Globular Cluster Subpopulations in Early-Type Galaxies: Insights into Galaxy Formation

Abstract

New and archival HST images of the globular cluster systems of 17 relatively nearby galaxies and 6 more distant galaxies have been used to establish the characteristics of GC subpopulations over a range of host galaxy morphological type from E5 to Sa. GC color/metallicity, size and luminosity distributions have been examined in the nearby galaxies and color distributions have been determined for the more distant sample. Correlations with parent galaxy properties and trends with galactocentric radius have been explored. Supplemented with Keck spectroscopy, our results are best explained by an in situ formation scenario in which both GC subpopulations formed at early times within the potential well of the protogalaxy, in multiple episodes of star formation. We have also discovered a third population of clusters, fundamentally distinct from the compact red and blue clusters common in early type galaxies.

arXiv commentProceedings of IAU Symposium 207 "Extragalactic Star Clusters" eds. E. Grebel, D. Geisler and D. Minniti, 9 pages, 4 figures

References in corpus (15)

• The SBF Survey of Galaxy Distances. IV. SBF Magnitudes, Colors, and Distances
• Detecting Bimodality in Astronomical Datasets
• Properties of Globular Cluster Systems in Nearby Early-type Galaxies
• On the Origin of Globular Cluster Systems in Elliptical and cD Galaxies
• The Formation of Giant Elliptical Galaxies and Their Globular Cluster Systems
• The Ages and Abundances of the M87 Globular Clusters
• The Metallicity Distribution in the Halo Stars of NGC 5128: Implications for Galaxy Formation
• Keck Spectroscopy of Globular Clusters around NGC 1399
• HST observations of star clusters in NGC 1023: Evidence for three cluster populations?
• The Age Difference between the Globular Cluster Sub-populations in NGC 4472
• The Connection between Globular Cluster Systems and the Host Galaxies
• Globular Cluster Systems As Distance Indicators: Metallicity Effects On The Luminosity Function
• Ages and Metallicities of Globular Clusters in NGC 4472
• Globular cluster systems II: On the formation of old globular clusters and their sites of formation
• A new look at globular cluster colors in NGC 3311 and the case for exclusively metal-rich globular cluster systems