APRIL 2015 - Dark Energy Survey: mapping the dark matter of the Universe

Scientists on the Dark Energy Survey have released the first in a series of dark matter maps of the cosmos. These maps, created with one of the world's most powerful digital cameras, are the largest contiguous maps created at this level of detail and will improve our understanding of dark matter's role in the formation of galaxies. Analysis of the clumpiness of the dark matter in the maps will also allow scientists to probe the nature of the mysterious dark energy, believed to be causing the expansion of the universe to speed up.

Scientists on the Dark Energy Survey have released the first in a series of dark matter maps of the cosmos. These maps, created with one of the world's most powerful digital cameras, are the largest contiguous maps created at this level of detail and will improve our understanding of dark matter's role in the formation of galaxies. Analysis of the clumpiness of the dark matter in the maps will also allow scientists to probe the nature of the mysterious dark energy, believed to be causing the expansion of the universe to speed up.

"We measured the barely perceptible distortions in the shapes of about two million galaxies to construct these new maps," Vikram said. "They are a testament not only to the sensitivity of the Dark Energy Camera, but also to the rigorous work by our lensing team to understand its sensitivity so well that we can get exacting results from it."

The Dark Energy Camera (DECam), a 570 megapixels camera powerful enough to see light from more than 9 billion light years away, is the main instrument used in the study. It is mounted on a telescope at the Cerro Tololo Inter-American Observatory in Chile and it is specially designed to measure the shape of very galaxies with unprecedented detail.

The Spanish contribution to the Project

The Institut de Física d'Altes Energies (IFAE) participates in the Project since its beginning. During the construction phase IFAE, in close collaboration with ICE (IEEC-CSIC) and CIEMAT, designed and built the Reading electronics of the DECam. Besides, two IFAE researchers have worked on the measurements of the galaxies included in the study.

Carles Sánchez, DES researcher at IFAE explains, "Not only it is important to measure the galaxies that we observe, but it is key to know the precisions of the measurements, so that we can use them to study the properties of dark energy"

With the new maps we are producing we will be able to study the evolution in time of the distribution of dark matter in the Universe. This will help us know more about the properties of dark energy." Adds Christopher Bonnet, DES researcher at IFAE.
The Dark Energy Survey is a collaboration of more than 300 scientists from 25 institutions in six countries. IFAE, ICE (IEEC-CSIC) and CIEMAT represent the Spanish collaboration in the project.

Dark matter maps

Dark matter, the mysterious substance that makes up roughly a quarter of 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 by studying a phenomenon called gravitational lensing – the distortion that occurs when the gravitational pull of dark matter bends light around distant galaxies. Understanding the role of dark matter is part of the research program to quantify the role of 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 will 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 large concentrations of dark matter (and hence stronger gravity) are 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.

More Information
DES webpage: http://www.darkenergysurvey.org/
Paper: Wide-Field Lensing Mass Maps from DES Science Verification Data
http://arxiv.org/pdf/1504.03002.pdf

Image caption
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: yellow and red are regions with more dense matter. The dark matter maps conform to the current picture of mass distribution in the universe where large filaments of matter align with galaxies and clusters of galaxies. The clusters of galaxies are shown by the gray dots in the map — bigger dots represent larger clusters. This map covers three percent of the area of sky that DES will eventually document over its five-year mission. Image: Dark Energy Survey

We use own and third-party cookies to improve our services by analyzing your browsing habits. If you continue browsing, we will consider that you allow us to use them. You can change the settings or get more information on our "Cookies policy".

I accept cookies from this site.