On the Convergence of the Milky Way and M31 Kinematics from Cosmological Simulations

Abstract The kinematics of the Milky Way (MW) and M31, dominant galaxies in Local Group (LG), can be used to estimate LG total mass. New results on M31 proper motion have recently been improve that estimate. Those are based kinematic priors sometimes guided evaluated using cosmological N -body simulations. However, properties simulated analogs could biased due effective power spectrum truncation induced by small size parent simulation. Here we explore dependence simulation box argue simulations need a order 1 Gpc claim convergence properties. Using large enough simulation, find tangential radial velocities relative MW range v tan = 105 ? 59 + 94 km s 1 ${v}_{\mathrm{rad}}=-{108}_{-81}^{+68}\,\mathrm{km}\,{{\rm{s}}}^{-1}$?> rad 108 81 68 , respectively. This study highlights derived from carefully interpreted, taking into account