GRB1 - Inner Engine: Symmetries and Spectra of Short GRBs |
Speaker_ |
Stephens, Branson |
Co-autors |
M. D. Duez, Y. T. Liu, S. L. Shapiro, and M. Shibata |
Talk _ |
Magnetized hypermassive neutron star collapse: a candidate central engine for short-hard GRBs |
Abstract _ |
Hypermassive neutron stars (HMNSs) are equilibrium configurations supported against collapse by rapid differential rotation and likely form as transient remnants of binary neutron star mergers. Though HMNSs are dynamically stable, secular effects such as viscosity or magnetic fields tend to bring HMNSs into uniform rotation and thus lead to collapse. We use our new code, which solves the Einstein-Maxwell-MHD system of equations, to simulate the evolution of magnetized HMNSs. We find that magnetic braking and the magnetorotational instability both contribute to the eventual collapse of HMNSs to rotating black holes surrounded by massive, hot accretion tori and collimated magnetic fields. Such hot tori radiate strongly in neutrinos, and the resulting neutrino-antineutrino annihilation could power short-hard GRBs. Coincident detection of a gravitational wave inspiral and merger signal followed by a short GRB would provide a stringent test of this model. |