Tayler-Spruit dynamo in binary neutron star merger remnants

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Auteurs principaux: Reboul-Salze, Alexis, Barrère, Paul, Kiuchi, Kenta, Guilet, Jérôme, Raynaud, Raphaël, Fujibayashi, Sho, Shibata, Masaru
Format: Preprint
Publié: 2024
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author Reboul-Salze, Alexis
Barrère, Paul
Kiuchi, Kenta
Guilet, Jérôme
Raynaud, Raphaël
Fujibayashi, Sho
Shibata, Masaru
author_facet Reboul-Salze, Alexis
Barrère, Paul
Kiuchi, Kenta
Guilet, Jérôme
Raynaud, Raphaël
Fujibayashi, Sho
Shibata, Masaru
contents In binary neutron star mergers, the remnant can be stabilized by differential rotation before it collapses into a black hole. Therefore, the angular momentum transport mechanisms are crucial for predicting the lifetime of the hypermassive neutron star. One such mechanism is the Tayler-Spruit dynamo, and recent simulations have shown that it could grow in proto-neutron stars formed during supernova explosions. We aim to investigate whether hypermassive neutron stars with high neutrino viscosity could be unstable to the Tayler-Spruit dynamo and study how magnetic fields would evolve in this context. Using a one-zone model based on the result of a 3D GRMHD simulation, we investigate the time evolution of the magnetic fields generated by the Tayler-Spruit dynamo. In addition, we analyze the dynamics of the 3D GRMHD simulation to determine whether the dynamo is present. Our one-zone model predicts that the Tayler-Spruit dynamo can increase the toroidal magnetic field to $ \ge 10^{17}$ G and the dipole field to amplitudes $\ge 10^{16}$ G. The dynamo's growth timescale depends on the initial large-scale magnetic field right after the merger. In the case of a long-lived hypermassive neutron star, an initial magnetic field of $\ge 10^{12}$ G would be enough for the magnetic field to be amplified in a few seconds. However, we show that the resolution of the current GRMHD simulations is insufficient to resolve the Tayler-Spruit dynamo due to high numerical dissipation at small scales. We find that the Tayler-Spruit dynamo could occur in hypermassive neutron stars and shorten their lifetime, which would have consequences on multi-messenger observations.
format Preprint
id arxiv_https___arxiv_org_abs_2411_19328
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Tayler-Spruit dynamo in binary neutron star merger remnants
Reboul-Salze, Alexis
Barrère, Paul
Kiuchi, Kenta
Guilet, Jérôme
Raynaud, Raphaël
Fujibayashi, Sho
Shibata, Masaru
High Energy Astrophysical Phenomena
In binary neutron star mergers, the remnant can be stabilized by differential rotation before it collapses into a black hole. Therefore, the angular momentum transport mechanisms are crucial for predicting the lifetime of the hypermassive neutron star. One such mechanism is the Tayler-Spruit dynamo, and recent simulations have shown that it could grow in proto-neutron stars formed during supernova explosions. We aim to investigate whether hypermassive neutron stars with high neutrino viscosity could be unstable to the Tayler-Spruit dynamo and study how magnetic fields would evolve in this context. Using a one-zone model based on the result of a 3D GRMHD simulation, we investigate the time evolution of the magnetic fields generated by the Tayler-Spruit dynamo. In addition, we analyze the dynamics of the 3D GRMHD simulation to determine whether the dynamo is present. Our one-zone model predicts that the Tayler-Spruit dynamo can increase the toroidal magnetic field to $ \ge 10^{17}$ G and the dipole field to amplitudes $\ge 10^{16}$ G. The dynamo's growth timescale depends on the initial large-scale magnetic field right after the merger. In the case of a long-lived hypermassive neutron star, an initial magnetic field of $\ge 10^{12}$ G would be enough for the magnetic field to be amplified in a few seconds. However, we show that the resolution of the current GRMHD simulations is insufficient to resolve the Tayler-Spruit dynamo due to high numerical dissipation at small scales. We find that the Tayler-Spruit dynamo could occur in hypermassive neutron stars and shorten their lifetime, which would have consequences on multi-messenger observations.
title Tayler-Spruit dynamo in binary neutron star merger remnants
topic High Energy Astrophysical Phenomena
url https://arxiv.org/abs/2411.19328