PEIRONE S.

Clusters of galaxies have the potential of providing powerful constraints on possible deviations from General Relativity. We use the catalog of Sunyaev-Zel'dovich (SZ) sources detected by Planck and consider a correction to the halo mass function for a f(R) class of modified gravity models, which has been recently found to reproduce well...

We investigate the impact of general conditions of theoretical stability and cosmological viability on dynamical dark energy models. As a powerful example, we study whether minimally coupled, single field quintessence models that are safe from ghost instabilities, can source the Chevallier-Polarski-Linder (CPL) expansion history recently shown...

We revisit the cosmology of covariant Galileon gravity in view of the most recent cosmological data sets, including weak lensing. As a higher derivative theory, covariant Galileon models do not have a ΛCDM limit and predict a very different structure formation pattern compared with the standard ΛCDM scenario. Previous cosmological analyses...

Phenomenological functions Σ and μ, also known as Glight/G and Gmatter/G, are commonly used to parametrize modifications of the growth of large-scale structure in alternative theories of gravity. We study the values these functions can take in Horndeski theories, i.e., the class of scalar-tensor theories with second order equations of motion....

Ongoing and upcoming cosmological surveys will significantly improve our ability to probe the equation of state of dark energy, wDE, and the phenomenology of large scale structure. They will allow us to constrain deviations from the Λ cold dark matter predictions for the relations between the matter density contrast and the weak lensing and the...

There has been substantial interest in modifications of the standard Λ cold dark matter (ΛCDM, where Λ is the cosmological constant) cosmological model prompted by tensions between certain datasets, most notably the Hubble tension. The late-time modifications of the ΛCDM model can be parameterized by three time-dependent functions describing...

We compare Einstein-Boltzmann solvers that include modifications to general relativity and find that, for a wide range of models and parameters, they agree to a high level of precision. We look at three general purpose codes that primarily model general scalar-tensor theories, three codes that model Jordan-Brans-Dicke (JBD) gravity, a code that...