The galactic population and birthrate of X-ray pulsars.

It is well known from analysis of the 330 observed radio pulsars that the total Galactic population must be of the order of 1,000,000 and lifetime estimates indicate a birthrate in the Galaxy of the order of one/decade. Similar estimates have not been made for the 24 observed X-ray pulsars, partly because this population has been assumed to be very small. In this paper, the surprising similarity of the observed distribution of X-ray and radio pulsars is used to show that the total Galactic population is of the order of 10,000. Using lifetime estimates, it is shown that the birthrate of X-ray pulsars may be comparable to the radio pulsar birthrate, and could be as frequent as one/year.