In their way through space, galaxies usually meet and interact, creating new structures. Thirty years ago a Canadian astronomer (Paul Hickson) created a catalogue of 462 such closely interacting systems, most often composed of 4-5 galaxies as closely packed together as the galaxies in the center of some clusters of galaxies. We don't know precisely yet how many of the galaxies in these systems are interacting and how many are just chance alignments, but studies have shown that for about half there is some physical connection involved.
A theory suggests that these systems are on their way of creating an elliptical galaxy, so stay tuned!
Below, the cosmic dance brought together in HCG 44 three spirals and a small elliptical galaxy, NGC 3190, NGC 3193, NGC 3185 and NGC 3187 and signs of their interactions abound (tidal tails, disc distortions...)
Meanwhile in Pegasus, ~40 million light years away, edge-on spiral galaxy NGC 7814 elegantly displays her slightly warped edge-on disc. It is also called Little Sombrero after her closer and larger brother M 104. There are many faint galaxies seen around it and as their light passed through the halo of the galaxy is gets a little redder.
Elegant, isn't it?
All images taken through the 0.5m Argelander Institute for Astronomy Institute in Bonn.