PIRSA:25120036

Video URL

https://pirsa.org/25120036

Cosmology with small-scale structure

Delos, S. (2025). Cosmology with small-scale structure. Perimeter Institute for Theoretical Physics. https://pirsa.org/25120036

Delos, Sten. Cosmology with small-scale structure. Perimeter Institute for Theoretical Physics, Dec. 08, 2025, https://pirsa.org/25120036 

          @misc{ scivideos_PIRSA:25120036,
            doi = {10.48660/25120036},
            url = {https://pirsa.org/25120036},
            author = {Delos, Sten},
            keywords = {Cosmology},
            language = {en},
            title = {Cosmology with small-scale structure},
            publisher = {Perimeter Institute for Theoretical Physics},
            year = {2025},
            month = {dec},
            note = {PIRSA:25120036 see, \url{https://scivideos.org/pirsa/25120036}}
          }

Sten Delos Carnegie Institution for Science

Talk numberPIRSA:25120036
DOI10.48660/25120036
Source RepositoryPIRSA
Collection
Talk Type Scientific Series
Subject

Abstract

The first and smallest systems of particle dark matter gravitationally condensed directly out of the smooth mass distribution of the early universe. This formation mechanism left these "prompt cusps" with uniquely compact r^-1.5 density profiles and linked their properties tightly with the cosmic initial conditions. Prompt cusps are the densest and most abundant dark matter systems. I will present their basis in simulations and theory, and I will show how they bring new opportunities to test the physics of dark matter and the early universe. For example, the measured kinematics of dwarf galaxies strongly constrain dark matter models that were primordially warm, while gamma rays from galaxy clusters strongly constrain dark matter models with matter-antimatter symmetry. I will also discuss small-scale structure formation for an alternative dark matter candidate – primordial black holes (PBHs) – based on a new simulation that fully resolves the inter-PBH dynamics. For example, gravitational interactions involving PBH binaries can eject PBHs at extreme speeds, making a component of "hot dark matter" that suppresses the growth rate of structure up to galaxy scales.