| Abstract: | Using the Planck 2015 data release (PR2) temperature observations, we perform
the separation of Galactic thermal dust emission and cosmic infrared background
(CIB) anisotropies. For this purpose, we implement a specifically tailored
component-separation method, the so-called generalized needlet internal linear
combination (GNILC) method. This makes use of the spatial information (angular
power spectrum) to disentangle the Galactic dust emission and CIB anisotropies.
A significantly improved all-sky map of the Planck thermal dust, with reduced
CIB contamination, is produced at 353, 545, and 857 GHz. From the reduction of
the CIB contamination in the thermal dust maps, we are able to provide a more
accurate estimate of the local dust temperature and dust spectral index over
the sky with reduced dispersion at high latitudes. We find that $T = (19.4 pm
1.3)$ K and $eta = 1.6 pm 0.1$ on the whole sky, while $T = (19.4 pm 1.5)$
K and $eta = 1.6 pm 0.2$ on 21 % of the sky at high latitudes, where the
error bars show the dispersion. Moreover, subtracting the new CIB-removed
thermal dust maps from the CMB-removed Planck maps gives access to CIB maps
over a large part of the sky. The new CIB maps can be regarded as indirect
tracers of the dark matter over 60% of the sky and they are recommended for
exploring cross-correlations with lensing and large-scale structure optical
surveys. The reconstructed GNILC thermal dust and CIB maps are delivered as
Planck products. |
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