Colliding galaxies create 'missing link' mega-galaxy

Two colliding galaxies have formed a fragile mega-galaxy, a short-lived phenomenon U.S. astronomers are calling a cosmic "missing link." Two young galaxies that collided 11 billion years ago rapidly formed a massive galaxy about 10 times the size of the Milky Way, University of California, Irvine, postdoctoral researcher Hai Fu says. Capturing images of the creation of this type of large, short-lived star body is extremely rare, researchers said, the equivalent of discovering a missing link between winged dinosaurs and early birds. The mega-galaxy dubbed HXMM01 faded away as fast as it formed, they said, a victim of its own cataclysmic birth as the colliding galaxies gobbled up huge amounts of hydrogen, emptying that corner of the universe of the star-making gas. "These galaxies entered a feeding frenzy that would quickly exhaust the food supply in the following hundreds of million years and lead to the new galaxy's slow starvation for the rest of its life," Fu said in a university release Wednesday. The discovery solves a riddle of how giant elliptical galaxies could develop quickly in the early universe and why they stopped producing stars soon after, he said. "Finding this type of galaxy is as important as the discovery of the archaeopteryx was in understanding dinosaurs' evolution into birds, because they were both caught at a critical transitional phase," Fu said.