Cosmological simulations allow us to study in detail the evolution of galaxy halos in cluster environments, but the extremely low surface brightness of such components makes it difficult to gather observational constraints. Planetary nebulas (PNs) offer a unique tool to investigate these environments owing to their strong [OIII] emission line. We study the light and kinematics of the Virgo cluster and its central galaxy, M87, prime targets to address the topic of galaxy formation and evolution in dense environments. We make use of a deep and extended PN sample (~300 objects) that extends out to 150 kpc in radius from M87’s centre. We show that at all distance the galaxy halo overlaps with the Virgo intracluster light (ICL). Halo and ICL are dynamically distinct components with different parent stellar populations, consistent with the halo of M87 being redder and more metal rich than the ICL. The synergy between PN kinematic information and deep V/B-band photometry made it possible to unravel an ongoing accretion process in the outskirt of M87. This accretion event represents a non-negligible perturbation of the halo light, showing that this galaxy is still growing by accretion of smaller systems.

We present the internal velocity dispersions and spectral line indices for six Virgo ultra-compact dwarf (UCD) galaxies obtained from spectroscopy with the Keck II 10-m telescope. We use these results: 1) to compare the Virgo UCDS with the Fornax UCD population; 2) to compare UCDs with globular clusters (GCs) to determine if UCDs and the most luminous GCs are the same or distinct systems; 3) to further test the nucleated dwarf elliptical (dE,N) stripping hypothesis for UCD formation.