Stability and collapse of rapidly rotating, supramassive neutron stars: 3Dsimulations in general relativity - art. no. 044012

We perform 3D numerical simulations in full general relativity to study the stability of rapidly rotating, supramassive neutron stars at the mass-shed ding limit to dynamical collapse. We adopt an adiabatic equation of state w ith Gamma = 2 and focus on uniformly rotating stars. We find that the onset of dynamical instability along mass-shedding sequences nearly coincides wi th the onset of secular instability. Unstable stars collapse to rotating bl ack holes within about one rotation period. We also study the collapse of s table stars which have been destabilized by pressure depletion (e.g., via a phase transition) or mass accretion. in no case do we find evidence for th e formation of massive dish or any ejecta around the newly formed Kerr blac k holes, even though the progenitors are rapidly rotating.