IAU Symposium Abstract S186-049T

Globular Clusters in Ellipticals

Steven Zepf1,2
1Department of Astronomy, Yale University < zepf@astro.yale.edu >
2Department of Astronomy, University of California, Berkeley, California < zepf@palan.berkeley.edu >

I will review the properties of globular cluster systems around elliptical galaxies, with a particular emphasis on how these properties constrain the formation history of their host galaxy. One of the most powerful dscriminants between models of elliptical galaxy formation is the color distribution within globular cluster systems. Merger models predict the existence of two or more populations of globular clusters, whereas other models for elliptical galaxy formation predict only a single population. I will show that detailed studies of the globular cluster systems of a number of elliptical galaxies indicate that most of these have bimodal color distributions. Moreover, recent spectroscopic studies suggest that the populations identified by colors also have distinct kinematics. Thus the merger model is confirmed. More generally, the presence of distinct populations of globular clusters within ellipticals requires an episodic formation history for these galaxies, with mergers as the only extant model that offers a physical explanation for this episodic formation history. I will conclude by discussing future challenges for the field, which include comparing to the merging history expected in standard heirarchical models and the use of spectroscopy of globular clusters to probe the mass distribution of elliptical galaxies at large radii.