  We have used an Imaging Fabry-Perot Spectrophotometer with the Adaptive
Optics Bonnette on the Canada-France-Hawaii Telescope to measure stellar radial
velocities in the globular cluster M15. An average seeing of 0.15" full-width
at half maximum, with the best-seeing image having 0.09", allowed us to measure
accurately the velocities for five stars within 1" of the center of M15. Our
estimate of the second moment of the velocity distribution inside a radius of
2" is 11.5 km/s, the same value we find out to a radius of about 6". However,
the projected net rotation does increase dramatically at small radii, as our
previous observations led us to suspect. The rotation amplitude inside a radius
of 3.4" is v = 10.4 +- 2.7 km/s and the dispersion after removing the rotation
is sigma = 10.3 +- 1.4 km/s, so v/sigma = 1 in this region. In addition, the
position angle (PA) of the projected rotation axis differs by 100 degrees from
that of the net cluster rotation at larger radii. Current theoretical models do
not predict either this large an increase in the rotation amplitude or such a
change in the PA. However, a central mass concentration, such as a black hole,
could possibly sustain such a configuration. The rotation increase is
consistent with the existence of a central dark mass concentration equal to
2500 M_solar.
