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http://www.rssd.esa.int/Planck

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... HEALPix

http://healpix.jpl.nasa.gov/

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... beam

The pixel window function has been also taken into account, but its effect is not important here, because the pixel size is significantly smaller than $\sigma_{\rm b}$ .

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... grids

For this purpose we implemented a specific algorithm and tested its reliability with the MINUITS package of the CERN libraries (James & Roos 1975).

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... component

Such a tight synchrotron-dust correlation holds at all WMAP frequencies.

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... oscillations

Anafast computes the APS in the Fourier space by expressing the temperature fluctuation field in spherical harmonics. The APS is obtained working over the whole sky, even if the map is zero outside the patch taken into account (the derived APS is then renormalized to the case of a full sky coverage). This operation is heuristically equivalent to computing the Fourier transform of a discontinuos function, thus implying a Gibbs effect (Arfken & Weber 2001).

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... paradigm

Simple (standard) inflationary scenarios (see the reviews by Lyth & Riotto 1999; and Linde 2005) predict the existence of Gaussian density fluctuations and of gravitational waves with a nearly scale-invariant spectrum.

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... crucial

Standard cosmologies predict a minimum level of non-Gaussianity for the the primordial perturbations. In alternative cosmologies (Lyth et al. 2003; Arkani-Hamed et al. 2004; Alishahiha et al. 2004) such a lower limit is even higher. Consequently, detection or non-detection of non-Gaussianities sheds light on the physics of the early Universe.

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