# Planck component all sky maps.

The Planck All Sky Maps are made available as HEALPix (Hierarchical Equal Area isoLatitude Pixelization) files, which are implemented in FITS binary table format. For more information and software tools for analysis and display of HEALPix maps, please see http://healpix.sourceforge.net/.

## Additional products of the 2013 release

### Galactic Dust maps

Thermal emission from interstellar dust is captured by Planck-HFI over the whole sky, at all frequencies from 100 to 857 GHz. This emission is well modelled by a modified black body in the far-infrared to millimeter range. It is produced by the biggest interstellar dust grain that are in thermal equilibrium with the radiation field from stars. The grains emission properties in the sub-millimeter are therefore directly linked to their absorption properties in the UV-visible range. By modelling the thermal dust emission in the sub-millimeter, a map of dust reddening in the visible can then be constructed.
Model of thermal dust emission : The model of the thermal dust emission is based on a modify black body fit to the data: I_nu = AxB_nu(T)xnu^beta where B_nu(T) is the Planck function for dust equilibrium temperature T, A is the amplitude of the MBB and beta the dust spectral index.
The dust optical depth at frequency nu is tau_nu = Axnu^beta The dust parameters provided are T, beta and tau_353.
They were obtained by fitting the Planck data at 353, 545 and 857 GHz together with the IRAS (IRIS) 100 micron data.
The MBB fit was performed using a chi-square minimization, assuming errors for each data point that include instrumental noise, calibration uncertainties and uncertainties on the zero level. Because of the known degeneracy between T and beta in the presence of noise, we produced a model of dust emission using data smoothed to 35 arcmin; at such resolution no systematic bias of the parameters is observed. The map of the spectral index beta at 35 arcmin was than used to fit the data for T and tau at 5 arcmin.

For the production of the E(B-V) map, we used Planck and IRAS data from which point sources in diffuse areas were removed to avoid contamination by galaxies. In the hypothesis of constant dust emission cross-section, the optical depth map tau_353 is proportional to dust column density. It can then be used to estimate E(B-V), also proportional to dust column density in the hypothesis of a constant differential absorption cross-section between the B and V bands.

##### Dust optical depth products :
• Dust optical depth at 353 GHz : Nside=2048, fwhm=5 arcmin, no units
• Dust reddening E(B-V) : Nside=2048, fwhm=5 arcmin, units=magnitude
• Dust temperature : Nside 2048, fwhm=5 arcmin, units=Kelvin
• Dust spectral index : Nside=2048, fwhm=35 arcmin, no units

 Dust opacity map nside=2048 Multi-plane FITS file with maps of dust optical depth at 353 GHz, dust reddening E(B-V), dust temperature and spectral index.

### CO maps

CO rotational transition line emission is present in all HFI bands but for the 143 GHz channel. It is especially significant in the 100, 217 and 353 GHz channels (due to the 115 (1-0), 230 (2-1) and 345 GHz (3-2) CO transitions). This emission comes essentially from the Galactic interstellar medium and is mainly located at low and intermediate Galactic latitudes. Three approaches (summarised below) have been used to extract CO velocity-integrated emission maps from HFI maps and to make three types of CO products. A full description of how these products were produced is given in [Planck 2013 results XIII].

The released Type 1 CO maps have been produced using the MILCA-b algorithm, Type 2 maps using a specific implementation of the Commander algorithm, and the Type 3 map using the full Commander-Ruler component separation pipeline. We provide Healpix maps with Nside=2048. For one transition, the CO velocity-integrated line signal map is given in K_RJ.km/s units. A conversion factor from this unit to the native unit of HFI maps (K_CMB) is provided in the header of the data files.

##### Four maps are given per transition and per type :
• The signal map
• The standard deviation map (same unit as the signal),
• A null test noise map (same unit as the signal) with similar statistical properties. It is made out of half the difference of half-ring maps.
• A mask map (0B or 1B) giving the regions (1B) where the CO measurement is not reliable because of some severe identified foreground contamination.

All products of a given type belong to a single file. Type 1 products have the native HFI resolution i.e. approximately 10, 5 and 5 arcminutes for the CO 1-0, 2-1, 3-2 transitions respectively. Type 2 products have a 15 arcminute resolution The Type 3 product has a 5.5 arcminute resolution.

 Type 1 It is based on a single channel approach using the fact that each CO line has a slightly different transmission in each bolometer at a given frequency channel. These transmissions can be evaluated from bandpass measurements that were performed on the ground or empirically determined from the sky using existing ground-based CO surveys. From these, the J=1-0, J=2-1 and J=3-2 CO lines can be extracted independently. As this approach is based on individual bolometer maps of a single channel, the resulting Signal-to-Noise ratio (SNR) is relatively low. The benefit, however, is that these maps do not suffer from contamination from other HFI channels (as is the case for the other approaches) and are more reliable, especially in the Galactic Plane. Type 2 This product is obtained using a multi frequency approach. Three frequency channel maps are combined to extract the J=1-0 (using the 100, 143 and 353 GHz channels) and J=2-1 (using the 143, 217 and 353 GHz channels) CO maps. Because frequency channels are combined, the spectral behaviour of other foregrounds influences the result. The two type 2 CO maps produced in this way have a higher SNR than the type 1 maps at the cost of a larger possible residual contamination from other diffuse foregrounds. Type 3 Using prior information on CO line ratios and a multi-frequency component separation method, we construct a combined CO emission map with the largest possible SNR. This type 3 product can be used as a sensitive finder chart for low-intensity diffuse CO emission over the whole sky.

## Additional products of the 2018 release

### CO maps

First 12CO(J=1-0) and 13CO(J=1-0) fullsky maps constructed from Planck detectors observing the sky in the 100 GHz channel. These maps have been build from the Planck release 2 data (Planck collaboration 2015 results I). Each map is provided in K.km/s at an angular resolution of 9.88' FWHM with its associated error-map and a null-map.
The 12CO map is calibrated accordingly to the Dame et al. (2001) CO survey.
The 13CO map is calibrated accordingly to the BU FCRAO GRS (Jackson et al. 2006).
A full description of these two maps is provided in Hurier 2019 : https://arxiv.org/abs/1903.11883

 12CO map Map 12CO in nside=2048 signal map standard deviation map jackknife maps Figure shows the signal map smoothed at 30 arcmin FWHM 13CO map Map 13CO in nside=2048 signal map standard deviation map jackknife maps Figure shows the signal map smoothed at 30 arcmin FWHM