“ESTUDO DE MODELOS DE GRAVIDADE MODIFICADA USANDO DADOS COSMOLÓGICOS DE AGLOMERAÇÃO DE MATÉRIA”

Abstract

The growth of cosmic structures is investigated through the analyses of f(z) and σ8(z) cosmic observables data, using non-parametric Gaussian Process reconstructions combined with MCMC statistical analyses. The standard flat-LCDM model, General Relativity–based extensions, and F(R) modified gravity scenarios are systematically compared in terms of statistical performance, physical consistency, and the level of tension in the S8 parameter relative to the Planck -2018 benchmark. Our results show that, while LCDM remains consistent with current data, it exhibits deviations at high redshifts. Among physically viable alternatives, the Hu–Sawicki (n = 1) model emerges as the most robust scenario, providing good agreement with observational data and compatibility with local gravity tests, while the Starobinsky (n = 2) model appears as a competitive alternative by moderately alleviating the S8 tension.