Over 800 dark galaxies discovered in mysterious Coma cluster

A new study from scientists at Stony Brook University, using the Subaru telescope, describes more than 800 galaxies that could be made mostly out of dark matter.
By James Smith | Jun 24, 2015
The idea of "dark matter" has perplexed scientists for decades, and each day a new piece to the puzzle is discovered. According to a report from Sci-News, researchers from Stony Brook University have recently discovered 854 ultra-diffuse galaxies (UDGs) after examining the Coma cluster, about 300 million light years away, using the Subaru telescope. Many of the galaxies are similar in size to the Milky Way.

The galaxies are distributed around a center point, which suggests that most of them are members of the same cluster. According to the study's authors, the galaxies show no signature of H-alpha emission, meaning that they have ceased making new stars. Despite being similar in size to the Milky Way, many of these UDGs contain only 1/1000 of the stars that our galaxy currently does.

Astronomers believe that though these galaxies appear to be sparse, they are probably filled with dark matter. Dr. Jin Koda, the study's lead author, explains that despite how diffuse the galaxies appear, "they are very likely enveloped by something massive."

The galaxies contain less than one percent visible matter, which is very low compared to other galaxies. The UDGs may help provide scientists insight into what happens near the end of a galaxy's lifespan. The scientists plan to conduct follow-up spectroscopic observations in the near future to find more clues about the mysterious galaxies.


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