Inclusive Constraints on Unified Dark Matter Models from Future Large-Scale Surveys

Understand

In the very last years, cosmological models where the properties of the dark components of the Universe - dark matter and dark energy - are accounted for by a single "dark fluid" have drawn increasing attention and interest.

• Amongst many proposals, Unified Dark Matter (UDM) cosmologies are promising candidates as effective theories.
• In these models, a scalar field with a non-canonical kinetic term in its Lagrangian mimics both the accelerated expansion of the Universe at late times and the clustering properties of the large-scale structure of the cosmos.
• However, UDM models also present peculiar behaviours, the most interesting one being the fact that the perturbations in the dark-matter component of the scalar field do have a non-negligible speed of sound.