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We investigate the large-scale influence of outflows from AGNs in enrichingthe IGM with metals in a cosmological context. We combine cosmologicalsimulations of large scale structure formation with a detailed model of metalenrichment, in which outflows expand anisotropically along the direction ofleast resistance, distributing metals into the IGM. The metals carried by theoutflows are generated by two separate stellar populations: stars located nearthe central AGN, and stars located in the greater galaxy. Using this algorithm,we performed a series of 5 simulations of the propagation of AGN-drivenoutflows in a cosmological volume of size (128/h Mpc)^3 in a Lambda-CDMuniverse, and analyze the resulting metal enrichment of the IGM. We found thatthe metallicity induced in the IGM is greatly dominated by AGNs havingbolometric luminosity L > 10^9 L_sun, sources with 10^8 < L / L_sun < 10^9having a negligible contribution. Our simulations produced an average IGMmetallicity of [O/H] = -5 at z = 5.5, which then rises gradually, and remainsrelatively flat at a value [O/H] = -2.8 between z = 2 and z = 0. The ejectionof metals from AGN host galaxies by AGN-driven outflows is found to enrich theIGM to > 10 - 20% of the observed values, the number dependent on redshift. Theenriched IGM volume fractions are small at z > 3, then rise rapidly to thefollowing values at z = 0: 6 - 10% of the volume enriched to [O/H] > -2.5, 14 -24% volume to [O/H] > -3, and 34 - 45% volume to [O/H] > -4. At z > 2, there isa gradient of the induced enrichment, the metallicity decreasing withincreasing IGM density, enriching the underdense IGM to higher metallicities, atrend more prominent with increasing anisotropy of the outflows. This canexplain observations of metal-enriched low-density IGM at z = 3 - 4.

Anisotropic AGN Outflows and Enrichment of the Intergalactic Medium. II. Metallicity