436 Numerical simulations in cosmology
Figure 15.6.Density profiles of four largest halos in simulations of Knebeet al(1999).
Note that the AP^3 M 3 run has formally the best force resolution, but its actual resolution
was much lower because of an insufficient number of steps.
number of steps (6000), not much smaller than the AP^3 M 5 (8000). But for its
force resolution, it should have many more steps. The lack of the number of steps
was devastating.
Figure 15.6 presents the density profiles of four of the most massive halos
in our simulations. We have not shown the profile of the most massive halo
because it appears to have undergone a recent major merger and is not very
relaxed. In this figure, we present only profiles of halos in the high-resolution
runs. Not surprisingly, the inner density of the PM halos is much smaller than
in the high-resolution runs and their profiles deviate strongly from the profiles of
high-resolution halos at the scales shown in figure 15.6. A glance at figure 15.6
shows that all profiles agree well atr& 30 h−^1 kpc. This scale is about eight times
smaller than the mean inter-particle separation. Thus, despite the very different