The Spatial Distribution of Metals in the Intergalactic Medium

We investigate the impact of environment on the metallicity of the diffuseintergalactic medium. We use pixel correlation techniques to search for weakCIV and OVI absorption in the spectrum of quasar Q1422+231 in regions of thespectrum close to and far from galaxies at z ~ 3. This is achieved both byusing the positions of observed Lyman break galaxies and by using strong CIVabsorption as a proxy for the presence of galaxies near the line of sight. Wefind that the metal line absorption is a strong function of not only the HIoptical depth (and thus gas density) but also proximity to highly enrichedregions (and so proximity to galaxies). The parameter ``proximity to galaxies''can account for some, but not all, of the scatter in the strength of CIVabsorption for fixed HI. Finally, we find that even if we limit our analysis tothe two thirds of the pixels that are at least 600 km/s from any CIV line thatis strong enough to detect unambiguously (tau_CIV > 0.1), our statisticalanalysis reveals only slightly less CIV for fixed HI than when we analyze thewhole spectrum. We conclude that while the metallicity is enhanced in regionsclose to (Lyman-break) galaxies, the enrichment is likely to be much morewidespread than their immediate surroundings.Comment: 16 pages, 7 figures. Accepted for publication in the Astrophysical Journal. Revised version taking referee's comments into account, minor change