Testing modified gravity models with recent cosmological observations
  We explore the cosmological implications of five modified gravity (MG) models
by using the recent cosmological observational data, including the recently
released SNLS3 type Ia supernovae sample, the cosmic microwave background
anisotropy data from the Wilkinson Microwave Anisotropy Probe 7-yr
observations, the baryon acoustic oscillation results from the Sloan Digital
Sky Survey data release 7, and the latest Hubble constant measurement utilizing
the Wide Field Camera 3 on the Hubble Space Telescope. The MG models considered
include the Dvali-Gabadadze-Porrati(DGP) model, two $f(R)$ models, and two
$f(T)$ models. We find that compared with the $\Lambda$CDM model, MG models can
not lead to a appreciable reduction of the $\chi^2_{min}$. The analysis of AIC
and BIC shows that the simplest cosmological constant model($\Lambda$CDM) is
still most preferred by the current data, and the DGP model is strongly
disfavored. In addition, from the observational constraints, we also
reconstruct the evolutions of the growth factor in these models. We find that
the current available growth factor data are not enough to distinguish these MG
models from the $\Lambda$CDM model.
