SIMBAD references

We present UVES observations of the log N(HI)=21.7 damped Lyman-α system at z_abs=2.03954 towards the quasar PKS 0458-020. HI Lyman-α emission is detected in the center of the damped Lyman-α absorption trough. Metallicities are derived for Mg II, SIII, P II, Cr II, Mn II, Fe II and Zn II and are found to be -1.21±0.12, -1.28±0.20, -1.54±0.11, -1.66±0.10, -2.05±0.11, -1.87±0.11, -1.22±0.10, respectively, relative to solar. The depletion factor is therefore of the order of [Zn/Fe]=0.65. We observe metal absorption lines to be blueshifted compared to the Lyman-α emission up to a maximum of ∼100 and 200km/s for low and high-ionization species respectively. This can be interpreted either as the consequence of rotation in a large (∼7kpc) disk or as the imprint of a galactic wind. The star formation rate (SFR) derived from the Lyman-α emission, 1.6M_☉/yr, is compared with that estimated from the observed C II^* absorption. No molecular hydrogen is detected in our data, yielding a molecular fraction logf←6.52. This absence of H₂ can be explained as the consequence of a high ambient UV flux which is one order of magnitude larger than the radiation field in the ISM of our Galaxy and originates in the observed emitting region.