Diffuse stellar Halos in elliptical Galaxies

Elliptical galaxies are surrounded by extended, diffuse stellar halos. In dense galaxy clusters, these halos interact and may be dissolved to form part of the so-called intracluster light. Through Planetary Nebula stars, it has been possible to investigate the kinematics and dynamics in some of these halos, giving new constraints on the formation and on-going evolution of these galaxies.