  By performing axisymmetric hydrodynamic simulations of core-collapse
supernovae with spectral neutrino transport based on the isotropic diffusion
source approximation scheme, we support the assumption that the
neutrino-heating mechanism aided by the standing accretion shock instability
and convection can initiate an explosion of a 13 $M_{\odot}$ star. Our results
show that bipolar explosions are more likely to be associated with models which
include rotation. We point out that models, which form a north-south symmetric
bipolar explosion, can lead to larger explosion energies than for the
corresponding unipolar explosions.
