Birth rates of different types of neutron star and possible evolutions of these objects

Abstract

We estimate the spatial densities of different types of neutron star near the Sun. It is shown that the distances of dim isolated thermal neutron stars must be on average about 300-400 pc. The combined birth rate of these sources together with radio pulsars and dim radio quiet neutron stars can be a little more than the supernova rate as some of the dim isolated thermal neutron stars can be formed from dim radio quiet neutron stars and radio pulsars. Some of these sources must have relations with anomalous X-ray pulsars and soft gamma repeaters. In order to understand the locations of different types of neutron star on the P-\.{P} diagram it is also necessary to take into account the differences in the masses and the structures of neutron stars.