Clumps and Streams in the Local Dark Matter Distribution

Nature has published "Clumps and Streams in the Local Dark Matter Distribution," authored by Jürg Diemand of the University of California-Santa Cruz; Michael Kuhlen, Astrophysics Member in the School of Natural Sciences (2006-09); Piero Madau and Marcel Zemp, UC-Santa Cruz; and Ben Moore, Doug Potter and Joachim Stadel of the University of Zurich. The article appeared in the August 7, 2008 issue.

In the standard model of cosmology, cold dark matter structures form and grow through the merging of smaller units. Numerical simulations of this process show that such merging is incomplete, and many clumps of gravitationally bound dark matter orbit within their hosts. In their paper, the group reports a simulation that resolves this substructure even in the innermost region of a galaxy-scale halo like the one harboring our own Milky Way galaxy. A visualization of this simulation may be seen at http://www.ucolick.org/~diemand/vl. More of Kuhlen's work is featured in the Summer 2008 issue of The Institute Letter.