Massive galaxy cluster found 10 billion light years away from Earth
Discovery could shed light on how the universe formed
The discovery of a cluster of galaxies 10 billion light years from Earth is giving astronomers from Liverpool John Moores University a unique insight on how the universe formed.
Professor Chris Collins, Director of LJMU's Astrophysics Research Institute, explains: "This galaxy cluster is a fossil of the early Universe. Not only is it the oldest confirmed cluster ever discovered but its surprising structure could pave the way for a better understanding of how clusters and their constituent galaxies have evolved since the Big Bang."
The cluster - known only as XMM-XCS 2215.9-1738 - is around 10 billion light years away from Earth and contains hundreds of galaxies, many of which could have a similar structure to our own galaxy, the Milky Way.
Professor Collins continues: "If we can establish how the more ancient cluster was formed and has evolved over the last 10 billion light years we could learn important lessons on how galaxies, such as the Milky Way, change over time."
Current theories on how the universe formed are based on clusters of galaxies growing continuously, getting more massive with every epoch. As a result, astronomers expect to find fewer massive clusters in the universe's distant past.
That's what makes this discovery so important, as at approximately 500 trillion times the mass of our Sun, the new cluster is the most massive ever discovered at such an early era in the universe.
What's equally unexpected is that it is also the hottest cluster discovered at this cosmological distance.
Professor Collins explains: "We still don't really understand how galaxies begin their lives and age, so that's why this cluster is so important. This cluster was formed three-quarters of the way back to the Big Bang. By examining its galaxies and establishing when they started to form, their shape, mass, colour and brightness, the chances are that we will gain a better understanding of the physical conditions in the early universe"
He continues: "It is surprising to find such a massive cluster at a relatively early era in the universe's life and it shows that large structures existed just three to four billion years after the Big Bang. Our research could provide vital evidence on how galaxies form, change over time and the relative importance that the environment and evolution play in this process."
The cluster was detected in observations covering just one-tenth of a percent of the whole sky which were recorded by the X-ray satellite, XMM-Newton. Once identified as a cluster, the team used some of the world's most advanced ground based telescopes, including the 10 metre Keck telescope on Hawaii, to verify the data.
The research team are continuing to search archived observations from the Newton satellite for more clusters. They have already identified 1000 other candidate galaxy clusters that require confirmation using ground-based optical telescopes.
Professor Collins, who is co-ordinating the ground-based observations, along with PhD student Matthew Hilton, says: "LJMU is working at the forefront of a very exacting area. We are using the largest and most powerful telescopes in the world to verify the X-ray data. This bodes well for the future and I expect our research will produce be the premier catalogue of clusters for years to come."
The research findings were presented at the 208th American Astronomical Society meeting in Calgary on Monday 5 June 2006.
Ends
Captions:
- Top: Image of the cluster XMM-XCS 2215.9-1738 at a distance of 10 billion light years, three quarters of the way back to the Big Bang. The diffuse colour represents the hot X-ray emitting gas which were detected by the XMM-Newton satellite. The cluster galaxies are coloured red and located near the centre of the image. (Acknowledgements: European Southern Observatory Imaging Survey, NOAO, ESA).
- Bottom: Professor Chris Collins
