Can a globular cluster formed in the galactic disk be raised into the halo? |
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Authors: | K A Innanen |
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Institution: | (1) Department of Physics and Astronomy, York University, 4700 Keele St, Toronto, ON, Canada, M3J 1P3 |
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Abstract: | The classical assumption that most globular clusters (hereafter GC) formed in situ in galactic halos is examined in an approximate,
empirical way. Although this viewpoint is not rejected per se, an alternative possibility is investigated: the presence of
multiple resonances in the galactic disk, together with the concurrent action of a resonant internal bar or distortion, may
stir these resonances. This may lead to chaotic motion which breaks the action of the third integral for moderately eccentric
orbits. These circumstances may consequently allow the formation of some GC’s in the disk with moderate to highly eccentric
orbits, with the action of the resonant bar subsequently gradually driving them (as well as other stars with similar orbits)
to spend most of their time in the Galaxy’s halo. The size of the resonant region and the probable effectiveness of the various
agents in the associated phase space in the axisymmetric model are listed. An n-body simulation would be required to establish this proposal in a fully self-consistent way.
Paper presented at the Division of Dynamical Astronomy Meetings in Halifax, N.S., Canada, June 2006. |
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Keywords: | Galaxy: kinematics & dynamics Galaxy: resonances & third integral Galaxy: solar neighborhood |
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