Grupos de galaxias enanas en un Universo CDM

C. Y. YARYURA; M. G. ABADI; A. N. RUIZ; S. A. CORA

Rosario

Congreso; Reunión Anual de la Asociación Argentina de Astronomía; 2020

Seven groups of dwarf galaxies were recently reported by observational results, being the largestnumber of systems of these characteristics so far. Motivated by these observational results, we study the ability of the cosmological model  CDM to reproduce them. We use the Small Multidark Planck cosmological simulation coupled to the semianalytical model of galaxy formation sag. We also use the percolating Friends of Friends algorithm (FoF) to identify galaxy systems. Then, we select groups composed only by dwarf galaxies and study their main dynamical properties, estimating mass, size and velocity dispersion. Our results suggest that the semianalitycal model sag coupled to a high-resolution cosmological simulation can naturally reproduce the existence and sizes of dwarf galaxies groups without much difficulty. However, velocity dispersions of our groups are significantly lower than those presented by observed groups. Given that the mass is proportional to the velocity dispersion, the estimated masses of the observed groups are significantly higher. These results could represent a potential problem for the  CDM model if they are confirmed for future more numerous samples of dwarf galaxies groups.