1998A&A...332..173P

The formation and evolution of binaries which contain two neutron stars or a neutron star with a black hole companion are discussed in detail. The evolution of the distributions in orbital period and eccentricity for neutron star binaries are studied as a function of time. In the model which fits the observations of high mass binary pulsars best the deposition of orbital energy into common envelopes has to be very efficient and a kick velocity distribution has to contain a significant contribution of low velocity kicks. The estimated age of the population has to be between several 100Myr and 1Gyr. The birthrate of neutron stars binary is ∼3.4x10^–5yr^–1 (assuming 100% binarity) and their merger rate is ∼2x10^–5yr^–1. The merger rate of neutron star binaries is consistent with the estimated rate of γ-ray bursts, if the latter are beamed into an opening angle of a few degrees. We argue that PSR B2303+46 is possibly formed in a scenario in which the common envelope is avoided while for the other three known high-mass binary pulsars a common envelope is required to explain their orbital period.