  It is known that a binary neutron star merger produces a hypermassive neutron
star. The lifetime of this compact remnant depends on the total mass and the
equation of state. The collapse of this compact remnant to a black- hole-torus
system is expected to give rise to a powerful jet and a short gamma-ray burst.
Nevertheless, if the collapse is delayed half a second or so, the surrounding
matter would be already accreted and/or expelled and hence no torus will be
formed. However, the collapse itself will give rise to a quasi-isotropic
magnetized fireball. This magnetic bomb will dissipate much of its energy due
to magnetic re-connection and will produce the prompt emission, when the
fireball will become transparent to gamma-rays. The energy range of such an
explosion depends on the initial magnetic field strength of the two neutron
stars and the amplification of the magnetic energy during merger. We discuss
the production of a quasi-isotropic magnetized fireball and its subsequent
interaction with the ejected matter during merger, as the outcome of the
coalescence of a binary neutron star system. We further discuss a possible
origin for the duration of the burst and the radial stratification of the flow
following the quasi-normal modes of the black hole.
