  The growth and virialization of spherical top-hat fluctuations, in coupled
Dark Energy models, causes segregation between Dark Matter (DM) and baryons, as
the gravitational infall into the potential well proceeds more slowly for the
baryons than for DM. As a consequence, after attaining their turn-around and
before full virialization, halos have outer layers rich of baryons.
Accordingly, a natural ambiguity exists on the definition of the virial density
contrast. In fact, when the outer baryon layers infall onto the DM-richer core,
they carry with them DM materials outside the original fluctuation; hence, no
time exists when all materials originally belonging to the fluctuation -and
only them- have virialized. Baryon-DM segregation can have various
astrophysical consequences on different length-scales. The smallest halos may
loose up to 50% of the original baryonic contents and become hardly visible.
Subhalos in cluster-size halos may loose much baryonic materials, which could
then be observed as intra-cluster light. Isolated halos, in general, can be
expected to have a baryon component richer than the cosmological proportions,
due to the cosmic enrichement of baryons lost in small halo encounters.
