I wanted to email you to let you know about a code for creating initial
conditions for Gadget2. I wrote this code, called Starscream, over the past
few months and wanted to make it available to anyone who would be interested
in studying galaxy collisions.
Starscream uses a Springel-Hernquist model to create a pair of galaxies that
can be collided in any N-body code, Gadget2 in particular. Users can read
and write Gadget2 snapshots of previous collisions, create new galaxies, or
load galaxies from snapshots AND place them on an orbit with a new galaxy.