The phase-space density of stars of different mass groups, f(x, m) for a mass function that scales as ﹩{dN}/{dm}\propto {m}^{-6}﹩, as given in Equation (27). The vertical axis, m ^5/2 f(x, m) represents the phase-space density of particles of mass of order m, multiplied by m ^3/2. Different curves correspond to different mass groups, evenly spaced in logarithmic scale, as shown in the legend, indicating the arbitrarily normalized particle mass. Asterisks represent the energy at which each mass group locally dominates the scatterings. The dominating mass increases as the energy x is increased.