From ESO: “El Gordo — A ‘Fat’ Distant Galaxy Cluster”
10 January 2012
An extremely hot, massive young galaxy cluster — the largest ever seen in the distant Universe — has been studied by an international team using ESO’s Very Large Telescope (VLT) in the Atacama Desert in Chile along with NASA’s Chandra X-ray Observatory and the Atacama Cosmology Telescope. The new results are being announced on 10 January 2012 at the 219th meeting of the American Astronomical Society in Austin, Texas.
The newly discovered galaxy cluster  has been nicknamed El Gordo — the “big” or “fat one” in Spanish. It consists of two separate galaxy subclusters colliding at several million kilometres per hour, and is so far away that its light has travelled for seven billion years to reach the Earth.
‘This cluster is the most massive, the hottest, and gives off the most X-rays of any cluster found so far at this distance or beyond,’ said Felipe Menanteau of Rutgers University, who led the study. ‘We devoted a lot of our observing time to El Gordo, and I’m glad our bet paid off and we found an amazing cluster collision.’
The team, led by Chilean and Rutgers astronomers, found El Gordo by detecting a distortion of the cosmic microwave background radiation. This faint glow is the remnant of the first light from the Big Bang, the extremely hot and dense origin of the Universe about 13.7 billion years ago. This radiation left over from the Big Bang interacts with electrons in the hot gas in galaxy clusters, distorting the appearance of the background glow seen from Earth. The denser and bigger the cluster, the bigger this effect. El Gordo was picked up in a survey of the microwave background with the Atacama Cosmology Telescope.”
See the full post here.
[A personal note, I am delighted to see scientists from my alma mater, Rutgers University, working with scientists from the ESO].
ALMA Atacama Large Millimeter/submillimeter Array
ESO, the European Southern Observatory, builds and operates a suite of the world’s most advanced ground-based astronomical telescopes.