A population synthesis study of high-mass X-ray binaries

The formation of high-mass X-ray binary systems is followed using a statistical Monte Carlo approach. The evolution of an initial distribution of binary systems is followed through mass transfer and mass loss or common envelope evolution to the supernova phase. The population synthesis is explored as a function of the form and magnitude of the kick velocity associated with asymmetric supernova explosions, the specific angular momentum of the matter lost from the system, the mass ratio above which the system enters into the common envelope phase, and the common envelope efficiency. To account for the observed systems with B-type companions in the orbital period-eccentricity plane, the results of the study strongly suggest that asymmetric explosions are required. Furthermore, the existence of systems with Be-type companions, in conjunction with the above, indicates that the specific angular momentum of matter lost (relative to that of the binary) during the mass transfer/ loss phase is high (∼5).