Studying black hole formation with gravitational-wave observations

The first observations of gravitational waves emitted by merging binary black holes demonstrated the existence of black holes more massive than ever observed in our Galaxy. Future observations with ground-based interferometers such as Advanced LIGO and Virgo will probe the mass and spin distributions of black holes in various galactic environments. Since stellar-mass black holes form at the end of the nuclear lifetimes of massive stars, these measurements will provide a new tool for stellar evolution studies. In the first part of this talk I will describe a cosmological framework for modeling the population of black holes and its evolution with redshift. I will then show which features of stellar evolution models can be constrained with future observations of binary black hole mergers. In the second part of this talk I will discuss the prospects of detecting the stochastic gravitational wave background from super-massive black hole binaries that form when galaxies merge. In particular, I will argue that even under the most conservative assumptions the signal from super-massive black holes will be detected in the coming years by Pulsar Timing Array experiments and possibly also by the space-based interferometer LISA, which is currently in its design stage.