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| Paper: |
Dark Matter in Disk Galaxies |
| Volume: |
182, Galaxy Dynamics: A Rutgers Symposium |
| Page: |
339 |
| Authors: |
Bosma, A. |
| Abstract: |
Recent work on the mass distribution in spiral galaxies, using mainly HI observations, is reviewed. The principal problem is still to determine to what extent the dark matter is important in the inner parts of a galaxy, or in other words, how dominant is the self-gravitation of the disk. Studies of the shapes of rotation curves show that in detail there is sufficient individuality in spiral galaxies to prohibit the construction of ``Universal Rotation Curves.'' A detailed account is given of the method of Athanassoula et al. (1987), where swing-amplifier criteria are applied to set a range in the mass-to-light ratio of the disk. To restrict this range further, other methods might be useful. For a number of bright spirals the rotation curve drops just outside the optical image, but this feature by itself cannot constrain mass models unambiguously. The use of velocity dispersions seems a promising way, though the observational problems are hard. Within the uncertainties, disks can be close to ``maximum,'' even though a range of values cannot be excluded. |
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