Galaxy Mergers: A Search for Chemical Signatures

Abstract

We have gathered high resolution echelle spectra for more than two dozen high-velocity metal-poor field stars, including BD+80 245, a star previously known to have extremely low [alpha/Fe] abundances, as well as G4-36, a new low-alpha star with unusually large [Ni/ Fe]. In this kinematically selected sample, other chemically anomalous stars have also been uncovered. In addition to deriving the alpha-element abundances, we have also analysed iron-group and s-process elements. Not only does chemical substructure exist in the halo, but the chemical anomalies are not all the same within all elemental groups.