  Recent high-resolution calculations of neutron star coalescences are used to
investigate whether nu bar{nu} annihilation can provide sufficient energy to
power gamma-ray bursts, especially those belonging to the short duration
category. Late time slices of the simulations, where the neutrino emission has
reached a maximum, stationary level are analyzed to address this question. We
find that nu bar{nu} annihilation can provide the necessary driving stresses
that lead to relativistic jet expansion. Maximum Lorentz factors of the order
of 15 are found along the binary rotation axis, but larger values are expected
to arise from higher numerical resolution. Yet the accompanying neutrino-driven
wind must be absent from the axis when the burst occurs or prohibitive baryon
loading may occur. We argue that even under the most favorable conditions, nu
bar{nu} annihilation is unlikely to power a burst in excess of ~ 10^{48} erg.
Unless the emission is beamed into less than one percent of the solid angle,
which we argue is improbable if it is collimated by gas pressure, this may fail
to satisfy the apparent isotropic energies inferred at cosmological distances.
This mechanism may nonetheless drive a precursor fireball, thereby evacuating a
cavity into which a later magnetic driven jet could expand. A large range of
time delays between the merger and the black hole formation are to be expected.
If the magnetic driven jet occurs after the black hole has formed, a time span
as long as weeks could pass between the neutrino powered precursor and the
magnetic driven GRB.
