We report the detection of a stellar density cusp and a velocity dispersion increase in the center of the globular cluster M54 , located at the center of the Sagittarius dwarf galaxy ( Sgr ) .
The central line of sight velocity dispersion is 20.2 \pm 0.7 { km s ^ { -1 } } , decreasing to 16.4 \pm 0.4 { km s ^ { -1 } } at 2 \mbox { \mbox { $ { } ^ { \prime \prime } $ } . } 5 ( 0.3 { pc } ) .
Modeling the kinematics and surface density profiles as the sum of a King model and a point-mass yields a black hole ( BH ) mass of \sim 9400 { M _ { \odot } } .
However , the observations can alternatively be explained if the cusp stars possess moderate radial anisotropy .
A Jeans analysis of the Sgr nucleus reveals a strong tangential anisotropy , probably a relic from the formation of the system .