is calculated by using the modified Bessel functions (e.g. Freeman 1970). The volume density in the galactic disk is approximated by dividing the surface density by scale height, which increases with the radius, which is equal to 144 pc in the solar vicinity. In Sofue et al. (2008), we have shown that the inner Galactic rotation curve is best-fitted by a combination of a bulge mass of $1.8\times 10^{10}\Msun$, its scale radius 0.5 kpc, disk mass $7\times10^{10}\Msun$ and scale radius 3.5 kpc, which are surrounded by a dark halo.

For the dark halo, we consider three cases of mass distributions: (1) semi-isothermal spherical distribution (Begeman et al. 1991), (2) NFW (Navarro, Frenk and White 1996), and (3) Burkert (1996) models. The density profiles are written, respectively, as \_[iso]{} (R)=[\_[iso]{} \^0 1+ (R/h)\^2]{}, \[eq\_iso\] \_[NFW]{} (R)=[\_[NFW]{} \^0 (R/h)/\[1+(R/h)\^2\]]{} , \[eq-nfw\] and \_[Bur]{} (R)=[\_[Bur]{} \^0 ]{} . \[eq-bur\] Here, $h$ is the scale radius (core radius) of the dark halo. The circular rotation velocity is calculated by V\_[h]{} (R)=, where M\_[h]{} (R)=4 \_0\^R \_i(x) x\^2 dx, with $i=$iso, Bur, or NFW.

A scale radius of $h=5.5$ kpc has been obtained for an isothermal halo, which best-fits the outer rotation curve after subtracting 