Number density distribution of the tail as a function of the distance y along the tail for model C10G13 (left panel) and model C10W1 (right panel) at selected times as indicated by the lines. Plots at times earlier than 300 Myr (solid lines) do not indicate epicyclic overdensities. Epicyclic overdensities appear later (400−600 Myr; dotted lines). The epicyclic overdensities are located at a distance very close to the one predicted by Küpper et al. (2008), which is indicated by the vertical dashed lines.