dark halo increases toward the nucleus inversely proportional to the radius (figure \[fig-rho\]). However, the bulge density, obeying the de Vaucouleurs law, is kept sufficiently large compared to the dark halo density near the Galactic Center. The Burkert and isothermal halo models indicate a finite mild density plateau at the center, which is negligible compared to the disk and bulge densities. Accordingly, in any models, the contribution from the dark halo to the rotation velocity is negligible in the inner Galaxy. It is, therefore, not possible to distinguish the dark halo models by comparing with the inner rotation curve.

On the other hand, in the outer Galaxy, the dark halo is the major mass component, and therefore, the rotation velocity is sensitive to the dark halo model. The outer rotation velocities for the three models are diverging as the radius increases, particularly at $R>\sim 20$ kpc. However, observational data are still restricted to the galactic disk at $R<20$ kpc, where the rotation curve is approximately flat. Also, the observations are largely scattered in the outer Galaxy, except for the recently added accurate value of $V=200\pm6$ at $R=13.1\pm0.2$ kpc from VERA observations (Honma et al. 2007). Hence, it may still be 