Discovery of a new stellar sub-population residing in the (inner)
  stellar halo of the Milky Way
  We report the discovery of a unique collection of metal-poor giant-stars,
that exhibit anomalously high levels of $^{28}$Si, clearly above typical
Galactic levels. Our sample spans a narrow range of metallicities, peaking at
$-1.07\pm 0.06$, and exhibit abundance ratios of [Si,Al/Fe] that are as extreme
as those observed in Galactic globular clusters (GCs), and Mg is slightly less
overabundant. In almost all the sources we used, the elemental abundances were
re-determined from high-resolution spectra, which were re-analyzed assuming
LTE. Thus, we compiled the main element families, namely the light elements (C,
N), $\alpha-$elements (O, Mg, Si), iron-peak element (Fe), $\textit{s}-$process
elements (Ce, Nd), and the light odd-Z element (Al). We also provide dynamical
evidence that most of these stars lie on tight (inner)halo-like and retrograde
orbits passing through the bulge. Such kinds of objects have been found in
present-day halo GCs, providing the clearest chemical signature of past
accretion events in the (inner) stellar halo of the Galaxy, formed possibly as
the result of dissolved halo GCs. Their chemical composition is, in general,
similar to that of typical GCs population, although several differences exist.
