1997A&A...317..416L

We present a high spectral resolution optical spectrum (FWHM=17km/s) of the bright quasar Q 1037-2704. The large number of absorption systems suggests the presence of an intervening supercluster, but the issue remains controversial. We demonstrate that the strong C IV system at z_abs∼2.08 spanning more than 1500km/s is made up of narrow components with typical Doppler parameter b∼8km/s. The gas is probably photo-ionized in which case the photo-ionizing spectrum should be dominated by stellar radiation. Analysis of H I, Si IV, N V and C IV absorptions shows that the gas has a fairly large metal content, Z>0.1Z_☉. We detect C II^*λ1335 absorption in subcomponents of the z_abs∼2.133 system, which have moderate total C II column densities implying an electronic density of n_e∼3cm^–3. In addition, the weakness of the O Iλ1302, Si IIλ1304 and Fe IIλ1608 lines allows a detailed analysis of the line profiles. The results are that the system has four narrow (b∼10km/s) components; the oxygen abundance is of the order of 0.03 solar; the iron abundance is surprisingly large [Fe/O]~[Fe/O]_☉+0.3. If photo-ionized by the UV flux from the quasar, the distance between the absorber and the quasar should be larger than 0.3h^–1Mpc (with h in units of H₀=100km/s/Mpc and q₀=0.5). This demontrates that the gas is not associated with the quasar and, together with the detection of eight multiple metal systems between z_abs=1.91 and 2.13, suggests the presence of a coherent structure extended over 80h^–1Mpc along the line of sight.