Methods (Word Document): A detailed discussion of the theoretical models and numerical methods employed in the Letter.)

Movies:

• Non-Rotating Progenitor
  • Entropy.qt (24MB, Quicktime) Evolution of the unstable accretion shock illustrating the transition from the sloshing mode of the SASI to the spiral mode. The flow is depicted with a set of transparent isosurfaces of constant entropy.
  • Slice.mpg (1MB, MPEG) 2D slice showing the flow in the equatorial plane (as defined by the SASI rotation) for one rotational period of the spiral SASI mode. The grey scale corresponds to gas entropy.
  • AngMom.mov (81MB, Quicktime) Volume rendering of the specific angular momentum from a phase of the evolution dominated by the spiral SASI mode. This rendering was created by Kwan-Liu Ma.

• Rotating Progenitor
  • Rotate.mov (10MB, Quicktime) The evolution of the accretion shock, as shown by a pressure isosurface. The color represents the gas density at the shock.