Camera, Stefano, Carbone, Carmelita and Moscardini, Lauro (2012), "Inclusive constraints on unified dark matter models from future
large-scale surveys", JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS, 3.
Abstract: 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 ``darkfluid'' have drawn increasing
attention and interest. Amongst many proposals, Unified Dark Matter
(UDM) cosmologies are promising candidates as effective theories. In
these models, a scalarfield 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 largescale 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.
This gives rise to an effective Jeans scale for the Newtonian potential,
below which the dark fluid does not cluster any more. This implies a
growth of structures fairly different from that of the concordance
Lambda CDM model. In this paper ,we demonstrate that forthcoming
large-scale surveys will be able to discriminate between viable UDM
models and Lambda CDM to a good degree of accuracy. To this purpose, the
planned Euclid satellite will be a powerful tool, since it will provide
very accurate data on galaxy clustering and the weak lensing effect of
cosmic shear. Finally, we also exploit the constraining power of the
ongoing CMB Planck experiment. Although our approach is the most
conservative, with the inclusion of only well-understood, linear
dynamics, in the end we also show what could be done if some amount of
non-linear information were included.
Keywords: dark matter theory; cosmological parameters from LSS; cosmology of
theories beyond the SM; dark energy theory