Direct N-body Simulations

TL;DR

This paper discusses high-accuracy direct N-body algorithms for simulating star clusters, comparing them with approximate methods, and exploring their astrophysical applications and parallel implementation challenges.

Contribution

It presents detailed explanations and comparisons of direct N-body algorithms and discusses their relevance for astrophysical simulations of star clusters.

Findings

Validation of direct N-body methods for star cluster evolution

Discussion on the limitations of Fokker-Planck approximation

Insights into parallel implementation of N-body codes

Abstract

Special high-accuracy direct force summation N-body algorithms and their relevance for the simulation of the dynamical evolution of star clusters and other gravitating N-body systems in astrophysics are presented, explained and compared with other methods. Other methods means here approximate physical models based on the Fokker-Planck equation as well as other, approximate algorithms to compute the gravitational potential in N-body systems. Questions regarding the parallel implementation of direct ``brute force'' N-body codes are discussed. The astrophysical application of the models to the theory of relaxing rotating and non-rotating collisional star clusters is presented, briefly mentioning the questions of the validity of the Fokker-Planck approximation, the existence of gravothermal oscillations and of rotation and primordial binaries.