W2 : Dynamics & Kinetic theory of self-gravitating systems
International Workshop from 4/11/13 to 8/11/13
organized by Jérôme
Perez, Mohamed Lemou & Florian Mehats
Dynamics and thermodynamics of self-gravitating systems are an interesting subject but not clearly established yet.
As Padmanabhan (1990) or Chandrasekhar fifty year before mentioned, it is probably fair to say that we do not have a systematic understanding of the self-gravitating system at a level similar to the kinetic theory of plasmas. Although some results from statistical mechanics may not be directly applied to systems with long-range forces like gravity (Binney & Tremaine 2008), self-gravitating systems are correctly described by standard statistical mechanics.
The theoretical context to describe self-gravitating systems is not clear, a very good example of this situation is the one of the globular clusters: they strive their entire life for thermal equilibrium, but their negative specific heat prevents them from ever reaching it. As a result, there is a continuous flow of energy that is driven outwards by relaxation. Therefore, any attempt to describe analytically cluster evolution turns out to be very complex due to the highly non-linear nature of these systems.
The development of system sized simulations allowed the community to produce a large range of tests and comparisons between models and actual self-gravitating systems. In this domain too, the situation is not so clear:
- Is there a universal density profile for self-gravitating systems? What are the fundamental phenomena taking place during the evolution of self-gravitating systems?
- What is the kinetic model describing at best the entire life of a self-gravitating system?
In order to provide an answer to these fundamental problems posed by our Universe, it is clear that one has to promote an encounter between astrophysics, mathematics and numerical analysis.
That would be profitable to the three communities.