The metallicity distribution of H I systems in the EAGLE cosmological simulations

The metallicity of strong HI systems, spanning from damped Lyman-alpha absorbers (DLAs) to Lyman-limit systems (LLSs) is explored between z = 5->0 using the EAGLE high-resolution cosmological hydrodynamic simulation of galaxy formation. The metallicities of LLSs and DLAs steadily increase with time in agreement with observations. DLAs are more metal rich than LLSs, although the metallicities in the LLS column density range (NHI = 10^17 -10^20 cm^-2) are relatively flat, evolving from a median HI-weighted metallicity of Z 3 that are not observed, which may indicate more widespread early enrichment in the real Universe compared to EAGLE.