Combined constraints on modified Chaplygin gas model from cosmological
  observed data: Markov Chain Monte Carlo approach
  We use the Markov Chain Monte Carlo method to investigate a global
constraints on the modified Chaplygin gas (MCG) model as the unification of
dark matter and dark energy from the latest observational data: the Union2
dataset of type supernovae Ia (SNIa), the observational Hubble data (OHD), the
cluster X-ray gas mass fraction, the baryon acoustic oscillation (BAO), and the
cosmic microwave background (CMB) data. In a flat universe, the constraint
results for MCG model are,
  $\Omega_{b}h^{2}=0.02263^{+0.00184}_{-0.00162}$ ($1\sigma$)
$^{+0.00213}_{-0.00195}$ $(2\sigma)$,
  $B_{s}=0.7788^{+0.0736}_{-0.0723}$ ($1\sigma$) $^{+0.0918}_{-0.0904}$
$(2\sigma)$,
  $\alpha=0.1079^{+0.3397}_{-0.2539}$ ($1\sigma$) $^{+0.4678}_{-0.2911}$
$(2\sigma)$,
  $B=0.00189^{+0.00583}_{-0.00756}$ ($1\sigma$) $^{+0.00660}_{-0.00915}$
$(2\sigma)$, and $H_{0}=70.711^{+4.188}_{-3.142}$ ($1\sigma$)
$^{+5.281}_{-4.149}$ $(2\sigma)$.
