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Séminaire du Vendredi 28 Juin 2013 (Exceptionnel !)

The large-scale structure measured by Planck and implications for star formation

Guilaine Lagache (IAS) Vendredi 28 Juin - 11 h 00 Salle Manuel Forestini - IPAG

All we need is six numbers to describe the Universe ! Planck data are extremely consistent with the predictions of the base Lambda-CDM cosmology. Remarkably, from an analysis of an extensive grid of models, we find no strong evidence to favor any extension to the base Lambda-CDM cosmology, either from the CMB temperature power spectrum alone, or in combination with the Planck lensing power spectrum and other astrophysical data sets.

This model sets the framework for the formation and evolution of large scale structures and galaxies. With Planck, those structures and the link between dark matter halos and star formation are probed by the cosmic infrared background (CIB) anisotropies. After a complex component separation process, it has been possible to extract CIB anisotropies from the maps on an unprecedented fraction of the sky. Auto- and cross-power spectra have been computed, from 143 to 3000 GHz. Two approaches have been developed to model the power spectra. The first one uses only the linear part of the clustering and give strong constraints on the evolution of the star formation rate up to high redshift. The second one is based on a parametrized relation between the dust-processed infrared luminosity and (sub-)halo mass, probing the interplay between baryonic and dark matter throughout cosmic times at an unmatched redshift depth, complementing current and foreseeable optical or near-infrared measurements. The first part of my talk will be dedicated to the cosmological results of Planck, and their connections to the large-scale structures. Then I will detailed the CIB measurements, the cross-correlation between CIB and the gravitationnal potentiel map (derived from the lensing of CMB photons by large-scale structures), and their implication for the star formation at high-redshift.

Slides in PDF format


Sous la tutelle de:

tutelles

Sous la tutelle de:

CNRS Université Grenoble Alpes