Merging Histories
-----------------------------------

A single binary is expected to eject about its own mass in stars from the center [@Merritt06]. Larger mass deficits can result from:

1.  the cumulative effect of repeated mergers [@Merritt06]

2.  repeated core passes of the post-binary-merger black hole due to gravitational-wave recoil [@Gualandris08] (${M_\mathrm{def}}\lesssim 5 \,
      {M_\bullet}$)

3.  multiple black hole systems that might form at high redshifts [@Kulkarni12] (${M_\mathrm{def}}\lesssim 5 \, {M_\bullet}$).

The mass deficits derived for our core galaxies are ${M_\mathrm{def}}\sim 1-6 \,
{M_\bullet}$ (Table \[tab:data\]) and, again, fit the numerical predictions well.

Most of our galaxies have mass deficits consistent with only one major merger, in agreement with their orbital anisotropy. A corresponding number of minor mergers, however, would give similar mass deficits. Studies of test-particle orbits around equal-mass as well as unequal-mass black hole binaries suggest that the central anisotropy, like the mass deficit, does not carry specific information about the merging history [@Meiron10].

Such information could, however, be encoded in the central rotation velocities. In equal-mass merger simulations, rotation velocities similar to the local velocity dispersion are found [@Milosavljevic01; @Meiron13]. Unequal-mass binaries likely induce less rotation through dynamical friction [@Meiron13]. Rotation velocities in our observed cores are small (Figure \[fig:intrinsic\]). 