the Bullet Cluster makes for a good comparison, there's a good image of it in the article. the bulk of the 2 galaxy clusters continued on but left behind 2 clouds of inter-cluster gas

my first impression was this could actually be a counterexample, because there we can see the heavy, dark matter-full clusters continuing on their trajectories at full speed whereas the gas slowed down and is being left behind. compared to these 3 lightweight galaxies which seem to be alone, rather than trailing behind their dark matter-hosting parents

but perhaps these 3 _are_ going slower than their full-scale origin galaxies. I would stake my view as a layman on whether anyone can find the dark matter galaxies that spawned these farther along their expected trajectories