Back to Volume
Paper: Dark Matter in the Draco and UMi dSphs
Volume: 327, Satellites and Tidal Streams
Page: 169
Authors: Kleyna, J.T.; Wilkinson, M.I.; Evans, N.W.; Gilmore, G.
Abstract: At least some of the dwarf spheroidals (dSphs) around the Galaxy dSphs are strongly dark matter dominated, with M/L ∼ 102 MSolar/LSolar. Until recently, stellar velocity measurements existed only in the comparatively densely populated centers of dSphs, allowing at best a model-dependent estimation of M/L. Here, we present velocity measurements at large radii in the Draco and Ursa Minor dSphs. Both dSphs have a velocity dispersion that first rises with radius and then falls off abruptly. Using distribution function models that fit the halo shape and anisotropy profile, we find that both UMi and Draco are fit best by an isotropic distribution function in an approximately isothermal halo. We also find that UMi has a kinematically cold region near its second morphological peak, consistent with the inner region of its dark halo having a harmonic core rather than a cusp.
Back to Volume