The structure and dynamics of galaxies formed by cold dissipationless collapse

Journal Article · Tue May 01 04:00:00 EDT 1990 · Astrophysical Journal; (USA)

DOI:https://doi.org/10.1086/168665· OSTI ID:6699242

Aguilar, L A; Merritt, D ^[1]

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1. Observatorio Astronomico Nacional, Ensenada (Mexico) Rutgers Univ., Piscataway, NJ (USA)

The observable characteristics and phase-space structure of systems formed by dissipationless collapse are investigated. An extensive set of N-body simulations is described; and three-dimensional and spherical collapses, their shapes, and dynamics are examined. It is demonstrated that collapses started from cold initial conditions are quantitatively different from warm collapses, in the sense that their final shapes are nearly uncorrelated with their initial shapes. It is suggested that this phenomenon is due to an instability similar to the radial-orbit instability in anisotropic equilibrium models. The results show that clumpy initial conditions are not required to produce a realistic final state via collapse, if the initial state is sufficiently cold; and that if elliptical galaxies collapsed from cold and smooth initial configurations (and did not evolve significantly thereafter), they should be triaxial or prolate, with intrinsic flattening of approximately 2:1. 24 refs.

• OSTI ID: 6699242
• Journal Information: Astrophysical Journal; (USA), Journal Name: Astrophysical Journal; (USA) Vol. 354; ISSN ASJOA; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

640105* -- Astrophysics & Cosmology-- Galaxies
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ASTROPHYSICS
CONFIGURATION
DENSITY
DISTRIBUTION FUNCTIONS
DYNAMICS
ELLIPTICAL CONFIGURATION
FUNCTIONS
GALACTIC EVOLUTION
GALAXIES
GRAVITATIONAL COLLAPSE
LUMINOSITY
MANY-BODY PROBLEM
MECHANICS
MORPHOLOGY
MOTION
OPTICAL PROPERTIES
PARTICLE KINEMATICS
PHYSICAL PROPERTIES
ROTATION
SIMULATION