Ghost Galaxy ‘Dragonfly 44’: Astronomers Discover Giant Galaxy Entirely Made Of Dark Matter
Astronomers have reportedly discovered a new giant galaxy which they claim is entirely made up of mysterious dark matter which makes up 27 per cent of the universe. Dubbed "Dragonfly 44," the newly discovered ghost galaxy is located in the Coma constellation which is around 330 million light years away.
What's interesting to note is that "Dragonfly 44" contains roughly same amount of mass as our own galaxy, the Milky Way. While, Milky Way consist of a trillion stars, only a small portion of Dragonfly 44 is formed of stars, dust and gas. About 99.99 percent of the new galaxy is made up of dark matter. The researchers claimed that they were unable to detect the galaxy for decades because it is completely dark and has a very small number of stars, according to research findings published in the Astrophysical Journal Letters.
The research team, led by Dr. Pieter van Dokkum, used the W.M. Keck Observatory and the Gemini North telescope in Hawaii to spot the new dark galaxy, reported Phys.org. They used observations from Keck, which were taken for 33.5 hours over a period of six nights, to measure the speed of stars in "Dragonfly 44." It is believed that the faster the stars rotate, the more mass the galaxy has to hold the stars together. The researchers estimated the new ghost galaxy's mass to be 1 trillion times the mass of the Sun, which is equivalent to 2 tredecillion kilograms.
— Phys.org (@physorg_com) August 25, 2016
This is not the first time that researchers have discovered a dark galaxy. But, "Dragon 44" is special because its mass is similar to the Milky Way. Dr. van Dokkum said they are hoping that the new discovery will help them learn more about what dark matter is. He added that they will continue their work to find more massive dark galaxies that are even closer than ghost galaxy "Dragonfly 44" until their ultimate goal to learn everything about the mysterious dark matter is met, reported Daily Mail.