  We use a 1-D Lagrangian code which follows both a gaseous and a dark
component to study the radiative shocks that appear in the evolution of
spherical scale-free perturbations in an Einstein-de Sitter Universe. The
detailed behaviour of the shock depends on whether the radiative cooling is
dominated by bremsstrahlung or line cooling. Bremsstrahlung is the main energy
loss mechanism for systems with circular velocity $V_{c} > 100 km s^{-1}$. In
this case, we can reproduce the kinematics of the shock and of the cooling wave
to a high degree of accuracy with a simple analytic model. When line cooling
dominates, the shock front can be unstable to oscillations. The period and
amplitude of the oscillations increase in time as the universe expands. For
such systems, our analytic model provides only a rough estimate of the mean
evolution. We believe that now we fully understand the effect radiative cooling
has in the shocks that appear in spherical models for galaxy formation.
