| Triaxial Elliptical Galaxies |
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| • | So,
are ellipticals simple to understand dynamically? |
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| Not
so clear. We’re seeing a 2D picture
of a 3D object. |
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| • | In
general, elliptical galaxies rotate too slowly for this |
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| to
account for the flattening observed.
In other words, |
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| their
ratios of rotational to random kinetic energy is |
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| too
low. |
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| • | If
ellipticity e were due to rotation (e.g., a pure oblate |
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| rotator
with an isotropic velocity distribution) then |
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| (Vrot/σ)iso
~ (e/(1-e))1/2.
Is it? |
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