This Targeted Simons Research Group is building a theoretical framework that translates particle physics models of dark matter with short-range forces into self-consistent galactic predictions. Our theoretical framework will empower next-generation extragalactic surveys to definitively test these fundamental interactions.
The standard Cold Dark Matter paradigm assumes dark matter is cold and collisionless. The collisionless hypothesis remains poorly constrained on galactic and sub-galactic scales. Data from the Vera C. Rubin Observatory, Euclid, JWST, and the Nancy Grace Roman Space Telescope now have the statistical power and spatial resolution to detect the signatures of collisional dark matter — if we know what to look for. This collaboration is built to define those signatures.
Assuming dark matter interacts only gravitationally is a working hypothesis, not a data-driven conclusion — no Standard Model particle behaves that way. Short-range forces are ubiquitous in particle physics and arise generically in extensions of the Standard Model. Such self interactions leave the Cosmic Microwave Background and large-scale structure essentially untouched, concentrating their effects on smaller scales.
Short-range elastic forces allow dark matter particles to collide, driving heat transfer through galactic halos. This initially creates a shallow, cored dark matter density profile. Eventually the core undergoes runaway gravothermal collapse — a phenomenon uniquely associated with self-interacting dark matter that may seed dense dark substructures.
Separating the effects of dark matter from the complex physics of baryonic galaxy formation remains our greatest challenge. To break this degeneracy, we deploy N-body and hydrodynamical simulations across several major frameworks ((MP-)GADGET, AREPO, ChaNGa, GIZMO) and semi-analytic models. By pushing these simulations across a full spectrum of environments, we aim to isolate the true, observable signatures of dark matter dynamics.
Dwarf galaxies are the smallest, most baryon-poor halos known — constituting excellent laboratories for constraining low-velocity dark matter collisions and exploring the emergence of rotation-curve diversity.
Satellite populations around Milky-Way-like hosts encode tidal stripping, evaporation, and drag — potentially differentiating dark matter physics from baryonic feedback.
Strong-lens host galaxies turn the abundance, mass distribution, and structure of substructure into a measurable signal through flux-ratio anomalies and gravitational imaging perturbers.
The fastest collisions occur in clusters: satellite-galaxy and lensing-arc statistics probe the high-velocity regime.
At high redshift, gravothermal seeding of supermassive black holes can be confronted with JWST ``Little Red Dots'' and luminous quasars.