Shea Garrison-Kimmel, Andrew R. Wetzel, James S. Bullock, Philip F. Hopkins, Michael Boylan-Kolchin, Claude-Andre Faucher-Giguere, Dusan Keres, Eliot Quataert, Robyn E. Sanderson, Andrew S. Graus, Tyler Kelley
Specifically, we compare simulations of the same two halos run using (1) DM-only (DMO), (2) full baryonic physics, and (3) DM with an embedded disk potential grown to match the FIRE simulation. Relative to baryonic simulations, DMO simulations contain ∼2× as many subhalos within 100 kpc of halo center;
They behave dark matter particles and baryonic particles in the same way and just add a factor to mass.
they used a central disk and they put it in x-y plane orientation and in the center of halo at redshift 3.
For center of mass they consider a big particle at the center of halo, so they don't need to calculate its center of mass !
They don't consider the effect of halo on disk and they are just interested to effect of disk on halo. according their comparison the difference between dark matter only (DMO) in one side and baryonic FIRE simulation and their simulations are big. Generally disk destroys more subhalos, especially in closer distances.
They show baryonic effects are extremely important and central galaxy is responsible for roughly half of the necessary changes for this system,
They also believe that important effective parameter is disk mass. Orientation and shape are in second priority.
I think their results are not bad for us but we should take these result serious.