Galactic merger implications for eccentric nuclear disks: a mechanism
  for disk alignment
  The nucleus of our nearest, large galactic neighbor, M31, contains an
eccentric nuclear disk--a disk of stars on eccentric, apsidally-aligned orbits
around a supermassive black hole (SMBH). Previous studies of eccentric nuclear
disks considered only an isolated disk, and did not study their dynamics under
galaxy mergers (particularly a perturbing SMBH). Here, we present the first
study of how eccentric disks are affected by a galactic merger. We perform
N-body simulations to study the disk under a range of different possible SMBH
initial conditions. A second SMBH in the disk always disrupts it, but more
distant SMBHs can shut off differential precession and stabilize the disk. This
results in a more aligned disk, nearly uniform eccentricity profile, and
suppression of tidal disruption events compared to the isolated disk. We also
discuss implications of our work for the presence of a secondary SMBH in M31.
