Institution(s): 1. INAF-Observatory of Capodimonte
We present orbital anisotropy and dark halo parameters of a sample of early-type galaxies (ETGs) for which hundreds of planetary nebulae (PNe) have been observed within the PN.S Elliptical Galaxy Survey. Recent analyses have shown that PNe closely follow the bulk of the stellar population and can be used in combination with long slit and integral field kinematics to constrain the mass and orbital distribution of early-type galaxies out to their outskirts (~6-10Re). Discrete tracers currently represent a powerful tool for the investigation of these otherwise inaccessible regions of galaxies with other standard techniques, where typical dynamical times are longer and we expect to measure the signature or recent evolutionary events. In particular, the possibility to infer the variation of the orbital distribution of stars in the galaxy haloes is a strong observational test for galaxy formation scenarios than can be compared with predictions of hydrodynamical simulations. Finally, we will discuss the dark matter concentration and virial mass results against the predictions of state-of-art cosmological simulation in the LambdaCDM cosmology defined by Planck cosmological parameters. All these evidence together will allow us to gain insight on the baryon and dark matter assembly in the halo regions of early-type galaxies.