Phenomenology of Unified Dark Matter Models with Fast Transition

Abstract

A fast transition between a standard matter-like era and a late ΛCDM-like epoch generated by a single Unified Dark Matter component can explain the observed acceleration of the Universe. UDM models with a fast transition should be clearly distinguishable from ΛCDM (and alternatives) through observations. Here we focus on a particularly simple model and analyse its viability by studying features of the background model and properties of the adiabatic UDM perturbations. © Springer-Verlag Berlin Heidelberg 2014.