Named CL J1001+0220, this cluster can be seen forming when the universe was less than three billion years old, becoming the oldest cluster of galaxies yet seen, beating the previous record holder by 700 million years.
Galactic clusters are huge; among the biggest known structures in the cosmos. They are so big that astronomers thought CL J1001 wouldn't have had the time to accumulate so many galaxies. But there it is. And it's having one heck of a star party.
"This galaxy cluster isn't just remarkable for its distance, it's also going through an amazing growth spurt unlike any we've ever seen," said astronomer Tao Wang, of the French Alternative Energies and Atomic Energy Commission (CEA), in a statement.
Deep inside that purple glow -- which is the X-ray glow of intragalactic gases observed by NASA's Chandra X-ray Observatory and European XMM-Newton space telescope -- 11 elliptical galaxies can be seen and nine of them are hothouses of stellar birth. These galaxies are creating an equivalent of 3,000 sun-like stars per year, making this cluster one of a kind.
"It appears that we have captured this galaxy cluster at a critical stage just as it has shifted from a loose collection of galaxies into a young, but fully formed galaxy cluster," said collaborator David Elbaz also from CEA.
By the researchers' reckoning, in a paper published in The Astrophysical Journal, elliptical galaxies only seem to experience this extreme starburst phase after they have accumulated gravitationally to form vast clusters like this. We are therefore having an extremely privileged view of a cluster when its inhabitants are undergoing a short yet extremely violent period of stellar activity.
The next step is to find more of these very distant and extremely active clusters in the hope of understanding more about the evolution of ancient galaxies.
From Discovery News
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