Testing Extended Theories of Gravity at different astrophysical scales

PROJECT DESCRIPTION

The project is focused on the possibility to explain the observed galactic and extragalactic dynamics using gravitational potentials derived from Extended Gravity Theories (ETGs) without considering the presence of dark matter (DM). ETGs are alternative theories of gravitational interaction, coming from the formulation of Quantum Field Theory on curved spacetime. They are developed starting from General Relativity with the aim to cure its shortcomings. They are based on straightforward generalizations of the Einstein theory assuming that the gravitational action is not only linear in the Ricci curvature scalar R but can be any function of curvature invariants, in particular f(R) gravity. These theories can have observational signatures at astrophysical and cosmological scales. In particular, we will consider possible signatures for different ETG potentials within the Galactic Central Parsec.
The simulated stellar orbits, obtained by modified gravity potentials, will be compared with astronomical observations. The results can give strong constraints on the gravity interaction parameters and then on the final theory of gravity. We will also use ETGs to investigate the possible existence of further gravitational radii which can play analogue roles as the Schwarzschild radius. Such new fundamental lengths emerge thanks to the further degrees of freedom of the considered theories. Our aim is to see if such features can be identified in the galactic and extragalactic structures, so we intend to study the baryonic Tully-Fisher relation of gas-rich galaxies and the Fundamental Plane of elliptical galaxies in order to see if their
intrinsic relations come out without the DM hypothesis. The compelling aspect of the project consists with the fact that astrophysical structures could be naturally explained without DM since no final evidence of this ingredient has been found, up to now, also with very high precision experiments as those running at CERN.