Abstract

In a Brans-Dicke (BD) cosmological model, the energy density associated with some scalar field decreases as a(-2[(omega 0+1/2)/(omega 0+1)]) with the scalefactor a(t) of the universe, giving matter with an equation of state p = -(1/3) [(2 + omega(0))(1 + omega(0))]rho. In this model, the universe could be closed but still have a non-relativistic matter density corresponding to its critical value, Ohm(0) = 1. Different cosmological expressions, such as luminosity distance, angular diameter, number count and ratio of the redshift thickness-angular size, are determined in terms of the redshift for this model.