Globular Clusters with the Extended Horizontal-Branch as Remaining Cores of Galaxy Building Blocks
The relics of building blocks that made stellar halo and bulge are yet to be discovered unless they were completely disrupted throughout the history of the Galaxy. Here we suggest that about 25% of the Milky Way globular clusters have characteristics of the remaining cores of these early building blocks rather than genuine star clusters. They are clearly distinct from other normal globular clusters in the presence of extended horizontal-branch and multiple stellar populations, in mass (brightness), and most importantly in orbital kinematics. Based on this result, a three-stage formation picture of the Milky Way is suggested, which includes early mergers, collapse, and later accretion.
KeywordsGlobular Cluster Dwarf Galaxy Disk Galaxy Orbital Kinematic Outer Halo
Unable to display preview. Download preview PDF.
- Freeman, K. C. 1993, ASP Conf. Ser., vol. 48, eds. G. H. Smith and J. P. Brodie (ASP, San Francisco) pp. 608–614Google Scholar
- Toomre, A. 1977, inEvolution of Galaxies and Stellar Populations, ed by B.M. Tinsley & R.B. Larson (Yale Univ. Obs., New Haven) pp. 401–426Google Scholar
- Zinn, R. 1993, ASP Conf. Ser., vol. 48, eds. G. H. Smith and J. P. Brodie (ASP, San Francisco) pp. 38–47Google Scholar