Astronomers detect most distant galaxy cluster yet discovered

October 23rd, 2009 - 12:39 pm ICT by ANI  

Washington, October 23 (ANI): Astronomers, by combining data from NASA’s Chandra X-ray Observatory and optical and infrared telescopes, have detected the most distant galaxy cluster yet discovered.

The cluster is located about 10.2 billion light-years away and is observed as it was when the universe was only about a quarter of its present age.

The galaxy cluster, known as JKCS041, beats the previous record holder by about a billion light-years. Galaxy clusters are the largest gravitationally bound objects in the universe.

Finding such a large structure at this very early epoch can reveal important information about how the universe evolved at this crucial stage.

JKCS041 is found at the cusp of when scientists think galaxy clusters can exist in the early universe based on how long it should take for them to assemble.

Therefore, studying its characteristics - such as composition, mass, and temperature - will reveal more about how the universe took shape.

“This object is close to the distance limit expected for a galaxy cluster,” said Stefano Andreon of the National Institute for Astrophysics (INAF) in Milan, Italy. “We don’t think gravity can work fast enough to make galaxy clusters much earlier,” he added.

Distant galaxy clusters are often detected first with optical and infrared observations that reveal their component galaxies dominated by old, red stars.

JKCS041 was originally detected in 2006 in a survey from the United Kingdom Infrared Telescope (UKIRT).

The distance to the cluster was then determined from optical and infrared observations from UKIRT, the Canada-France-Hawaii Telescope in Hawaii, and NASA’s Spitzer Space Telescope.

The Chandra data were the final - but crucial - piece of evidence as they showed that JKCS041 was, indeed, a genuine galaxy cluster.

The extended X-ray emission seen by Chandra shows that hot gas has been detected between the galaxies, as expected for a true galaxy cluster rather than one that has been caught in the act of forming.

“This discovery is exciting because it is like finding a Tyrannosaurus Rex fossil that is much older than any other known,” said co-author Ben Maughan, from the University of Bristol in the United Kingdom.

The previous record holder for a galaxy cluster was 9.2 billion light-years away, XMMXCS J2215.9-1738, discovered by ESA’s XMM-Newton in 2006.

This broke the previous distance record by only about 0.1 billion light-years, while JKCS041 surpasses XMMXCS J2215.9 by about 10 times that. (ANI)

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