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Symposium 241

Abstract details

Extragalactic Star Cluster in Merging/Interactive Galaxies
Gelys Trancho, Francois Schweizer, Nate Bastian, Bryan Miller

Studies of globular cluster systems play a critical role in our understanding of galaxy formation. Imaging with the Hubble Space Telescope has revealed that young star clusters are formed copiously in galaxy mergers, strengthening theories in which giant elliptical galaxies are formed by the merger of spirals (e.g.\ Whitmore et al.\1993; Miller et al.\ 1997; Zepf et al.\ 1999; Ashman \& Zepf 1992). However, the formation and evolution of globular cluster systems is still not well understood. Ages and metallicities of the clusters are uncertain either because of degeneracy in the broad-band colors or due to variable reddening. Also, the luminosity function of the young clusters, which depends critically on the metallicities and ages of the clusters, appears to be singe power-laws while the luminosity function of old clusters has a well-defined break. Either there is signicant dynamical evolution of the cluster systems or metallicity affects the mass function of forming clusters. Spectroscopy of these clusters are needed to improve the metallicity and age measurements and to study the kinematics of young cluster systems. Therefore, we have obtained spectra of two dozen of young star clusters in each merging/interactive galaxies (NGC3256, NGC4038, NGC6872, Stefan's Quintet) using GMOS-S. We will present the results of metallicities, ages, and velocities of these star clusters in each merger obtained from the MOS spectroscopy, using the Lick indices system in combination with the SSP models.

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