This is Arp 274, and is the latest target of the Galaxy Zoo project, Mergers. Volunteers get to play with a galaxy merger simulation to try to reproduce the appearance of Arp 274 as closely as possible.
From the website:
To see some lovely merging galaxy images, and how well the volunteers managed to simulate them, go to their Gallery.There are two main ways to participate. One is by volunteering your time to run simulations and study the results in the Merge Galaxies activity. The other way is to review results submitted by other volunteers in Merger Wars.