Chemical evolution of the Galactic bulge as traced by microlensed dwarf and subgiant stars V. Evidence for a wide age distribution and a complex MDF

• Published in: Astronomy and astrophysics (Berlin) Vol. 549; pp. A147 - 26
• Main Authors: Bensby, T., Yee, J. C., Feltzing, S., Johnson, J. A., Gould, A., Cohen, J. G., Asplund, M., Meléndez, J., Lucatello, S., Han, C., Thompson, I., Gal-Yam, A., Udalski, A., Bennett, D. P., Bond, I. A., Kohei, W., Sumi, T., Suzuki, D., Suzuki, K., Takino, S., Tristram, P., Yamai, N., Yonehara, A.
• Format: Journal Article
• Language: English
• Published: 01.01.2013
• Subjects: Astronomi, astrofysik och kosmologi; Astronomy; Astronomy, Astrophysics and Cosmology; Disk galaxies; Fysik; Galactic bulge; Galactic rotation; MDF; Milky Way Galaxy; Natural Sciences; Naturvetenskap; Physical Sciences; Spectra; Subgiant stars
• ISSN: 0004-6361; 1432-0746; 1432-0746
• DOI: 10.1051/0004-6361/201220678

Based on high-resolution spectra obtained during gravitational microlensing events we present a detailed elemental abundance analysis of 32 dwarf and subgiant stars in the Galactic bulge. Combined with the sample of 26 stars from the previous papers in this series, we now have 58 microlensed bulge dwarfs and subgiants that have been homogeneously analysed. The results from the microlensed bulge dwarf stars in combination with other findings in the literature, in particular the evidence that the bulge has cylindrical rotation, indicate that the Milky Way could be an almost pure disk galaxy. The bulge would then just be a conglomerate of the other Galactic stellar populations, residing together in the central parts of the Galaxy, influenced by the Galactic bar.