Weakly Inhomogeneous models for the Low-Redshift Universe.

We analyze two different algorithms for constructing weakly inhomogeneous models for the low-redshift Universe, in order to provide a tool for testing the photon dynamics, within the sphere of validity for the Universe acceleration. We first implement the so-called quasi-isotropic solution in the late Universe, when a pure dark energy equation of state for the cosmological perfect fluid is considered. We demonstrate, that a solution exists only if the physical scale of the inhomogeneities is larger then the Hubble scale of the microphysics, which implies that inhomogeneities could not be observed at present-stage time. Then, we analyze a weakly deformed isotropic Universe toward a spherically symmetric model, thought as the natural metric framework of the {\Lambda}CDM model. The obtained picture offer a useful scenario to investigate the influence of the inhomogeneity spectrum (left free in the obtained solution), on the photon propagation at low redshift values.