Constraints on scalar-tensor theories in an accelerating universe

We consider a presently accelerating universe in the framework of a scalar-tensor theory of gravity. We show how one can reconstruct the full theory - namely, the field potential and the functional form of the scalar-gravity coupling - along with the present density of dustlike matter using the following cosmological observations: luminosity distance data and linear dustlike matter density fluctuations data, both as functions of redshift. On the other hand luminosity distance observations on their own provide powerful constraints on classes of scalar-tensor theories.