Abstract :

Observations of gravitational waves from merging black-hole binaries are beginning to teach us about the population of stellar-mass black holes in the universe. An individual observation allows measurements of the black-hole masses, but only limited information about the black-hole spins, both their magnitude and orientation. Previous work has shown that from multiple signals we can infer the distribution of spin orientations, which allows us to distinguish between formation and evolution scenarios. In my presentation, I will go over some basics of population analysis and will show how by taking into account the variation in the signal strength with spin magnitude, the mass distribution of black holes, and the signal degeneracy between mass-ratio and spin the scenarios can be greatly constrained.