NASA identifies most distant galaxy cluster

13 Jan 2011

NASA astronomers have stumbled upon a galactic city of stars named COSMOS-AzTEC3, which is circa 12.6bn light years away from Earth – the most distant known in the early universe.

According to NASA, this ancient collection of galaxies most likely grew into a modern galaxy cluster similar to the massive ones seen today.

COSMOS-AzTEC3 was discovered and characterised by multi-wavelength telescopes, including NASA’s Spitzer, Chandra and Hubble space telescopes, and the ground-based W.M. Keck Observatory and Japan’s Subaru Telescope.

“This exciting discovery showcases the exceptional science made possible through collaboration among NASA projects and our international partners,” said Jon Morse, NASA’s astrophysics division director at NASA headquarters in Washington.


NASA says COSMOS-AzTEC3 is the most distant massive proto-cluster known, and also one of the youngest, because it is being seen when the universe itself was young.

The cluster is roughly 12.6bn light years away from Earth, the space agency says.

“Our universe is estimated to be 13.7bn years old. Previously, more mature versions of these clusters had been spotted at 10bn light years away,” said NASA in a release on Tuesday.

The astronomers also found that this cluster is buzzing with extreme bursts of star formations and one enormous feeding black hole.

“We think the starbursts and black holes are the seeds of the cluster,” said Peter Capak of NASA’s Spitzer Science Center at the California Institute of Technology in Pasadena.

“These seeds will eventually grow into a giant, central galaxy that will dominate the cluster – a trait found in modern-day galaxy clusters.”

Jupitor NASA

Jupiter eruptions captured in infrared. Image courtesy of NASA

Massive galaxies

Capak, along with his colleagues, first used the Chandra X-ray Observatory and the UK’s James Clerk Maxwell Telescope on Mauna Kea, Hawaii, to search for the black holes and bursts of star formations needed to form the massive galaxies at the centres of modern galaxy cities.

The astronomers then used Hubble and the Subaru telescopes to estimate the distances to these objects, and look for higher densities of galaxies around them. Finally, the Keck telescope was used to confirm that these galaxies were at the same distance and part of the same galactic sprawl.

Once the scientists found this lumping of galaxies, they measured the combined mass with the help of Spitzer.

NASA says that, at this distance, the optical light from stars is shifted, or stretched, to infrared wavelengths that can only be observed in outer space by Spitzer.

City of galaxies

The Spitzer observations also helped confirm a massive galaxy at the centre of the cluster was forming stars at an impressive rate.

Then, the Institut de Radioastronomie Millimétrique’s interferometer telescope in France and 30-metre telescope in Spain, along with the National Radio Astronomy Observatory’s Array telescope in New Mexico, measured the amount of gas, or fuel for future star formation, in the cluster.

The results indicate the cluster will keep growing into a modern city of galaxies, says NASA.

“It really did take a village of telescopes to nail this cluster,” said Capak. “Observations across the electromagnetic spectrum, from X-ray to millimetre wavelengths, were all critical in providing a comprehensive view of the cluster’s many facets.”

European Space Agency and Ireland

Last week, reported on how Discover Science & Engineering (DSE) had partnered with the European Space Agency to set up the European Space Education Resource Office here as a new space education resource, so students can capitalise on the career opportunities out there.

Carmel Doyle was a long-time reporter with Silicon Republic