Brans-Dicke model constrained from the Big Bang nucleosynthesis and magnitude redshift relations of supernovae (Research Note)
We investigated the Brans-Dicke model with a variable cosmological term (BDΛ) with the coupling constant ω = 10 4 . We constrained the parameters inherent in this model from a comparison between the Big Bang nucleosynthesis and the observed abundances. Furthermore, we studied the magnitude redshift (m − z) relations for the BDΛ with and without another constant cosmological term in a flat universe. Observational data of type Ia supernovae (SNIa) are used in the redshift range of 0.01 < z < 2. We found that our model with an energy density of the constant cosmological term of 0.7 can explain the SNIa observations, though the model parameters are insensitive to the m − z relation.