Researchers describe one of the most massive large-scale structures in the universe

July 14, 2017
Researchers describe one of the most massive large-scale structures in the universe
The distribution of galaxies, from Sloan Digital Sky Survey (SDSS), in Saraswati supercluster. It is clearly visible that the density of galaxies is very high in the Saraswati supercluster region. The typical size of a galaxy here is around 250,000 light years. The galaxy sizes are increased for representation. Credit: Inter University Centre for Astronomy & Astrophysics (IUCAA)

A team of astronomers from the Inter University Centre for Astronomy & Astrophysics (IUCAA), and Indian Institute of Science Education and Research (IISER), both in Pune, India, and members of two other Indian universities, have identified a previously unknown, extremely large supercluster of galaxies located in the direction of constellation Pisces. This is one of the largest known structures in the nearby Universe, and is at a distance of 4,000 million (400 crore) light-years away from us.

This novel discovery is being published in the latest issue of The Astrophysical Journal, the premier research journal of the American Astronomical Society.

Large-scale structures in the Universe are found to be hierarchically assembled, with galaxies, together with associated gas, and dark matter, being clumped in clusters, which are organized with other clusters, smaller groups, filaments, sheets and large empty regions ("voids") in a pattern called the "Cosmic web" which spans the observable Universe.

Superclusters are the largest coherent structures in the Cosmic Web. A 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, for instance, extends over a scale of 600 million light-years and may contain the mass equivalent of over 20 million billion suns.

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.

Two most massive clusters of galaxies in the Saraswati supercluster : “ABELL 2631” cluster (left) and “ZwCl 2341.1+0000” cluster (right). “ABELL 2631” resides in the core of the Saraswatisupercluster. The Saraswati supercluster has a total of 43 clusters of galaxies. Credit: Inter University Centre for Astronomy & Astrophysics (IUCAA)

The long-popular "Cold dark matter" model of the evolution of the Universe predicts that small structures like galaxies form first, which congregate into larger structures. Most forms of this model do not predict the existence of large structures such as the "Saraswati Supercluster" within the current age of the Universe. The discovery of these extremely large structures thus force astronomers into re-thinking the popular theories of how the Universe got its current form, starting from a more-or-less uniform distribution of energy after the Big Bang. In recent years, the discovery of the present-day Universe being dominated by "Dark Energy", which behaves very differently from Gravitation, might play a role in the formation of these structures.

It is believed that galaxies are formed mostly on the filaments and sheets that are part of the , and many of the galaxies travel along these filaments, ending up in the rich clusters, where the crowded environment switches off their star formation and aids in the transformation of galaxies to disky blue spiral galaxies to red elliptical galaxies. Since there is an extensive variation of environment within a Supercluster, galaxies travel through these varied environments during their "lifetime". To understand their formation and evolution, one needs to identify these Superclusters and closely study the effect of their environment on the galaxies. This is a very new research area- with the aid of observations of new observational facilities, astronomers are now beginning to understand galaxy evolution. This discovery will greatly enhance this field of research.

"Saraswati" (or "Sarasvati"), a word that has proto-Indo-European roots, is a name found in ancient Indian texts to refer to the major river around which the people of the ancient Indian civilization lived. It is also the name of the celestial goddess who is the keeper of the celestial rivers. In modern India, Saraswati is worshipped as the goddess of knowledge, music, art, wisdom and nature – the muse of all creativity.

Our own galaxy is part of a Supercluster called the Laniakea Supercluster, announced in 2014 by Brent Tully at the University of Hawaii and collaborators.

Interestingly, Somak Raychaudhury, currently Director of IUCAA, Pune, who is a co-author of this paper, also discovered the first massive Supercluster of galaxies on this scale (the "Shapley Concentration"), during his PhD research at the University of Cambridge. In his paper, published in the journal 'Nature' in 1989, he had named the supercluster after the American astronomer Harlow Shapley, in recognition of his pioneering survey of galaxies, from the Southern hemisphere, in which this massive super-structure was first imaged, way back in 1932.

Joydeep Bagchi from IUCAA, the lead 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 , known as the Sloan Digital Sky Survey (see figure above). This supercluster is clearly embedded in a large network of cosmic filaments traced by clusters and large voids. Previously only a few comparatively large superclusters have been reported, for example the 'Shapley Concentration' or the 'Sloan Great Wall' in the , while the 'Saraswati' supercluster is far more distant one. Our work will help to shed light on the perplexing question; 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 formation.''

Explore further: Astronomers find supercluster of galaxies near Milky Way

More information: Saraswati: An Extremely Massive ~ 200 Megaparsec Scale Supercluster. arxiv.org/abs/1707.03082

Related Stories

Cosmic environments and their influence in star formation

March 6, 2017

The scaffolding that holds the large-scale structure of the universe constitutes galaxies, dark matter and gas (from which stars are forming), organized in complex networks known as the cosmic web. This network comprises ...

Discovered: Fast-growing galaxies from early universe

May 24, 2017

A team of astronomers including Carnegie's Eduardo Bañados and led by Roberto Decarli of the Max Planck Institute for Astronomy has discovered a new kind of galaxy which, although extremely old—formed less than a billion ...

Recommended for you

Solar eruptions could electrify Martian moons

October 18, 2017

Powerful solar eruptions could electrically charge areas of the Martian moon Phobos to hundreds of volts, presenting a complex electrical environment that could possibly affect sensitive electronics carried by future robotic ...

Potential human habitat located on the moon

October 18, 2017

A study published in Geophysical Research Letters confirms the existence of a large open lava tube in the Marius Hills region of the moon, which could be used to protect astronauts from hazardous conditions on the surface.

A solar-powered asteroid nursery at the orbit of Mars

October 18, 2017

The planet Mars shares its orbit with a handful of small asteroids, the so-called Trojans. Among them, one finds a unique group, all moving in very similar orbits, suggesting that they originated from the same object. But ...

Scientists dig into the origin of organics on Ceres

October 18, 2017

Since NASA's Dawn spacecraft detected localized organic-rich material on Ceres, Southwest Research Institute (SwRI) has been digging into the data to explore different scenarios for its origin. After considering the viability ...

10 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

eachus
5 / 5 (4) Jul 14, 2017
"4,000 million (400 crore) light-years"

I've seen lakh or crore used for Indian currency or population, but never for light-years. ;-)
cantdrive85
1.7 / 5 (12) Jul 14, 2017
The long-popular "Cold dark matter" model of the evolution of the Universe predicts that small structures like galaxies form first, which congregate into larger structures. Most forms of this model do not predict the existence of large structures such as the "Saraswati Supercluster" within the current age of the Universe.

That's no small problem, doesn't slow down the fanciful pontifications of the plasma ignoramuses though.

The discovery of these extremely large structures thus force astronomers into re-thinking the popular theories of how the Universe got its current form, starting from a more-or-less uniform distribution of energy after the Big Bang.

Patching in ad hoc guesses is not rethinking at all, it's sloppy science boarding on complete BS.
cantdrive85
1.4 / 5 (10) Jul 14, 2017
Large-scale structures in the Universe are found to be hierarchically assembled, with galaxies, together with associated gas, and dark matter, being clumped in clusters, which are organized with other clusters, smaller groups, filaments, sheets and large empty regions ("voids") in a pattern called the "Cosmic web" which spans the observable Universe.

This is the observation, not prediction of the standard theory, as pointed out above.

"I have never thought that you could obtain the extremely clumpy, heterogeneous universe we have today, strongly affected by plasma processes, from the smooth, homogeneous one of the Big Bang, dominated by gravitation."
— Hannes Alfvén

BTW, Alfven predicted the observed structure of the Universe 50-years before it was confirmed.
rrwillsj
4.5 / 5 (8) Jul 14, 2017
cd85, I know all too well from my own failures to accept accumulating evidence against my most cherished hypothesis?

That new evidence can be true or false, right or wrong. Obscured by unresolved comprehension of what we think we know. Or falsified, whether deliberate or by inattention.

Now there is new evidence, newly applied research. Resulting in new conclusions that offend your opinions.

So what is the new evidence to be presented that would support your conclusions? And not just a stale rehash of obsolete speculation.
Tony Lance
1 / 5 (3) Jul 15, 2017
The Outlandish Particle Periodic Table
(Classification System beats Monte Carlo One)
Pure Mathematics by Tony Lance Dip.Math.(Open)
http://www.bigber...ag03.png
http://www.bigber...irm.html
IMP-9
4.4 / 5 (7) Jul 15, 2017
Most forms of this model do not predict the existence of large structures such as the "Saraswati Supercluster" within the current age of the Universe.


Which is not true and not a point made in the actual paper. The authors actually cite Park et al. 2012 who studied the superstructures in the Horizon Run 2 LCDM simulation and found not just analogues of the Sloan Great Wall but even larger structures including one at 250 Mpc in length. Larger than this overdensity. The paper itself doesn't attempt to compare directly with simulations so the press release shouldn't be making claims like this.
cantdrive85
1.6 / 5 (7) Jul 15, 2017
Which is not true and not a point made in the actual paper.

It's actually a statement of fact, whereas "most" LCDM models don't do so, only the ad hoc adjustments do so...
Shootist
3 / 5 (2) Jul 15, 2017
When astronomers look far away, they see the Universe from long ago, since light takes a while to reach us.


Good to know.
HeloMenelo
not rated yet Jul 17, 2017
cd85, I know all too well from my own failures to accept accumulating evidence against my most cherished hypothesis?

That new evidence can be true or false, right or wrong. Obscured by unresolved comprehension of what we think we know. Or falsified, whether deliberate or by inattention.

Now there is new evidence, newly applied research. Resulting in new conclusions that offend your opinions.

So what is the new evidence to be presented that would support your conclusions? And not just a stale rehash of obsolete speculation.


This monkeyjack (aka cantdrive, antigoracle sock puppet) stomps around spewing bubblegum opinions for 2 decades now, the new evidence he provides is always the same utter nothingness he always provides, nothing ever enters that hollow skull of his to light up some sense of understanding (and nothing probably ever will)
HeloMenelo
not rated yet Jul 17, 2017
When astronomers look far away, they see the Universe from long ago, since light takes a while to reach us.


Good to know.


But you already forgot... again ;)

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.