Stellar velocity dispersion of the leo a dwarf galaxy

We measure the first stellar velocity dispersion of the Leo A dwarf galaxy, sigma = 9.3 +/- 1.3 km s(-1). We derive the velocity dispersion from the radial velocities of 10 young B supergiants and two H II regions in the central region of Leo A. We estimate a projected mass of (8 +/- 2.7) x 10(7) M-circle dot within a radius of 2' and a mass-to-light ratio of at least 20 +/- 6 M-circle dot/L-circle dot. These results imply Leo A is at least similar to 80% dark matter by mass.