Dark Matter Map May Reveal New Insights into the Cosmos

The first ever dark matter map may help to reveal new insights into the cosmos, according to recent research.

As part of the Dark Energy Survey (DES), scientists have created the largest contiguous maps at this level of detail which will hopefully improve our understanding of dark matter's role in the formation of galaxies. Also, by analyzing the "clumpiness" of dark matter, we may learn more about the mysterious nature of this dark energy - believed to be accelerating the expansion of the Universe.

Even though we cannot see it, dark matter supposedly makes up roughly a quarter of the Universe. The substance is invisible to even the most sensitive astronomical instruments because it does not emit or block light; however, its effects can be seen by studying a phenomenon called gravitational lensing. This refers to the distortion that occurs when the gravitational pull of dark matter bends light around distant galaxies. By better understanding the role of dark matter and dark energy, the researchers hope to provide new insights into the cosmos.

To create these highly detailed maps, a team of scientists, led by Vinu Vikram of Argonne National Laboratory, used one of the world's most powerful digital cameras - the Dark Energy Camera, a 570-megapixel imaging device that is the primary instrument for the DES.

"We measured the barely perceptible distortions in the shapes of about 2 million galaxies to construct these new maps," Vikram said in a press release. "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."

It should be noted that the new dark matter map covers only about three percent of the area of sky DES will document over its five year mission. It has just completed its second year, and hopefully as scientists expand their search, they will be able to better test current cosmological theories by comparing the amounts of dark and visible matter.

According to one of these theories, galaxies will form where there are large concentrations of dark matter - since there is much more dark matter in the Universe than visible matter.

And the good news is, so far the DES supports this idea. That is, the maps show large filaments of matter along which visible galaxies and galaxy clusters lie, and cosmic voids where very few galaxies reside.

"Our analysis so far is in line with what the current picture of the Universe predicts," added researcher Chihway Chang. "Zooming into the maps, we have measured how dark matter envelops galaxies of different types and how together they evolve over cosmic time. We are eager to use the new data coming in to make much stricter tests of theoretical models."

The new maps were released Monday at the April meeting of the American Physical Society in Baltimore, Maryland.

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