Cosmic Mystery –An Ancient Bygone Cluster Mirrors Young Galaxy Clusters


A surprisingly large collections of galaxies (red dots in center) stands out at a remarkably large distance in this composite image combining infrared and visible-light observations. NASA’s Spitzer Space Telescope contributed to the infrared component of the observations, while shorter-wavelength infrared and visible data are provided by Japan’s Subaru telescope atop Mauna Kea, Hawaii.

This ancestor to today’s grouped galaxies looks shockingly modern -atronomers liken it to finding modern skyscrapers in an archeological dig of ancient Rome. Called CLG J02182-05102, the ancient cluster is dominated by old, red and massive galaxies, typical of present-day clusters.

The ancient cluster is similar to a young version of the Coma Cluster of today, which has had billions of more years to develop. Most of the galaxies that inhabit the central portion of the Coma Cluster are ellipticals. Both dwarf, as well as giant ellipticals, are found in abundance.

Coma “We are seeing something already aged and red like a younger version of the Coma Cluster [left] from a distant, bygone era,” said Casey Papovich, lead author of a new study and an assistant professor of physics and astronomy at Texas A&M University in College Station.Papovich added, “it is as though we dug an archeological site in Rome and found pieces of modern Rome in amongst the ruins.”

ClG J02182-05102 might have indeed been ahead of its time. Just as Rome was the world’s biggest city more than 2,000 years ago with a population of about a million residents, observed Papovich – so too was this galactic grouping an advanced civilization for so early an era in the developing universe.

Galaxy clusters are the largest gravitationally bound structures in the universe and are thought to have formed piecemeal over cosmic time. For now, ClG J02182-05102 is the only known galactic grouping so far away in the past, and studying it will help researchers understand the overall history of how galaxies congregate and evolve.

The Daily Galaxy via NASA/JPL-Caltech/Subaru

Image middle of page: Gregory Bothun -University of Oregon. The color shades represent different brightness levels, to make subtle detail more obvious.




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