Impact of Magnetic-field-driven Anisotropies on the Equation of State Probed in Neutron Star Mergers

Binary neutron star mergers can produce extreme magnetic fields, some of which can lead to strong magnetar-like remnants. While strong magnetic fields have been shown to affect the dynamics of outflows and angular momentum transport in the remnant, they can also crucially alter the properties of nuc...

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Main Authors: Elias R. Most, Jeffrey Peterson, Luigi Scurto, Helena Pais, Veronica Dexheimer
Format: Article
Language:English
Published: IOP Publishing 2025-01-01
Series:The Astrophysical Journal Letters
Subjects:
Online Access:https://doi.org/10.3847/2041-8213/adf62d
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author Elias R. Most
Jeffrey Peterson
Luigi Scurto
Helena Pais
Veronica Dexheimer
author_facet Elias R. Most
Jeffrey Peterson
Luigi Scurto
Helena Pais
Veronica Dexheimer
author_sort Elias R. Most
collection DOAJ
description Binary neutron star mergers can produce extreme magnetic fields, some of which can lead to strong magnetar-like remnants. While strong magnetic fields have been shown to affect the dynamics of outflows and angular momentum transport in the remnant, they can also crucially alter the properties of nuclear matter probed in the merger. In this work, we provide a first assessment of the latter, determining the strength of the pressure anisotropy caused by Landau-level quantization and the anomalous magnetic moment. To this end, we perform the first numerical relativity simulation with a magnetic polarization tensor and a magnetic-field-dependent equation of state using a new algorithm we present here, which also incorporates a mean-field dynamo model to control the magnetic field strength present in the merger remnant. Our results show that—in the most optimistic case—corrections to the anisotropy can be in excess of 10% and are potentially largest in the outer layers of the remnant. This work paves the way for a systematic investigation of these effects.
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spelling doaj-art-abe79071d49342f08f61e149c4650e2e2025-08-20T03:36:38ZengIOP PublishingThe Astrophysical Journal Letters2041-82052025-01-019892L2910.3847/2041-8213/adf62dImpact of Magnetic-field-driven Anisotropies on the Equation of State Probed in Neutron Star MergersElias R. Most0https://orcid.org/0000-0002-0491-1210Jeffrey Peterson1https://orcid.org/0000-0002-6703-418XLuigi Scurto2https://orcid.org/0000-0002-8763-5660Helena Pais3https://orcid.org/0000-0001-7247-1950Veronica Dexheimer4https://orcid.org/0000-0001-5578-2626TAPIR, Mailcode 350-17, California Institute of Technology , Pasadena, CA 91125, USA; Walter Burke Institute for Theoretical Physics, California Institute of Technology , Pasadena, CA 91125, USADepartment of Physics, Kent State University , Kent, OH 44243, USACFisUC, Department of Physics, University of Coimbra , 3004-516 Coimbra, PortugalCFisUC, Department of Physics, University of Coimbra , 3004-516 Coimbra, PortugalDepartment of Physics, Kent State University , Kent, OH 44243, USABinary neutron star mergers can produce extreme magnetic fields, some of which can lead to strong magnetar-like remnants. While strong magnetic fields have been shown to affect the dynamics of outflows and angular momentum transport in the remnant, they can also crucially alter the properties of nuclear matter probed in the merger. In this work, we provide a first assessment of the latter, determining the strength of the pressure anisotropy caused by Landau-level quantization and the anomalous magnetic moment. To this end, we perform the first numerical relativity simulation with a magnetic polarization tensor and a magnetic-field-dependent equation of state using a new algorithm we present here, which also incorporates a mean-field dynamo model to control the magnetic field strength present in the merger remnant. Our results show that—in the most optimistic case—corrections to the anisotropy can be in excess of 10% and are potentially largest in the outer layers of the remnant. This work paves the way for a systematic investigation of these effects.https://doi.org/10.3847/2041-8213/adf62dNeutron starsNuclear astrophysicsGeneral relativityNuclear physicsMagnetohydrodynamics
spellingShingle Elias R. Most
Jeffrey Peterson
Luigi Scurto
Helena Pais
Veronica Dexheimer
Impact of Magnetic-field-driven Anisotropies on the Equation of State Probed in Neutron Star Mergers
The Astrophysical Journal Letters
Neutron stars
Nuclear astrophysics
General relativity
Nuclear physics
Magnetohydrodynamics
title Impact of Magnetic-field-driven Anisotropies on the Equation of State Probed in Neutron Star Mergers
title_full Impact of Magnetic-field-driven Anisotropies on the Equation of State Probed in Neutron Star Mergers
title_fullStr Impact of Magnetic-field-driven Anisotropies on the Equation of State Probed in Neutron Star Mergers
title_full_unstemmed Impact of Magnetic-field-driven Anisotropies on the Equation of State Probed in Neutron Star Mergers
title_short Impact of Magnetic-field-driven Anisotropies on the Equation of State Probed in Neutron Star Mergers
title_sort impact of magnetic field driven anisotropies on the equation of state probed in neutron star mergers
topic Neutron stars
Nuclear astrophysics
General relativity
Nuclear physics
Magnetohydrodynamics
url https://doi.org/10.3847/2041-8213/adf62d
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