Dynamics of Galaxy Interactions

7. Remnant Structure


Phase Mixing

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Rotation, t = 3. Just after merger, a remnant is rotated about the vertical axis to illustrate the shells, plumes, and tails typical of very young merger remnants (Barnes 1992).

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Rotation, t = 6. About 750 million years after the merger, the remnant has substantially relaxed and appears more smooth and regular. Note the faint loops and tails which still surround it.

Orbit Structure

Shown below are examples of orbits identified in the strongly triaxial merger remnant produced by encounter A1. These orbits were classified by the crossing-pattern algorithm (Fulton & Barnes, in preparation).

The orbit movies all follow the same format. In each one, the major axis is indicated by a blue line; the minor axis is vertical. The particle is a white point which leaves a green trail as it orbits in the potential. At the same time, the view point circles around to show the orbit in three dimensions. Note that the potential is not rotating; only the point of view changes!

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Box orbit. Boxes are the main orbit family fully consistent with triaxial density distributions.

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X-Tube orbit. X-tube orbits loop around the major axis; they are the only family present in strictly prolate potentials.

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Z-Tube orbit. Z-tube orbits loop around the minor axis; they are the only family present in strictly oblate potentials.

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Fish orbit. In triaxial potentials with sufficiently deep potential wells, 3:2 resonances become stable; the result is fish-shaped orbit.

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Pretzel orbit. Likewise, 4:3 resonances may also become stable; the result is pretzel-shaped.


Joshua E. Barnes (barnes@galileo.ifa.hawaii.edu)

Last modified: February 1, 2000