Gravitational radiation from stellar collapse - Ellipsoidal models

The burst of gravitational radiation emitted during the initial collapse and rebound of a homogeneous ellipsoid with internal pressure is analyzed numerically. A configuration of mass 1.4 solar masses is assumed to collapse aspherically from rest at an initial density of 10 billion g per cu cm. The deviations from spherical symmetry arise from rotation and internal magnetic fields; deviations from axisymmetry are also considered. By following the collapse along two distinct low-entropy adiabats ('hot' and 'cold' collapse) on free-fall time scales, the maximum amount of gravitational radiation liberated during the initial implosion of a compact stellar core is estimated. The total gravitational (quadrupole) radiation energy loss, the radiation spectra, and the wave forms for several collapse sequences, parameterized by their initial deviations from spherical symmetry, are calculated. A minimum estimate of the total neutrino losses during this initial collapse phase is also provided.