Mass Models of Dwarf Spheroidal Galaxies with Variable Stellar Anisotropy. I. Jeans Analysis

Understand

Using a flexible galactic model with variable stellar velocity anisotropy, I apply the classical Jeans mass modeling approach to the five dwarf spheroidal galaxies with the largest homogeneous datasets of stellar line-of-sight velocities (between 330 and 2500 stars per galaxy) -- Carina, Fornax, Leo~I, Sculptor, and Sextans.

• I carry out an exhaustive model parameter search, assigning absolute probabilities to each parameter combination.
• My main finding is that there is a well defined radius (unique for each galaxy) where the Jeans analysis constraints on the enclosed mass are tightest, and are much better than the constraints at previously suggested radii (e.g.
• 300~pc).