A New Multi-Dimensional General Relativistic Neutrino Hydrodynamics Code for Core-Collapse Supernovae II. Relativistic Explosion Models of Core-Collapse Supernovae

摘要

We present the first two-dimensional general relativistic (GR) simulations ofstellar core collapse and explosion with the CoCoNuT hydrodynamics code incombination with the VERTEX solver for energy-dependent, three-flavor neutrinotransport, using the extended conformal flatness condition for approximatingthe spacetime metric and a ray-by-ray-plus ansatz to tackle themulti-dimensionality of the transport. For both of the investigated 11.2 and 15solar mass progenitors we obtain successful, though seemingly marginal,neutrino-driven supernova explosions. This outcome and the time evolution ofthe models basically agree with results previously obtained with the PROMETHEUShydro solver including an approximative treatment of relativistic effects by amodified Newtonian potential. However, GR models exhibit subtle differences inthe neutrinospheric conditions compared to Newtonian and pseudo-Newtoniansimulations. These differences lead to significantly higher luminosities andmean energies of the radiated electron neutrinos and antineutrinos andtherefore to larger energy-deposition rates and heating efficiencies in thegain layer with favorable consequences for strong non-radial mass motions andultimately for an explosion. Moreover, energy transfer to the stellar mediumaround the neutrinospheres through nucleon recoil in scattering reactions ofheavy-lepton neutrinos also enhances the mentioned effects. Together withprevious pseudo-Newtonian models the presented relativistic calculationssuggest that the treatment of gravity and energy-exchanging neutrinointeractions can make differences of even 50-100% in some quantities and islikely to contribute to a finally successful explosion mechanism on no minorlevel than hydrodynamical differences between different dimensions.