Persistent Influence of the Dark First Structures

This astrophysics seminar explores how the earliest dark matter structures, known as "prompt cusps," form and persist throughout cosmic evolution. Learn about these uniquely compact structures with r^-1.5 density profiles that emerge from the smooth mass distribution of the early universe. Discover how these ancient cosmic elements remain largely intact through the growth and clustering of dark matter halos, making them the densest and most abundant dark matter systems in the present universe. The presentation covers both simulation and theoretical foundations of prompt cusps, examining how they provide new opportunities to test dark matter properties and early universe physics. Specific applications include how these structures would dominate annihilation rates if dark matter annihilates, and how they might influence dwarf galaxy kinematics if dark matter is warm. The talk also addresses alternative dark matter candidates like primordial black holes (PBHs), presenting findings from new simulations that fully resolve inter-PBH dynamics, including how gravitational interactions can create a "hot dark matter" component that affects structure growth up to galaxy scales.