Substructure in the Andromeda galaxy globular cluster system

In the most prominent current scenario of galaxy formation, galaxies form hierarchically through the merger of smaller systems. Such mergers could leave behind dynamical signatures that may linger long after the event. In particular, the globular cluster system (GCS) of a merging satellite galaxy may remain as a distinct subpopulation within the GCS of a massive galaxy. Using the latest available globular cluster velocities and metallicities, we present the results of a search for grouping in the GCS of our nearest large spiral galaxy neighbor, M31. A modified friends-of-friends algorithm is used to identify a number of possible merger remnants in projected position, radial velocity, and [Fe/H] parameter space. Numerical simulations are used to check that such merger remnants are indeed plausible over the timescales of interest. The identification of stellar streams associated with these groups is required in order to confirm that they represent merger remnants.