WP7 – Physical Interpretation



Under very general assumptions, the primary CMB temperature and polarization anisotropies are expected to be Gaussian and statistically isotropic. The average amplitude of CMB fluctuations on different scales is related to the details of the underlying cosmological model, while tiny deviations from Gaussianity and statistical isotropy provide additional information on the properties of the Universe. Extracting the physical information encoded in the CMB maps requires then a detailed characterization of their statistical properties.


The current science analysis of Planck maps is limited by an imperfect understanding of instrumental systematics and a simplified component separation approach. This WP aims at two main objectives:

  • development of tools for the likelihood analysis of the improved maps, which are able to fully propagate the uncertainties from residual instrumental systematics and component separation all the way to the cosmological parameters;
  • perform the final cosmological analysis of the maps, either alone or in conjunction of other cosmological datasets.

Description of work

This WP consists of two main phases, tools development and science exploitation. The first phase involves the development of a likelihood module to be integrated in the main Gibbs pipeline. This module will take maps (either single frequency or component separated) as inputs and produce power spectra and posterior distributions for the cosmological parameters of interest. Once the full pipeline is completed, the focus of the WP will shift to the scientific characterization of the maps, and the production of the final science results. Given the nature of LFI data, the focus will be on the analysis of large angle features, while the analysis of the small angle features will be used mainly as a consistency check.