Galaxy evolution through resolved stellar populations in the nearby Centaurus A group

Abstract

The CenA group is a nearby dense complex (∼ 4 Mpc) dominated by an active elliptical galaxy, hosting more than 60 dwarf companions with a variety of morphological types and stellar contents. We study the resolved stellar populations of a sample of dwarfs using optical and near-infrared data from ACS/HST and ISAAC/VLT. We characterize their recent star formation histories and metallicity content, and compare them to what is known for Local Group dwarfs, underlining similarities and differences. Our results probe the fundamental interplay between nature and nurture in the evolution of dwarfs in such a dense environment. We further present the results of the first deep survey of resolved stellar populations in the remote outer halo of our nearest giant elliptical, CenA (VIMOS/VLT optical data). Tracing its halo structure (radial profile, extent and metallicity) out to a remarkable ∼ 85 kpc and comparing the halo stellar populations to those of CenA’s dwarf companions enables us to constrain the mechanisms that contributed to the build-up of CenA in the context of cosmological galaxy formation models.