nominal_ringhalf_1.fits}} || {{PLAMaps|type=SURVEY|inst=HFI|freq=143|link=HFI_SkyMap_143_2048_R1.nn_nominal_ringhalf_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}}
 
|-
 
|-
−
| '''217GHz''' || {{PLAMaps|type=SURVEY|inst=HFI|freq=217|link=HFI_SkyMap_217_2048_R1.nn_nominal_ringhalf_1.fits}} || {{PLAMaps|type=SURVEY|inst=HFI|freq=217|link=HFI_SkyMap_217_2048_R1.nn_nominal_ringhalf_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}}
 
|-
 
|-
−
| '''353GHz''' || {{PLAMaps|type=SURVEY|inst=HFI|freq=353|link=HFI_SkyMap_353_2048_R1.nn_nominal_ringhalf_1.fits}} || {{PLAMaps|type=SURVEY|inst=HFI|freq=353|link=HFI_SkyMap_353_2048_R1.nn_nominal_ringhalf_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}}
 
|-
 
|-
−
| '''545GHz''' || {{PLAMaps|type=SURVEY|inst=HFI|freq=545|link=HFI_SkyMap_545_2048_R1.nn_nominal_ringhalf_1.fits}} || {{PLAMaps|type=SURVEY|inst=HFI|freq=545|link=HFI_SkyMap_545_2048_R1.nn_nominal_ringhalf_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
 
|-
 
|-
−
| '''857GHz''' ||  {{PLAMaps|type=SURVEY|inst=HFI|freq=857|link=HFI_SkyMap_857_2048_R1.nn_nominal_ringhalf_1.fits}} || {{PLAMaps|type=SURVEY|inst=HFI|freq=857|link=HFI_SkyMap_857_2048_R1.nn_nominal_ringhalf_2.fits}}
+
| '''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}}
 
|}
 
|}
 +
--->
  
 +
== FITS file structure ==
  
 +
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.
  
 +
[[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:
  
  
−
; Zodi and Far-side-lobes corrected maps :
+
{| border="1" cellpadding="3" cellspacing="0" align="center" style="text-align:left" width=800px
−
HFI_SkyMap_100_2048_R1.nn_nominal_ZodiCorrected.fits
+
|+ '''Sky map file data structure'''
−
HFI_SkyMap_143_2048_R1.nn_nominal_ZodiCorrected.fits
+
|- bgcolor="ffdead" 
−
HFI_SkyMap_217_2048_R1.nn_nominal_ZodiCorrected.fits
+
!colspan="4" | 1. EXTNAME = 'FREQ-MAP' : Data columns
−
HFI_SkyMap_353_2048_R1.nn_nominal_ZodiCorrected.fits
+
|- bgcolor="ffdead" 
−
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
 
−
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
 
−
 
 
−
== FITS file structure ==
 
−
----------------------
 
−
 
 
−
[[File:FITS_FreqMap.png | 500px  | right | thumb | '''FITS file structure''']]
 
−
 
 
−
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 at right. 
 
−
 
 
−
The ''FREQ-MAP'' extension contains is a 3-column table of that contain the signal, variance, and hit-count maps, all in Healpix format, in columns 1, 2, and 3, respectively.  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 three 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 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 are the datasum and 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).  The COMMENT fields give further information including some traceability data for the DPC's.  The main parameters are summarised below:
 
−
 
 
−
{| border="1" cellpadding="3" cellspacing="0" align="center" style="text-align:left"
 
−
|+ Map file data structure
 
 
! Column Name || Data Type || Units || Description
 
! Column Name || Data Type || Units || Description
 
|-
 
|-
−
!colspan="4" style="background:#ffdead;"| 1. EXTNAME = 'FREQ-MAP' : Data columns
+
|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)
 
|-
 
|-
−
|I_STOKES || Real*4 || K_cmb or MJy/sr || The signal map
+
|U_STOKES || Real*4 || K_cmb or MJy/sr || The Stokes U map (optional)
 
|-
 
|-
 
|HITS || Int*4 || none || The hit-count map
 
|HITS || Int*4 || none || The hit-count map
 
|-
 
|-
−
|II_COV || Real*4 || K_cmb^2 or (MJy/sr)^2 || The variance map
+
|II_COV || Real*4 || K_cmb<sup>2</sup> or (MJy/sr)<sup>2</sup> || The II variance map
 
|-
 
|-
−
!colspan="4"| Keywords
+
|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 ||
 
|PIXTYPE ||  string || HEALPIX ||
Line 287: Line 537:
 
|ORDERING || string || NESTED  || Healpix ordering
 
|ORDERING || string || NESTED  || Healpix ordering
 
|-
 
|-
−
|NSIDE  ||  Int || 1024 or 2048 || Healpix Nside for LFI and HFI, respectively
+
|POLCCONV || String || COSMO  || Polarization convention
 +
|-
 +
|NSIDE  ||  Int || 1024 or 2048 || Healpix <math>N_{side}</math>
 
|-
 
|-
 
|FIRSTPIX ||  Int*4 ||                  0 || First pixel number
 
|FIRSTPIX ||  Int*4 ||                  0 || First pixel number
 
|-
 
|-
−
|LASTPIX ||  Int*4 || 12582911 or 50331647 || Last pixel number, for LFI and HFI, respectively
+
|LASTPIX ||  Int*4 || 12 <math>N_{side}</math><sup>2</sup> – 1 || Last pixel number
 
|-
 
|-
 
|FREQ ||    string ||                nnn || The frequency channel   
 
|FREQ ||    string ||                nnn || The frequency channel   
Line 297: Line 549:
  
  
−
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).
+
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).
  
−
An example of a frequency map header is given below (LFI, 30 GHz):
+
==Polarization convention used in the Planck project==
  
−
<pre>
+
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.
−
XTENSION= 'BINTABLE'          / binary table extension
 
−
BITPIX  =                    8 / 8-bit bytes
 
−
NAXIS  =                    2 / 2-dimensional binary table
 
−
NAXIS1  =                  12 / width of table in bytes
 
−
NAXIS2  =            12582912 / number of rows in table
 
−
PCOUNT  =                    0 / size of special data area
 
−
GCOUNT  =                    1 / one data group (required keyword)
 
−
TFIELDS =                    3 / number of fields in each row
 
−
TTYPE1  = 'I_Stokes'          / label for field  1
 
−
TFORM1  = 'E      '          / data format of field: 4-byte REAL
 
−
TUNIT1  = 'K_CMB  '          / physical unit of field
 
−
TTYPE2  = 'Hits    '          / label for field  2
 
−
TFORM2  = 'J      '          / data format of field: 4-byte INTEGER
 
−
TUNIT2  = 'none    '          / physical unit of field
 
−
TTYPE3  = 'II_cov  '          / label for field  3
 
−
TFORM3  = 'E      '          / data format of field: 4-byte REAL
 
−
TUNIT3  = '(K_CMB)^2'          / physical unit of field
 
−
EXTNAME = 'FREQ-MAP'
 
−
DATE    = '2012-12-12T15:48:55' / file creation date (YYYY-MM-DDThh:mm:ss UT)
 
−
CHECKSUM= 'NenJQblINblINblI'  / HDU checksum updated 2012-12-12T15:48:57
 
−
DATASUM = '5363685 '          / data unit checksum updated 2012-12-12T15:48:57
 
−
COMMENT
 
−
COMMENT *** Planck params ***
 
−
COMMENT
 
−
PIXTYPE = 'HEALPIX '          / HEALPIX pixelisation
 
−
ORDERING= 'NESTED  '          / Pixel ordering scheme, either RING or NESTED
 
−
NSIDE  =                1024 / Resolution parameter for HEALPIX
 
−
FIRSTPIX=                    0 / First pixel # (0 based)
 
−
LASTPIX =            12582911 / Last pixel # (0 based)
 
−
INDXSCHM= 'IMPLICIT'          / Indexing: IMPLICIT or EXPLICIT
 
−
EXTVER  = '2      '
 
−
PROCVER = 'DX9_Delta'
 
−
BAD_DATA=          -1.6375E+30
 
−
FREQ    =                  30
 
−
COORDSYS= 'GALACTIC'
 
−
FILENAME= 'LFI_SkyMap_030_1024_R1.10_nominal.fits'
 
−
COMMENT ---------------------------------------------------------------------
 
−
COMMENT LFI RIMO 10.1
 
−
COMMENT Madam version 3.7.4
 
−
COMMENT Added monopole offset 0.000365224 to column I_Stokes
 
−
COMMENT LFI-DMC object:
 
−
COMMENT TOODI%ACCTOODI%%madam_IQUmap_LFI_calib_30GHz_DX9d_nom_1sec:0%
 
−
COMMENT TOODI%ACCTOODI%%madam_hit_LFI_calib_30GHz_DX9d_nom_1sec:0%
 
−
COMMENT TOODI%ACCTOODI%%madam_cov_LFI_calib_30GHz_DX9d_nom_1sec:0%
 
−
COMMENT ---------------------------------------------------------------------
 
−
END
 
  
−
</pre>
+
[[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>.
 +
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>
−
=== Detector-set maps ===
+
  (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>
  
−
<span style="color:Red">NOT FOR 1st RELEASE … put detset table elsewhere ????</span>
+
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>
  
−
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:
+
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>).
−
 
 
−
{| class="wikitable"  align="center" style="text-align:center" border="1" cellpadding="5" cellspacing="0"
 
−
|+ '''HFI detector sets or quads'''
 
−
| '''100–ds1:''' 100-1a,100-1b,100-4a,100-4b || '''100–ds2:''' 100-2a,100-2b,100-3a,100-3b
 
−
|-
 
−
| '''143–ds1:''' 143-1a,143-1b,143-3a,143-3b || '''143–ds2:''' 143-2a,143-2b,143-4a,143-4b
 
−
|-
 
−
| '''217–ds1:''' 217-5a,217-5b,217-7a,217-7b || '''217–ds2:''' 217-6a,217-6b,217-8a,217-8b
 
−
|-
 
−
| '''353–ds1:''' 353-5a,353-5b,353-3a,353-3b || '''353–ds2:''' 353-6a,353-6b,353-4a,353-4b
 
−
|}
 
−
 
 
−
The LFI Detector-set maps are built using pairs of horns in the same scanning row, namely:
 
−
 
 
−
{| class="wikitable"  align="center" style="text-align:center" border="1" cellpadding="5" cellspacing="0"
 
−
|+ '''LFI Couple Horn sets'''
 
−
| '''18_23:''' 18M,18S,23M,23S
 
−
|-
 
−
| '''19_22:''' 19M,19S,22M,22S
 
−
|-
 
−
| '''20_21:''' 20M,20S,21M,21S
 
−
|-
 
−
| '''24:''' 24M,24S
 
−
|-
 
−
| '''25_26:''' 25M,25S,26M,26S
 
−
|}
 
  
 +
[[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).''']]
  
−
---- '''A comment from E. Keihänen: '''
+
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.  
  
−
Here is a list of things that should go into this section:
+
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.
−
Insert a table of maps delivered:
 
−
*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 ------
+
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) ===
 +
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.
  
 
== References ==
 
== References ==
 +
<References />
  
  
−
<biblio force=false>
 
−
#[[References]]
 
−
</biblio>
 
  
  
−
[[Category:Mission science products|002]]
+
[[Category:Mission products|002]]

Latest revision as of 11:55, 16 May 2017

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, as indicated below, in order to maintain compatibility with the PR1 products. We stress that the correction applies only to the Q and U maps contained in the files; the temperature maps are not affected, and thus all temperature-only maps (like the 545 and 857 GHz channel maps and the single SWB maps) are not affected.
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, 7 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. LFI Q and U maps at Nside 1024 and 2048 are not corrected for bandpass leakage (shown as BPL uncorr in the PLA archive), but LFI nside 256 have been corrected for bandpass leakage.

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

Full mission light maps, full channel maps (6 HFI, 7 LFI)[edit]

These maps are based on the Full mission maps but contain fewer columns, IQU from 30 to 353 GHz, and I only at 545 and 857 GHz. These maps have been produced to reduce the transfer time of the most downloaded frequency full mission maps.

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

[LFI meaning]: absolute calibration refers to the 0th order calibration for each channel, 1 single number, while the relative calibration refers to the component of the calibration that varies pointing period by pointing period.

Noise Equivalent Temperature

reduced IMO

random telegraphic signal

Planck Legacy Archive

Data Processing Center

Full-Width-at-Half-Maximum

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