S E M I N A R IDepartament d'Astronomia i Astrofísica
Universitat de València
Magneto-Rotational-Instability in Magnetized Hypermassive Neutron Stars
Albert Einstein Institute, Potsdam, Alemanya
Seminari del departament d'Astronomia i AstrofÃsica
Dimarts 05 febrer 2013
Differentially rotating hypermassive neutron stars (HMNSs) are metastable configurations which can be formed in the latest stage of binary neutron star mergers. Their eventual collapse produces a spinning black hole surrounded by a hot and thick accretion disk. The dynamics of such a system is of crucial importance, since it could generate the relativistic jets observed in short gamma-ray bursts. By performing simulations of very high resolution, we study the influence of magnetic fields on the evolution of HMNSs. In particular, we provide convincing evidence for the occurrence of the magneto-rotational instability (MRI), potentially responsible for strong magnetic field amplification and angular momentum redistribution. Characteristic features of the MRI are discussed and quantities such as the characteristic growth rate and the wavelength of the fastest growing mode are extracted and compared with analytical predictions.