Astronomers map the universe's dark matter at unprecedented scale

Jan 09, 2012
Astronomers map the universe's dark matter at unprecedented scale
The observations show that dark matter in the Universe is distributed as a network of gigantic dense (white) and empty (dark) regions, where the largest white regions are about the size of several Earth moons on the sky. Credit: Van Waerbeke, Heymans, and CFHTLens collaboration.

(PhysOrg.com) -- For the first time, astronomers have mapped dark matter on the largest scale ever observed. The results, presented by Dr Catherine Heymans of the University of Edinburgh, Scotland, and Associate Professor Ludovic Van Waerbeke of the University of British Columbia, Vancouver, Canada, are being presented today to the American Astronomical Society meeting in Austin, Texas. Their findings reveal a Universe comprised of an intricate cosmic web of dark matter and galaxies that spans more than one billion light years.

University of British Columbia and University of Edinburgh astronomers have mapped dark matter on the largest scale ever observed, according to results released today at the American Astronomical Society meeting in Austin, Texas.

The findings, presented by Dr Catherine Heymans of the University of Edinburgh, Scotland, and Associate Professor Ludovic Van Waerbeke of UBC, reveal a Universe comprised of an intricate cosmic web of and galaxies that spans more than one billion light years.

An international team of researchers lead by Van Waerbeke and Heymans achieved their results by analysing images of about 10 million galaxies in four different regions of the sky. They studied the distortion of the light emitted from these galaxies, which is bent as it passes massive clumps of dark matter during its journey to Earth.

Astronomers map the universe's dark matter at unprecedented scale
The observations show that dark matter in the Universe is distributed as a network of gigantic dense (light) and empty (dark) regions, where the largest dense regions are about the size of several Earth moons on the sky. Credit: Van Waerbeke, Heymans, and CFHTLens collaboration.

Their project, known as the Canada-France-Hawaii Telescope Lensing Survey (CFHTLenS), uses data from the Canada-France-Hawaii Telescope Legacy Survey. This accumulated images over five years using the wide field imaging camera MegaCam, a 1 degree by 1 degree field-of-view 340 Megapixel camera on the CFHT in Hawaii.

Galaxies included in the survey are typically six billion light years away. The light captured by the telescope images used in the study was emitted when the Universe was six billion years old – roughly half the age it is today.

The densest regions of the dark matter cosmic web host massive clusters of galaxies. Credit: Van Waerbeke, Heymans, and CFHTLens collaboration.

The team's result has been suspected for a long time from studies based on computer simulations, but was difficult to verify owing to the invisible nature of dark matter. This is the first direct glimpse at dark matter on large scales showing the cosmic web in all directions.

Professor Ludovic Van Waerbeke, from the University of British Columbia, said: "It is fascinating to be able to 'see' the dark matter using space-time distortion. It gives us privileged access to this mysterious mass in the Universe which cannot be observed otherwise. Knowing how dark matter is distributed is the very first step towards understanding its nature and how it fits within our current knowledge of physics."

The ubiquitous dark matter cosmic web is seen in all four directions surveyed by the Canada-France-Hawaii Telescope during each season of the year. The central colour inset shows the previous largest COSMOS Dark Matter map (credit: NASA, ESA, P. Simon and T. Schrabback) and the full moon to scale. Credit: Van Waerbeke, Heymans, and CFHTLens collaboration.

Dr Catherine Heymans, a Lecturer in the University of Edinburgh's School of Physics and Astronomy, said: "By analysing light from the distant Universe, we can learn about what it has travelled through on its journey to reach us. We hope that by mapping more dark matter than has been studied before, we are a step closer to understanding this material and its relationship with the galaxies in our Universe."

Professor Lance Miller, from Oxford University said: "This result has been achieved through advances in our analysis techniques which we are now applying to data from the Very Large Telescope's (VLT) Survey Telescope in Chile."

Professor Koen Kuijken, from Leiden University, said: "Over the next three years we will image more than 10 times the area mapped by CFHTLenS, bringing us ever closer to our goal of understanding the mysterious dark side of the Universe."

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User comments : 14

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dtyarbrough
1.6 / 5 (13) Jan 09, 2012
amazing that the size of these clumps of dark matter appear somewhat uniform, especially since a clump 1 light year away should appear 6 billion time larger that the most distant ones.
El_Nose
1 / 5 (4) Jan 09, 2012
The only issue i really suspect is that clumps of DM hide other clumps of DM they are in front of --- giving rise to speculation of the size and distance to that clump.

Other than that -- Good Job team - take a bow
typicalguy
3.9 / 5 (16) Jan 09, 2012
I will wait patiently for legions of dark matter 'haters' to show up and comment on how all of modern physics is wrong but they single-handedly came up with a thought experiment (non computational) way to explain everything in the universe....
rawa1
1.1 / 5 (14) Jan 09, 2012
In AWT the gravity is the result of tachyon shielding with massive bodies. The dark matter is the result of shielding of this shielding with neighbouring massive bodies. Dark matter sucks...
...
...
...
...antimatter.
marcin_szczurowski
3.6 / 5 (5) Jan 09, 2012
Could someone please explain how we know if and how light is distorted? It really bugs me as I know the effect of gravitational lensing and the situations when it's pretty obvious. How can we tell light is distorted in such scale?
Deathclock
3.4 / 5 (7) Jan 09, 2012
amazing that the size of these clumps of dark matter appear somewhat uniform, especially since a clump 1 light year away should appear 6 billion time larger that the most distant ones.


I think they are smart enough to take perspective into account...
Noumenon
3.6 / 5 (74) Jan 09, 2012
Could someone please explain how we know if and how light is distorted? It really bugs me as I know the effect of gravitational lensing and the situations when it's pretty obvious. How can we tell light is distorted in such scale?


A whole galaxy will appear stretched or smeared out perpendicular to the location of the DM. There will be several such galaxies distorted into "arcs" around the DM area. I don't know if there would be multiple images of the same galaxy like it can occur with individual stars around a BH.

There should be some images of this on the net somewhere.
yyz
5 / 5 (7) Jan 09, 2012
Noumenon & marcin,

This survey and other like it are looking for the effects of weak gravitational lensing, which (statistically) affects the shapes of galaxies over wide fields but rarely produces giant arcs and multiply-imaged galaxies as is seen in strong lensing (which is usually confined to galaxy clusters): http://en.wikiped..._lensing
verkle
2.6 / 5 (15) Jan 09, 2012
Hi typical,

I will wait patiently for science to come up with even an elementary explanation of what DM is. I am not a DM hater. I just want to point out that up until now DM has just been some kind of convenience to lean on when we can't explain physics on the universal scale.

We should be arrogant to assume that we know even 1% of true physics. There is just so much more to learn, and I commend all those who continue to seek truth.

Noumenon
3.6 / 5 (73) Jan 09, 2012
Noumenon & marcin,

This survey and other like it are looking for the effects of weak gravitational lensing, which (statistically) affects the shapes of galaxies over wide fields but rarely produces giant arcs and multiply-imaged galaxies as is seen in strong lensing (which is usually confined to galaxy clusters): http://en.wikiped..._lensing


Thanks for that link!
ubavontuba
2.8 / 5 (12) Jan 09, 2012
amazing that the size of these clumps of dark matter appear somewhat uniform, especially since a clump 1 light year away should appear 6 billion time larger that the most distant ones.
I will venture that this is a highly astute observation. However, it's not like taking random pictures in a forest. They chose a particular field to view. It's more like peering across a large meadow and taking pictures of the forest on the other side. All the trees will look surprisingly uniform.

However, it would certainly be interesting to develop a 3D edition of this map.

slatsmandu
not rated yet Jan 10, 2012
found a typo. "galaxies that spans" "should be galaxies that span", drop the s.
vidyunmaya
1 / 5 (5) Jan 10, 2012
sub:Search cosmological Index
Plasma occupies the shape of the body- Universal plasma Energy Model-iEEE-iCOPS-1991 explains more.
The images cannot be sterio-typed. There must be plasma Regulated Electromagnetic Phenomena in magnetic Environment- See Cosmology Vedas Interlinks and Cosmic Pot Energy of the universe-STSCI-symposium-May 3-8, 2003 my papers.see Carnegie-Jan 1993-Centenary symposium 3 -my paper-Cosmology Structures new modeling.
Light automatically bends -otherwise the question of Energy distribution does not arise-Request keep open mind for Science to progress.Nature provides solutions. One lives under shaded groove or Milky way under Shaded Universe .
http://vidyardhic...spot.com
Rohitasch
5 / 5 (1) Jan 14, 2012
sub:Search cosmological Index
Plasma occupies the shape of the body- Universal plasma Energy Model-iEEE-iCOPS-1991 explains more.
The images cannot be sterio-typed. There must be plasma Regulated Electromagnetic Phenomena in magnetic Environment- See Cosmology Vedas Interlinks and Cosmic Pot Energy of the universe-STSCI-symposium-May 3-8, 2003 my papers.see Carnegie-Jan 1993-Centenary symposium 3 -my paper-Cosmology Structures new modeling.
Light automatically bends -otherwise the question of Energy distribution does not arise-
.
.

Ramdev, stick to yoga.