A Model Distribution Function for Violently Relaxed N-Body Systems

  • N. Voglis
  • C. Efthymiopoulos
Conference paper


A system of N particles collapsing under their collective self-gravity serves as a model to study galaxy formation from density inhomogeneities in the expanding universe. Such a system is being subject to a’violent relaxation’ towards a quasi-equilibrium state reached after a few dynamical times \( \tau_{d} = (G\bar{p})^{-1}, \bar{p} \) is the mean spatial density of particles). The violent relaxation is driven mainly by the rapid oscillations of the ’smooth’ self-gravitational potential ψ(r, t) derived by Poisson equation ∇2ψ(r, t)= 47π(r, t). During the potential oscillations the particles’ individual energy changes with time. A fraction of particles may acquire positive energies and escape. The rest form a bound configuration made of a tight ’core’ and a loose ’halo.


Circular Orbit Violently Relax Radial Density Profile Constant Angular Momentum Model Distribution Function 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Aguilar, A., and Merritt, D., 1990, Ap.J., 354, 33ADSCrossRefGoogle Scholar
  2. Allen, A.J., Palmer, P.L., and Papaloizou, J., 1990, MNRAS 242, 576MathSciNetADSzbMATHGoogle Scholar
  3. Davies, M., Efstathiou, G., Frenk, C.S., and White S.D.M., 1985, Ap.J., 292, 371ADSCrossRefGoogle Scholar
  4. Efthymiopoulos, C., and Voglis, N., 1996 (in preparation)Google Scholar
  5. Hénon, M., 1959, Ann. d’Astrophys., 22, 126ADSGoogle Scholar
  6. Hénon, M., 1964, Ann. d’Astrophys., 27, 83ADSGoogle Scholar
  7. Hernquist, L., 1987, Ap.J. Suppl., 64, 715ADSCrossRefGoogle Scholar
  8. Lecar, M., and Cohen, L., 1972, in ”Gravitational N-Body Problem”, M. Lecar (ed.), Reidei, HollandCrossRefGoogle Scholar
  9. Lynden-Bell, D., 1967, MNRAS, 136, 101ADSGoogle Scholar
  10. May, A., and van Albada, T.S., 1984, MNRAS, 209, 15ADSGoogle Scholar
  11. Merritt, D., Tremarne, S., and Johnstone, D., 1989, MNRAS, 236, 829ADSGoogle Scholar
  12. Palmer, P.L., and Voglis, N., 1983, MNRAS, 205, 543ADSGoogle Scholar
  13. Peebles, P.J.E., 1980, ”The Large Scale Structure of the Universe”, Princeton University Press.Google Scholar
  14. Shu, F.H., 1969, Ap.J., 158, 505ADSCrossRefGoogle Scholar
  15. Spitzer, L., and Shapiro, S.L., 1972, Ap.J., 173, 529ADSCrossRefGoogle Scholar
  16. Stiavelli, M., and Bertin, G., 1985, MNRAS, 217, 735ADSGoogle Scholar
  17. Voglis, N., 1994a, MNRAS, 267, 379ADSGoogle Scholar
  18. Voglis, N., 1994b, in ”Galactic Dynamics and N-Body Simulations”, G. Contopoulos, N.K. Spyrou, and L. Vlahos (Eds), Lecture Notes in Physics, Springer-VerlagGoogle Scholar
  19. Voglis, N., Hiotelis, N., and Höflich, P., 1991, A&A 249, 5ADSGoogle Scholar
  20. Voglis, N., Hiotelis, N., and Harsoula, M., Astr. Sp. Sci. 226, 213Google Scholar
  21. Voglis, N., and Efthymiopoulos, C., 1996, preprintGoogle Scholar
  22. White, S.D.M., 1979, MNRAS, 189, 831ADSGoogle Scholar

Copyright information

© Kluwer Academic Publishers 1996

Authors and Affiliations

  • N. Voglis
    • 1
  • C. Efthymiopoulos
    • 1
  1. 1.Department of AstronomyUniversity of Athens PanepistimiopolisAthensGreece

Personalised recommendations