An international team of astronomers has discovered, by the
help of NASA/ESA Hubble Space Telescope, a gargantuan galaxy cluster with core
bursting with new stars----an incredibly rare find. It was the first to show
that gigantic galaxies at the centers of massive clusters can grow
significantly by feeding off gas stolen from other galaxies.
Galaxy clusters are vast families of galaxies bounded
together by gravity. For example, our own galaxy the Milky Way resides within a
small galaxy group known as the Local Group, which itself is a member of the
massive Laniakea super-cluster.
Galaxies at the center of the cluster are usually old, made
of stellar fossils---old, red or dead stars. However, astronomers have now
discovered a giant galaxy at the heart of a cluster named SpARCS1049+56 that
seems to bucking the trend, instead forming new stars at an incredible rate.
Tracy Webb of McGill University explained that the giant
galaxy at the centre of this cluster is furiously making new stars after
merging with a smaller galaxy.
The SpARCS1049+56 is so far away that its light took 9.8
billion years to reach earth. It houses at least 27 galaxies and has combined
mass of 400 trillion Suns, how I wish our technology could reach us in these
awesome places. It is a truly unique cluster in one aspect----its vibrant heart
of new stars. The cluster brightest galaxy is rapidly spitting out 800 new
stars per year. The Milky Way forms 2 stars per year at most.
The galaxy was initially discovered using NASA’s Spitzer
Telescope and Canada-France Telescope, located on Mauna Kea in Hawaii and
confirmed using the W.M Keck Observatory. Follow up was done by Hubble Space
Telescope allowing the astronomers to explore galaxy’s activities.
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The Spitzer data showed a truly enormous amount
of star formation in the heart of the cluster, something which is rarely seen
before.
Spitzer picks up infrared light, so it can detect the warm
glow of hidden, dusty regions of star birth. Follow up studies with Hubble in
visible light helped to pinpoint what was fueling the new star formation.
It appears that a smaller galaxy has recently emerged with
the monster in the middle of the cluster, lending its gas to larger galaxy and
igniting a furious episode of new star-birth.
The new discovery is one of the first known cases of a wet
merger at the core of a galaxy cluster. Hubble recently found a galaxy
containing a wet merger but it wasn’t forming stars vigorously.
The astronomers now aims how common this type of growth
mechanism is in galaxy clusters-----it may even represent an early time in our
own Universe when messy eating was the norm.
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