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

Year: 2024

Type: article

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.

Source: The Astrophysical Journal Letters

DOI: 10.3847/2041-8213/ad785c

Authors: Elias R. Most, Yoonsoo Kim, Katerina Chatziioannou, Isaac Legred

Institution: California Institute of Technology

Language: English

Topic: Pulsars and Gravitational Waves Research

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, Simons Foundation, National Centre for Supercomputing Applications, National Energy Research Scientific Computing Center, Office of Advanced Cyberinfrastructure

OpenAlex ID: W4402745828