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We test a cosmological model which the only component is a pressureless fluidwith a constant bulk viscosity as an explanation for the present acceleratedexpansion of the universe. We classify all the possible scenarios for theuniverse predicted by the model according to their past, present and futureevolution and we test its viability performing a Bayesian statistical analysisusing the SCP ``Union'' data set (307 SNe Ia), imposing the second law ofthermodynamics on the dimensionless constant bulk viscous coefficient \zeta andcomparing the predicted age of the universe by the model with the constraintscoming from the oldest globular clusters.  The best estimated values found for \zeta and the Hubble constant Ho are:\zeta=1.922 \pm 0.089 and Ho=69.62 \pm 0.59 km/s/Mpc with a \chi^2=314. The ageof the universe is found to be 14.95 \pm 0.42 Gyr. We see that the estimatedvalue of Ho as well as of \chi^2 are very similar to those obtained from LCDMmodel using the same SNe Ia data set. The estimated age of the universe is inagreement with the constraints coming from the oldest globular clusters.Moreover, the estimated value of \zeta is positive in agreement with the secondlaw of thermodynamics (SLT).  On the other hand, we perform different forms of marginalization over theparameter Ho in order to study the sensibility of the results to the way how Hois marginalized. We found that it is almost negligible the dependence betweenthe best estimated values of the free parameters of this model and the way howHo is marginalized in the present work. Therefore, this simple model might be aviable candidate to explain the present acceleration in the expansion of theuniverse.

Can a matter-dominated model with constant bulk viscosity drive the accelerated expansion of the universe?