HAL CCSD
Self-gravity, Resonances, and Orbital Diffusion in Stellar Disks
Fouvry, Jean-Baptiste
Binney, James
Pichon, Christophe
Institut d'Astrophysique de Paris (IAP) ; Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)
Université Pierre et Marie Curie - Paris 6 (UPMC)
International audience
ISSN: 0004-637X
EISSN: 1538-4357
The Astrophysical Journal
American Astronomical Society
insu-03644938
https://insu.hal.science/insu-03644938
https://insu.hal.science/insu-03644938
The Astrophysical Journal, 2015, 806, ⟨10.1088/0004-637X/806/1/117⟩
ARXIV: 1504.04834
info:eu-repo/semantics/altIdentifier/arxiv/1504.04834
BIBCODE: 2015ApJ...806..117F
DOI: 10.1088/0004-637X/806/1/117
info:eu-repo/semantics/altIdentifier/doi/10.1088/0004-637X/806/1/117
en
diffusion
galaxies: evolution
galaxies: kinematics and dynamics
galaxies: spiral
gravitation
Astrophysics - Astrophysics of Galaxies
[SDU]Sciences of the Universe [physics]
info:eu-repo/semantics/article
Journal articles
Fluctuations in a stellar system's gravitational field cause the orbits of stars to evolve. The resulting evolution of the system can be computed with the orbit-averaged Fokker-Planck equation once the diffusion tensor is known. We present the formalism that enables one to compute the diffusion tensor from a given source of noise in the gravitational field when the system's dynamical response to that noise is included. In the case of a cool stellar disk we are able to reduce the computation of the diffusion tensor to a one-dimensional integral. We implement this formula for a tapered Mestel disk that is exposed to shot noise and find that we are able to explain analytically the principal features of a numerical simulation of such a disk. In particular the formation of narrow ridges of enhanced density in action space is recovered. As the disk's value of Toomre's Q is reduced and the disk becomes more responsive, there is a transition from a regime of heating in the inner regions of the disk through the inner Lindblad resonance to one of radial migration of near-circular orbits via the corotation resonance in the intermediate regions of the disk. The formalism developed here provides the ideal framework in which to study the long-term evolution of all kinds of stellar disks.
2015