NASA | JPL-Caltech | 2016 Jan 25
[img3="This comparison of galaxy clusters from the Sloan Digital Sky Survey DR8 galaxy catalog shows a spread-out cluster (left) and a more densely-packed cluster (right). A new study shows that these differences are related to the surrounding dark-matter environment. Credit: Sloan Digital Sky Survey"]http://www.jpl.nasa.gov/images/universe ... 160125.jpg[/img3][hr][/hr]Dark matter is a mysterious cosmic phenomenon that accounts for 27 percent of all matter and energy. Though dark matter is all around us, we cannot see it or feel it. But scientists can infer the presence of dark matter by looking at how normal matter behaves around it.
Galaxy clusters, which consist of thousands of galaxies, are important for exploring dark matter because they reside in a region where such matter is much denser than average. Scientists believe that the heavier a cluster is, the more dark matter it has in its environment. But new research suggests the connection is more complicated than that.
"Galaxy clusters are like the large cities of our universe. In the same way that you can look at the lights of a city at night from a plane and infer its size, these clusters give us a sense of the distribution of the dark matter that we can't see," said Hironao Miyatake at NASA's Jet Propulsion Laboratory, Pasadena, California.
A new study in Physical Review Letters, led by Miyatake, suggests that the internal structure of a galaxy cluster is linked to the dark matter environment surrounding it. This is the first time that a property besides the mass of a cluster has been shown to be associated with surrounding dark matter. ...
Galaxy Cluster Environment Not Dictated by Its Mass Alone
Kavli IPMU | University of Tokyo | 2016 Jan 25
Evidence of Halo Assembly Bias in Massive Clusters - Hironao Miyatake et al
- Physical Review Letters 116:041301 (25 Jan 2016) DOI: 10.1103/PhysRevLett.116.041301
arXiv.org > astro-ph > arXiv:1506.06135 > 19 Jun 2015 (v1), 30 Jun 2015 (v2)