We present new radial velocity results for 176 stars in the Fornax dwarf spheroidal galaxy , of which at least 156 are probable Fornax members .
We combine with previously published data to obtain a radial velocity sample with 206 stars , of which at least 176 are probable Fornax members .
We detect the hint of rotation about an axis near Fornax ’ s morphological minor axis , although the significance of the rotation signal in the galactic rest frame is sensitive to the adopted value of Fornax ’ s proper motion .
Regardless , the observed stellar kinematics are dominated by random motions , and we do not find kinematic evidence of tidal disruption .
The projected velocity dispersion profile of the binned data set remains flat over the sampled region , which reaches a maximum angular radius of 65 ^ { \prime } .
Single-component King models in which mass follows light fail to reproduce the observed flatness of the velocity dispersion profile .
Two-component ( luminous plus dark matter ) models can reproduce the data , provided that the dark component extends sufficiently beyond the luminous component and the central dark matter density is of the same order as the central luminous density .
These requirements suggest a more massive , darker Fornax than standard core-fitting analyses have previously concluded , with M / L _ { V } over the sampled region reaching 10 to 40 times the M / L _ { V } of the luminous component .
We also apply a non-parametric mass estimation technique , introduced in a companion paper .
Although it is designed to operate on data sets containing velocities for > 1000 stars , the estimation yields preliminary results suggesting M / L _ { V } \sim 15 inside r < 1.5 kpc .