Rapster: a fast code for dynamical formation of black-hole binaries*

Gravitational wave observations revealed the existence of binary black-hole mergers with unusually asymmetric and massive components that could have formed in dense stellar environments. I present Rapster, a rapid cluster evolution code, that simulates the dynamical assembly of black-hole binaries in the cores of dense massive star clusters implementing semi-analytic prescriptions. The code is fast, and evolves a typical globular cluster within a minute. Then, I discuss applications of Rapster, such as hierarchical mergers and merger rates.