From neutron star binaries to gamma-ray bursts

I summarize recent results about how a neutron star binary coalescence can produce short gamma-ray bursts (GRBs). Two possibilities are discussed: the nu(i)(nu) over bar (i)-annihilation above the merged remnant and the experiential amplification of magnetic fields in the central object tip to values close to equipartition. We find that the annihilation of nu(i)(nu) over bar (i)-pairs drives bipolar, relativistic outflows with Lorentz-factors large enough to circumvent the GRB "compactness problem". The total energy within these outflows is moderate by GRB-standards (similar to 10(48)-10(49) ergs), but the interaction with the baryonic material blown-off by the neutrinos collimates the outflows into opening angles of typically 0.1 sterad, yielding isotropic energies close to 10(51) ergs. We further want to stress the plausibility of the central object resisting the immediate collapse to a black hole. In this case the central object will - similar to a proto-neutron star - be subject to neutrino driven convection that - together with the rapid, differential rotation - will lead to a drastic amplification of preexisting magnetic fields. Within fractions of a, second. field strengths comparable to equipartition field strength (> 10(17) G) will be reached. These will produce large torques that will spin-down the object within about 0.2 s, and would thus naturally explain the duration of short GRBs.