B. Mueller, H. -Th. Janka, A. Marek
We present the first two-dimensional general relativistic (GR) simulations of
stellar core collapse and explosion with the CoCoNuT hydrodynamics code in
combination with the VERTEX solver for energy-dependent, three-flavor neutrino
transport, using the extended conformal flatness condition for approximating
the spacetime metric and a ray-by-ray-plus ansatz to tackle the
multi-dimensionality of the transport. For both of the investigated 11.2 and 15
solar mass progenitors we obtain successful, though seemingly marginal,
neutrino-driven supernova explosions. This outcome and the time evolution of
the models basically agree with results previously obtained with the PROMETHEUS
hydro solver including an approximative treatment of relativistic effects by a
modified Newtonian potential. However, GR models exhibit subtle differences in
the neutrinospheric conditions compared to Newtonian and pseudo-Newtonian
simulations. These differences lead to significantly higher luminosities and
mean energies of the radiated electron neutrinos and antineutrinos and
therefore to larger energy-deposition rates and heating efficiencies in the
gain layer with favorable consequences for strong non-radial mass motions and
ultimately for an explosion. Moreover, energy transfer to the stellar medium
around the neutrinospheres through nucleon recoil in scattering reactions of
heavy-lepton neutrinos also enhances the mentioned effects. Together with
previous pseudo-Newtonian models the presented relativistic calculations
suggest that the treatment of gravity and energy-exchanging neutrino
interactions can make differences of even 50-100% in some quantities and is
likely to contribute to a finally successful explosion mechanism on no minor
level than hydrodynamical differences between different dimensions.
View original:
http://arxiv.org/abs/1202.0815
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