We have obtained radial velocity measurements for 51 new globular clusters around the Sombrero galaxy .
These measurements were obtained using spectroscopic observations from the AAOmega spectrograph on the Anglo-Australian Telescope and the Hydra spectrograph at WIYN .
Combined with our own past measurements and velocity measurements obtained from the literature we have constructed a large database of radial velocities that contains a total of 360 confirmed globular clusters .
Previous studies ’ analyses of the kinematics and mass profile of the Sombrero globular cluster system have been constrained to the inner \sim 9′Â ( \sim 24 kpc or \sim 5 R _ { e } ) , but our new measurements have increased the radial coverage of the data , allowing us to determine the kinematic properties of M104 out to \sim 15′Â ( \sim 41 kpc or \sim 9 R _ { e } ) .
We use our set of radial velocities to study the GC system kinematics and to determine the mass profile and V-band mass-to-light profile of the galaxy .
We find that M / L _ { V } increases from 4.5 at the center to a value of 20.9 at 41 kpc ( \sim 9 R _ { e } or 15′ ) , which implies that the dark matter halo extends to the edge of our available data set .
We compare our mass profile at 20 kpc ( \sim 4 R _ { e } or \sim 7.4′ ) to the mass computed from x-ray data and find good agreement .
We also use our data to look for rotation in the globular cluster system as a whole , as well as in the red and blue subpopulations .
We find no evidence for significant rotation in any of these samples .