Constraints from High Redshift Supernovae upon Scalar Field Cosmologies

Abstract

Recent observations of high-redshift Type Ia supernovae have placed stringent constraints on the cosmological constant $Λ$. We explore the implications of these SNe observations for cosmological models in which a classically evolving scalar field currently dominates the energy density of the Universe. Such models have been shown to share the advantages of $Λ$ models: compatibility with the spatial flatness predicted inflation; a Universe older than the standard Einstein-de Sitter model; and, combined with cold dark matter, predictions for large-scale structure formation in good agreement with data from galaxy surveys. Compared to the cosmological constant, these scalar field models are consistent with the SNe observations for a lower matter density, $Ω_{m0} \sim 0.2$, and a higher age, $H_0 t_0 \gtrsim 1$. Combined with the fact that scalar field models imprint a distinctive signature on the cosmic microwave background anisotropy, they remain currently viable and should be testable in the near future.

RevTex style format, 14 pages, 11 eps figures included with epsf, submitted to Phys. Rev. D