Dissipationless collapse of dense stellar systems

Thesis/Dissertation · Fri Jan 01 04:00:00 EST 1982

OSTI ID:5019957

McGlynn, T A

A new numerical technique is applied to the dissipationless collapse of point masses. The numerical scheme involves an expansion of the potential in a radial grid, using spherical harmonics to express the angular dependence. Advantages are an ability to model extremely high density cores in systems, a strong damping of two body interactions, and an efficient algorithm for integrating the equations of motion. A very wide range of initial conditions is considered, with particular emphasis on the initial temperature and clumpiness of the systems. Some simulations consider extremely anisotropic initial conditions and the effects of large angular momenta. The final states of the system are strongly dependent on the initial temperature, but information on the initial inhomogeneity appears to be lost. Large density contrasts are obtainable in systems starting with low temperatures. These systems also appear to give reasonable fits to Hubble or de Vaucouleurs profiles over virtually their entire mass. The distribution function of the final states is computed as a function of energy, and alternately as a function of energy and angular momentum. When using the former, the system is best approximated as a singular polytrope with a index near 5. However this assumption for the form of the distribution function appears to be inadequate except for describing the gross features of the models.

• Research Organization: Princeton Univ., NJ (USA)
• OSTI ID: 5019957
• Country of Publication: United States
• Language: English

Related Subjects

640102* -- Astrophysics & Cosmology-- Stars & Quasi-Stellar
Radio & X-Ray Sources
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ANGULAR MOMENTUM
DENSITY
DIFFERENTIAL EQUATIONS
EQUATIONS
EQUATIONS OF MOTION
GRAVITATIONAL COLLAPSE
MASS
NUMERICAL SOLUTION
PARTIAL DIFFERENTIAL EQUATIONS
PHYSICAL PROPERTIES
SPHERICAL HARMONICS
STARS
TEMPERATURE DEPENDENCE