Interaction of clumpy dark matter with interstellar medium in
  astrophysical systems
  Contemporary cosmological conceptions suggest that the dark matter in haloes
of galaxies and galaxy clusters has most likely a clumpy structure. If a stream
of gas penetrates through it, a small-scale gravitational field created by the
clumps disturbs the flow resulting in momentum exchange between the stream and
the dark matter. In this article, we perform an analysis of this effect, based
on the hierarchial halo model of the dark matter structure and
Navarro-Frenk-White density profiles. We consider the clumps of various masses,
from the smallest up to the highest ones $M\ge 10^{9} M_\odot$. It has been
found that in any event the effect grows with the mass of the clump: not only
the drag force $\mathfrak F$ acting on the clump, but also its acceleration
$w=\mathfrak F/M$ increases.
  We discuss various astrophysical systems. The mechanism proved to be
ineffective in the case of galaxy or galaxy cluster collisions. On the other
hand, it played an important role during the process of galaxy formation. As a
result, the dark matter should have formed a more compact, oblate, and faster
rotating substructure in the halo of our Galaxy. We have shown that this thick
disk should be more clumpy than the halo. This fact is very important for the
indirect detection experiments since it is the clumps that give the main
contribution to the annihilation signal. Our calculations show that the
mechanism of momentum exchange between the dark and baryon matter is
ineffective on the outskirts of the galactic halo. It means that the clumps
from there were not transported to the thick disk, and this regions should be
more clumpy than the halo on the average.
