Takami Kuroda, Kei Kotake, Tomoya Takiwaki
We present results from the first generation of multi-dimensional
hydrodynamic core-collapse simulations in full general relativity (GR) that
include an approximate treatment of neutrino transport. Using a M1 closure
scheme with an analytic variable Eddington factor, we solve the
energy-independent set of radiation energy and momentum based on the Thorne's
momentum formalism. To simplify the source terms of the transport equations, a
methodology of multiflavour neutrino leakage scheme is partly employed. Our
newly developed code is designed to evolve the Einstein field equation together
with the GR radiation hydrodynamic equations. We follow the dynamics starting
from the onset of gravitational core-collapse of a 15 $M_{\odot}$ star, through
bounce, up to about 100 ms postbounce in this study to study how the spacial
multi-dimensionality and GR would affect the dynamics in the early postbounce
phase. Our 3D results support the anticipation in previous 1D results that the
neutrino luminosity and average neutrino energy of any neutrino flavor in the
postbounce phase increase when switching from SR to GR hydrodynamics. This is
because the deeper gravitational well of GR produces more compact core
structures, and thus hotter neutrino spheres at smaller radii. By analyzing the
residency timescale to the neutrino-heating timescale in the gain region, we
show that the criterion to initiate neutrino-driven explosions can be most
easily satisfied in 3D models, irrespective of SR or GR hydrodynamics. Our
results suggest that the combination of GR and 3D hydrodynamics provides the
most favorable condition to drive a robust neutrino-driven explosion.
View original:
http://arxiv.org/abs/1202.2487
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