Neutron Stars and Black Holes in X-Ray Binaries

Abstract

Galactic accretion driven stellar X-ray sources can be divided into groups in different ways. An important division, which covers almost all known X-ray binaries, can be made according to the mass of the donor star: high-mass X-ray binaries and low-mass X-ray binaries. Another distinction (partially overlapping with the previous one) can be made on the basis of the nature of the accreting object: a strongly magnetized neutron star, a neutron star with a weak magnetic field, or a black hole. In this review I describe the properties of these different types of X-ray binaries, and discuss the mass determinations which are the basis for distinguishing accreting neutron stars from black holes.