Dissection of an N-body bar

We present a detailed study of a two-dimensional N-body bar formed through a global disc instability. The rapidly tumbling figure is made up almost exclusively of orbits trapped or semi-trapped about the main family of prograde periodic orbits, which is aligned with the long axis of the bar. The bar also appears to be stable and is very robust. Iso-density contours of the mass distribution are nearly rectangular, and differ markedly from the elliptical shape commonly assumed for bars.