Satellite Galaxy Phase Space Correlations

Poorly understood baryonic processes have prevented traditional challenges to LambdaCDM, such as the core/cusp and missing satellite problems, from providing sharp tests of the standard paradigm. On the other hand, in the past 2 years a new set of entirely kinematic challenges has arisen in the form of phase space correlations in the dwarf satellite galaxy populations. For example, the Local Group contains a large number of binary satellite galaxies and half of Andromeda’s satellites inhabit a thin corotating disk. I will review these new challenges and contrast them with the results of simulations.