Speaker

Dmitry Makarov

Special Astrophysical Observatory of the Russian Academy of Sciences

Abstract

Nearby dwarf galaxies are test particles for the study of the Local Group. The kinematics of satellites within the virial zones of Andromeda and the Milky Way provide mass estimates on scales from 50 to 300 kpc. While objects at the stage of their first fall into the Local Group give an independent estimate of the total Local Group mass at distances from 400 kpc to 1.5 Mpc. Despite the complex dumbbell shape of the Local Group, this approach yields reliable estimates of the total mass MLG = (2.42±0.12)×10^12 Msun. The Hubble Flow model is in remarkable agreement with the sum of the virial masses of the two main galaxies, M(MW+M31) = (2.49±0.43)×10^12 Msun. Comparisons with Hestia cosmological simulations show good qualitative agreement, but the velocity dispersion at the boundary of the systems turns out to be significantly larger than observed in the Local Group.

Scientific theme

Local Group, Hubble Flow, Hestia simulations