Disc galaxy dynamics on the computer

Abstract

This review gives a brief summary of the most commonly used techniques for disc galaxy simulations and a more detailed discussion of a few numerical subtleties associated with them. The most important of these is that gravitational interactions cause the positions of particles to become weakly correlated, increasing the amplitude of random density fluctuations. The enhanced noise causes the system to relax more quickly than would otherwise be expected. It also has the appearance of fluctuating spiral structure, making it considerably more difficult to demonstrate the existence of genuine spiral instabilities in numerical models.