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GR: Fachverband Gravitation, Relativistische Astrophysik und Kosmologie
GR 12: Relativistic Astrophysics III / Gravitational waves III
GR 12.3: Vortrag
Donnerstag, 19. März 2026, 14:15–14:30, KH 01.016
Dynamo processes and jets from long-lived remnants from binary neutron star mergers — •Michael Mueller1, Luciano Combi2, and Daniel Siegel1 — 1University of Greifswald, Greifswald, Germany — 2Perimeter Institute for Theoretical Physics, Waterloo, Canada
Identifying the mechanisms behind the generation of short gamma-ray bursts (GRBs) in compact object mergers, such as the one accompanying GW170817, is necessary to connect the observed GRB and merger populations. Current observations indicate that accreting neutron star remnants are a likely outcome for binary neutron star (BNS) mergers, and it is key to understand whether such systems can give rise to GRB emission. Dynamo processes and magnetic winding have been identified as critical components in producing the necessary large-scale coherent magnetic field to power the jet without a black hole central engine. We present new results from three-dimensional general-relativistic magnetohydrodynamic simulations of equal-mass binary neutron star mergers resulting in a long-lived hypermassive neutron star. The binary system is evolved without symmetry assumptions, employing a tabulated, composition-dependent, finite-temperature equation of state, a vector potential formalism for the magnetic field evolution, and approximate neutrino transport. We demonstrate that the magnetorotational instability is well resolved in the disk, and we study the dynamo action of the resulting turbulence in the disk and at the disk-star interface with new diagnostics to identify the processes involved in generating coherent field structures.
Keywords: binary neutron star mergers; gamma-ray bursts; dynamo theory; magnetohydrodynamic turbulence; magnetorotational instability