Dark matter halos 467Figure 15.21.Analytical fits to the density profile of halo A 1 (see table 15.4) from our
set of simulations. The fits are of the formρ(r)∝(r/r 0 )−γ[ 1 +(r/r 0 )α]−(β−α)/γ.The
legend in each panel indicates the corresponding values ofα,βandγof the fit; the digit
in parentheses indicates whether the parameter was kept fixed (0) or not (1) during the fit.
Note that various sets of parameters,α,β,γ, provide equally good fits to the simulated
halo profile in the whole resolved range of scales≈(0.005–1)rvir. This indicates a large
degree of degeneracy in the parametersα,βandγ.
circles. The legend in each panel indicates the corresponding values ofα,βand
γof the fit; the digit in parentheses indicates whether the parameter was kept
fixed (0) or not (1) during the fit. The two right-hand panels show the fits of the
NFW and Mooreet alprofiles; the bottom left-hand panel shows fit of the profiles
used by Jing and Suto (2000). The top left-hand panel shows a fit in which the
inner slope was fixed butαandβwere fitted. The figure shows that all four
analytic profiles can provide a nice fit to the numerical profile in the whole range
(0.005–1)rvir.