Indian scientists discover ‘Saraswati’, a supercluster of galaxies.
Indian
scientists have discovered Saraswati, a large supercluster of galaxies located
in the direction of the constellation Pisces, and at a distance of 4,000
million light years away from Earth.
A
team of astronomers from the Inter-University Centre for Astronomy and
Astrophysics (IUCAA) and Indian Institute of Science Education and Research
(IISER), Pune, and members of two other Indian universities, have discovered
this supercluster of galaxies.
Supercluster
is a chain of galaxies and galaxy clusters, bound by gravity, often
stretching to several hundred times the size of clusters of galaxies,
consisting of tens of thousands of galaxies. This newly-discovered
Saraswati supercluster, extends over a scale of 600 million light years
and may contain the mass equivalent of over 20 million billion suns.
The
discovery will be published in the latest issue of The Astrophysical Journal,
the premier research journal of the American Astronomical Society.
Joydeep
Bagchi from IUCAA, the main author of the paper and co-author Shishir
Sankhyayan (PhD scholar at IISER, Pune) said, ‘’We were very surprised to spot
this giant wall-like supercluster of galaxies, visible in a large spectroscopic
survey of distant galaxies, known as the Sloan Digital Sky Survey. This
supercluster is clearly embedded in a large network of cosmic filaments traced
by clusters and large voids. “
They
stated that previously only a few comparatively large superclusters have been
reported, for example the Shapley Concentration or the Sloan Great Wall in
the nearby universe, while the Saraswati supercluster is far more distant
one.
“Our
work will help to shed light on the perplexing question of how such extreme
large-scale, prominent matter-density enhancements had formed billions of years
in the past when the mysterious Dark Energy had just started to dominate
structure formation,’’ they added.
Officials
also stated that to understand galaxy formation and evolution, one needs to
identify these superclusters and closely study the effect of their environment
on the galaxies. This is a new research area and the discovery will enhance this
field of research.
They
added that when astronomers look far away, they see the universe from long ago,
since light takes a while to reach us. The Saraswati supercluster is observed
as it was when the Universe was 10 billion years old.
Officials
from IUCAA said the paper was special because it is a direct product of IUCAA’s
associateship programme. While two of the authors are faculty members of IUCAA
namely Prof. Joydeep Bagchi and Prof. Somak Raychaudhury, Director IUCAA), the
other authors are Shishir Sankhyayan - PhD student at Indian Institute of
Science Education and Research (IISER) Pune and regular visiting student at
IUCAA, Pratik Dabhade - Research Fellow at IUCAA, Joe Jacob - Department of
Physics, Newman College, Thodupuzha, Kerala (IUCAA Associate) and Prakash
Sarkar - Dept. of Physics, National Institute of Technology, Jamshedpur
(ex- IUCAA Postdoctoral Fellow).
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