THE E-ELT DESIGN REFERENCE MISSION - SCIENCE CASE C7
Is the low density IGM at z ~ 2-3 metal-enriched?
At the epoch of peak activity of galaxy and quasar formation (redshift z ~ 2-3), over 90% of the baryons are in the IGM, but only ~40% of the metals produced by star formation in detected high-redshift galaxies have been measured. The missing metals could reside in regions with temperatures T > 2 × 104 K and HI column densities N(HI) < 1014 cm-2, as suggested by hydrodynamic simulations with galactic superwinds. In these models, underdense regions of the IGM could be metal-enriched with mean abundances up to 10-2 solar. Our goal is to determine the metallicity level of the low density IGM. This requires detecting CIV column densities at least 10 times smaller than currently achieved, thus selecting as background targets the very brightest quasars and possibly GRBs. This will constrain the occurence and strength of galactic superwinds at z ~ 2-3 and help solving the problem of missing metals.
Project Science Team
Phase B (2006 – 2011)