Inhomogeneous cosmologies with Q matter and varying Λ

Starting from the inhomogeneous shear-free Nariai metric we show, by solving the Einstein-Klein-Gordon field equations, how a self-interacting scalar field plus a material fluid, a variable cosmological term, and a heat flux can drive the universe to its currently observed state of homogeneous accelerated expansion. A quintessence scenario where power-law inflation takes place for a string-motivated potential in the late-time dominated field regime is proposed. ©1999 The American Physical Society.