Galaxies in clusters

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Galaxies in clusters
The picture to the right shows the wealth of
galaxies in clusters. By studying them we can
test theories of galaxy evolution in the densest
parts of the universe. Old red galaxies inhabit
the dense centre surrounded by hot x-ray gas.
Younger spiral galaxies have fallen into the
cluster later and lie on its edges.
Credit NASA, N. Benitez (JHU), T. Broadhurst
(Racah Institute of Physics/The Hebrew
University), H. Ford (JHU), M. Clampin (STScI),
G. Hartig (STScI), G. Illingworth (UCO/Lick
Observatory), the ACS Science Team and ESA.
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Galaxies in clusters
This cluster was found by the XMM Cluster Survey
led from Sussex University. By studying clusters
we can test theories of galaxy evolution in the
densest parts of the universe. Old red galaxies
inhabit the dense centre surrounded by hot x-ray
gas. Younger spiral galaxies have fallen into
the cluster later and lie on its edges.