Black hole neutron star coalescence as a source of gamma-ray bursts

We present the results of hydrodynamic (SPH) simulations showing the coalescence of a black hole with a neutron star to be a promising theoretical source of short duration gamma-ray bursts. The favorable features of the process include rapid onset, millisecond variability, a duration much longer than the dynamical timescale, and a range of outcomes sufficient to allow variety in the properties of individual gamma-ray bursts. Interestingly, the process of coalescence differs rather markedly from past predictions.