A natural boundary of dark matter haloes revealed around the minimum bias and maximum infall locations

Understand

We explore the boundary of dark matter haloes through their bias and velocity profiles.

• Using cosmological $N$-body simulations, we show that the bias profile exhibits a ubiquitous trough that can be interpreted as created by halo accretion that depletes material around the boundary.
• The inner edge of the active depletion region is marked by the location of the maximum mass inflow rate that separates a growing halo from the draining environment.
• This inner depletion radius can also be interpreted as the radius enclosing a highly complete population of splashback orbits, and matches the optimal exclusion radius in a halo model of the large-scale structure.