  Time-dependent and direction-dependent neutrino and gravitational-wave (GW)
signatures are presented for a set of 3D hydrodynamic models of parametrized,
neutrino-driven supernova explosions of non-rotating 15 and 20 solar mass
stars. We employ an approximate treatment of neutrino transport. Due to the
excision of the high-density core of the proto-neutron star and the use of an
axis-free overset grid, the models can be followed from the post-bounce
accretion phase for more than one second without imposing any symmetry
restrictions. GW and neutrino emission exhibit the generic time-dependent
features known from 2D models. Non-radial hydrodynamic mass motions in the
accretion layer and their interaction with the outer layers of the
proto-neutron star together with anisotropic neutrino emission give rise to a
GW signal with an amplitude of ~5-20 cm and frequencies 100--500 Hz. The GW
emission from mass motions reaches a maximum before the explosion sets in.
Afterwards the GW signal exhibits a low-frequency modulation, in some cases
describing a quasi-monotonic growth, associated with the non-spherical
expansion of the explosion shock wave and the large-scale anisotropy of the
escaping neutrino flow. Variations of the mass-quadrupole moment due to
convective activity inside the nascent neutron star contribute a high-frequency
component to the GW signal during the post-explosion phase. The GW signals
exhibit strong variability between the two polarizations, different explosion
simulations and different observer directions, and does not possess any
template character. The neutrino emission properties show fluctuations over the
neutron star surface on spatial and temporal scales that reflect the different
types of non-spherical mass motions. The modulation amplitudes of the
measurable neutrino luminosities and mean energies are significantly smaller
than predicted by 2D simulations.
