Radial velocity dispersion profile of BHB stars from HVS survey (solid circles), from SDSS DR6 (open circles, offset by 1 kpc for clarity), and from a combined sample of globular clusters, satellite galaxies, and halo red giants (triangles). Long dashed line is a power-law fit, σ( r) = 111( r/40) ^−0.08 km s ⁻¹. Solid line shows the mean streaming radial velocity for the HVS sample. Shaded regions illustrate the allowed range of circular velocity when the anisotropy parameter is varied from β = 0 to β = 0.5 for a fixed tracer density γ _tr = 4 (bottom left toward top right) and when the tracer density is varied from γ _tr = 3.5 to γ _tr = 4.5 for a fixed β = 0.4 (top left toward bottom right). Middle solid line is for γ _tr = 4, β = 0.4. Filled circles connected by vertical lines show the Watkins et al. (2010) mass estimator applied to the HVS sample at 40, 60, and 80 kpc.