Simulating cosmic metal enrichment by the first galaxies

We study cosmic metal enrichment via AMR hydrodynamical simulations in a (10 Mpc h−1)3 volume following the Pop III – Pop II transition and for different Pop III IMFs. We have analyzed the joint evolution of metal enrichment on galactic and in-tergalactic scales at z = 6 and z = 4. Galaxies account for ∼ 9 % of the baryonic mass; the remaining gas resides in the diffuse phases: (a) voids, i.e. regions with extremely low density ( ∆ 6 1), (b) the true intergalactic medium (IGM, 1 ∆ 6 10) and (c) the circumgalactic medium (CGM, 10 ∆ 6 102.5), the interface between the IGM and galaxies. By z = 6 a galactic mass-metallicity relation is established. At z = 4, galaxies with a stellar mass M? 108.5M show log(O/H) + 12 = 8.19, consistent with observations. The total amount of heavy elements rises from ΩSFHZ = 1.52×10−6 at z = 6 to 8.05 × 10−6 at z = 4. Metals in galaxies make up to 0.89 of such budget at z = 6; this fraction increases to 0.95 at z = 4. At z = 6 (z = 4) the remaining metals are distributed in CGM/IGM/voids with the following mass frac-tions: 0.06/0.04/0.01 (0.03/0.02/0.01). Analogously to galaxies, at z = 4 a density-