  We present a detailed theoretical analysis of the gravitational-wave (GW)
signal of the post-bounce evolution of core-collapse supernovae (SNe),
employing for the first time relativistic, two-dimensional (2D) explosion
models with multi-group, three-flavor neutrino transport based on the
ray-by-ray-plus approximation. The waveforms reflect the accelerated mass
motions associated with the characteristic evolutionary stages that were also
identified in previous works: A quasi-periodic modulation by prompt postshock
convection is followed by a phase of relative quiescence before growing
amplitudes signal violent hydrodynamical activity due to convection and the
standing accretion shock instability during the accretion period of the stalled
shock. Finally, a high-frequency, low-amplitude variation from proto-neutron
star (PNS) convection below the neutrinosphere appears superimposed on the
low-frequency trend associated with the aspherical expansion of the SN shock
after the onset of the explosion. Relativistic effects in combination with
detailed neutrino transport are shown to be essential for quantitative
predictions of the GW frequency evolution and energy spectrum, because they
determine the structure of the PNS surface layer and its characteristic g-mode
frequency. Burst-like high-frequency activity phases, correlated with sudden
luminosity increase and spectral hardening of electron (anti-)neutrino emission
for some 10ms, are discovered as new features after the onset of the explosion.
They correspond to intermittent episodes of anisotropic accretion by the PNS in
the case of fallback SNe. We find stronger signals for more massive progenitors
with large accretion rates. The typical frequencies are higher for massive
PNSs, though the time-integrated spectrum also strongly depends on the model
dynamics.
