Dark Matter Halos from the Inside Out
The balance of evidence indicates that individual galaxies and groups or clusters of galaxies are embedded in enormous distributions of cold, weakly interacting dark matter. These dark matter “halos” provide the scaffolding for all luminous structures in the universe, and their properties comprise a...
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| Main Author: | |
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| Format: | Article |
| Language: | English |
| Published: |
Wiley
2011-01-01
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| Series: | Advances in Astronomy |
| Online Access: | http://dx.doi.org/10.1155/2011/604898 |
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| Summary: | The balance of evidence indicates that individual galaxies and groups or clusters of galaxies are embedded in enormous distributions of cold, weakly interacting dark matter. These dark matter “halos” provide the scaffolding for all luminous structures in the universe, and their properties comprise an essential part of the current cosmological model. I review the
internal properties of dark matter halos, focussing on the simple universal trends predicted by numerical simulations of structure
formation. Simulations indicate that halos should all have roughly the same spherically averaged density profile and kinematic
structure and predict simple distributions of shape, formation history, and substructure in density and kinematics, over an
enormous range of halo mass and for all common variants of the concordance cosmology. I describe observational progress towards
testing these predictions by measuring masses, shapes, profiles, and substructure in real halos using baryonic tracers or
gravitational lensing. An important property of simulated halos (possibly the most important property) is their dynamical “age”, or degree of internal relaxation. I review recent gravitational lensing studies of galaxy clusters which will measure substructure and relaxation in a large sample of individual cluster halos, producing quantitative measures of age that are well matched to
theoretical predictions. |
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| ISSN: | 1687-7969 1687-7977 |