The Spatial Distributions of Red and Blue Globular Clusters in Major Dry Merger Remnants

Using high-resolution N-body simulations, we examine whether a major dry merger mitigate the different radial density distributions of red and blue globular clusters (GCs), since in nearby elliptical galaxies the red GCs have a steeper radial profile than the blue GCs. To this end, we study the relation between the density slope of the GCs in merger progenitors and that in a merger remnant, when the density distribution is described by nGC ∝ r . We also study how our results depend on the merger orbit and the size of the core radius of the initial GC density distribution. We find that a major dry merger makes the GC profile flatter, and as the initial GC profile steepens, the flattening strengthen, especially if the initial slope is steeper than α ∼ 3.5. We conclude that the difference in the slopes between two populations becomes much smaller by dry merging. Therefore, the observed slopes of red and blue GCs can be a diagnostic of the importance of dry merging. The current observational data show that the red and blue GCs have more comparable and shallower slopes in some of luminous galaxies, although the total number of systems studied is still small. This may indicate that dry mergers are more important for luminous galaxies. Subject headings: galaxies: elliptical galaxies: evolution galaxies: star clusters globular clusters: general