Free access article

A&A 457, L1-L4 (2006)
DOI: 10.1051/0004-6361:20065659

Letter

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

M. Zoccali¹, A. Lecureur², B. Barbuy³, V. Hill², A. Renzini⁴, D. Minniti¹, Y. Momany⁵, A. Gómez² and S. Ortolani<sup>5

1</sup>  P. Universidad Católica de Chile, Departamento de Astronomía y Astrofísica, Casilla 306, Santiago 22, Chile
    e-mail: [mzoccali;dante]@astro.puc.cl
²  Observatoire de Paris-Meudon, 92195 Meudon Cedex, France
    e-mail: [Vanessa.Hill;Aurelie.Lecureur;Ana.Gomez]@obspm.fr
³  Universidade de São Paulo, IAG, Rua do Matão 1226, Cidade Universitária, São Paulo 05508-900, Brazil
    e-mail: barbuy@astro.iag.usp.br
⁴  INAF - Osservatorio Astronomico di Padova, Vicolo dell'Osservatorio 2, 35122 Padova, Italy
    e-mail: renzini@pd.astro.it
⁵  Università di Padova, Dipartimento di Astronomia, Vicolo dell'Osservatorio 5, 35122 Padova, Italy
    e-mail: [momany;ortolani]@pd.astro.it

(Received 22 May 2006 / Accepted 16 July 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 () 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.

Key words: Galaxy: bulge -- stars: abundances -- stars: atmospheres

© ESO 2006

The OpenURL standard is a protocol for transmission of metadata describing the resource that you wish to access. An OpenURL link contains article metadata and directs it to the OpenURL server of your choice. The OpenURL server can provide access to the resource and also offer complementary services (specific search engine, export of references...). The OpenURL link can be generated by different means.

• If your librarian has set up your subscription with an OpenURL resolver, OpenURL links appear automatically on the abstract pages.
• You can define your own OpenURL resolver with your EDPS Account. In this case your choice will be given priority over that of your library.
• You can use an add-on for your browser (Firefox or I.E.) to display OpenURL links on a page (see http://www.openly.com/openurlref/). You should disable this module if you wish to use the OpenURL server that you or your library have defined.