Numerical Relativity Simulations of Magnetized Black Hole-Neutron Star Mergers

TL;DR

This paper introduces new numerical techniques for simulating magnetized black hole-neutron star mergers, revealing that magnetic fields minimally affect gravitational waveforms but can influence the remnant disk, potentially powering short gamma-ray bursts.

Contribution

Developed novel numerical methods for magnetized BHNS merger simulations and demonstrated magnetic fields' limited impact on gravitational waveforms.

Findings

Magnetic fields have negligible impact on gravitational waveforms.

Magnetic fields can influence the properties of the remnant disk.

Seeding the disk with magnetic fields may support short gamma-ray burst engines.

Abstract

We present new numerical techniques we developed for launching the first parameter study of {\it magnetized} black hole--neutron star (BHNS) mergers, varying the magnetic fields seeded in the initial neutron star. We found that magnetic fields have a negligible impact on the gravitational waveforms and bulk dynamics of the system during merger, regardless of magnetic field strength or BH spin. In a recent simulation, we seeded the remnant disk from an unmagnetized BHNS merger simulation with large-scale, purely poloidal magnetic fields, which are otherwise absent in the full simulation. The outcome appears to be a viable sGRB central engine.