Gemini Observatory. Australian students take note, they are running the contest again this year.
Here are some details on the collision from the Gemini press release:
The primary galaxy in the image (NGC 6872) exemplifies what happens when galaxies interact and their original structure and form is distorted. When galaxies like these grapple with each other, gravity tugs at their structures, catapulting spiral arms out to enormous distances. In NGC 6872, the arms have been stretched out to span hundreds of thousands of light-years—many times further than the spiral arms of our own Milky Way galaxy. Over hundreds of millions of years, NGC 6872’s arms will fall back toward the central part of the galaxy, and the companion galaxy (IC 4970) will eventually be merged into NGC 6872. The coalescence of galaxies often leads to a burst of new star formation. Already, the blue light of recently created star clusters dot the outer reaches of NGC 6872’s elongated arms. Dark fingers of dust and gas along the arms soak up the visible light. That dust and gas is the raw material out of which future generations of stars could be born.You can get a 13.3 TIFF version of the image here.