Linear coasting in cosmology and SNe Ia

A strictly linear evolution of the cosmological expansion scale factor is a characteristic feature in several classes of alternative gravity theories as also in the standard (Big-bang) model with specially chosen equations of state of matter. Such an evolution has no free parameters as far as the classical cosmological tests are concerned and should therefore be easily falsifiable. In this Letter we demonstrate how such models present very good fits to the current supernovae Ia data. We discuss the overall viability of such models.