COSMOLOGIA COM LENTES GRAVITACIONAIS FRACAS: TESTES DE ISOTROPIA, SOMA DAS MASSAS DE NEUTRINOS E EVOLUÇÃO DE ESTRUTURAS

Abstract

The photons propagating in the Universe have their trajectories disturbed due to the presence of massive structures along the line-of-sight, producing the so-called gravitational lensing effect. Because it is sensitive to the large-scale structure, this effect provides a unique method for mapping the distribution of dark matter, to understand the process of structure formation, as well as setting limits to shed a light in some fundamental questions still open in Cosmology. The present thesis aims to investigate the weak gravitational lensing effect (WL) of the galaxies and of the cosmic microwave background (CMB) to extract cosmological information. In particular, we perform a statistical isotropy test by studying the angular distribution of the variance of the WL map of the Planck collaboration. Our results agree with the statistical isotropy, although there are some regions that deserve to be highlighted as possible indicators of local effects, such as residual contaminants or the presence of (sub) superdensities. In addition, we explore the potentiality to constrain the neutrino mass sum ($\sum m_{\nu}$) using the morphological properties of WL maps. Specifically, we calculate the Minkowski Functionals (MFs) and the power spectrum (PS) in convergence simulations considering the features of the Large Synoptic Survey Telescope-like survey. We find that the MFs are powerful to constrain $\sum m_{\nu}$, since they improve significantly the marginalized errors in comparison with those imposed using only the EP. Finally, going beyond WL, we cross-correlate the WL of the CMB with photometric data of the galaxy clustering combining with the PS data to estimate the linear growth factor of the structures tomographically. In addition, we determine the galaxy bias and the amplitude of the cross-correlation to each redshift bins between $0.1<z<0.7$ and we measure the linear growth factor with amplitude equal to $A_{D}= 1.04 \pm 0.14$, in excellent agreement with the $\Lambda$CDM model. .