La radiación del fondo cósmico de microondas a gran escala y la teoría de picos

Résumé

In this PhD thesis, the large-scale anisotropies in the Cosmic Microwave Background (CMB) radiation are analysed. In particular, the theory of peaks in a Gaussian random field on the sphere is reviewed and applied to the CMB temperature and polarization fields, including the eccentricity of the peaks in the formalism. Previous to the characterization of the large-scale peaks, a general study of the derivatives up to second order of the Planck CMB temperature data is performed at different scales, identifying the most significant deviations from the standard cosmological model prediction. A more detailed anaylsis is applied to the largest peaks on the CMB temperature and the Cold Spot. The formalism of the multipolar profiles is used to characterize the shape and geometry of those peaks. Finally, the large-scale anisotropies produced by the Integrated Sachs-Wolfe (ISW) effect are analysed in the last two chapters. In the first one, the claim that the Cold Spot can be originated by the imprint on the CMB temperature of a supervoid is analysed, considering different dark energy models and void geometries. On the other hand, in the last chapter, the ISW effect is detected from the cross-correlation between the CMB temperature and large-scale structure tracers. In particular, the redshift distribution and angular power spectrum of the NRAO VLA Sky Survey (NVSS) are studied in order to have a theoretical model of the angular cross-power spectrum between the CMB temperature and this galaxy catalogue. Some results presented in the latter chapter are included in the çcolaboración Planck en los artículos dedicados al estudio del efecto Sachs-Wolfe integrado.