The mass of the Milky Way based on the kinematics of satellites

The Milky Way satellite system is the most studied group of galaxies. Currently, 64 satellites within 260 kpc are known. We have measured high-precision distances, radial and tangential velocities for most of them. We have estimated the total mass of our galaxy to be $M=(7.9\pm2.1)\times10^{11}$ $M_\odot$ using a modification of the projected mass method that takes into account the three-dimensional distribution of galaxies in the group, assuming an isotropic distribution of satellite orbits. The infall of galaxies located outside the virial zone at a distance of 400 kpc allows us to estimate the mass of the system to be of the order of $9\times10^{11}$ $M_\odot$, which is in excellent agreement with the mass inside the virial zone of our Galaxy.