Orador: Diego Sáez-Gómez (Universidade de Lisboa). Data, hora e local: 13 de Outubro de 2015, às 11h30m na sala de reuniões do Departamento de Matemática.
Resumo: Over the last years, several model-independent methods in cosmology have been proposed as a tool for reconstructing theoretical models departing from observational data. This may be used to test the Standard cosmological model and its comparison with other theories. One such model-independent method is the so-called cosmographic approach, which relies only in the homogeneity and isotropy of the Universe on large scales. In this talk, I review some model-independent parametrizations of dark energy, and in particular I will focus on the many shortcomings within cosmographic approach, which provide biased results depending on the auxiliary variable used in the series expansion and is unable to rule out models or adequately reconstruct theories with higher-order derivatives in either the gravitational or matter sector.