Power-law cosmology, SN Ia, and BAO
  We revise observational constraints on the class of models of modified gravity which at low redshifts lead to a power-law cosmology. To this end we use available public data on Supernova Ia and on baryon acoustic oscillations. We show that the expansion regime $a(t) \sim t^{\beta}$ with $\beta$ close to 3/2 a spatially flat universe is a good fit to these data. 
A. Dolgov, V. Halenka, and I. Tkachev
astro-ph.CO