Substructure in the Andromeda Galaxy Globular Cluster System

In the most prominent current scenario of galaxy formation, galaxies formhierarchically through the merger of smaller systems. Such mergers could leavebehind dynamical signatures which may linger long after the event. Inparticular, the globular cluster system (GCS) of a merging satellite galaxy mayremain as a distinct sub-population within the GCS of a massive galaxy. Usingthe latest available globular cluster velocities and metallicities, we presentthe results of a search for grouping in the GCS of our nearest large spiralgalaxy neighbor, M31. A modified friends-of-friends algorithm is used toidentify a number of possible merger remnants in projected position, radialvelocity and [Fe/H] parameter space. Numerical simulations are used to checkthat such merger remnants are indeed plausible over the timescales of interest.The identification of stellar streams associated with these groups is requiredin order to confirm that they represent merger remnants.Comment: 19 pages, 3 figures, accepted for publication in the Ap