General-Relativistic Simulations of Three-Dimensional Core-Collapse Supernovae

Abstract

We study the three-dimensional (3D) hydrodynamics of the post-core-bounce phase of the collapse of a 27 M star and pay special attention to the development of the standing accretion shock instability (SASI) and neutrino-driven convection. To this end, we perform 3D general-relativistic simulations with a three-species neutrino leakage scheme. The leakage scheme captures the essential aspects of neutrino cooling, heating, and lepton number exchange as predicted by radiation-hydrodynamics simulations. The 27 M progenitor was studied in 2D by Müller et al., who observed strong growth of the SASI while neutrino-driven convection was suppressed. In our 3D simulations, neutrino-driven convection grows from numerical perturbations imposed by our Cartesian grid. It becomes the dominant instability and leads to large-scale non-oscillatory deformations of the shock front. These will result in strongly aspherical explosions without the need for large-scale SASI shock oscillations. Low--mode SASI oscillations are present in our models, but saturate at small amplitudes that decrease with increasing neutrino heating and vigor of convection. Our results, in agreement with simpler 3D Newtonian simulations, suggest that once neutrino-driven convection is started, it is likely to become the dominant instability in 3D. Whether it is the primary instability after bounce will ultimately depend on the physical seed perturbations present in the cores of massive stars. The gravitational wave signal, which we extract and analyze for the first time from 3D general-relativistic models, will serve as an observational probe of the postbounce dynamics and, in combination with neutrinos, may allow us to determine the primary hydrodynamic instability.

General-Relativistic Three-Dimensional Multi-Group Neutrino Radiation-Hydrodynamics Simulations of Core-Collapse Supernovae

“…We employ the GR Zelmani CCSN simulation package described in Ott et al (2012Ott et al ( , 2013 and Reisswig et al (2013). Zelmani is based on the open-source Einstein Toolkit (Löffler et al 2012;Mösta et al 2014a) and implements GR hydrodynamics and spacetime evolution with adaptive mesh refinement (AMR).…”

“…Zelmani is based on the open-source Einstein Toolkit (Löffler et al 2012;Mösta et al 2014a) and implements GR hydrodynamics and spacetime evolution with adaptive mesh refinement (AMR). See Ott et al (2013), Reisswig et al (2013), and Löffler et al (2012) for implementation details.…”

“…We draw from Woosley et al (2002) the progenitor model s27, which has been studied in a number of previous works (e.g., Müller et al 2012a;Hanke et al 2013;Ott et al 2013;Couch & O'Connor 2014;Abdikamalov et al 2015). In all simulations, we employ the = K 220 MeV 0 variant of the equation of state of Lattimer & Swesty (1991) .…”

Sources of Gravitational Waves: Theory and Observations

“…What causes shock revival in supernovae that form a NS: neutrino, acoustic and/or magneto-rotational mechanisms? Depending on the supernova mechanism, the predicted energy in GWs from supernovae varies by large factors (see, e.g., [460,461]), indicating the complexity of the problem in numerical simulations. Until we know the mechanism that revives the stalled shock it will not be possible to correctly predict the amplitude of the emitted gravitational radiation or its time-frequency structure.…”

The Development of Explosions in Axisymmetric Ab Initio Core-Collapse Supernova Simulations of 12–25 Stars

“…Takiwaki et al (2012Takiwaki et al ( , 2014 also report 3D Newtonian simulations using Zeus +IDSA. Fully general relativistic simulations with reduced neutrino physics (a leakage scheme for neutrino transport with a reduced set of neutrino interactions)have also beenper-formed using the ZELMANI code (Ott et al 2013;Mösta et al 2014).…”