Seminarium "High Energy, Cosmology and Astro-particle Physics (HECA)"

Note an unusual date and place (room 2.25)! Dark matter is one of the major components in our universe and plays an important role in structure formation. In the standard cosmology, the nature of the dark matter is generally thought that it is cold, and interacts with other matter only through gravity. The so-called Λ Cold Dark Matter (ΛCDM) model can successfully explain a broad range of observations at large length scales. However, there are several discrepancies at small scales, known as small-scale problems. To alleviate these problems, alternative dark matter models such as fuzzy dark matter (FDM) are considered. FDM is a scalar particle coupled to a gravitational field without self-interaction whose mass is around 10^{-22} eV. Due to the small mass of the FDM, the de Broglie wavelength becomes large and wave nature can be seen on a cosmological scale. The wave nature can be seen inside halos, where two unique features can be observed, soliton core and granular structures. In this talk, I first review the standard ΛCDM cosmology and the small-scale problems and introduce the FDM model. Then I show the structures in FDM halos in detail with our studies.