Growth of structures in non-standard Dark Energy models

Despite the fact that the ΛCDM model has been highly successful over the last few decades in providing an accurate fit to a broad range of cosmological and astrophysical observations, different intriguing tensions and anomalies emerged at various statistical levels. Among these, the H0 tension is now exceeding five standard deviations, pointing to new physics beyond the ΛCDM model. Alternative appealing models, still allowed by observations, include the interacting dark energy (IDE) scenario, where dark matter and dark energy interact non-gravitationally. It is well-known that within these interacting cosmologies the growth of structure is modified and departures from the standard cosmological model of structure formation are parameterised via the growth rate f . This study explores the growth of structure in non-standard dark energy cosmologies, trying to extend the standard parametrisation for f to take into account the dependence on the coupling ξ between dark matter and dark energy. We aim as well to place constraints on the phenomenological parameters of these alternative models, by considering different datasets related to different cosmological measurements, to achieve a complementary analysis. We put emphasis, in particular, on redshift space distortion measurements (RSD), whose role has not been recently highlighted.