  Coupling the dark matter (DM) and baryonic components in galaxies via
dynamical friction (by allowing the latter to be clumpy) leads to energy input
into the DM. The resulting expanding tendency in the DM component overcomes the
competing effect of adiabatic contraction, resulting from the shrinking gas
component, and leads to a nearly constant density core. The baryonic mass
inflow also leads to the coupling of the structure at the kpc scale and below
and that of the structure of the DM at the 10 kpc scale and above, with rate of
mass inflow being dependent on the initial halo central concentration. The
latter also determines the final halo core radius.
