A core-halo pattern of entropy creation in gravitational collapse
  This paper presents a kinetic theory model of gravitational collapse due to a
small perturbation. Solving the relevant equations yields a pattern of entropy
destruction in a spherical core around the perturbation, and entropy creation
in a surrounding halo. This indicates collisional "de-relaxation" in the core,
and collisional relaxation in the halo. Core-halo patterns are ubiquitous in
the astrophysics of gravitational collapse, and are found here without any of
the prior assumptions of such a pattern usually made in analytical models.
Motivated by this analysis, the paper outlines a possible scheme for
identifying structure formation in a set of observations or a simulation. This
scheme involves a choice of coarse-graining scale appropriate to the structure
under consideration, and might aid exploration of hierarchical structure
formation, supplementing the usual density-based methods for highlighting
astrophysical and cosmological structure at various scales.
