Session Q20 - Gravitational Radiation - Theory and Numerical Relativity.
MIXED session, Monday afternoon, May 01
102A, LBCC
One interesting class of gravitational wave sources encompasses rapidly rotating stellar cores that have expended their nuclear fuel and are prevented from undergoing further collapse by centrifugal forces. The development of global rotational instabilities in such a ``centrifugally-hung'' object can produce gravitational radiation and may shed enough angular momentum to allow full collapse to a supernova.
We are using 3-D numerical simulations to investigate the stability of rotating stellar cores modeled as polytropes with N > 3 for various rotation laws. The hydrocode calculates the gravitational field in the Newtonian limit, and the resulting gravitational radiation is computed in the quadrupole approximation. In certain cases we find that such cores can be unstable at values of \beta = T/|W| considerably lower than the Maclaurin limit \beta_d \approx 0.27 for the dynamical bar instability.