The Big Flow
The late infall of cold dark matter onto an isolated galaxy, such as our own, produces streams and caustics in its halo. The outer caustics are topological spheres whereas the inner caustics are rings. The self-similar model of galactic halo formation predicts that the caustic ring radii $a_n$ follo...
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| Format: | Text |
| Language: | unknown |
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arXiv
2001
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| Online Access: | https://dx.doi.org/10.48550/arxiv.astro-ph/0112072 https://arxiv.org/abs/astro-ph/0112072 |
| Summary: | The late infall of cold dark matter onto an isolated galaxy, such as our own, produces streams and caustics in its halo. The outer caustics are topological spheres whereas the inner caustics are rings. The self-similar model of galactic halo formation predicts that the caustic ring radii $a_n$ follow the approximate law $a_n \sim 1/n$. In a study of 32 extended and well-measured external galactic rotation curves evidence was found for this law. In the case of the Milky Way, the locations of eight sharp rises in the rotation curve fit the prediction of the self-similar model at the 3% level. Moreover, a triangular feature in the IRAS map of the galactic plane is consistent with the imprint of a ring caustic upon the baryonic matter. These observations imply that the dark matter in our neighborhood is dominated by a single flow. Estimates of that flow's density and velocity vector are given. : 8 pages, to appear in the Proceedings of the International Workshop COSMO-01 on Particle Physics and the Early Universe, Rovaniemi, Finland, August 29 - September 4, 2001 |
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