Bulk viscous cosmological model with interacting dark fluids
  The objective of the present work is to study a cosmological model for a
spatially flat Universe whose constituents are a dark energy field and a matter
field which includes baryons and dark matter. The constituents are supposed to
be in interaction and irreversible processes are taken into account through the
inclusion of a non-equilibrium pressure. The non-equilibrium pressure is
considered to be proportional to the Hubble parameter within the framework of a
first order thermodynamic theory. The dark energy and matter fields are coupled
by their barotropic indexes, which are considered as functions of the ratio
between their energy densities. The free parameters of the model are adjusted
from the best fits of the Hubble parameter data. A comparison of the viscous
model with the non-viscous one is performed. It is shown that the equality of
the dark energy and matter density parameters and the decelerated-accelerated
transition occur at earlier times when the irreversible processes are present.
Furthermore, the density and deceleration parameters and the distance modulus
have the correct behavior which is expected for a viable scenario of the
present status of the Universe.
