The origin of the quasi-stellar object absorption lines

In recent years, several results concerning the QSO absorption-line systems indicate the possibility that they may be associated with star-forming regions in intervening galaxies. In this paper, the hypothesis that the metal absorption lines are produced in H II regions of intervening galaxies is explored. The method of analysis is mainly based on the C IV and Si IV absorption lines. A comparison between observed and calculated equivalent widths fix the characteristics of the absorbing H II region. The calculated equivalent widths are obtained from column densities given by photoionization models. The column densities are calculated for different lines of sight crossing the H II region at different distances from the star. The analysis of 20 absorption line systems shows that H II regions in intervening galaxies can be the origin of the metal-line absorption systems. 37 refs.