Comparison of cosmological models using standard rulers and candles
  In this paper, we used standard rulers and standard candles (separately and
jointly) to explore five popular dark energy models under assumption of spatial
flatness of the Universe. As standard rulers, we used a data set comprising 118
galactic-scale strong lensing systems (individual standard rulers if properly
calibrated for the mass density profile) combined with BAO diagnostics
(statistical standard ruler). Supernovae Ia served asstandard candles. Unlike
in the most of previous statistical studies involving strong lensing systems,
we relaxed the assumption of singular isothermal sphere (SIS) in favor of its
generalization: the power-law mass density profile. Therefore, along with
cosmological model parameters we fitted the power law index and its first
derivative with respect to the redshift (thus allowing for mass density profile
evolution). It turned out that the best fitted $\gamma$ parameters are in
agreement with each other irrespective of the cosmological model considered.
This demonstrates that galactic strong lensing systems may provide a
complementary probe to test the properties of dark energy. Fits for
cosmological model parameters which we obtained are in agreement with
alternative studies performed by the others. Because standard rulers and
standard candles have different parameter degeneracies, combination of standard
rulers and standard candles gives much more restrictive results for
cosmological parameters. At last, we attempted at model selection based on
information theoretic criteria (AIC and BIC). Our results support the claim,
that cosmological constant model is still the best one and there is no (at
least statistical) reason to prefer any other more complex model.
