A massive
so-called galaxy cluster, one of the largest structures in the universe,
has been discovered about 5.7 billion light years from Earth and
credited with setting several important new cosmic records.
The cluster, which has shown a prodigious
rate of star formation, may force astronomers to rethink how such
colossal structures and galaxies that inhabit them evolve over time.
Known officially by an alphabet soup of numbers and letters as
SPT-CLJ2344-4243, the cluster has been nicknamed “Phoenix,” after the
mythological bird that rose from the dead.
That's partly due to the constellation in which it lies. The Phoenix was also a great way of thinking about the latest
astronomical marvel.
“While galaxies at the center of most clusters may have been dormant
for billions of years, the central galaxy in this cluster seems to have
come back to life with a new burst of star formation,” said McDonald,
the lead author of the paper on Phoenix, appearing in the Aug. 16 issue
of Nature.
Based on observations from NASA's Chandra X-ray Observatory, the U.S.
National Science Foundation's South Pole Telescope and eight other
observatories, researchers said the centre of the Phoenix cluster had
been linked to the creation of about “740 solar masses” or stars a year. By comparison, the Perseus cluster forms stars at a rate about 20 times slower than Phoenix.
Huge clusters like Phoenix are thought to host thousands of galaxies and
there was still a lot to learn about what goes on within them.
Supermassive black holes in the central galaxy of a cluster have long
been associated with low observed star formation rates, as they pump
energy into the system and prevent the cooling of gases needed for the
creation of stars.
But researchers said the “massive starburst” seen in Phoenix, as it
gave birth to about two stars per day, suggested that its central
galaxy's black hole had failed to interfere with an extremely strong
cooling flow.
Stars are forming in the Phoenix cluster at the highest rate ever
observed for the middle of a galaxy cluster. The object also is the most powerful producer of X-rays of any known
cluster and among the most massive. The data also suggest the rate of
hot gas cooling in the central regions of the cluster are the largest
ever observed.
Read more here.
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