Welcome to the website of CAUSTIC which is an astrophysics and cosmological physics group at the University of Torino . We currently investigate two connected aspects of modern cosmology:

Large-scale cosmic structure

Alternative Theories of Gravity & Cosmology

We are based in the beautiful Italian city of Torino, at the foothills of the Alps. We are affiliated to the
• Departments of Physics at the
• University of Torino (UNITO) , the
• Istituto Nazionale di Fisica Nucleare (INFN) and the
• Istituto Nazionale di Astrofisica (INAF) .

Large Scale Cosmic Structure

We use N-body/hydrodynamical simulations and observations in different bands to investigate the formation and evolution of galaxies, clusters and larger structures.

We investigate the role of high-energy astrophysical processes (supernovae explosions and Active Galactic Nuclei energy emission) in the formation efficiency of stars and galaxies.

We have also developed the caustic technique, a unique method to estimate the mass of galaxy clusters well beyond the region of dynamical equilibrium. The method is based on galaxy redshifts alone and is complementary to the more popular gravitational lensing techniques.

Alternative Theories of Gravity & Cosmology

The wealth of cosmological data is currently interpreted with the Lambda-CDM model: Einstein's cosmological constant and cold dark matter.

However, there is no obvious physical mechanism that can generate the cosmological constant or more sophisticated dark energy fluids, nor is there any direct or indirect confirmation of the existence of the cold dark matter particle.

There are also many puzzling aspects of related physical fields: inflation is still not well understood, we do not comprehend the full details of neutrino oscillations and we do not have a theory of quantum gravity.

There are a large number of alternative theories to Einstein's General Relativity. We do not devote ourselves to a single theory, but investigate a wide range of models, successful at different scales.

These include Conformal Gravity, notable for naturally explaining the presence of dark energy (DE). Modified Newtonian Dynamics which began as an algorithm to match the asymptotic flatness of rotation curves and the tight slope of the Tully-Fisher relation. Also, Unified Dark Matter (UDM) models that reduce DM and DE to a single dark fluid owed to a scalar field with a standard kinetic term.

We make the best possible use of all observational constraints to test their viability at all scales and epochs.