EAS Publications Series
Volume 24, 2007CRAL-2006. Chemodynamics: From First Stars to Local Galaxies
|Page(s)||177 - 182|
|Published online||21 April 2007|
E. Emsellem, H. Wozniak, G. Massacrier, J.-F. Gonzalez, J. Devriendt and N. Champavert (eds)
EAS Publications Series, 24 (2007) 177-182
Abundances in High-Velocity Clouds
Argelander-Institut für Astronomie, Bonn University,
Auf dem Hügel 71, 53121 Bonn, Germany
In this article I briefly review recent abundance measurements in intermediate- and high-velocity clouds (IVCs and HVCs, respectively) in the halo of the Milky Way. FUSE and STIS absorption line data indicate that these clouds span a metallicity range between ~0.1−1.0 solar, suggesting that they cannot have a single origin. Most likely, the infall of gas from the intergalactic medium and from satellite galaxies is responsible for the population of low-metallicity HVCs like Complex C, while the more metal-rich clouds (in particular the IVCs) represent Galactic material as part of a galactic fountain. The detailed analysis of particularly interesting ions and molecules (e.g., O i, D i, N i, O vi, and H2) gives a detailed insight into the chemical composition of individual clouds and further provides important information on the physical conditions in these objects.
© EAS, EDP Sciences, 2007
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