Radial velocities of blue horizontal branch field stars in the outer galactic halo.

A sample of distant blue horizontal branch field (bhbf) stars has been identified. Thirty of the stars are located at Galactocentric distances between 15 and 40 kpc. Radial velocities of the bhbf stars have been obtained with good accuracy (≡20 km s^-1). The radial velocity dispersion of a subsample of 17 stars with a mean Galactocentric distance of 19 kpc is 100±18 km s^-1 and the radial velocity dispersion of a subsample of 13 stars with a mean Galactocentric distance of 29 kpc is 73±15 km s^-1 (assuming V_sun; = 225 km s^-1).