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stormwyrm [soylentnews.org] writes:

The Chandra X-Ray observatory [harvard.edu] in concert with the ESO’s UltraVISTA [ultravista.org] infrared telescope and the ALMA radio telescope [almaobservatory.org] have discovered the most distant galaxy cluster yet [harvard.edu], designated CL J1001+0220. The galaxy cluster is 11.1 billion light years from Earth, and we may be seeing it just as it is forming. A paper [arxiv.org] describing these results is available. The extremely remote cluster is remarkable not only for its distance:

In addition to its extraordinary distance, CL J1001 is remarkable because of its high levels of star formation in galaxies near the center of the cluster. Within about 250,000 light years of the center of the cluster (its core), eleven massive galaxies are found and nine of those display high rates of formation. Specifically, stars are forming in the cluster core at a rate equivalent to about 3,400 Suns per year.

The large amount of growth through star formation in the galaxies in CL J1001 distinguishes it from other galaxy clusters found at distances of about 10 billion light years and closer, where little growth is occurring. These results suggest that elliptical galaxies in clusters may form their stars through more violent and shorter bursts of star formation than elliptical galaxies outside clusters.

The latest study shows that CL 1001 galaxy cluster may be undergoing a transformation from a galaxy cluster that is still forming, known as a "protocluster," to a mature one. Astronomers have never found a galaxy cluster at this precise stage. These results may also imply that star formation slows down in large galaxies within clusters after the galaxies have already come together during the development of a galaxy cluster.

Astrophysicist Ethan Siegel [forbes.com] remarks that this latest finding validates the current cosmological theory of a dark matter universe [forbes.com]:

The most exciting part, from a cosmology point of view, is that the first true galaxy clusters will only form at this particular juncture in the game — between two and three billion years of age — if the Universe is dominated by dark matter. Without the addition of dark matter (i.e., with normal matter alone), there isn’t enough massive material to form these huge structures so early in the Universe. If we hadn’t discovered clusters forming this early, it would’ve posed some big trouble for dark matter; similarly, if we find them when the Universe is only 1 billion years old (at a redshift of 5 or 6), that will spell trouble for dark matter, too. Instead, we’re seeing these cosmic behemoths forming exactly where and when they should.

Original Submission