An Upper Limit on the Coalescence Rate of Double Neutron-Star Binaries in the Galaxy

In the context of assessing the detectability of the coalescence of two neutron stars (NS) by currently built gravitational wave experiments, we present a way of obtaining an upper limit to the coalescence rate in the Galaxy. We consider the NS/NS progenitors just before the second supernova explosion. We combine the theoretical understanding of orbital dynamics at NS formation with methods of empirically estimating pulsar birth rates and derive an upper limit of a few mergers every 105 yr. Such a Galactic rate implies a possible detection by the "enhanced" LIGO of up to a few to 10 mergers per year.