The origin of intergalactic metals around lyman break galaxies

Theoretical and observational arguments suggest that the intergalactic medium (IGM) might have been polluted with metals produced by early star formation. In this scenario, Lyman break galaxies (LBGs) at redshift z = 3 are likely to be surrounded by old metal bubbles, relics of an era when the characteristic mass of galaxies was small and gas retainment more difficult. We find that pregalactic enrichment of the IGM from 108-1010 M⊙ dwarf galaxies at 6 < z < 12 can quantitatively explain the high cross-correlation between C IV systems and LBGs observed at z = 3. The reason is twofold. First, both LBGs and high-z dwarfs are biased tracers of the mass distribution and form from exceptionally high density fluctuations that are strongly clustered. Second, the action of gravity tends to increase the spatial association between metal bubbles and LBGs. Our analysis shows that, in order to match the abundance of C IV systems observed at z = 3, the metal bubbles generated by high-z dwarfs must have comoving sizes of ∼100 kpc. We conclude that the observed galaxy-C IV spatial association does not need to be generated by late "superwinds" from LBGs.