Time-dependent cosmologies and their duals

We construct a family of solutions in IIB supergravity theory. These are time-dependent or depend on a light-like coordinate and can be thought of as deformations of AdS₅×S⁵. Several of the solutions have singularities. The light-like solutions preserve 8 supersymmetries. We argue that these solutions are dual to the N=4 gauge theory in a $3+1$ dimensional space-time with a metric and a gauge coupling that is varying with time or the light-like direction, respectively. This identification allows us to map the question of singularity resolution to the dual gauge theory.