Light, Alpha, and Fe-Peak Element Abundances in the Galactic Bulge
  We present radial velocities and chemical abundances of O, Na, Mg, Al, Si,
Ca, Cr, Fe, Co, Ni, and Cu for a sample of 156 red giant branch stars in two
Galactic bulge fields centered near (l,b)=(+5.25,-3.02) and (0,-12). The
(+5.25,-3.02) field also includes observations of the bulge globular cluster
NGC 6553. The results are based on high resolution (R~20,000), high
signal-to-noise (S/N>70) FLAMES-GIRAFFE spectra obtained through the ESO
archive. However, we only selected a subset of the original observations that
included spectra with both high S/N and that did not show strong TiO absorption
bands. The present work extends previous analyses of this data set beyond Fe
and the alpha-elements Mg, Si, Ca, and Ti. While we find reasonable agreement
with past work, the data presented here indicate that the bulge may exhibit a
different chemical composition than the local thick disk, especially at
[Fe/H]>-0.5. In particular, the bulge [alpha/Fe] ratios may remain enhanced to
a slightly higher [Fe/H] than the thick disk and the Fe-peak elements Co, Ni,
and Cu appear enhanced compared to the disk. There is also some evidence that
the [Na/Fe] (but not [Al/Fe]) trends between the bulge and local disk may be
different at low and high metallicity. We also find that the velocity
dispersion decreases as a function of increasing [Fe/H] for both fields, and do
not detect any significant cold, high velocity population. A comparison with
chemical enrichment models indicates that a significant fraction of hypernovae
are required to explain the bulge abundance trends, and that initial mass
functions that are steep, top-heavy (and do not include strong outflow), or
truncated to avoid including contributions from stars >40 solar masses are
ruled out, in particular because of disagreement with the Fe-peak abundance
data. [abridged]
