Abstract

Recent measurements of the cosmic microwave background (CMB) radiation have shown an apparent tension with the present value of the Hubble parameter inferred from local observations of supernovae, which look closer, i.e. brighter, than what is expected in a homogeneous model with a value of the Hubble parameter equal to the one estimated from CMB observations(H^CMB_0).

We examine the possibility that such a discrepancy is the consequence of the presence of a local inhomogeneity seeded by primordial curvature perturbations, finding that a negative peak of the order of less than two standard deviations could allow to fit low red-shift supernovae observations without the need of using a value of the Hubble parameter different from HCMB_0. The type of inhomogeneity we consider does not modify the distance to the last scattering, making it compatible with the constraints of the PLANCK mission data.

We also consider the effects on the value of cosmological constant, finding a possible correction up to the order of 1.5% respect to the value obtained by fitting supernovae ignoring the effects of local inhomogeneities.