An artist’s rendition of the newly discovered most distant galaxy z8-GND-5296. (The galaxy looks red in the actual Hubble Space Telescope image because the collective blue light from stars get shifted toward redder colors due to the expansion of the universe and its large distance from Earth.) (Photo : V. Tilvi, S.L. Finkelstein, C. Papovich, NASA, ESA, A. Aloisi, The Hubble Heritage, HST, STScI, and AURA)
Researchers from Stony Brook University and the National Astronomical Observatory of Japan (NAOJ) have discovered a whopping 854 "ultra-dark galaxies," which may hold clues to how these mysterious galaxies evolve. The data was collected via the Subaru Telescope, an 8.2-meter optical-infrared telescope perched atop Mauna Kea on the island of Hawaii. The findings were published in the June 2015 edition of the journal Astrophysical Journal Letters.
A previous discovery of 47 dark galaxies made headlines back in 2014. This latest discovery exceeds the 2014 findings by leaps and bounds, and has provided information about the forces and contents that make up these perplexing systems.
"The findings suggests that these galaxies appear very diffuse and are very likely enveloped by something very massive," said Jin Koda, a principal investigator of the study and an associate professor in the Department of Physics and Astronomy at Stony Brook University.
"We believe that something invisible must be protecting the fragile star systems of these galaxies, something with a high mass. That 'something' is very likely an excessive amount of dark matter."
The dark galaxies were found within the Coma Cluster, a large cluster that contains over 1,000 galaxies within. The Coma is one of two major clusters comprising the Coma Supercluster; the other being the Leo Cluster.
The galaxies are similar in size to our Milky Way, but have only about 1/1,000 the number of stars. They are believed to contain old stellar populations and are rendered dark because of the loss of interstellar gases. The basis of dark matter continues to challenge scientists, but the researchers at Stony Brook hope their latest discovery might spur additional research.
"The discovery of dark galaxies may be the tip of the iceberg," Koda says. "We may find more if we look for fainter galaxies embedded in a large amount of dark matter, with the Subaru Telescope, and additional observations may expose this hidden side of the Universe."