Speaker
Description
In the fuzzy dark matter model, dark matter consists of “axion-like” ultra-light scalar particles with a mass of around $10^{-22}$ eV. This candidate behaves similarly to cold dark matter on large scales, but exhibits different properties on smaller (galactic) scales due to macroscopic wave effects arising from the extremely light particles’ large de Broglie wavelengths. It has both particle physics motivations and a rich astrophysical phenomenology, giving rise to notable differences in the structures on highly non-linear scales due to the manifestation of wave effects, which can impact a number of contentious small-scale tensions in the standard cosmological model, $\Lambda$CDM. Some of the unique features include transient wave interference patterns and granules, the presence of flat-density cores (solitons) at the centers of dark matter halos, and the formation of quantized vortices. I will present large numerical simulations of cosmic structure formation with this dark matter model – including the full non-linear wave dynamics –, discussing observables such as the evolution of the matter power spectrum, the fuzzy dark matter halo mass function, dark matter halo density profiles, and the question of a fuzzy dark matter core–halo mass relation, using results obtained from these simulations, and contrast them with corresponding results for the cold dark matter model. Particularly striking is the difference in the structure of cosmic filaments, which, with fuzzy dark matter, rather than halos, could be the sites of first star formation.
