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The work presented in this thesis studies the role that accretion\nevents play in the evolution of galaxies in dense environments, such as\ngalaxy clusters. Cosmological simulations allow us to study in detail\nthe evolution of galaxies' halos in cluster environments and have shown\nthat the formation of extended halos around central cluster\ngalaxies and intracluster light (ICL) is closely correlated to the\nmorphological transformation of galaxies in clusters. However, the\nextremely low surface brightness of these components makes it\ndifficult to gather observational constraints.\n\nThis thesis studies the light and stellar motion in the halo of the\ngiant elliptical galaxy M87 and its surrounding IC component at the\ncentre of the Virgo cluster. Virgo is the nearest ($\\sim 15$~Mpc away)\nlarge scale structure, a young cluster characterised by both spatial\nand kinematic substructures. M87 has one of the oldest stellar\npopulations in the local Universe and a stellar halo that contains\n$\\sim$ 70\\% of the galaxy light down to $\\rm{\\mu_{V}=27\\, mag\\,\n arcsec^{-2}}$. Moreover, deep images of the Virgo cluster core have\nrevealed an extended network of tidal features suggesting that\naccretion events characterise its mass assembly. Thus, M87 and its host\nenvironment are prime targets to shed light on the hierarchical\nassembly of structure in the Universe.\n\nThis work uses new Suprime-Cam@Subaru photometry and FLAMES@VLT\nspectroscopy to study a $\\sim 0.5\\, \\rm{deg^2}$ area around\nM87, in the transition region between galaxy halo and ICL. We use\nplanetary nebulas (PNs) as tracers, whose strong [OIII] $\\lambda$5007\n\\AA\\ emission line makes them excellent photometric and kinematic\nprobes, also at large distances from the galaxy's centre.\n\nThe photometric analysis of the PN sample shows the superposition of\ntwo stellar populations, both halo and ICL. This is confirmed by\nspectroscopically detected PNs, whose velocity phase-space also\nreveals that halo and ICL split into two different kinematic\ncomponents. They have very different spatial distributions and parent\nstars, as indicated by the properties of the PN populations they are\nassociated with, such as the $\\alpha$-parameter and the slope of the\nplanetary nebula luminosity function (PNLF).\n\nIn this thesis I give the observational proof that in Virgo\nthe central galaxy and the ICL both evolve through the\nongoing accretion of smaller systems. However, stellar halo and ICL\nare dynamically distinct components with different velocity and\ndensity distributions, and parent stellar populations. Whether or not\nthese conclusions are true for different galaxies in different Virgo\nsubclusters is still an open question and the topic of one of\nmy planned future studies.