1210.7527 (Prajwal R. Kafle et al.)

Kinematics of the stellar halo and the mass distribution of the Milky Way using BHB stars    [PDF]

Prajwal R. Kafle, Sanjib Sharma, Geraint F. Lewis, Joss Bland-Hawthorn

Here we present a kinematic study of the Galactic halo out to a radius of $\sim$ 60 kpc, using 4664 blue horizontal branch (BHB) stars selected from the SDSS/SEGUE survey, to determine key dynamical properties. Using a maximum likelihood analysis, we determine the velocity dispersion profiles in spherical coordinates ($\sigma_{r}$, $\sigma_{\theta}$, $\sigma_{\phi}$) and the anisotropy profile ($\beta$). The radial velocity dispersion profile ($\sigma_{r}$) is measured out to a galactocentric radius of $r \sim 60$ kpc, but due to the lack of proper-motion information, $\sigma_{\theta}$, $\sigma_{\phi}$ and $\beta$ could only be derived directly out to $r \sim25$ kpc. From a starting value of $\beta\approx 0.5$ in the inner parts ($9View original: http://arxiv.org/abs/1210.7527