Cylindrical collapse and gravitational waves
Résumé
We study the matching conditions for a collapsing anisotropic cylindrical perfect fluid, and we show that its radial pressure is non-zero on the surface of the cylinder and proportional to the time-dependent part of the field produced by the collapsing fluid. This result resembles the one that arises for the radiation---though non-gravitational---in the spherically symmetric collapsing dissipative fluid, in the diffusion approximation.