GR-Athena++: General-relativistic Magnetohydrodynamics Simulations of Neutron Star Spacetimes
We present the extension of GR-Athena++ to general-relativistic magnetohydrodynamics (GRMHD) for applications to neutron star spacetimes. The new solver couples the constrained transport implementation of Athena++ to the Z4c formulation of the Einstein equations to simulate dynamical spacetimes with...
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| Language: | English |
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IOP Publishing
2025-01-01
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| Series: | The Astrophysical Journal Supplement Series |
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| Online Access: | https://doi.org/10.3847/1538-4365/ad87d4 |
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| author | William Cook Boris Daszuta Jacob Fields Peter Hammond Simone Albanesi Francesco Zappa Sebastiano Bernuzzi David Radice |
| author_facet | William Cook Boris Daszuta Jacob Fields Peter Hammond Simone Albanesi Francesco Zappa Sebastiano Bernuzzi David Radice |
| author_sort | William Cook |
| collection | DOAJ |
| description | We present the extension of GR-Athena++ to general-relativistic magnetohydrodynamics (GRMHD) for applications to neutron star spacetimes. The new solver couples the constrained transport implementation of Athena++ to the Z4c formulation of the Einstein equations to simulate dynamical spacetimes with GRMHD using oct-tree adaptive mesh refinement. We consider benchmark problems for isolated and binary neutron star spacetimes demonstrating stable and convergent results at relatively low resolutions and without grid symmetries imposed. The code correctly captures magnetic field instabilities in nonrotating stars with total relative violation of the divergence-free constraint of 10 ^−16 . It handles evolutions with a microphysical equation of state and black hole formation in the gravitational collapse of a rapidly rotating star. For binaries, we demonstrate correctness of the evolution under the gravitational radiation reaction and show convergence of gravitational waveforms. We showcase the use of adaptive mesh refinement to resolve the Kelvin–Helmholtz instability at the collisional interface in a merger of magnetised binary neutron stars. GR-Athena++ shows strong scaling efficiencies above 80% in excess of 10 ^5 CPU cores and excellent weak scaling is shown up to ∼5 × 10 ^5 CPU cores in a realistic production setup. GR-Athena++ allows for the robust simulation of GRMHD flows in strong and dynamical gravity with exa-scale computers. |
| format | Article |
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| institution | Kabale University |
| issn | 0067-0049 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
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| series | The Astrophysical Journal Supplement Series |
| spelling | doaj-art-d9f0aa4d27e9478f9f8a5bc1ad2e004a2025-02-12T08:59:37ZengIOP PublishingThe Astrophysical Journal Supplement Series0067-00492025-01-012771310.3847/1538-4365/ad87d4GR-Athena++: General-relativistic Magnetohydrodynamics Simulations of Neutron Star SpacetimesWilliam Cook0https://orcid.org/0000-0003-2244-3462Boris Daszuta1Jacob Fields2https://orcid.org/0000-0001-5705-1712Peter Hammond3Simone Albanesi4https://orcid.org/0000-0001-7345-4415Francesco Zappa5Sebastiano Bernuzzi6https://orcid.org/0000-0002-2334-0935David Radice7https://orcid.org/0000-0001-6982-1008Theoretisch-Physikalisches Institut , Friedrich-Schiller-Universität Jena, 07743 Jena, Germany ; william.cook@uni-jena.deTheoretisch-Physikalisches Institut , Friedrich-Schiller-Universität Jena, 07743 Jena, Germany ; william.cook@uni-jena.deInstitute for Gravitation and the Cosmos, The Pennsylvania State University , University Park, PA 16802, USA; Department of Physics, The Pennsylvania State University , University Park, PA 16802, USAInstitute for Gravitation and the Cosmos, The Pennsylvania State University , University Park, PA 16802, USADipartimento di Fisica, Universitá di Torino , Torino 10125, Italy; INFN Sezione di Torino , Torino 10125, ItalyTheoretisch-Physikalisches Institut , Friedrich-Schiller-Universität Jena, 07743 Jena, Germany ; william.cook@uni-jena.deTheoretisch-Physikalisches Institut , Friedrich-Schiller-Universität Jena, 07743 Jena, Germany ; william.cook@uni-jena.deInstitute for Gravitation and the Cosmos, The Pennsylvania State University , University Park, PA 16802, USA; Department of Physics, The Pennsylvania State University , University Park, PA 16802, USA; Department of Astronomy and Astrophysics, The Pennsylvania State University , University Park, PA 16802, USAWe present the extension of GR-Athena++ to general-relativistic magnetohydrodynamics (GRMHD) for applications to neutron star spacetimes. The new solver couples the constrained transport implementation of Athena++ to the Z4c formulation of the Einstein equations to simulate dynamical spacetimes with GRMHD using oct-tree adaptive mesh refinement. We consider benchmark problems for isolated and binary neutron star spacetimes demonstrating stable and convergent results at relatively low resolutions and without grid symmetries imposed. The code correctly captures magnetic field instabilities in nonrotating stars with total relative violation of the divergence-free constraint of 10 ^−16 . It handles evolutions with a microphysical equation of state and black hole formation in the gravitational collapse of a rapidly rotating star. For binaries, we demonstrate correctness of the evolution under the gravitational radiation reaction and show convergence of gravitational waveforms. We showcase the use of adaptive mesh refinement to resolve the Kelvin–Helmholtz instability at the collisional interface in a merger of magnetised binary neutron stars. GR-Athena++ shows strong scaling efficiencies above 80% in excess of 10 ^5 CPU cores and excellent weak scaling is shown up to ∼5 × 10 ^5 CPU cores in a realistic production setup. GR-Athena++ allows for the robust simulation of GRMHD flows in strong and dynamical gravity with exa-scale computers.https://doi.org/10.3847/1538-4365/ad87d4Compact binary starsGravitational wavesGeneral relativityMagnetohydrodynamicsMagnetohydrodynamical simulationsNeutron stars |
| spellingShingle | William Cook Boris Daszuta Jacob Fields Peter Hammond Simone Albanesi Francesco Zappa Sebastiano Bernuzzi David Radice GR-Athena++: General-relativistic Magnetohydrodynamics Simulations of Neutron Star Spacetimes The Astrophysical Journal Supplement Series Compact binary stars Gravitational waves General relativity Magnetohydrodynamics Magnetohydrodynamical simulations Neutron stars |
| title | GR-Athena++: General-relativistic Magnetohydrodynamics Simulations of Neutron Star Spacetimes |
| title_full | GR-Athena++: General-relativistic Magnetohydrodynamics Simulations of Neutron Star Spacetimes |
| title_fullStr | GR-Athena++: General-relativistic Magnetohydrodynamics Simulations of Neutron Star Spacetimes |
| title_full_unstemmed | GR-Athena++: General-relativistic Magnetohydrodynamics Simulations of Neutron Star Spacetimes |
| title_short | GR-Athena++: General-relativistic Magnetohydrodynamics Simulations of Neutron Star Spacetimes |
| title_sort | gr athena general relativistic magnetohydrodynamics simulations of neutron star spacetimes |
| topic | Compact binary stars Gravitational waves General relativity Magnetohydrodynamics Magnetohydrodynamical simulations Neutron stars |
| url | https://doi.org/10.3847/1538-4365/ad87d4 |
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