Constraining unified dark matter models with weak lensing

Unified Dark Matter (UDM) models provide an intriguing alternative to Dark Matter (DM) and Dark Energy (DE) through only one exotic component, i.e. a classical scalar field φ(t, x ). Thanks to a non–canonical kinetic term, this scalar field can mimic both the behaviour of the matter–dominated era at earlier times, as DM do, and the outcoming late–time acceleration, as a cosmological constant DE. Thus, it has been shown that these models can reproduce the same expansion history of the ΛCDM concordance model. In this work I review the first prediction of a physical observable, the power spectrum of the weak lensing cosmic convergence (shear). I present the weak lensing signal as predicted by the standard ΛCDM model and by a family of viable UDM models parameterized by the late–time sound speed c ∞ of the scalar field.last–scattering surface and a series of background galaxies peaked at different redshifts and spread over different redshifts as described by a functional form of their distribution of sources.