A Check on the Cardassian Expansion Model with Type-la Supernovae Data

摘要

We use the magnitude-redshift relation for the type Ia supernova datacompiled by Riess et al. to analyze the Cardassian expansion scenario. This sce-nario assumes the universe to be fiat, matter dominated, and accelerating, butcontains no vacuum contribution. The best fitting model parameters are Ho =65.3kms-1 Mpc-1, n = 0.35 and Ωm = 0.05. When the highest redshift supernova,SN 1997ck, is excluded, Ho remains the same, but n becomes 0.20 and Ωm, 0.15, andthe matter density remains unreasonably low. Our result shows that this particularscenario is strongly disfavoured by the SNeIa data.