Core-collapse supernovae in the hall of mirrors

Abstract

Context. Modeling core-collapse supernovae (SNe) with neutrino transport in three dimensions (3D) requires tremendous computing resources and some level of approximation. We present a first comparison study of core-collapse SNe in 3D with different physics approximations and hydrodynamics codes. Aims. The objective of this work is to assess the impact of the hydrodynamics code, approximations for the neutrino, gravity treatments, and rotation on the simulation of core-collapse SNe in 3D. Methods. We use four different hydrodynamics codes in this work (ELEPHANT, FLASH, fGR1, and SPHYNX) in combination with two different neutrino treatments, the isotropic diffusion source approximation (IDSA) and two-moment M1, and three different gravity treatments (Newtonian, 1D General Relativity correction, and full General Relativity). Additional parameters discussed in this study are the inclusion of neutrino-electron scattering via a parametrized deleptonization and the influence of rotation. Results. The four codes compared in this work include Eulerian and fully Lagrangian (smoothed particle hydrodynamics) codes for the first time. They show agreement in the overall evolution of the collapse phase and early post-bounce within the range of 10% (20% in some cases). The comparison of the different neutrino treatments highlights the need to further investigate the antineutrino luminosities in IDSA, which tend to be relatively high. We also demonstrate the requirement for a more detailed heavy-lepton neutrino leakage. When comparing with a full General Relativity code, including an M1 transport method, we confirm the influence of neutrino-electron scattering during the collapse phase, which is adequately captured by the parametrized deleptonization scheme. Also, the effective general relativistic potential reproduces the overall dynamic evolution correctly in all Newtonian codes. Additionally, we verify that rotation aids the shock expansion and estimate the overall angular momentum losses for each code in rotating scenarios.

Post-explosion evolution of core-collapse supernovae

“…In the determination of the electron fraction, there are two critical quantities: the energy difference be- tween antineutrinos and neutrinos (∆ ν = νe − νe ) and the ratio of neutrino number luminosities (RL n = L n,νe /L n,νe ). Following previous studies based on simulations with accurate neutrino transport (see e.g., Liebendörfer et al 2005;Bruenn et al 2016;Takiwaki et al 2016;Kotake et al 2018;Cabezón et al 2018;Just et al 2018;O'Connor & Couch 2018;Summa et al 2018;Vartanyan et al 2018Vartanyan et al , 2019aMüller 2019;Pan et al 2019;Powell & Müller 2020;Kuroda et al 2020), one can find typical energy differences of ∆ ν = νe − νe ≈ 2 − 2.5 MeV. In our models we have on average ∆ ν = (2.3 ± 0.6) MeV after the explosion time.…”

Microscopic equation of state of hot nuclear matter for numerical relativity simulations

“…These represent the minimal set of the most relevant weak processes during the collapse and in the early post-bounce phase. The emission of µ and τ (anti)neutrinos in the post-bounce phase is handled by a gray leakage scheme (Cabezón et al 2018). This scheme has been gauged on detailed Boltzmann transport models, and includes pair annihilation, nucleon-nucleon bremsstrahlung, and scattering off nucleons.…”

Simple method of diagnosing fast flavor conversions of supernova neutrinos

“…This is a computationally demanding task even for the simplest toy models and perhaps prohibitively difficult for the multidimensional continuous angular distributions found in SN simulations. Second, most of the state-ofthe-art simulations [25][26][27][28][29][30][31][32][33] maintain only the moments of the angular distributions of fluxes and not the full distributions. This lack of information seems to preclude even a linear stability analysis that requires knowing these distributions.…”