Comparing Various Approaches to Simulating the Formation of Shell   Galaxies
  The model of a radial minor merger proposed by Quinn (1984), which successfully reproduces the observed regular shell systems in shell galaxies, is ideal for a test-particle simulation. We compare such a simulation with a self-consistent one. They agree very well in positions of the first generation of shells but potentially important effects -- dynamical friction and gradual decay of the dwarf galaxy -- are not present in the test-particle model, therefore we look for a proper way to include them. 
Ivana Ebrova, Katerina Bartoskova, Bruno Jungwiert, Lucie Jilkova,   Miroslav Krizek
astro-ph.GA astro-ph.CO