An international team of astronomers has discovered a massive galaxy that consists of 99.99 percent dark matter. Even though it is relatively nearby, astronomers had missed the galaxy, named Dragonfly 44, for decades because it is very dim. The galaxy lies about 300 million light-years away in the constellation Coma.
At CASCA 2015, Roberto Abraham from the University of Toronto describes the first results from the Dragonfly Telephoto Array — an innovative, multi-lens system designed to produce digital images of ultra-low surface brightness objects at visible wavelengths — that is at least ten times more efficient than its nearest rival.
An international team of researchers have used the W. M. Keck Observatory to confirm the existence of the most diffuse class of galaxies known in the universe. These Ultra Diffuse Galaxies (UDGs) are nearly as wide as our own Milky Way galaxy — about 60,000 light-years — yet harbour only one percent as many stars.