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Session 71 - Globular Clusters.
Display session, Wednesday, January 15
The properties of systems of globular clusters in galaxies depend on the initial characteristics of the primordial compact clusters, and the disruptive processes of cluster evaporation and gravitational shocking due to the parent galaxy, acting over a Hubble time. We present a study of the evolution of globular cluster systems (GCSs) employing the internal processes of evaporation and stellar mass-loss, and the external effects of gravitational shocking due to a cluster's passage through the disk or close to the bulge of the parent galaxy. Results of evolutionary scenarios with different initial properties of the GCS (functions of mass and half-mass radius, a mass-radius relation, and orbital parameters) will be shown for various galaxy models. Preliminary results indicate that while disk shocking has little effect on the GCS as a whole, bulge shocking is sensitive to the orbital parameters and is important in selectively destroying low-mass clusters and thus determining the shape of the resultant luminosity function and the location of the peak. The importance of the galaxian bulge in determining the luminosity function will be discussed with regards to the apparent insensitivity of observed cluster luminosity functions to galaxy type among major Local Group galaxies and Virgo ellipticals. Constraints on initial properties of a GCS which can result in globulars like those of the Milky Way and Virgo ellipticals will address the possible relation between young compact clusters observed in recently-merged galaxies (e.g. the Antennae, Whitmore amp; Schweizer 1995, AJ, 109, 960) and the progenitors of present-day globular clusters.
Program listing for Wednesday