| High redshift quasars (z>6) have been used as versatile probes of the physical conditions in the gas around the quasars and along their lines of sight. Metal absorption lines reveal chemical enrichment by some of the first generations of stars. Of particular interest is the oxygen absorption line (OI 1302) because its ionization potential is the same as that of hydrogen. A forest of OI lines is expected to appear towards the epoch of reionisation, and can be used to probe to topology of reionization and metal enrichment in the early Universe. In this talk, I will present NIRSpec absorption line spectra extending to the highest redshifts to date. Since the same stars that produce metals also contribute to reionization, we can investigate the correlation between both high- and low-ionization metal absorbers and transmission peaks that appear in the Gunn-Peterson troughs of the quasars. Finally, the metal abundance patterns in the presumably low-metallicity high-redshift environments probed by the quasars reveal enrichment from the first generation of stars. |
