The existence of dark matter (DM) has been made robust through multiple orthogonal astrophysical probes, yet the microscopic properties of DM remain unknown. In particular, it is unclear whether DM interacts with itself and/or with the standard model non-gravitationally. Cold DM, a single, collision-less particle species with negligible primordial thermal dispersion is largely considered the “concordance” DM model in the astrophysical community. Yet, observations on dwarf scales suggest that DM might be self-interacting. In this tea talk, I will discuss self-interacting DM (SIDM), in which DM interacts only with itself non-gravitationally. Specifically, I will discuss my recent work using hydrodynamic zoom-in simulations which demonstrate SIDM induced delay of super-massive black hole growth in Milky-Way mass galaxies. This work suggests new ways to probe SIDM, including via gravitational waves.
Until recently, much of our understanding of the 3D structure of our Milky Way was based on 2D observations of stars and dust, or spectral-line observations of gas. Distance measurements needed to turn the 2D sky into a 3D physical picture of the stars and interstellar clouds that form them were few and far between. In this short talk, I will discuss how the rise of Gaia and large photometric surveys — in combination with new data science and visualization techniques — are quickly changing this landscape. In particular, I will show how 3D dust mapping has received a huge distance resolution boost from Gaia (leading to new discoveries in our solar neighborhood; tinyurl.com/radwave), and how 3D dust maps can be “knitted” together with velocity information from gas to render never-before-seen views of the spatial-kinematic (and in future, magnetic field) structure of the interstellar medium.