  Accurate models of the structural evolution of dark matter subhaloes, as they
orbit within larger systems, are fundamental to understanding the detailed
distribution of dark matter at the present day. Numerical simulations of
subhalo evolution support the idea that the mass loss associated with tidal
stripping is most naturally understood in energy space, with the particles that
are the least bound being removed first. Starting from this premise, we
recently proposed a zero-parameter "energy-truncation model" for subhalo
evolution. We tested this model with simulations of tidal stripping of
satellites with initial NFW profiles, and showed that the energy-truncation
model accurately predicts both the mass loss and density profiles. In this
work, we apply the model to a variety of Hernquist, Einasto and King profiles.
We show that it matches the simulation results quite closely in all cases,
indicating that it may serve as a universal model to describe tidally stripped
collisionless systems. A key prediction of the energy-truncation model is that
the central density of dark matter subhaloes is conserved as they lose mass;
this has important implications for dark matter annihilation calculations, and
for other observational tests of dark matter.
