35th Meeting of the AAS Division on Dynamical Astronomy, April 2004
Session 3 Stars \& Galaxies
Oral, Wednesday, April 21, 2004, 2:15-6:20pm,

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[3.02] The Effect of Spiral Arms on Star Cluster Evolution

M. Gieles (Observatoire de Marseille / Utrecht University), E. Athanassoula (Observatoire de Marseille), S. Portegies-Zwart (University of Amsterdam)

In this study we use direct N-body simulations to investigate the effect of spiral arms on the evolution of star clusters in disks.

The great sensitivity and resolution of the Hubble Space Telescope made it possible to resolve individual extra-galactic star clusters. This lead to the discovery of young massive clusters in star burst galaxies and interacting galaxies, with an apparent similar structure and morphology as the globular clusters seen in our Milky Way. A key question is whether these young massive cluster populations will evolve into an old population comparable to the globular cluster population seen in the halo of almost every galaxy.

The internal evolution of star clusters has been studied quite extensively and is pretty well understood. External perturbations, however, may play a determining role in the evolution of a star cluster. When in a disk, clusters experience a tidal field, due to spiral arms. In grand design spiral galaxies, such as M51, the arm/inter-arm density ratio can be of the order of 3-5. This is comparable to the difference between the average density of the cluster and its surroundings.

We study the effect of slow/fast passages through the spiral arms. The slow passage close to corotation can lead to significant mass loss and significant deformation of the cluster morphology, including the formation of large tidal tails.

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Bulletin of the American Astronomical Society, 36 #2
© 2004. The American Astronomical Soceity.