45 million light years away in the constellation Corvus are the colliding galaxies NGC 4038 and NGC 4039. In about 400 million years, the cores of the galaxies will merge and they will become one large spiral galaxy. My fave galaxy :)
Cartwheel Galaxy, ESO 350-40, is a lenticular galaxy about 500 mly away in the constellation Sculptor. It is an estimated 150,000 light-years across. The galaxy was once a normal spiral galaxy like the Milky Way before it apparently underwent a head-on collision with a smaller companion approximately 200 mya.
Astronomy Photographer of the Year 2012 - Winner. M51 The Whirlpool Galaxy by Martin Pugh. M51 or the Whirlpool is the archetypal spiral galaxy and for centuries astronomers have studied it in order to understand how galaxies form and evolve. Here the photographer has made use of exceptionally stable atmospheric conditions, minimizing the twinkling or ‘seeing’ caused by air turbulence to produce a sharp, clear image in which every detail of the galaxy is visible.
Collisional ring galaxy NGC 922, the result of two galaxies that collided 300 million years ago. Intense waves of energy moving outward following the merge have created vast pinkish star forming regions around the edge. This galaxy is perplexing for scientists, because it's host to an unusually high number of black holes. It's made even more strange because it's composed largely of heavy elements which is not conducive to forming black holes. It lies 150 million light years away in Fornax.