Universality of dark matter haloes shape over six decades in mass: Insights from the Millennium XXL and SBARBINE simulations

Understand

For the last 30 years many observational and theoretical evidences have shown that galaxy clusters are not spherical objects, and that their shape is much better described by a triaxial geometry.

• With the advent of multi-wavelength data of increasing quality, triaxial investigations of galaxy clusters is gathering a growing interest from the community, especially in the time of "precision cosmology".
• In this work, we aim to provide the first statistically significant predictions in the unexplored mass range above 3x10^14 Mo/h, using haloes from two redshifts (z=0 and z=1) of the Millennium XXL simulation.
• The size of this cosmological dark matter only simulation (4.1 Gpc) allows the formation of a statistically significant number of massive cluster scale haloes (about 500 with M>2x10^15 Mo/h and 780000 with M>10^14 Mo/h).