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Oxygen abundances in the Galactic Bulge: evidence for fast chemical enrichment

M. Zoccali·A. Lecureur·B. Barbuy·V. Hill·A. Renzini·D. Minniti·Y. Momany·A. Gomez·S. Ortolani
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Abstract

AIMS: We spectroscopically characterize the Galactic Bulge to infer its star formation timescale, compared to the other Galactic components, through the chemical signature on its individual stars. METHODS: We derived iron and oxygen abundances for 50 K giants in four fields towards the Galactic bulge. High resolution (R=45,000) spectra for the target stars were collected with FLAMES-UVES at the VLT. RESULTS: Oxygen, as measured from the forbidden line at 6300 Å, shows a well-defined trend with [Fe/H], with [O/Fe] higher in bulge stars than in thick disk ones, which were known to be more oxygen enhanced than thin disk stars. CONCLUSIONS: These results support a scenario in which the bulge formed before and more rapidly than the disk, and therefore the MW bulge can be regarded as a prototypical old spheroid, with a formation history similar to that of early-type (elliptical) galaxies.

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M. Zoccali, A. Lecureur, B. Barbuy, V. Hill, A. Renzini, D. Minniti, Y. Momany, A. Gomez, S. Ortolani. 2006-09-05. Oxygen abundances in the Galactic Bulge: evidence for fast chemical enrichment. https://doi.org/10.1051/0004-6361%3A20065659

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