Dark matter distribution and dynamics of dwarf spheroidal galaxies

Abstract

I review the current status of dynamical modelling of dwarf spheroidal galaxies focusing on estimates of their dark matter content. Starting with the simplest methods using the velocity dispersion profiles I discuss the inherent issues of mass-anisotropy degeneracy and contamination by unbound stars. I then move on to methods of increasing complexity, aiming to break the degeneracy, up to recent applications of the Schwarzschild orbit superposition method. The dynamical modelling is placed in the context of possible scenarios for the formation of dwarf spheroidal galaxies, including the tidal stirring model and mergers of dwarf galaxies. The two scenarios are illustrated with examples from simulations: a comparison between the tidal evolution of dwarfs with cuspy and cored dark matter profiles and the formation of a dwarf spheroidal with prolate rotation.

Fundamental Properties of the Dark and the Luminous Matter from the Low Surface Brightness Discs

“…On the observational side, the special importance of certain families of galaxies is well known. In detail, dwarf spheroidals are a primary target to study the DM phenomenon (e.g., [29]). They have the advantage to be dark matter dominated at any radius and to lay in a dark halo mass range in which the discrepancy between the ΛCDM scenario predictions and the actual observations are expected to be very apparent.…”