3D intervelocity, v_3D and calculated circular velocity v_circ for galaxy pairs identified in the simulation with separations r_3D <  100 kpc (blue) and 100 kpc <  r_3D <  1 Mpc. For sufficiently separated pairs, the circular velocity provides a good estimate of the 3D intervelocity, suggesting a physical origin of the intervelocity peak driven by the typical masses and separations of the selected galaxy pairs.