We present the projected velocity dispersion profile for the remote ( d=233 kpc ) Galactic dwarf spheroidal ( dSph ) galaxy Leo II , based on 171 discrete stellar radial velocities that were obtained from medium-resolution spectroscopy using the FLAMES/GIRAFFE spectrograph at the European Southern Observatory , Chile .
The dispersion profile of those stars with good membership probabilities is essentially flat with an amplitude of 6.6 \pm 0.7 km s ^ { -1 } over the full radial extent of our data , which probe to the stellar boundary of this galaxy .
We find no evidence of any significant apparent rotation or velocity asymmetry which suggests that tidal effects can not be invoked to explain Leo II ’ s properties .
From basic mass modeling , employing Jeans ’ equation , we derive a mass out to the limiting radius of ( 2.7 \pm 0.5 ) \times 10 ^ { 7 } M _ { \odot } and a global mass to light ratio of 27–45 in solar units , depending on the adopted total luminosity .
A cored halo profile and a mild amount of tangential velocity anisotropy is found to account well for Leo II ’ s observed kinematics , although we can not exclude the possibility of a cusped halo with radially varying velocity anisotropy .
All in all , this galaxy exhibits dark matter properties which appear to be concordant with the other dSph satellites of the Milky Way , namely a halo mass profile which is consistent with a central core and a total mass which is similar to the common mass scale seen in other dSphs .