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Galaxy Cluster Smashes Distance Record

For Release: October 22, 2009


Credit: X-ray: NASA/CXC/INAF/S.Andreon et al Optical: DSS; ESO/VLT.
Press Image and Caption

The most distant galaxy cluster yet has been discovered by combining data from NASA's Chandra X-ray Observatory and optical and infrared telescopes. 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."

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. Infrared observations are important because the optical light from the galaxies at large distances is shifted into infrared wavelengths because of the expansion of the universe.

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.

Also, without the X-ray observations, the possibility remained that this object could have been a blend of different groups of galaxies along the line of sight, or a filament, a long stream of galaxies and gas, viewed front on. The mass and temperature of the hot gas detected estimated from the Chandra observations rule out both of those alternatives.

The extent and shape of the X-ray emission, along with the lack of a central radio source argue against the possibility that the X-ray emission is caused by scattering of cosmic microwave background light by particles emitting radio waves.

It is not yet possible, with the detection of just one extremely distant galaxy cluster, to test cosmological models, but searches are underway to find other galaxy clusters at extreme distances.

"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. "One fossil might just fit in with our understanding of dinosaurs, but if you found many more, you would have to start rethinking how dinosaurs evolved. The same is true for galaxy clusters and our understanding of cosmology."

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 ten times that.

"What's exciting about this discovery is the astrophysics that can be done with detailed follow-up studies," said Andreon.

Among the questions scientists hope to address by further studying JKCS041 are: What is the build-up of elements (such as iron) like in such a young object? Are there signs that the cluster is still forming? Do the temperature and X-ray brightness of such a distant cluster relate to its mass in the same simple way as they do for nearby clusters?

The paper describing the results on JKCS041 from Andreon and his colleagues will appear in an upcoming issue of the journal Astronomy and Astrophysics. NASA's Marshall Space Flight Center in Huntsville, Ala., manages the Chandra program for NASA's Science Mission Directorate in Washington, DC. The Smithsonian Astrophysical Observatory controls Chandra's science and flight operations from Cambridge, Mass.

More information, including images and other multimedia, can be found at: and

Media contacts:
Janet Anderson
NASA Marshall Space Flight Center, Ala.

Megan Watzke
Chandra X-ray Center, Cambridge, Mass.

Visitor Comments (26)

It looks to me like individual galaxies in the cluster and the cluster as a whole are gravitationally lensing objects farther away making rings around the galaxies and a large ring around the cluster defined by the xray image.

Posted by Richard L Blake on Friday, 11.27.09 @ 23:22pm

Dear Harry,
Thanks for your question. This image contains a mixture of objects: some foreground stars (in our galaxy), some foreground galaxies like the obvious spirals in the lower right part of the image and, of course, objects in the galaxy cluster itself. There also may be objects that are more distant than the galaxy cluster. The X-ray sources are mostly active galactic nuclei, or rapidly growing supermassive black holes.

Posted by CXC on Tuesday, 11.3.09 @ 11:41am

Dear Mark,
Thanks for your question. Please see:
for an explanation of why the gas in galaxy clusters is so hot and
for an explanation of how the gas stays hot.

Posted by CXC on Tuesday, 11.3.09 @ 11:38am

Is every object visible in the photograph an individual galaxy, or are there some Milky Way objects that are in the way, between us and the cluster? For example, are the optically visible objects near-field while the x-ray objects, are they galaxies? Some objects appear in both, but most are in one or the other. I'm confused.

Posted by Harry on Thursday, 10.29.09 @ 11:02am

Why is the gas in this and other galaxy clusters so hot? What is the source's for keeping such large amounts of gas at such high temperatures?

Posted by Mark on Wednesday, 10.28.09 @ 14:49pm

Dear Roberto,
Thanks for your question. Dark matter should dominate the mass and gravity of this cluster and would have been a critical factor in the formation of this object.
P. Edmonds, CXC

Posted by P. Edmonds on Wednesday, 10.28.09 @ 08:47am

Thanks Tom - we've fixed this error. It was meant to be 370 arcsec!

P. Edmonds, CXC

Posted by P. Edmonds on Tuesday, 10.27.09 @ 13:37pm

Dear Carl,
There is a good chance there are other planets like Earth in the galaxy
cluster, but it's much too far away to travel there.
P. Edmonds, CXC

Posted by P. Edmonds on Tuesday, 10.27.09 @ 13:35pm

Dear Navaneeth,
The redshift -or distance- of the galaxy cluster was estimated using several different methods, including a study of how the observed colors of galaxies depends on the distance to the galaxies. Full details are in the paper at including a discussion of the measurement errors.

P. Edmonds, CXC

Posted by P. Edmonds on Tuesday, 10.27.09 @ 13:28pm

Thanks Elizabeth - we've done that.
P. Edmonds, CXC

Posted by P. Edmonds on Tuesday, 10.27.09 @ 13:25pm

Thanks Alan - we have now posted the redshift of 1.9. Note that the final
version of the paper is available at

P. Edmonds, CXC

Posted by P. Edmonds on Tuesday, 10.27.09 @ 13:15pm

Thanks Mark for your comment. I don't have any extra information about that possible feature. One's eye can be easily fooled because random distributions of stars or galaxies often produce features that don't look random.
P. Edmonds, CXC

Posted by P. Edmonds on Tuesday, 10.27.09 @ 13:10pm

Chandra did it, every day we know more about the universe, it is enormous. How gravity function on the cluster due to the dark matter?

Posted by Roberto Gonzalez Davisonn on Monday, 10.26.09 @ 16:30pm

Congratulations on an excellent discovery.
I have a question.
Do you have any further information concerning the string a galaxies that seem to be forming a neat curve?
Best wishes

Posted by Mark Ballingotn on Monday, 10.26.09 @ 10:49am

As always, the astronomers at Chandra continue to provide and astonish the community with its discoveries. Providing data to better understand the creation of the universe and all her wonders.
Cheers to all at Chandra
Heidi-Ann Kennedy
Scientific Frontline

Posted by Heidi-Ann Kennedy on Sunday, 10.25.09 @ 11:02am

Sir, my congratulations on this discovery. I hope future observations will reveal more details that will help us in understanding the evolution of the universe. With best wishes

AK Sharma

Posted by AK Sharma on Sunday, 10.25.09 @ 08:55am

Scale 370 arcmin? Isn't that 6 degrees? At 10 billion light years away that would make the image 1 billion light years across. Does that seem right?

Posted by Tom on Sunday, 10.25.09 @ 08:34am

Exquisite use of a most valuable piece of equipment. Thank you for the picture and my appreciation goes out to all the team members that put their time and talents into all the research they are doing.

My fascination of the universe only grows with each and every discovery that you make. Thank you again for helping the apes continue their trek out of the tree.

Dan Pitney

Posted by Daniel R Pitney on Sunday, 10.25.09 @ 01:07am

It is very very beautiful.

Posted by Valter Rodrigues on Friday, 10.23.09 @ 07:34am

Do you think there is any other planet like earth around there, where we can live in future?

Posted by Carl Vertuin on Friday, 10.23.09 @ 02:05am

Good News. Very interesting to hear this story.
How can we measure the distance of these galaxy clusters? How much accuracy is there?

Posted by Navaneeth Krishnan S on Friday, 10.23.09 @ 00:53am

It would be nice to include the redshift of the cluster.

Posted by Elizabeth P Bozyan on Thursday, 10.22.09 @ 20:58pm

Today's technology is astounding the distance of this object and the fact we can see it at all is mind numbing, but extremely exciting as well.

Posted by David Stalker on Thursday, 10.22.09 @ 19:54pm

Very nice. It's mind-boggling to think that the light for this image had already been traveling for 6 billion years before the earth formed.

Posted by David Guidos on Thursday, 10.22.09 @ 18:16pm

Ahh, to be out there somewhere on the Voyager under the command of Captain Janeway. One can only imagine what beauty lies yonder. These fantastic images keep fueling the imagination. Cheers Peter

Posted by Peter on Thursday, 10.22.09 @ 16:14pm

So what's it's redshift? If the story is that it sets a redshift record tell the redshift. That's why to put out a press release so we don't have to phone to get the basics.

P. S. The distance cited is by the look-back time and maybe should be identified as such. This is only one version of the distance of a high-redshift object, though it's the most commonly used.

Posted by Alan MacRobert on Thursday, 10.22.09 @ 12:23pm