摘要：We study the distributions of the baryons in massive halos (Mvir > 1013 h −1 M) in the Magneticum suite of smoothed particle hydrodynamical cosmological simulations, out to the unprecedented radial extent of 10R500,c . We confirm that, under the action of non-gravitational physical phenomena, the baryon mass fraction is lower in the inner regions ( 6R500,c), where the baryon depletion factor Ybar = fbar/(Ωb/Ωm) approaches the value of unity, expected for ‘closed-box’ systems. We find that both the radial and mass dependence of the baryon, gas, and hot depletion factors are predictable and follow a simple functional form. The star mass fraction is higher in less massive systems, decreases systematically with increasing radii, and reaches a constant value of Ystar ≈ 0.09, where the gas metallicity is also constant, regardless of the host halo mass, as a result of the early (z > 2) enrichment process.
关键词：methods: numerical;large-scale structure of Universe;galaxies: clusters: intracluster medium;galaxies: groups: general;hydrodynamics;galaxies: clusters: general
