2006ApJ...638...45P

We investigate the impact of environment on the metallicity of the diffuse intergalactic medium. We use pixel correlation techniques to search for weak C IV and O VI absorption in the spectrum of quasar Q1422+231 in regions of the spectrum close to and far from galaxies at z∼3. This is achieved both by using the positions of observed Lyman-break galaxies and by using strong C IV absorption as a proxy for the presence of galaxies near the line of sight. We find that the metal line absorption is a strong function of not only the H I optical depth, and thus gas density, but also proximity to highly enriched regions, and so proximity to galaxies. The parameter ``proximity to galaxies'' can account for some, but not all, of the scatter in the strength of C IV absorption for fixed H I. Finally, we find that even if we limit our analysis to the two-thirds of the pixels that are at least 600 km/s from any C IV line that is strong enough to detect unambiguously (τ_CIV_>0.1), our statistical analysis reveals only slightly less C IV for fixed H I than when we analyze the whole spectrum. We conclude that while the metallicity is enhanced in regions close to (Lyman-break) galaxies, the enrichment is likely to be much more widespread than their immediate surroundings.