The asymptotic regimes of tilted Bianchi II cosmologies

In this paper we give. For the first time, a complete description of the dy namics of tilted spatially homogeneous cosmologies of Bianchi type II. The source is assumed to be a perfect fluid with equation of state p = (upsilon - 1)mu, where gamma is a constant. We show that unless the perfect fluid i s stiff, the tilt destabilizes the Kasner solutions. leading to a Mixmaster -like initial singularity. with the tilt being dynamically significant. At late times the tilt becomes dynamically negligible unless the equation of s tate parameter satisfies upsilon > 10/7. We also find that the tilt does no t destabilize the flat FL model, with the result that the presence of tilt increases the likelihood of intermediate isotropization.