Scientists on the Dark Energy Survey have released the first in a series of dark matter maps of the
cosmos1. 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
galaxies2. 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. The new maps were released today at the April meeting of the American Physical Society in Baltimore, Maryland. They were 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).
Dark matter, the mysterious substance that makes up roughly a quarter of the universe, is invisible to even the most sensitive
astronomical3 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.
This analysis was led by Vinu Vikram of Argonne National Laboratory (then at the University of Pennsylvania) and Chihway Chang of ETH Zurich. Vikram, Chang and their collaborators at Penn, ETH Zurich, the University of Portsmouth, the University of Manchester and other DES institutions worked for more than a year to carefully
validate4 the lensing maps.
"We measured the barely perceptible distortions in the shapes of about 2 million galaxies to construct these new maps," Vikram said. "They are a
testament5 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
exacting6 results from it."