In Ann.Rev.Astron.Astrophys. 44 (2006) 193-267
astro-ph/0602601

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EXTRAGALACTIC GLOBULAR CLUSTERS AND GALAXY FORMATION

Jean P. Brodie, Jay Strader


UCO/Lick Observatory


Abstract. Globular cluster (GC) systems have now been studied in galaxies ranging from dwarfs to giants and spanning the full Hubble sequence of morphological types. Imaging and spectroscopy with the Hubble Space Telescope and large ground-based telescopes have together established that most galaxies have bimodal color distributions that reflect two subpopulations of old GCs: metal-poor and metal-rich. The characteristics of both subpopulations are correlated with those of their parent galaxies. We argue that metal-poor GCs formed in low-mass dark matter halos in the early universe and that their properties reflect biased galaxy assembly. The metal-rich GCs were born in the subsequent dissipational buildup of their parent galaxies and their ages and abundances indicate that most massive early-type galaxies formed the bulk of their stars at early times. Detailed studies of both subpopulations offer some of the strongest constraints on hierarchical galaxy formation that can be obtained in the near-field.


Key Words globular clusters, galaxy formation, stellar populations


Table of Contents

INTRODUCTION

COLOR BIMODALITY: GLOBULAR CLUSTER SUBPOPULATIONS
Scenarios for Bimodality

GLOBAL PROPERTIES
Specific Frequency
Radial and Azimuthal Distributions
Variations with Galaxy Morphology

SPECTROSCOPY
Metallicities and Ages
[alpha/Fe]
Abundance Anomalies

NEAR-IR IMAGING

GLOBULAR CLUSTER-FIELD STAR CONNECTIONS
M31
NGC 5128
Other Galaxies

KINEMATICS
Ellipticals
Disk Galaxies

LUMINOSITY FUNCTIONS

SIZES

DWARF GALAXIES
Specific Frequencies and Luminosity Functions
Color Distributions
Kinematics

GLOBULAR CLUSTER FORMATION
Classical Scenarios
Hierarchical Merging and Biasing: Recent Scenarios

COSMOLOGICAL FORMATION OF METAL-POOR GLOBULAR CLUSTERS

FUTURE DIRECTIONS

REFERENCES

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