Observational constraints on phantom power-law cosmology
  We investigate phantom cosmology in which the scale factor is a power law,
and we use cosmological observations from Cosmic Microwave Background (CMB),
Baryon Acoustic Oscillations (BAO) and observational Hubble data, in order to
impose complete constraints on the model parameters. We find that the power-law
exponent is $\beta\approx-6.51^{+0.24}_{-0.25}$, while the Big Rip is realized
at $t_s\approx104.5^{+1.9}_{-2.0}$ Gyr, in 1$\sigma$ confidence level.
Providing late-time asymptotic expressions, we find that the dark-energy
equation-of-state parameter at the Big Rip remains finite and equal to
$w_{DE}\approx -1.153$, with the dark-energy density and pressure diverging.
Finally, we reconstruct the phantom potential.
