2015/06/11 by Sinziana Paduroiu, Paduroiu, Sinziana, Yves Revaz +4 · 1 citation
Physics and Astronomy · #Cosmology and Gravitation Theories #Cosmology and Nongalactic Astrophysics (astro-ph.CO) #Dark Matter and Cosmic Phenomena #FOS: Physical sciences #Galaxies: Formation, Evolution, Phenomena #astro-ph.CO
paper · pdf · doi:10.48550/arxiv.1506.03789
16 pages, 11 figures, submitted to MNRAS, figures and typos corrected
openalex publication_date 2015/06/11 · arxiv created 2015/06/23 · arxiv updated 2015/06/24 · openalex created_date 2022/10/04 · openalex updated_date 2026/07/28
The damping on the fluctuation spectrum and the presence of thermal velocities as properties of warm dark matter particles like sterile neutrinos imprint a distinct signature found from the structure formation mechanisms to the internal structures of halos. Using warm dark matter simulations we explore these effects on the structure formation for different particle energies and we find that the formation of structure is more complex than originally assumed, a combination of top-down collapse and hierarchical (bottom-up) clustering on multiple scales. The degree on which one scenario is more prominent with respect to the other depends globally on the energy of the particle and locally on the morphology and architecture of the analyzed region. The presence of shells and caustics in warm dark matter halos is another important effect seen in simulations. Furthermore, we discuss the impact of thermal velocities on the structure formation from theoretical considerations as well as from the analysis of the simulations. We re-examine the assumptions considered when estimating the velocity dispersion for warm dark matter particles that have been adopted in previous works for more than a decade and we give an independent estimation for the velocities. We identify some inconsistencies in previous published results. The relation between the warm dark matter particle mass and its corresponding velocity dispersion is strongly model dependent, hence the constraints on particle mass from simulation results are weak. Finally, we review the technical difficulties that arise in warm dark matter simulations along with possible improvements of the methods.