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 .