Davide Fiacconi - May 16, 2014

Evolution of massive black hole pairs in clumpy environments: from
circumnuclear discs to major mergers

Massive black hole pairs with separations of ~100 pc are expected to
form during the cosmic assembly of galaxies. A few mechanism involving
stellar and gas dynamics can lead to the orbital decay of the pairs
and the formation of bound black hole binaries that could eventually
coalesce because of emission of gravitational waves. I will describe
the evolution of massive black hole pairs in circumnuclear discs
characterized by an highly inhomogeneous and clumpy distribution of
matter. This can influence the dynamics of the pair, spreading the
interval of possible orbital decay timescales. These results are
corroborated by a self-consistent simulation of a gas-rich major merger
where the multi-phase structure of the ISM is taken into account,
following the pair down to 1 pc separation.