We present a kinematic analysis of the globular cluster ( GC ) system in M31 .
Adding new velocity data for 150 GCs in our wide-field survey to those in the literature , we increase the number of M31 GCs with measured velocities by 42 per cent , to 504 .
Using the photometric and spectroscopic database of these 504 GCs , we have investigated the kinematics of the M31 GC system .
We find that the all GC system shows strong rotation , with rotation amplitude of v _ { rot } \sim 190 km s ^ { -1 } , and that a weak rotation persists even for the outermost samples at |Y| \geq 5 kpc where Y represents the projected distance from the major axis .
The rotation-corrected velocity dispersion for the GC system is estimated to be \sigma _ { p,r } \sim 130 km s ^ { -1 } , and it increases from \sigma _ { p,r } \sim 120 km s ^ { -1 } at |Y| < 1 kpc to \sigma _ { p,r } \sim 150 km s ^ { -1 } at |Y| \geq 5 kpc .
These results are very similar to those for the metal-poor GCs .
This shows that there is a dynamically hot halo in M31 that is rotating but primarily pressure-supported .
We have identified 50 “ friendless ” GCs , and they appear to rotate around the major axis of M31 , unlike M31 ’ s disk rotation around the minor axis .
For the subsamples of metal-poor and metal-rich GCs , we have found that the metal-rich GCs are more centrally concentrated than the metal-poor GCs , and both subsamples show strong rotation .
For the subsamples of bright and faint GCs , it is found that the rotation for the faint GCs is stronger than that for the bright GCs .
We have identified 56 GCs and GC candidates with X-ray detection including 39 genuine GCs with measured velocities .
It is found that the majority of X-ray emitting GCs follow the disk rotation , and that the redder , more metal-rich , and brighter GCs are more likely to be detected as X-ray emitting GCs , as seen for GCs in early-type galaxies .
We have derived a rotation curve of M31 using the GCs at |Y| \leq 0.6 kpc , and it agrees well for the range of R = 20 - 45 \arcmin to that based on other tracers except for the planetary nebulae .
We have estimated the dynamical mass of M31 using ‘ Projected Mass Estimator ( PME ) ’ and ‘ Tracer Mass Estimator ( TME ) ’ as M _ { PME } = 5.5 _ { -0.3 } ^ { +0.4 } \times 10 ^ { 11 } M _ { \odot } out to a radius of \sim 55 kpc and M _ { TME } = 19.2 _ { -1.3 } ^ { +1.4 } \times 10 ^ { 11 } M _ { \odot } for a radius of \sim 100 kpc , respectively .
We finally discuss the implication of these results and compare the kinematics of GCs with that of planetary nebulae in M31 .