A UNIVERSAL MASS PROFILE FOR DWARF SPHEROIDAL GALAXIES?

We apply the Jeans equation to estimate masses for eight of the brightest dwarf spheroidal (dSph) galaxies. For Fornax, the dSph with the largest kinematic data set, we obtain a model-independent constraint on the maximum circular velocity, Vmax = 20+4−3 km s−1. Although we obtain only lower limits of Vmax ≳ 10 km s−1 for the remaining dSphs, we find that in all cases the enclosed mass at the projected half-light radius is well constrained and robust to a wide range of halo models and velocity anisotropies. We derive a simple analytic formula that estimates M(rhalf) accurately with respect to results from the full Jeans analysis. Applying this formula to the entire population of Local Group dSphs with…

• SA
  Science and Technology Facilities Council

  Award: PP/E00105X/1