The Galactic population and birthrate of X-ray pulsars

Abstract
It is well known from analysis of the 330 observed radio pulsars that the total Galactic population must be of the order of 106 and lifetime estimates indicate a birthrate in the Galaxy of the order of one per 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 to show that the total Galactic population is of the order of 104. 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 per year.