Semi-Analytic Model Predictions of Mass Segregation from Groups to
  Clusters
  Taking advantage of a high-resolution simulation coupled with a state-of-art
semi-analytic model of galaxy formation, we probe the mass segregation of
galaxies in groups and clusters, focusing on which physical mechanisms are
driving it. We find evidence of mass segregation in groups and clusters up to
the virial radius, both looking at the galaxy stellar mass and subhalo mass.
The physical mechanism responsible for that is consistent with dynamical
friction, a drag-force that brings more massive galaxies faster towards the
innermost regions of the halo. At odds with observational results, we do not
find the inclusion of low-mass galaxies in the samples, down to stellar mass
$M_* = 10^9 \, M_{\odot}$, to change the overall trend shown by intermediate
and massive galaxies. Moreover, stellar stripping as well as the growth of
galaxies after their accretion, do not contribute either in shaping mass
segregation or mixing the radial mass distribution. Beyond the virial radius we
find an "anti-mass segregation" in groups that progressively weakens in
clusters. The continuous accretion of new objects and recent merger events play
a different role depending on the halo mass onto which accreting material is
falling.
