Brans-Dicke model constrained from Big Bang nucleosynthesis and magnitude redshift relations of Supernovae

Abstract

The Brans-Dicke model with a variable cosmological term ($BDΛ$) has been investigated with use of the coupling constant of $ω=10^4$. Parameters inherent in this model are constrained from comparison between Big Bang nucleosynthesis and the observed abundances. Furthermore, the magnitude redshift ($m-z$) relations are studied for $BDΛ$ with and without another constant cosmological term in a flat universe. Observational data of Type Ia Supernovae are used in the redshift range of $0.01<z<2$. It is found that our model with energy density of the constant cosmological term with the value of 0.7 can explain the SNIa observations, though the model parameters are insensitive to the $m-z$ relation.

Submitted to A&A, 4 pages, 3 figures