Internal kinematics of the MW dwarf spheroidal satellites revealed by Gaia DR3

Dwarf galaxies are the most abundant in the Universe. They show a wide variety of morphologies, gas contents, and SFHs, none of which are fully understood. Due to their low self-gravity, they are more susceptible to stellar feedback and hydrodynamic forces, and so are natural laboratories for star-formation and galaxy-formation models. The Milky Way (MW) satellite galaxies offers us a chance to study the processes affecting the evolution of dwarfs in ways that are impossible elsewhere. Their proximity allows us to obtain valuable information about their stellar content and, up to some extend, their internal kinematics through the study of the line-of-sigh (LOS) velocities of their stars. However, having only 1D velocity information is not enough to determine the dynamical state of these systems, a crucial piece of information to understand their formation and evolution. In order to shed light on the internal kinematics of the MW satellites, we have combined proper motions (PM) from the Gaia Data Release 3 and line-of-sight velocity catalogues from the literature for 14 dwarf satellites of the MW. This has enabled us to derive the 3D velocity vector of their individual stars and to study, for the first time, their internal kinematics in 3D of six of the galaxies. We find significant velocity gradients in most of them and that the interaction with the MW has played a key role in their evolution.