Speaker
Description
The Ultra-Light Axion (ULA) is a dark matter candidate with mass 10^{-22} eV and
de-Broglie wavelength of order kpc. Such an axion, also called the Fuzzy Dark Matter (FDM), thermalizes via the gravitational force and forms a Bose-Einstein condensate. The quantum pressure from FDM can significantly affect the structure formation in small scales, thus alleviating the so-called "small-scale crisis." We develop a new technique to discretize the quantum pressure and use N-body simulations to show the formation of the dark matter halo and its inner structure. We find a constant density solitonic core, which potentially solves the problems of small-scale crisis.
We also investigate the effects of quantum pressure (QP) in cosmological simulations and find that QP leads to further suppression of the matter power spectrum at small scales. We then estimate the flux power spectrum of Lyman-alpha forest, and compare it to the data from BOSS and XQ-100 to set the lower bound on the FDM particle mass to 10^{−23} eV.
