The absorbing haloes around high-redshift radio galaxies: the UVES view

We summarise the properties of the absorbing haloes around two high-redshift radio galaxies studied with the VLT-UVES echelle spectrograph. The absorbers in 0943−242 (<F>z=2.92</F>) exhibit little further structure compared with previous data—the main absorber still has <F>N(HI)≃1019</F> cm−2—reinforcing the picture in which the absorbing gas occupies a smooth shell beyond the emission line halo. In 0200+015 (<F>z=2.23</F>) the main absorber now splits into two spatially-resolved systems with <F>N(HI)≃4×1014</F> cm−2, one of which has strong CIV absorption, implying a metallicity of <F>Z≃10</F> Z◎. We explain the differences between the two sources with an evolutionary scenario, invoking interaction with the expanding radio source and metal enrichment via a starburst superwind. [Copyright &y& Elsevier]