2007A&A...464..465R

Extinction due to intergalactic grey dust has been proposed as an alternative to accelerated expansion to account for the dimming of SnIa fluxes beyond z≃0.5. The ``replenishing'' grey dust model, although fitting the observational data, does not seem to be based on physical assumptions. For this reason, in this paper we propose a new grey dust model whose dust distribution follows the comoving SFR density evolution, a reasonably established phenomenon. This new model is compared with the updated photometric data sample from the High Z Supernova Search Team (HZT). Also, using pairs of supernovae at different redshifts, the possibility of any ``patchy'' distribution proposed to explain the discrepancies between the ``high z'' dust model and the SnIa observations at very high redshift (z≥0.9) is ruled out. Finally, the data are compared with different models with and without dark energy and a best fit to a universe with adimensional parameters Ω_m0=0.31 and Ω_Λ0=0.69 is obtained, from which an age of the universe of t₀≃14.6x10⁹years is derived. This age is compatible with the age of the globular clusters using an equation of state ω=-1 and it obviates the need to resort to any kind of phantom energy.