Constraints on Cardassian universe from Gamma ray bursts
  Constraints on the original Cardassian model and the modified polytropic
Cardassian model are examined from the recently derived 42 gamma-ray bursts
(GRBs) data calibrated with the method avoiding the circularity problem. The
results show that GRBs can be an optional observation to constrain on the
Cardassian models. Combining the GRBs data with the newly derived size of
baryonic acoustic oscillation peak from the Sloan Digital Sky Survey (SDSS),
and the position of first acoustic peak of the Cosmic Microwave Background
radiation (CMB) from Wilkinson Microwave Anisotropy Probe (WMAP), we find
$\Omega_{m0}=0.27_{-0.02}^{+0.02}, n=0.06_{-0.08}^{+0.07}$ ($1\sigma$) for the
original Cardassian model, and $\Omega_{m0}=0.27^{+0.03}_{-0.02}$,
$n=-0.09_{-1.91}^{+0.23}, \beta=0.82_{-0.62}^{+2.10}$ ($1\sigma$) for the
modified polytropic Cardassian model.
