Simultaneous expansion and rotation of shear-free universes in modified gravity

Abstract

We show in a fully covariant way that, there exist a class of $f(R)$ models for which a shear-free, almost FLRW universe can expand and rotate at the same time .

arXiv comment4 pages, no figures. Contribution submitted to the proceedings of the Spanish Relativity Meeting ERE2011, September 2011, Madrid, Spain