The Final Parsec Problem

Nov 12, 2019 - 12:15 pm to 1:15 pm
Location

Campus, PAB 232

Speaker
Andrew Eberhardt

Numerical simulations and calculations are creating an increasingly complete picture of the universe. We think we have a good idea of the content of galaxies and the mechanisms that form them. Given that we expect galaxies to form from hierarchical mergers and that most galaxies have SMBHs at their cores we may be interested in the dynamics of the SMBHs following merging. Dynamical friction is known to push SMBHs to about 1pc and at about 1e-2 pc we known that GW will cause them to merge in a Hubble time. But the mechanism that moves the black holes beyond this final pc is unclear. In this talk we will discuss the details of dynamical friction and why we expect this mechanism to become inefficient at 1 pc. Following this, we will discuss two mechanisms that may solve the final parsec problem. The first argues galaxy triaxiality will increase the efficiency of dynamical friction at tight radii and the second argues that three body interactions force black holes into tight binaries. Finally, we will discuss measurements relevant to this problem that will be made in the near future.