The Outermost Edges of the Milky Way Halo from Galaxy Kinematics

We measure for the first time outermost edges of Milky Way (MW) halo in terms depletion and turnaround radii. The inner radius, rid, identified at location maximum infall velocity, separates a growing from draining environment, while rta, marks edge infalling material toward halo, both which are located well outside virial radius. Using motions nearby dwarf galaxies within 3 Mpc, we obtain marginal detection zone around MW with velocity . This enables us to rid = 559 ± 107 kpc rta 839 121 kpc. measured radius is about 1.5 times (R200m) internal dynamics. Compared halos cosmological simulation Illustris TNG100, factor consistent that similar masses dynamical environments but slightly smaller than typical values Local Group analogs, potentially indicating unique evolution history MW. These measurements directly quantify ongoing outer provide constraints on current state independent