Speaker
Description
Dark matter (DM) makes up most of the mass of the Universe but remains mysterious. I discuss recent progress in constraining its properties through its gravitational influence. I show that the latest constraints from dwarf galaxies, galaxy clusters and the cosmic microwave background rule out weak-field alternative gravity explanations for DM, favouring a new, cold, collisionless, particle (CDM). However, CDM has, for a long time, faced a range of "small scale tensions", including the "cusp-core", "missing satellites" and "satellite planes" problems. I show that all of these are likely solved by "baryonic effects" during galaxy formation. I present observational evidence that the cusp-core problem owes to baryonic feedback "heating up" DM, while "missing satellites" is solved by an improved empirical mapping of starlight to DM, combined with satellite destruction by the Milky Way's stellar disc. Finally, I present new high resolution numerical simulations of MW-mass galaxies in which long-lived satellite planes naturally emerge. I conclude with a discussion of the latest constraints on self-interacting, wave-like and warm dark matter models.