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arXiv · 2306.15721

A large-scale magnetic field produced by a solar-like dynamo in binary neutron star mergers

Kenta Kiuchi·Alexis Reboul-Salze·Masaru Shibata·Yuichiro Sekiguchi
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Abstract

The merger of neutron stars drives a relativistic jet which can be observed as a short gamma-ray burst. A strong large-scale magnetic field is necessary to launch the relativistic jet. However, the magnetohydrodynamical mechanism to build up this magnetic field remains uncertain. Here we show that the $\alpha\Omega$ dynamo mechanism driven by the magnetorotational instability builds up the large-scale magnetic field inside the long-lived binary neutron star merger remnant by performing an {\it ab initio} super-high resolution neutrino-radiation magnetohydrodynamics merger simulation in full general relativity. As a result, the magnetic field induces the Poynting-flux dominated relativistic outflow with the luminosity $\sim 10^{51}$\,erg/s and magnetically-driven post-merger mass ejection with the mass $\sim 0.1M_\odot$. Therefore, the magnetar scenario in binary neutron star mergers is possible. These can be the engines of short-hard gamma-ray bursts and very bright kilonovae. Therefore, this scenario is testable in future observation.

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Kenta Kiuchi, Alexis Reboul-Salze, Masaru Shibata, Yuichiro Sekiguchi. 2023-06-27. A large-scale magnetic field produced by a solar-like dynamo in binary neutron star mergers. https://arxiv.org/abs/2306.15721

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