Inhomogeneous cosmological models in scalar-tensor theories

Exact self-similar spatially inhomogeneous G(2) cosmological models are found in a class of scalar-tensor theories of gravity by exploiting the formal equivalence of this class of theories (under a conformal transformation and field redefinition) to general relativity minimally coupled to a scaler field with an exponential potential. We argue that these exact self-similar solutions may play an important role in describing the asymptotic behaviour (both at early and at late times) of more general scalar-tensor G(2) models. The possible isotropization and the homogenization of these models is briefy discussed.