Core-collapse simulations of rotating stars

We present the results from a series of two-dimensional core-collapse simul ations using a rotating progenitor star. We find that the convection in the se simulations is less vigorous because (1) rotation weakens the core bounc e that seeds the neutrino-driven convection and (2) the angular momentum pr ofile in the rotating core stabilizes against convection. The limited conve ction leads to explosions that occur later and are weaker than the explosio ns produced from the collapse of nonrotating cores. However, because the co nvection is constrained to the polar regions, when the explosion occurs it is stronger along the polar axis. This asymmetric explosion may explain the polarization measurements of core-collapse supernovae. These asymmetries a lso provide a natural mechanism to mix the products of nucleosynthesis out into the helium and hydrogen layers of the star. We also discuss the role t he collapse of these rotating stars plays in the generation of magnetic fie lds and neutron star kicks. Given a range of progenitor rotation periods, w e predict a range of supernova energies for the same progenitor mass. The c ritical mass for black hole formation also depends upon the rotation speed of the progenitor.