Measuring the dark matter equation of state and its cosmological consequences

We explore the consequences of the measurements of the equation of state of dark matter(7), on the homogenous FRW universe dynamics and build an alternative cosmological scenario to the concordance Lambda CDM universe. The new paradigm is based on the introduction of an effective scalar field replacing the undetected components of the dark sector: dark matter and dark energy in the form of a cosmological constant. The scalar field obeys a barotropic equation of state p = omega rho with omega = -1/3 and dominates the cosmological dynamics in the last 14.27 Gyr, in a universe with an age of 14.83 Gyr. Before that epoch, baryons and photons drove the general behaviour of the universe as in the standard Lambda CDM scenario. We compute a minimal set of cosmological parameters which allow us to reproduce several observational results such us baryon abundance, constrains on the age of the universe, the astronomical scale of distance and the high redshift supernova data with a high degree of precision. However, it should be emphasized that the new model is not accelerating, instead expands asymptotically towards an Einstein Static Universe. We briefly mention the possible mechanisms behind the origin of such dominant component and analyze the prospective of reproducing the success of the standard cosmological model explaining the process of structure formation.