Dynamical modelling of dwarf spheroidals

The large stellar kinematic data sets for dwarf spheroidal galaxies (dSphs) which are 
now becoming available offer the prospect of constraining their dark matter density 
profiles and exploring in detail the role of external tides in the evolution of dSphs. I will 
present two MCMC-based approaches to the modelling of dSphs which aim to extract 
as much information as possible from the observed data. The first approach constructs 
distribution functions for the stellar component of the Fornax dSph and uses MCMC to 
explore the associated parameter space and place constraints on its halo density 
profile. The second approach combines MCMC with full N-body simulations of the 
evolution of a dSph in an external tidal field in order to explore the degeneracies  
between the signatures of unseen mass and external tides in the observed internal 
kinematics of a dSph. Preliminary results for the  Carina dSph will be presented.