The Shape of Dark Matter Halos as a Strong Cosmological Probe

Abstract

Halo Dark Matter (DM) formation is a complex process, intertwining both gravitational and cosmological nonlinear phenomena. One of the manifestations of this complexity is the shape of the resulting present-day DM halos: simulations and observations show that they are triaxial objects. Interestingly, those shapes carry cosmological information. We prove that cosmology, and particularly the dark energy model, leaves a lasting trace on the present-day halos and their properties: the overall shape of the DM halo exhibits a different behavior when the DE model is varied. We explain how that can be used to literally “read” the fully nonlinear power spectrum within the halos’ shape at z=0. To that end, we worked with “Dark Energy Universe Simulations” DM halos: DM halos are grewed in three different dark energy models, whose parameters were chosen in agreement with both CMB and SN Ia data.

Keywords

• clusters
• power spectrum
• gravitation
• cosmology