Black holes and neutron stars

Black holes and neutron stars are the compact remnants of massive stars. They represent one of the key intersections between astronomy and fundamental physics – both are classes of objects which are sufficiently compact that Newtonian gravity cannot be used to describe the forces near their surfaces. The structure of neutron stars furthermore presents one of the few key tests of the equation of state of nuclear matter. This chapter will review some of the key theoretical results underpinning the current understanding of neutron stars and black holes. It will also describe the observations of neutron stars and black holes both in isolation (as thermal emitters and as radio pulsars for the case of neutron stars) and in close binaries, where accretion processes can make these objects bright X-ray sources. Additionally, this chapter will detail the formation processes of both neutron stars and black holes in general, and also the formation of close binaries containing such objects.