Impact of Magnetic-field-driven Anisotropies on the Equation of State Probed in Neutron Star Mergers
Year: 2025
Type: article
Abstract: 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.
Authors: Elias R. Most, Jeffrey Peterson, Luigi Scurto, Helena Pais, Veronica Dexheimer
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,400
Funders: National Science Foundation, U.S. Department of Energy, National Aeronautics and Space Administration, National Centre for Supercomputing Applications, National Energy Research Scientific Computing Center, Office of Science, Fundação para a Ciência e a Tecnologia, Office of Advanced Cyberinfrastructure
Awards: G122673668, G1286236842, G1353381076, G1366167006, G1453181110, G1503004319, G1513662220, G1632040200, G1677143136, Matéria em condições extremas: estrelas de neutrões na era multi-mensageiro, G1863003419, Track 4: Advanced CI Coordination Ecosystem: Monitoring and Measurement Services, G2271788581, G229093490, G298330452, G3096413036, Centro de Física da Universidade de Coimbra, G3304567311, G3457066133, G3562386289, Frameworks: MUSES, Modular Unified Solver of the Equation of State, G3907738059, WoU-MMA: Aspects of Numerical Relativity and Relativistic Astrophysics, Track 1: ACCESS Resource Allocations Marketplace and Platform Services (RAMPS), G4010157413, G419881185, G42916606, G4403015908, G4501827968, G4646331299, ACO: An Open CI Ecosystem to Advance Scientific Discovery (OpenCI), G498139845, G5076365615, Track 3: COre National Ecosystem for CyberinfrasTructure (CONECT), G5259912098, XMatStar: Compact objects in the new multi-messenger era: exploring matter under extreme conditions, G5367127336, G5418235317, G5464919783, G643508668, G6652958823, Centro de Física da Universidade de Coimbra, G8103039852, G8108599699, Track 2: Customized Multi-tier Assistance, Training, and Computational Help (MATCH) for End User ACCESS to CI, G8590638883
OpenAlex ID: W4416260225