Observational constraints on finite scale factor singularities
  We discuss the combined constraints on a Finite Scale Factor Singularity (FSF) universe evolution scenario, which come from the shift parameter R, baryon acoustic oscillations (BAO) A, and from the type Ia supernovae. We show that observations allow existence of such singularities in the 2x10^9 years, in future, at the 1{\sigma} CL, and that at the present moment of the cosmic evolution, one cannot differentiate between cosmological scenario which allow finite scale factor singularities and the standard dark energy models. We also show that there is an allowed value of m = 2/3 within 1{\sigma} CL, which corresponds to a dust-filled Einstein-de-Sitter universe limit of the early time evolution. 
Tomasz Denkiewicz
astro-ph.CO gr-qc hep-th