Comparing dark energy models with current observational data
  We make a comparison for thirteen dark energy (DE) models by using current
cosmological observations, including type Ia supernova, baryon acoustic
oscillations, and cosmic microwave background. To perform a systematic and
comprehensive analysis, we consider three statistics methods of SNIa, including
magnitude statistic (MS), flux statistic (FS), and improved flux statistic
(IFS), as well as two kinds of BAO data. In addition, Akaike information
criteria (AIC) and Bayesian information criteria (BIC) are used to assess the
worth of each model. We find that: (1) The thirteen models can be divided into
four grades by performing cosmology-fits. The cosmological constant model,
which is most favored by current observations, belongs to grade one;
$\alpha$DE, constant $w$ and generalized Chaplygin gas models belong to grade
two; Chevalliear-Polarski-Linder (CPL) parametrization, Wang parametrization,
doubly coupled massive gravity, new generalized Chaplygin gas and holographic
DE models belong to grade three; agegraphic DE, Dvali-Gabadadze-Porrati, Vacuum
metamorphosis and Ricci DE models, which are excluded by current observations,
belong to grade four. (2) For parameter estimation, adopting IFS yields the
biggest $\Omega_m$ and the smallest $h$ for all the models. In contrast, using
different BAO data does not cause significant effects. (3) IFS has the
strongest constraint ability on various DE models. For examples, adopting IFS
yields the smallest value of $\Delta$AIC for all the models; in addition,
making use of this technique yields the biggest figure of merit for CPL and
Wang parametrizations.
