Heavy-element enrichment in low-density regions of the intergalactic medium

Low-density intergalactic gas at high redshift is predicted to be poor in heavy elements in models for the composition of the diffuse intergalactic medium. A method to analyze carbon and oxygen absorption lines in quasar spectra is presented, enabling the probing of heavy-element abundances at a redshift of three within low density areas of intergalactic gas. The unexpected enrichment of low density gas in heavy elements in the experiment, indicates that early small galaxies could be more efficient at ejecting heavy elements that was previously thought.