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Dark Energy Survey creates detailed guide to spotting dark matter

13 Apr 2015

Dark Matter map
This is the first Dark Energy Survey map to trace the detailed distribution of dark matter across a large area of sky. The color scale represents projected mass density: red and yellow represent regions with more dense matter. The dark matter maps reflect the current picture of mass distribution in the universe where large filaments of matter align with galaxies and clusters of galaxies. This map covers three percent of the area of sky that DES will eventually document over its five-year mission. The size of the Moon is shown at top left for scale. Image credit: Dark Energy Survey.

Dark Matter map
The dark matter mass map with superimposed DES optical images of two galaxy clusters and a cosmic void. Image credit: Dark Energy Survey.

The largest single high definition map of mysterious dark matter has been produced, with the help of UK scientists. And it could reveal more about how galaxies formed in our Universe.

Researchers at the Dark Energy Survey (DES), including several from the University of Manchester’s Jodrell Bank Centre for Astrophysics, have released the first in a series of dark matter maps of the cosmos. The map, created with one of the world’s most powerful digital cameras, is the largest contiguous map created at this level of detail, and will improve our understanding of dark matter’s role in the formation of galaxies.

The map was released today at the April meeting of the American Physical Society in Baltimore, Maryland. It was created using data captured by the Dark Energy Camera, a 570-megapixel imaging device that is the primary instrument for the Dark Energy Survey (DES) led by Fermilab in the US.

A team from the University of Manchester, led by Professor Sarah Bridle, has spent the last 2 years measuring the shapes of galaxies used to construct the map.

“It is amazing to see a map of the dark matter over such a large region of the sky”, said Prof Bridle “and the full Dark Energy Survey mass map will be more than 30 times bigger still!”
“Analysis of the clumpiness of the dark matter in the maps will also allow us to probe the nature of the mysterious dark energy, believed to be causing the expansion of the universe to speed up.”

The team at Manchester analysed about 130 million separate telescope images of these galaxies. The process of measuring the galaxies is so complex and time consuming that some of the world's largest supercomputers are needed to do it - each time a new catalog is made it takes about as much computing power as running 500 ordinary desktop computers for two weeks.

“We have to measure the shape of each galaxy - how distorted it is - with extremely high precision, about 1 part in 1000”, said Dr Joe Zuntz, also of the University of Manchester, who has been making the measurements.

Dark matter, the mysterious substance that makes up 80% of all matter in the Universe, is invisible to even the most sensitive astronomical instruments because it does not emit or block light. But its effects can be seen using a technique called gravitational lensing – studying the distortion that occurs when the gravitational pull of dark matter bends light around distant galaxies. Understanding how the clumpiness of dark matter changes with time will reveal the nature of the enigmatic dark energy, which is the ultimate goal of the survey.

The dark matter map released today makes use of early DES observations and cover only about three percent of the area of sky DES will document over its five-year mission. The survey has just completed its second year. As scientists expand their search, they’ll be able to better test current cosmological theories by comparing the amounts of dark and visible matter.

Those theories suggest that, since there is much more dark matter in the universe than visible matter, galaxies will form where there are large concentrations of dark matter (and hence stronger gravity) present. So far, the DES analysis backs this up: the maps show large filaments of matter along which visible galaxies and galaxy clusters lie and cosmic voids where very few galaxies reside. Follow-up studies of some of the enormous filaments and voids, and the enormous volume of data, collected throughout the survey will reveal more about this interplay of mass and light.

The Jodrell Bank Centre for Astrophysics group working on this project include Sarah Bridle, Joe Zuntz, Michael Troxel and Niall MacCrann. You can read more in Joe’s blog at the Jodrell Bank Discovery Centre website.

Media enquiries

Sam Wood
Media Relations Officer
The University of Manchester
Tel: 0161 275 8155

Background notes

The Dark Energy Survey is a collaboration of more than 300 scientists from 25 institutions in six countries. Its primary instrument, the Dark Energy Camera, is mounted on the 4-meter Blanco telescope at the National Optical Astronomy Observatory’s Cerro Tololo Inter-American Observatory in Chile, and its data is processed at the National Center for Supercomputing Applications at the University of Illinois at Urbana-Champaign.

Funding for the DES Projects has been provided by the U.S. Department of Energy Office of Science, the U.S. National Science Foundation, the Ministry of Science and Education of Spain, the Science and Technology Facilities Council of the United Kingdom, the Higher Education Funding Council for England, the National Center for Supercomputing Applications at the University of Illinois at Urbana-Champaign, the Kavli Institute of Cosmological Physics at the University of Chicago, Financiadora de Estudos e Projetos, Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro, Conselho Nacional de Desenvolvimento Científico e Tecnológico and the Ministério da Ciência e Tecnologia, the Deutsche Forschungsgemeinschaft and the collaborating institutions in the Dark Energy Survey. The DES participants from Spanish institutions are partially supported by MINECO under grants AYA2012-39559, ESP2013-48274, FPA2013-47986 and Centro de Excelencia Severo Ochoa SEV-2012-0234, some of which include ERDF funds from the European Union.

Jodrell Bank Centre for Astrophysics is part of the School of Physics & Astronomy at The University of Manchester. The Centre has over 180 staff and postgraduate students working on all areas of astronomy and astrophysics and incorporates the radio astronomy facilities of the Jodrell Bank Observatory - the Lovell Telescope and the e-MERLIN array.

Fermilab is America’s premier national laboratory for particle physics and accelerator research. A U.S. Department of Energy Office of Science laboratory, Fermilab is located near Chicago, Illinois, and operated under contract by the Fermi Research Alliance, LLC. Visit Fermilab’s website at and follow us on Twitter at @Fermilab.

The DOE Office of Science is the single largest supporter of basic research in the physical sciences in the United States and is working to address some of the most pressing challenges of our time. For more information, please visit