Nonlinear Alfvén-wave Dynamics and Premerger Emission from Crustal Oscillations in Neutron Star Mergers

Abstract Neutron stars have solid crusts threaded by strong magnetic fields. Perturbations in the crust can excite nonradial oscillations, which can in turn launch Alfvén waves into the magnetosphere. In the case of a compact binary close to merger involving at least one neutron star, this can happe...

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Published inAstrophysical journal. Letters Vol. 973; no. 2; p. L37
Main Authors Most, Elias R., Kim, Yoonsoo, Chatziioannou, Katerina, Legred, Isaac
Format Journal Article
LanguageEnglish
Published Austin The American Astronomical Society 01.10.2024
IOP Publishing
Subjects
Alfven waves
Astronomical simulations
Binary stars
Crusts
Current sheets
Electrodynamics
Emission
Emissions
General relativity
Gravitational wave sources
Magnetic fields
Magnetohydrodynamic waves
Magnetospheres
Magnetospheric radio emissions
Neutron stars
Nonlinear dynamics
Oscillations
Perturbation
Plasma astrophysics
Radio transient sources
Star mergers
Stars
Stellar magnetic fields
Transient current
X-ray transient sources
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Summary:Abstract Neutron stars have solid crusts threaded by strong magnetic fields. Perturbations in the crust can excite nonradial oscillations, which can in turn launch Alfvén waves into the magnetosphere. In the case of a compact binary close to merger involving at least one neutron star, this can happen through tidal interactions causing resonant excitations that shatter the neutron star crust. We present the first numerical study that elucidates the dynamics of Alfvén waves launched in a compact binary magnetosphere. We seed a magnetic field perturbation on the neutron star crust, which we then evolve in fully general-relativistic force-free electrodynamics using a GPU-based implementation. We show that Alfvén waves steepen nonlinearly before reaching the orbital light cylinder, form flares, and dissipate energy in a transient current sheet. Our results predict radio and X-ray precursor emission from this process.
Bibliography:High-Energy Phenomena and Fundamental Physics
AAS56943
ISSN:2041-8205
2041-8213
DOI:10.3847/2041-8213/ad785c