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Advances in Astronomy
Volume 2010 (2010), Article ID 478910, 14 pages
Review Article

Gravitational Lensing as a Probe of Cold Dark Matter Subhalos

Department of Astronomy, Oskar Klein Centre for Cosmoparticle Physics, Stockholm University, 10691 Stockholm, Sweden

Received 30 April 2009; Accepted 10 September 2009

Academic Editor: Regina Schulte-Ladbeck

Copyright © 2010 Erik Zackrisson and Teresa Riehm. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


In the cold dark matter scenario, dark matter halos are assembled hierarchically from smaller subunits. Some of these subunits are disrupted during the merging process, whereas others survive temporarily in the form of subhalos. A long-standing problem with this picture is that the number of subhalos predicted by simulations exceeds the number of luminous dwarf galaxies seen in the vicinity of large galaxies like the Milky Way. Many of the subhalos must therefore have remained dark or very faint. If cold dark matter subhalos are as common as predicted, gravitational lensing may in principle offer a promising route to detection. In this paper, we describe the many ways through which lensing by subhalos can manifest itself, and summarize the results from current efforts to constrain the properties of cold dark matter subhalos using such effects.