National Astronomical Observatory of Japan

Astronomers Discover More than 800 Dark Galaxies in the Famous Coma Cluster

| Science

A group of researchers from the Stony Brook University (the State University of New York) and the National Astronomical Observatory of Japan has discovered 854 “ultra dark galaxies” in the Coma Cluster by analyzing archival data from the Subaru Telescope. The discovery of 47 such mysterious dark galaxies was a surprising find in 2014, and the new discovery of more than 800 suggests galaxy clusters as the key environment for the evolution of these mysterious dark galaxies. “Not only these galaxies appear very diffuse,” said Jin Koda, principal investigator of the study, “but they are very likely enveloped by something very massive.”

A color image made with B, R, and i-band images from the Subaru Telescope.
A color image made with B, R, and i-band images from the Subaru Telescope. A small region of 6 x 6 arcmin is cut out from large Coma Cluster images. Yellow circles show two of the 47 dark galaxies discovered last year, and green circles are the ones discovered in this new study.Original size (3.7MB)

This discovery will be published on June 24, 2015 in the Astrophysical Journal Letters by the American Astronomical Society (Koda et al. 2015, “Approximately A Thousand Ultra Diffuse Galaxies in the Coma cluster”).

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