What system structure is often present surrounding the most massive elliptical galaxies?

An extensive system of globular clusters

The most massive elliptical galaxies, especially those residing in dense cluster environments, are frequently surrounded by an extensive and populous system of globular clusters. These satellite systems are crucial indicators of the host galaxy's complex evolutionary path. Observations often reveal two distinct populations within these accompanying globular clusters: one older, redder, and metal-rich component, and another younger, bluer, and metal-poor component. The existence of these two distinct stellar age groups strongly suggests that the massive elliptical likely grew through multiple accretion or merger events involving smaller galaxies, each contributing its own set of older and younger stellar structures.