Non-vacuum exact gravitational waves invariant for a non Abelian two-dimensional Lie algebra generated by two Killing fields whose commutator is of light type, are described. The polarization of these waves, already known from previous works, is related to their natural sources consisting of cosmic strings and γ-ray bursts. Non vacuum exact gravitational waves admitting only one Killing field o...

We show that gravitational waves can act as waveguides for electromagnetic radiation, is, if the latter is initially aligned with waves, then alignment will survive during propagation. The analysis performed using Hamiltonian formalism and Jacobi equation null geodesics, conditions certain cases of polarization are obtained. effect waveguiding by influence interpretation associated wave events,...

1550-7998=20 The most promising way to compute the gravitational waves emitted by binary black holes (BBHs) in their last dozen orbits, where post-Newtonian techniques fail, is a quasistationary approximation introduced by Detweiler and being pursued by Price and others. In this approximation the outgoing gravitational waves at infinity and downgoing gravitational waves at the holes’ horizons a...