The remnant of a neutron star binary coalescence is expected to be
temporarily stabilised against gravitational collapse by its differential
rotation. We explore the possibility of dynamo activity in this remnant and
assess the potential for powering a short-duration gamma-ray burst (GRB). We
analyse our three-dimensional hydrodynamic simulations of neutron star mergers
with respect to the flow pattern inside the remnant. If the central, newly
formed super-massive neutron star remains stable for a good fraction of a
second an efficient low-Rossby number α−Ω-dynamo will amplify the
initial seed magnetic fields exponentially. We expect that values close to
equipartition field strength will be reached within several tens of
milliseconds. Such a super-pulsar could power a GRB via a relativistic wind,
with an associated spin-down time scale close to the typical duration of a
short GRB. Similar mechanisms are expected to be operational in the surrounding
torus formed from neutron star debris.Comment: 5 pages, 1 figure, Proceedings of the Gamma-ray Burst Symposium 2003,
Santa Fe; Reference adde
