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Extragalactic Globular Clusters: Old Spectroscopic Ages and New Views on Their Formation

Jay Strader·Jean P. Brodie·A. J. Cenarro·Michael A. Beasley·Duncan A. Forbes
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Abstract

We present the results of a meta-analysis of Keck spectra of extragalactic globular clusters (GCs) in a sample of eight galaxies, ranging from dwarfs to massive ellipticals. We infer ages for the metal-poor and metal-rich GCs in these galaxies through comparisons to Galactic GCs. Both subpopulations appear to be no younger than their Galactic counterparts, with ages ~> 10 Gyr. This is the largest sample of galaxies for which ages have been constrained spectroscopically. Our results support the formation of most GCs in massive galaxies at high redshift. We propose a scenario for the formation of GC subpopulations that synthesizes aspects of both accretion and in situ approaches in the context of galaxy formation through hierarchical merging.

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Jay Strader, Jean P. Brodie, A. J. Cenarro, Michael A. Beasley, Duncan A. Forbes. 2005-06-13. Extragalactic Globular Clusters: Old Spectroscopic Ages and New Views on Their Formation. https://doi.org/10.1086/432717

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