Data di Pubblicazione:
2006
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.
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.
Tipologia CRIS:
01.01 - Articolo in rivista
Elenco autori:
Zoccali, M; Lecureur, A; Barbuy, B; Hill, V; Renzini, A; Minniti, D; Momany, Y; Gomez, A; Ortolani, Sergio
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