Search for: All records

Abstract Galaxy clusters are powerful laboratories for studying both cosmic structure formation and galaxy evolution. We present a comprehensive analysis of the velocity anisotropy profile,β(r), in galaxy clusters using the Uchuu-UniverseMachine mock galaxy catalog, which combines the large-volume UchuuN-body simulation with the UniverseMachine galaxy formation model. Focusing on clusters with $\log M_{200}\ge 13.9\left[h^{-1}{M}_{\odot }\right]$up to redshiftz= 1.5, we investigate the behavior ofβ(r) as a function of clustercentric radius, mass, and redshift. We find thatβ(r) exhibits a universal shape: it rises from isotropic values near the cluster core, peaks at ∼1.7R₂₀₀, declines around 3.4R₂₀₀due to orbital mixing, and increases again in the outskirts, due to the dominance of first-infalling galaxies. Our results show that more massive clusters have higher radial anisotropy and larger peakβvalues. Moreover,β(r) evolves with redshift, with high-redshift clusters displaying more radially dominated orbits and enhanced infall motions. We further derive redshift-dependent power-law scaling relations betweenM₂₀₀and key physical radii—hydrostatic (R_hs), infall ( $R_{\inf }$), and turnaround (R_ta). These findings offer a robust theoretical framework for interpreting the dynamical properties of observed galaxy clusters and provide key insights into the evolution of their dynamical state over cosmic time.