Neutrino distributions for a rotating core-collapse supernova with a Boltzmann-neutrino-transport

Abstract

We simulate the collapse of a rotating core of the progenitor with 11.2 solar mass with the Boltzmann-radiation-hydrodynamics code, which solves the Boltzmann equations for neutrino transfer directly. We pay particular attention to the neutrino distribution in phase space, which is affected by the rotation. By solving the Boltzmann equations directly, we can assess the rotation-induced distortion of the angular distribution in momentum space, which gives rise to the rotational component of the neutrino flux. We compare the Eddington tensors calculated both from the raw data and from the M1-closure approximation. We find that the difference in the Eddington factors reaches ˜ 20% in our simulation. This is due to the different dependence of the Eddington and flux factors on the angular profile of the neutrino distribution function, and hence modification to the closure relation is needed.