Author(s): , , , , , , , , ,
Institution(s): 1. Australian National University, 2. ESO, 3. INAF, 4. Liden University, 5. MPE, 6. UCO/Lick, 7. University of Groningen, 8. University of Nottingham, 9. University of Sao Paulo
The kinematics and dynamical properties of galaxy halos are difficult to measure, given the faint stellar surface brightness that characterizes those regions. Gas-rich systems such as spiral galaxies can be probed using the radio emission of their gas component. Early type galaxies contain less gas, therefore alternative kinematic tracers need to be used.
By exploiting the bright emissions of the [OIII] and Hα lines of Planetary Nebulae (PNe), we can map the stellar kinematics far out in the halo, typically out to 5 effective radii or beyond, also in early type galaxies. Thanks to the recent spectroscopic surveys targeting extra-galactic PNe, we can now rely on few tens of galaxies where the kinematics of the stellar halos are measured. I will discuss the properties of their stellar halos as revealed by PNe: (a) the relation of the stellar surface brightness and the PNe number density; (b) two-dimensional velocity and velocity fields; (c) the radial profiles of angular momentum and Vrms; (d) the relation of the halo kinematics and other physical properties; and (e) the mass content and dynamic structure. Also, I will compare these properties with those revealed by Globular Clusters for a number of interacting systems.