  Neutron star binaries, such as the one observed in the famous binary pulsar
PSR 1916+13, end their life in a catastrophic merge event (denoted here
NS$^2$M). The merger releases $\approx 5 \cdot 10^{53}$ergs, mostly as
neutrinos and gravitational radiation. A small fraction of this energy suffices
to power $\gamma$-ray bursts (GRBs) at cosmological distances. Cosmological
GRBs must pass, however, an optically thick fireball phase and the observed
$\gamma$-rays emerge only at the end of this phase. Hence, it is difficult to
determine the nature of the source from present observations (the agreement
between the rates of GRBs and NS$^2$Ms being only an indirect evidence for this
model). In the future a coinciding detection of a GRB and a gravitational
radiation signal could confirm this model.
