Gravitational radiation from convective instabilities in Type II supernova explosions.

Abstract

We present two- and three-dimensional simulations of convective instabilities during the first second of a Type II supernova explosion. Convective overturn occurs in two distinct, spatially well separated regions: (i) inside the proto-neutron star immediately below the neutrinosphere (r<or#approx#50 km) and (ii) in the neutrino-heated ''hot-bubble'' region interior to the outward propagating revived shock wave (100 km <or#approx#r<or#approx#1000 km). We have calculated the gravitational wave signature of both convective instabilities including the quadrupole waveforms, the energy spectra, and the total amount of the emitted gravitational wave energy. Moreover, we have estimated the amplitude and energy of gravitational waves associated with the anisotropic neutrino emission that is caused by the convective transport of neutrinos and by aspherical perturbations of temperature and density in the neutrinospheric region. For a supernova located at a distance of 10 kpc the maximum dimensionless gravitational wave amplitudes due to convective mass motions range from vertical stroke h"T"T vertical stroke #approx#2.10"-"2"2 for the three-dimensional simulation to vertical stroke h"T"T vertical stroke #approx#7.10"-"2"1 for the most strongly radiating two-dimensional model. The total emitted energy varies from 10"-"1"3 M_sunc"2 to 2.10"-"9 M_sunc"2