Stellar Core-collapse Simulations with the Boltzmann-radiation-hydrodynamics Code under Axisymmetry

Abstract

We report the stellar core-collapse simulations of the 11.2 \(M_{ \odot }\) progenitor under axisymmetry with varying the nuclear equations of state (EOSs) and the rotational velocities by using the Boltzmann-radiation-hydrodynamics code. The problem of the explosion mechanism of core-collapse supernovae involves a variety of physical processes such as neutrino transport and the nuclear force. Such a complicated phenomenon requires numerical simulations to be examined. The Boltzmann-Radiation-Hydrodynamics code developed by us solves the hydrodynamics and the Boltzmann equations for neutrino transport. The employed models are the non-rotating models with the Lattimer & Swesty (LS) EOS and the Furusawa & Shen (FS) EOS, and the rotating model with the FS EOS. The shock in the non-rotating LS model seems to revive, while those in both the non-rotating and rotating FS model do not revive because of the difference in the nuclear compositions and the slow rotational velocity. The momentum distributions of neutrinos are also examined. Especially, the Eddington tensors are investigated. The Eddington tensor is the key quantity in the M1-closure method, a commonly used approximation for neutrino transport. We report the accuracy of the approximation, and this evaluation offers useful insight into the calibration of the M1-closure scheme.