Binary Eccentricity is Stochastic

Computer simulations of galaxy mergers are affected by the discretisation of the phase space: the exact positions and velocities of particles will influence the orbital dynamics of the supermassive black holes in the system. Increasing the number of particles used to represent the galaxy merger reduces the uncertainty in the impact parameter of the two SMBHs, but this does not necessarily translate to a convergence in the SMBH eccentricity.

The full details of the study can be found in the article Reviving stochasticity: uncertainty in SMBH binary eccentricity is unavoidable.