Texas A&M, College Station, TX, May 11, 2010
Using NASA’s Spitzer Space Telescope, a Texas A&M University-led team of astronomers has uncovered what may be the earliest, most distant cluster of galaxies ever detected.
The group of roughly 60 galaxies, called CLG J02182-05102, is nearly 10 billion years old – born just 4 billion years after the Big Bang. However, it’s not the size nor the age of the cluster that amazes the team of researchers led by Dr. Casey Papovich, an assistant professor in the Texas A&M Department of Physics and Astronomy and member of the George P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy. Rather, it’s the surprisingly modern appearance of CLG J02182-05102 that has them baffled – a huge, red collection of galaxies typical of only present-day galaxies.
“It’s like we dug an archaeological site in Rome and found pieces of modern Rome amongst the ruins,” explains Papovich, lead author of the team’s study to be published in Astrophysical Journal.
While its neighboring galaxies appear vastly smaller and far fainter, Papovich says CLG J02182-05102 stands out as a densely-populated bundle of ancient galaxies. Enormous red galaxies at the center contain almost 10 times as many stars as our Milky Way, he notes, combining for a total size that rivals that of the most monstrous galaxies of our nearby universe.
Before now, Papovich says, such a finding would be considered by many astronomers to be highly unlikely, considering the time frame in which they were found.
Ancient City of Galaxies Looks Surprisingly Modern
NASA JPL Spitzer - 12 May 2010
A Spitzer-Selected Galaxy Cluster at z=1.62Astronomers are a bit like archeologists as they dig back through space and time searching for remnants of the early universe. In a recent deep excavation, courtesy of NASA's Spitzer Space Telescope, astronomers have unearthed what may be the most distant, primitive cluster of galaxies ever found.
In a twist, however, this apparent ancestor to today's "big cities" of grouped galaxies looks shockingly modern. Called CLG J02182-05102, the ancient cluster is dominated by old, red and massive galaxies, typical of present-day clusters. For example, it is similar to a young version of the Coma Cluster of today, which has had billions of more years to develop.
For now, ClG J02182-05102 stands out as a greatly over-dense region of galaxies - a metropolis in a land of isolated villages. At its center regions loom red, monster galaxies containing about 10 times as many stars as our Milky Way galaxy. This puts them on par with the most mammoth galaxies in the nearby universe, which have grown fat through repeated mergers of other galaxies. These big galaxies are so uncharacteristic of those in the early universe that in some sense it is like finding modern skyscrapers in ancient Rome.
- arXiv.org > astro-ph > arXiv:1002.3158
(Submitted: 16 Feb 2010 (v1), Last Revised: 21 Apr 2010 (v3))
Accepted for publication in The Astrophysical Journal
Carnegie Institution of Science, Washington, DC - 12 May 2010