Formation and Evolution of Black Holes

This chapter discusses the formation and evolution of black holes. Stellar-mass black holes are generally understood to be created in supernova explosions that mark the end of the life of a massive star. However, many supernovae create neutron stars rather than black holes, and the precise conditions under which black holes form are still not fully understood. If the black hole is to be detected, further events are required, such as the formation of a binary star system of a kind that can be observed, and in which the existence of a black hole can be demonstrated. In contrast with stellar-mass black hole formation, there is no obvious route to the creation of a supermassive black hole directly from collapsing interstellar gas. Most discussions of the origin and evolution of supermassive black holes posit an initial “seed” black hole of relatively low mass, which then grows over time.