title: Nonlinear r-modes in rapidly rotating relativistic stars.
abstract: The r-mode instability in rotating relativistic stars has been shown recently to have important astrophysical implications, provided that r-modes are not saturated at low amplitudes by nonlinear effects or by dissipative mechanisms. Here, we present the first study of nonlinear r-modes in isentropic, rapidly rotating relativistic stars, via 3D general-relativistic hydrodynamical evolutions. We find that (1) on dynamical time scales, there is no strong nonlinear coupling of r-modes to other modes at amplitudes of order one-the maximum r-mode amplitude is of order unity. (2) r-modes and inertial modes in isentropic stars are predominantly discrete modes. (3) The kinematical drift associated with r-modes appears to be present in our simulations, but confirmation requires more precise initial data.
authors.affiliation: Department of Physics, Aristotle University of Thessaloniki, Thessaloniki 54006, Greece.
authors.forename: N
authors.initials: N
authors.lastname: Stergioulas
authors.forename: J A
authors.initials: JA
authors.lastname: Font