Yaryura, Yamila
Argentina – IATE
Associations of dwarf galaxies in a ΛCDM Universe
Associations of dwarf galaxies are extended systems composed exclusively of dwarf galaxies, which were identified in the Local Volume for the first time more than thirty years ago. We identify these particular systems using a semi-analytical model of galaxy formation coupled to a dark matter only simulation in the Λ Cold Dark Matter cosmological model. Our systems have typical sizes of ∼ 0.2 Mpc/h and velocity dispersion of ∼ 30 km/s in good agreement with observationally detected dwarf galaxy associations. Such large typical sizes suggest that individual members of a given dwarf association reside in different dark matter haloes. Furthermore, associations located in more dense environments present significantly higher velocity dispersion than those located in less dense environments, evidencing that the environment plays a fundamental role in their dynamical properties. However, this connection between velocity dispersion and the environment depends exclusively on whether the systems are gravitational bound or unbound. Although less than a dozen observationally detected associations of dwarf galaxies are currently known, our results are predictions on the eve of forthcoming large surveys of galaxies, which will enable the identification and study of these very particular systems.