We report a new analysis of the stellar dynamics in the Galactic centre , based on improved sky and line-of-sight velocities for more than one hundred stars in the central few arcseconds from the black hole candidate SgrA* .
The main results are :

\bullet Overall the stellar motions do not deviate strongly from isotropy .
For those 32 stars with a determination of all three velocity components the absolute , line of sight and sky velocities are in good agreement , consistent with a spherical star cluster .
Likewise the sky-projected radial and tangential velocities of all 104 proper motion stars in our sample are also consistent with overall isotropy .

\bullet However , the sky-projected velocity components of the young , early type stars in our sample indicate significant deviations from isotropy , with a strong radial dependence .
Most of the bright HeI emission line stars at separations from 1 ” to 10 ” from SgrA* are on tangential orbits .
This tangential anisotropy of the HeI stars and most of the brighter members of the IRS16 complex is largely caused by a clockwise ( on the sky ) and counter-rotating ( line of sight , compared to the Galaxy ) , coherent rotation pattern .
The overall rotation of the young star cluster probably is a remnant of the original angular momentum pattern in the interstellar cloud from which these stars were formed .

\bullet The fainter , fast moving stars within \approx { } 1 ^ { \prime \prime } from SgrA* appear to be largely moving on radial or very elliptical orbits .
We have so far not detected deviations from linear motion ( i.e .
acceleration ) for any of them .
Most of the SgrA* cluster members also are on clockwise orbits .
Spectroscopy indicates that they are early type stars .
We propose that the SgrA* cluster stars are those members of the early type cluster that happen to have small angular momentum and thus can plunge to the immediate vicinity of SgrA* .

\bullet We derive an anisotropy-independent estimate of the Sun-Galactic centre distance between 7.8 and 8.2 kpc , with a formal statistical uncertainty of \pm 0.9 { { kpc } } .

\bullet We explicitly include velocity anisotropy in estimating the central mass distribution .
We show how Leonard-Merritt and Bahcall-Tremaine mass estimates give systematic offsets in the inferred mass of the central object when applied to finite concentric rings for power law clusters .
Corrected Leonard-Merritt projected mass estimators and Jeans equation modelling confirm previous conclusions ( from isotropic models ) that a compact central mass concentration ( central density \geq 10 ^ { { 12.6 } } M _ { { \sun } } pc ^ { { -3 } } ) is present and dominates the potential between 0.01 and 1 pc .
Depending on the modelling method used the derived central mass ranges between 2.6 and 3.3 \times 10 ^ { { 6 } } M _ { { \sun } } for R _ { { \sun } } = 8.0 { { kpc } } .