A group of scientists led by Dr. Patrick Ogle from the California Institute of Technology recently discovered a new type of galaxy called a super spiral.
These super spirals are incredibly bright, shining from 8 to 14 times the brightness of our own Milky Way Galaxy. Not only that, they are extremely massive. The diameter of some super spiral galaxies discovered reaches up to 437,000 light years with solar masses of up to 340 billion. Super spirals are also creating stars at a very high rate, up to 30 times that of our Milky Way. Extreme amounts of UV and mid-IR light are also given off.
Dr. Ogle and his team discovered the super spirals by pure chance as they searched for extremely luminous and large galaxies in the NASA/IPAC Extragalactic Database (NED). Dr. George Helou, the teams leader has said, “Remarkably, the finding of super spiral galaxies came out of purely analyzing the contents of the NED database, thus reaping the benefits of the careful, systematic merging of data from many sources on the same galaxies.”
The astronomers thought that older, massive galaxies known as ellipticals would be dominating their search within NED but instead the team discovered was surprised with the new category of galaxies. The sample size of around 800,000 galaxies about 3.5 billion light-years from Earth, had a mere 53 of the brightest galaxies that showed to have a spiral shape rather than an elliptical one. After the team cross checked the distances to the spirals and saw that none were nearby, they realized even the closest spirals lay 1.2 billion light-years away.
The largest and brightest super spiral galaxy discovered, named SDSS J094700.08+254045.7, is a starry disk with spiral arms that stretch out about 320,000 light-years across. This is more than three times the full width of our Milky Way Galaxy.
The only clue we have about the origin of these super spiral galaxies is that 4 out of the 53 seen by the scientists contain two galactic nuclei, instead of the usual one. The scientists explains that double nuclei are a telltale sign of two galaxies having just merged together. Traditionally, mergers of spiral galaxies were believe to be destined to become bloated, elliptical galaxies.
The team is still speculating however. that a special merger involving two, regular gas-rich spiral galaxies could see their combined gases settle down into a new, larger stellar disk, which would be a super spiral.
Dr. Ogle, the lead author of the paper on super spirals published in the Astrophysical Journal has that that “Super spirals could fundamentally change our understanding of the formation and evolution of the most massive galaxies.”