The luminosity-redshift relation in brane-worlds: II. Confrontation with experimental data

Abstract

The luminosity distance - redshift relation for a wide class of generalized Randall-Sundrum type II brane-world models with Weyl fluid is compared to the presently available supernova data. We find that there is a class of spacially flat models with different amounts of matter $Ω_ρ$ and Weyl fluid $Ω_{d}$, which have a very similar fitting quality. The best-fit models are equally likely and can be regarded as extensions of the $Λ$CDM model, which is also included. We examine three models with different evolutionary history of the Weyl fluid, characterized by a parameter $α=0,~2$ and$~3$. The first model describes a brane which had radiated energy into the bulk some time ago, but in recent times this energy exchange has ceased and only a dark radiation ($α=0$) is left. In the other two models the Weyl-fluid describes a radiating brane throughout the cosmological evolution, up to our days. We find that the trought of the fitting surface extends over a wider $Ω_{d}$-range with increasing $α$, but the linear correlation of $Ω_{d}$ and $Ω_ρ$ holds all over the examined $Ω_{d}$ range.

Comparison with observations enhanced as compared to v1 of astro-ph/0606698. Discussion based on Gold2006 data set included, preferred values of cosmological parameters given. Argument supporting a relatively high value of the dark radiation developed. v2: Tests of radiating brane models included, published version (15 pages, 10 figures)