Magnetic Field Amplification in Hypermassive Neutron Stars via the Magnetorotational Instability
Mergers of binary neutron stars likely lead to the formation of a hypermassive neutron star (HMNS), which is metastable and eventually collapses to a black hole. This merger scenario is thought to explain the phenomenology of short gamma-ray bursts (SGRBs). The very high energies observed in SGRBs have been suggested to stem from neutrino-antineutrino annihilation and/or from very strong magnetic fields created during or after the merger by mechanisms like the magnetorotational instability. Here, we report on results that show for the first time the development of the magnetorotational instability in HMNSs in three-dimensional, fully general-relativistic magnetohydrodynamic simulations. This instability amplifies magnetic fields exponentially and could be a vital ingredient in solving the SGRB puzzle.
DMS greatly acknowledges the award of the first Karl Schwarzschild Prize sponsored by Springer for the best talk in the student section of the first Karl Schwarzschild Meeting, held in Frankfurt, Germany, July 2013. DMS also thanks the organizers of this meeting for travel support.
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