A core-halo pattern of entropy creation in gravitational collapse

Abstract 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-re...

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Bibliographic Details
Published in:Monthly notices of the Royal Astronomical Society 2018-07, Vol.477 (3), p.3983-4008
Main Author: Wren, Andrew J
Format: Article
Language:English
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Summary:Abstract 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.
ISSN:0035-8711
1365-2966
DOI:10.1093/mnras/sty786