Fluid accretion onto relativistic stars and gravitational radiation

This article reports results from numerical simulations of the gravitational radiation emitted from nonrotating relativistic stars as a result of the axisymmetric accretion of layers of perfect fluid matter, shaped in the form of quadrupolar shells. We adopt a {\em hybrid} procedure where we evolve numerically the polar nonspherical perturbations equations of the star coupled to a fully nonlinear hydrodynamics code that calculates the motion of the accreting matter. Self-gravity of the accreting fluid as well as radiation reaction effects are neglected.