Manganese abundances in Galactic bulge red giants
  Manganese is mainly produced in type II SNe during explosive silicon burning,
in incomplete Si-burning regions, and depends on several nucleosynthesis
environment conditions, such as mass cut beween the matter ejected and falling
back onto the remnant, electron and neutron excesses, mixing fallback, and
explosion energy. Manganese is also produced in type Ia SNe. The aim of this
work is the study of abundances of the iron-peak element Mn in 56 bulge giants,
among which 13 are red clump stars. Four bulge fields along the minor axis are
inspected. The study of abundances of Mn-over-Fe as a function of metallicity
in the Galactic bulge may shed light on its production mechanisms.
High-resolution spectra were obtained using the FLAMES+UVES spectrograph on the
Very Large Telescope. The spectra were obtained within a program to observe 800
stars using the GIRAFFE spectrograph, together with the present UVES spectra.
We aim at identifying the chemical evolution of manganese, as a function of
metallicity, in the Galactic bulge. We find [Mn/Fe] ~-0.7 at [Fe/H]~-1.3,
increasing to a solar value at metallicities close to solar, and showing a
spread around -0.7<[Fe/H]<-0.2, in good agreement with other work on Mn in
bulge stars. There is also good agreement with chemical evolution models. We
find no clear difference in the behaviour of the four bulge fields. Whereas
[Mn/Fe] vs. [Fe/H] could be identified with the behaviour of the thick disc
stars, [Mn/O] vs. [O/H] has a behaviour running parallel, at higher
metallicities, compared to thick disc stars, indicating that the bulge
enrichment might have proceeded differently from that of the thick disk.
