Observational Constraints on Cardassian Expansion

In this work, we have studied the observational constraints on the Cardassian model for dark energy. We have compared the model with existing supernova data. The dependence of the locations of the cosmic microwave background radiation (CMBR) peaks on the parameters of the model have also been studied. We find, in particular, that observational data from Archeops for the location of the first peak and BOOMERANG for the location of the third peak, together with the supernova data, significantly constrain the parameter space.