Constraints on interacting Dark Energy models from galaxy rotation curves

Interacting Dark Energy models have been as a possible to the standard ΛCDM concordance cosmological in order to ease the fine-tuning problems of the cosmological . However, the interaction of the Dark Energy field with other particles in the universe induces also an effective modification structure formation processes, leading to a different dynamical of density perturbations with respect to the standard scenario. particular, high-resolution N-body simulations have recently shown also the structural properties of highly nonlinear objects, as e.g. average concentration at a given mass, could be significantly in the presence of an interaction between Dark Energy and Dark . While a constant interaction strength leads to less concentrated profiles, a steep growth in time of the coupling function has shown to determine a large increase of halo concentrations over a range of masses, including the typical halos hosting luminous galaxies. This determines a substantial worsening of the "cusp-core" tension arising in the standard ΛCDM model and a direct way to constrain the form of the Dark Energy . In the present paper we make use of the outcomes of some -resolution N-body simulations of a specific class of interacting Energy models to compare the predicted rotation curves of luminous galaxies forming in these cosmologies against real observational . Our results show how some specific interacting Dark Energy featuring a steep growth in time of the coupling function — which are virtually indistinguishable from ΛCDM in the — cannot fit the observed rotation curves of luminous galaxies and can therefore be ruled out only on the basis of properties of small-scale structures. Our study is a pilot of the effects of a Dark Energy interaction at small , and demonstrates how the dynamical properties of visible can in some cases provide direct constraints on the nature of Energy.