Chemical evolution of the inner 2 degrees of the Milky Way bulge:
  [alpha/Fe] trends and metallicity gradients
  The structure, formation, and evolution of the Milky Way bulge is a matter of
debate. Important diagnostics for discriminating between bulge models include
alpha-abundance trends with metallicity, and spatial abundance and metallicity
gradients. Due to the severe optical extinction in the inner Bulge region, only
a few detailed investigations have been performed of this region. Here we aim
at investigating the inner 2 degrees by observing the [alpha/Fe] element trends
versus metallicity, and by trying to derive the metallicity gradient.
[alpha/Fe] and metallicities have been determined by spectral synthesis of 2
micron spectra observed with VLT/CRIRES of 28 M-giants, lying along the
Southern minor axis at (l,b)=(0,0), (0,-1), and (0,-2). VLT/ISAAC spectra are
used to determine the effective temperature of the stars. We present the first
connection between the Galactic Center and the Bulge using similar stars, high
spectral resolution, and analysis techniques. The [alpha/Fe] trends in all our
3 fields show a large similarity among each other and with trends further out
in the Bulge, with a lack of an [\alpha/Fe] gradient all the way into the
centre. This suggests a homogeneous Bulge when it comes to the enrichment
process and star-formation history. We find a large range of metallicities
(-1.2<[Fe/H]<+0.3), with a lower dispersion in the Galactic center:
-0.2<[Fe/H]<+0.3. The derived metallicities get in the mean, progressively
higher the closer to the Galactic plane they lie. We could interpret this as a
continuation of the metallicity gradient established further out in the Bulge,
but due to the low number of stars and possible selection effects, more data of
the same sort as presented here is necessary to conclude on the inner
metallicity gradient from our data alone. Our results firmly argues for the
center being in the context of the Bulge rather than very distinct.
