Observations of stellar streams in M31 ’ s outer halo suggest that M31 is actively accreting several dwarf galaxies and their globular clusters ( GCs ) .
Detailed abundances can chemically link clusters to their birth environments , establishing whether or not a GC has been accreted from a satellite dwarf galaxy .
This talk presents the detailed chemical abundances of seven M31 outer halo GCs ( with projected distances from M31 greater than 30 kpc ) , as derived from high-resolution integrated-light spectra taken with the Hobby Eberly Telescope .
Five of these clusters were recently discovered in the Pan-Andromeda Archaeological Survey ( PAndAS ) —this talk presents the first determinations of integrated Fe , Na , Mg , Ca , Ti , Ni , Ba , and Eu abundances for these clusters .
Four of the target clusters ( PA06 , PA53 , PA54 , and PA56 ) are metal-poor ( [ Fe / H ] < -1.5 ) , \alpha -enhanced ( though they are possibly less alpha-enhanced than Milky Way stars at the 1 sigma level ) , and show signs of star-to-star Na and Mg variations .
The other three GCs ( H10 , H23 , and PA17 ) are more metal-rich , with metallicities ranging from [ Fe/H ] = -1.4 to -0.9 .
While H23 is chemically similar to Milky Way field stars , Milky Way GCs , and other M31 clusters , H10 and PA17 have moderately-low [ Ca/Fe ] , compared to Milky Way field stars and clusters .
Additionally , PA17 ’ s high [ Mg/Ca ] and [ Ba/Eu ] ratios are distinct from Milky Way stars , and are in better agreement with the stars and clusters in the Large Magellanic Cloud ( LMC ) .
None of the clusters studied here can be conclusively linked to any of the identified streams from PAndAS ; however , based on their locations , kinematics , metallicities , and detailed abundances , the most metal-rich PAndAS clusters H23 and PA17 may be associated with the progenitor of the Giant Stellar Stream , H10 may be associated with the SW Cloud , and PA53 and PA56 may be associated with the Eastern Cloud .