On the formation and dynamics of shells around elliptical galaxies

As an attempt to model shell-like structures around elliptical galaxies, experiments involving the radial encounter of self-gravitating, N-body disks and fixed spherical potentials have been conducted. Two dimensional encounters have produced sharp, incomplete 'shell-like' structures which appear on either side of the post-collision system and spread slowly in radius. The shell distribution may be evidence that the history of ellipticals is linked to mergers involving disk galaxies. (Auth.)