Enrichment of the High-Redshift IGM by Galactic Winds

This paper discusses a semi-numerical method of investigating the enrichment of the intergalactic medium by galactic winds. We find that most galaxies at z

~ 3 should be driving winds, and that (if these winds are similar to those at low-z) these winds should escape to large distances. Our calculations – which permit exploration of a large region of model parameter space – indicate that the wind velocity, the mass of the wind-driving galaxies, the fraction of ambient material entrained, and the available time (between wind launch and the observed redshift) all affect wind propagation significantly; other physical effects can be important but are sub-dominant. We find that under reasonable assumptions, the enrichment by 3 <~ z <~ 6 galaxies could account for the quantity of metals seen in the Ly-alpha forest, though it is presently unclear whether this enrichment is compatible with the intergalactic medium’s detailed metal distribution or relative quiescence.