Clues to the origin of metals in the Ly-alpha forest

Abstract

We analyze the z=2 Ly-alpha and CIV forest along two adjacent lines-of-sight at high S/N and spectral resolution to assess the question of the origin of metals in the intergalactic medium. We find that the gas containing detectable amounts of metals (as seen in absorption by CIV) is less quiescent on scales of a few kpc than the gas without metals. Although it is difficult to discriminate unequivocally between possible sources of enrichment and the extent to which each contributes to line-of-sight differences, those suggest that the metal-enriched systems are bound to galaxies (i.e., they do not arise in the IGM nor in galactic winds).