http://arxiv.org/abs/1311.1021
The prospects for using the present-day data on metallicity of globular clusters (GCs) of the Galaxy to put constraints on the distance to the Galactic center, $R_0$, are considered. We have found that the GCs of the metal-rich and metal-poor subsystems separately form a bar-like structure in metallicity maps whose parameters are very close to those for the Galactic bar. The results indicate the existence of a bar component within both the metal-rich and metal-poor subsystems of GCs. The bar GCs could have formed within the already existing Galactic bar or could have later been locked in resonance with the bar. We conclude that substantial constraints on the $R_0$ value can be obtained only with non-axisymmetric models for the space distribution of GC metallicities with the allowance for the subdivision of GCs into subsystems. We found evidence for a bar extinction component that causes the observational incompleteness of GCs in the far side of the Galactic bar and in the “post-central” region. This selection effect should be taken into account when determining $R_0$ from the spatial distribution of GCs.
Wed, 6 Nov 13
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