The merger of binary neutron stars (BNSs) can lead to large amplifications of the magnetic field due to the development of turbulence and instabilities in the fluid, such as the Kelvin'Helmholtz shear instability, which drive small-scale dynamo activity. In order to properly resolve such instabilities and obtain the correct magnetic field amplification, one would need to employ resolutions that are currently unfeasible in global general relativistic magnetohydrodynamic simulations of BNS mergers. Here, we present a subgrid model that allows global simulations to take into account the small-scale amplification of the magnetic field which is caused by the development of turbulence during BNS mergers. Assuming dynamo saturation, we show that magnetar-level fields (∼1016 G) can be easily reached, and should therefore be expected from the merger of magnetized BNSs. The total magnetic energy can reach values up to ∼1051 erg and the post-merger remnant can therefore emit strong electromagnetic signals and possibly produce short gamma-ray bursts.

Giacomazzo, B., Zrake, J., Duffell, P., Macfadyen, A., Perna, R. (2015). Producing Magnetar Magnetic Fields in the Merger of Binary Neutron Stars. THE ASTROPHYSICAL JOURNAL, 809(1) [10.1088/0004-637X/809/1/39].

Producing Magnetar Magnetic Fields in the Merger of Binary Neutron Stars

Giacomazzo, Bruno
Primo
;
2015

Abstract

The merger of binary neutron stars (BNSs) can lead to large amplifications of the magnetic field due to the development of turbulence and instabilities in the fluid, such as the Kelvin'Helmholtz shear instability, which drive small-scale dynamo activity. In order to properly resolve such instabilities and obtain the correct magnetic field amplification, one would need to employ resolutions that are currently unfeasible in global general relativistic magnetohydrodynamic simulations of BNS mergers. Here, we present a subgrid model that allows global simulations to take into account the small-scale amplification of the magnetic field which is caused by the development of turbulence during BNS mergers. Assuming dynamo saturation, we show that magnetar-level fields (∼1016 G) can be easily reached, and should therefore be expected from the merger of magnetized BNSs. The total magnetic energy can reach values up to ∼1051 erg and the post-merger remnant can therefore emit strong electromagnetic signals and possibly produce short gamma-ray bursts.
Articolo in rivista - Articolo scientifico
gamma-ray burst: general; magnetohydrodynamics (MHD); methods: numerical; stars: magnetars; stars: neutron; Space and Planetary Science; Astronomy and Astrophysics
English
2015
809
1
39
reserved
Giacomazzo, B., Zrake, J., Duffell, P., Macfadyen, A., Perna, R. (2015). Producing Magnetar Magnetic Fields in the Merger of Binary Neutron Stars. THE ASTROPHYSICAL JOURNAL, 809(1) [10.1088/0004-637X/809/1/39].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/243061
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