Metal abundances and kinematics of quasar absorbers. I. Absorption systems toward J2233-606

Abstract

The metal line profiles of different ions observed in high H I column density systems [N(H I) > 10¹⁶ cm^-2] in quasar spectra can be used to constrain the ionization structure and kinematic characteristics of the absorbers. For these purposes, a modified Monte Carlo Inversion (MCI) procedure was applied to the study of three absorption systems in the spectrum of the HDF-South quasar J2233-606 obtained with the UVES spectrograph at the VLT/Kueyen telescope. The MCI does not confirm variations of metal abundances within separate systems which were discussed in the literature. Instead, we found that an assumption of a homogeneous metal content and a unique photoionizing background is sufficient to describe the observed complex metal profiles. It was also found that the linear size L and the line-of-sight velocity dispersion sigma_v measured within the absorbers obey a scaling relation, namely, sigma_v increases with increasing L, and that metal abundance is inversely proportional to the linear size of the system: the highest metallicity was measured in the system with the smallest L. Based on public data released from UVES Commissioning at the VLT Kueyen telescope (ESO, Paranal, Chile), the New Technology Telescope (ESO, La Silla, Chile) and the NASA/ESA Hubble Space Telescope obtained at the Space Telescope Science Institute, which is operated by the Association of Universities of Research in Astronomy, Inc. under NASA contract NAS 5-26555.