Paper: astro-ph/0512355
Date: Wed, 14 Dec 2005 05:20:28 GMT (78kb)

Title: Exponential Cardassian Universe

Authors: Dao-jun Liu, Chang-bo Sun, Xin-zhou Li

Comments: 13 pages, 5 eps figures, using Latex with elsart.cls
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The expectation of explaining cosmological observations without requiring new
energy sources is forsooth worthy of investigation. In this letter, a new kind
of Cardassian models, called exponential Cardassian models, for the late-time
universe are investigated in the context of the spatially flat FRW universe
scenario. We fit the exponential Cardassian models to current type Ia
supernovae data and find they are consistent with the observations.
Furthermore, we point out that the equation-of-state parameter for the
effective dark fluid component in exponential Cardassian models can naturally
cross the cosmological constant divide $w=-1$ that observations favor mildly
without introducing exotic material that destroy the weak energy condition.

\\ ( http://arXiv.org/abs/astro-ph/0512355 , 78kb)