Detailed abundances in the Galactic center: Evidence of a metal-rich
  alpha-enhanced stellar population
  We present a detailed study of the composition of 20 M giants in the Galactic
center with 15 of them confirmed to be in the Nuclear Star Cluster. As a
control sample we have also observed 7 M giants in the Milky Way Disk with
similar stellar parameters. All 27 stars are observed using the NIRSPEC
spectograph on the KECK II telescope in the K-band at a resolving power of
R=23,000. We report the first silicon abundance trends versus [Fe/H] for stars
in the Galactic center. While finding a disk/bulge like trend at subsolar
metallicities, we find that [Si/Fe] is enhanced at supersolar metallicities. We
speculate on possible enrichment scenarios to explain such a trend. However,
the sample size is modest and the result needs to be confirmed by additional
measurements of silicon and other \textalpha-elements. We also derive a new
distribution of [Fe/H] and find the most metal rich stars at [Fe/H]=+0.5 dex,
confirming our earlier conclusions that the Galactic center hosts no stars with
extreme chemical composition.
