Tilted string cosmologies

Global symmetries of the string effective action are employed to generate t ilted, homogeneous Bianchi type VIh string cosmologies from a previously kn own stiff perfect fluid solution to Einstein gravity. The dilaton field is not constant on the surfaces of homogeneity. The future asymptotic state of the models is interpreted as a plane wave and is itself an exact solution to the string equations of motion to all orders in the inverse string tensi on. An inhomogeneous generalization of the Bianchi type III model is also f ound. (C) 1999 Elsevier Science B.V. All rights reserved.