A NEW MULTI-DIMENSIONAL GENERAL RELATIVISTIC NEUTRINO HYDRODYNAMIC CODE FOR CORE-COLLAPSE SUPERNOVAE. I. METHOD AND CODE TESTS IN SPHERICAL SYMMETRY
- Max-Planck-Institut fuer Astrophysik, Karl-Schwarzschild-Str. 1, D-85748 Garching (Germany)
- Physics Department, Aristotle University of Thessaloniki, GR-54124 Thessaloniki (Greece)
We present a new general relativistic code for hydrodynamical supernova simulations with neutrino transport in spherical and azimuthal symmetry (one dimension and two dimensions, respectively). The code is a combination of the COCONUT hydro module, which is a Riemann-solver-based, high-resolution shock-capturing method, and the three-flavor, fully energy-dependent VERTEX scheme for the transport of massless neutrinos. VERTEX integrates the coupled neutrino energy and momentum equations with a variable Eddington factor closure computed from a model Boltzmann equation and uses the 'ray-by-ray plus' approximation in two dimensions, assuming the neutrino distribution to be axially symmetric around the radial direction at every point in space, and thus the neutrino flux to be radial. Our spacetime treatment employs the Arnowitt-Deser-Misner 3+1 formalism with the conformal flatness condition for the spatial three metric. This approach is exact for the one-dimensional case and has previously been shown to yield very accurate results for spherical and rotational stellar core collapse. We introduce new formulations of the energy equation to improve total energy conservation in relativistic and Newtonian hydro simulations with grid-based Eulerian finite-volume codes. Moreover, a modified version of the VERTEX scheme is developed that simultaneously conserves energy and lepton number in the neutrino transport with better accuracy and higher numerical stability in the high-energy tail of the spectrum. To verify our code, we conduct a series of tests in spherical symmetry, including a detailed comparison with published results of the collapse, shock formation, shock breakout, and accretion phases. Long-time simulations of proto-neutron star cooling until several seconds after core bounce both demonstrate the robustness of the new COCONUT-VERTEX code and show the approximate treatment of relativistic effects by means of an effective relativistic gravitational potential as in PROMETHEUS-VERTEX to be remarkably accurate in spherical symmetry.
- OSTI ID:
- 21455201
- Journal Information:
- Astrophysical Journal, Supplement Series, Vol. 189, Issue 1; Other Information: DOI: 10.1088/0067-0049/189/1/104; ISSN 0067-0049
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
COSMOLOGY AND ASTRONOMY
AXIAL SYMMETRY
BOLTZMANN EQUATION
COMPUTERIZED SIMULATION
COSMIC NEUTRINOS
ENERGY CONSERVATION
ENERGY DEPENDENCE
HYDRODYNAMICS
LEPTON NUMBER
METRICS
NEUTRON STARS
RELATIVISTIC RANGE
SPACE-TIME
SPHERICAL CONFIGURATION
SUPERNOVAE
BINARY STARS
CONFIGURATION
COSMIC RADIATION
DIFFERENTIAL EQUATIONS
ELEMENTARY PARTICLES
ENERGY RANGE
EQUATIONS
ERUPTIVE VARIABLE STARS
FERMIONS
FLUID MECHANICS
INTEGRO-DIFFERENTIAL EQUATIONS
IONIZING RADIATIONS
KINETIC EQUATIONS
LEPTONS
MASSLESS PARTICLES
MECHANICS
NEUTRINOS
PARTIAL DIFFERENTIAL EQUATIONS
RADIATIONS
SIMULATION
STARS
SYMMETRY
VARIABLE STARS