Testing the homogeneity and isotropy of the Universe with recent observations

by Elisabetta Majerotto

Friday 10 Apr 2015, 15:00 → 16:00 Europe/Rome

Aula Conversi (Dipartimento di Fisica - Ed. G. Marconi)

In this seminar I will illustrate constraints on the homogeneity and isotropy of the Universe obtained with the most recent data. In the first part of my talk I will describe the Clarkson et al. test of the Friedmann-Lemaitre-Robertson-Walker cosmology, which consists in analysing the possible deviation of the ΩK(z) function from a constant. The test was performed by reconstructing in a model-independent way both the Hubble parameter and the comoving distance via the most recent Hubble and Supernovae Ia data. Good agreement was found with the expected values of the standard cosmological model within the experimental errors, which are, however, large enough to allow for alternative cosmologies. A discrimination between the models may be possible for more precise future data. In the second part of the talk I will show recent constraints to the backreaction model based on the template metric proposed in Larena et al. (2008). A higher matter density with respect to the corresponding FLRW cosmology is necessary to fit both Supernovae Ia and angular diameter distances from clusters data, while CMB data seem to require a lower matter density. I will conclude by exploring the possible reasons for this result.