Photoionized absorbers toward the bright QSO HE 0515–4414^*

¹ Department of Theoretical Astrophysics, Ioffe Physico-Technical Institute, 194021 St. Petersburg, Russia
² Hamburger Sternwarte, Universität Hamburg, Gojenbergsweg 112, 21029 Hamburg, Germany

Corresponding author: S. A. Levshakov, lev@astro.ioffe.rssi.ru

Received: 20 December 2002
Accepted: 31 March 2003

Abstract

We report on detailed Monte Carlo inversion analysis of five systems from the spectrum of the bright quasar HE 0515–4414 (= 1.71). The associated system at = 1.697 with the neutral hydrogen column density N()  cm^-2  shows pronounced absorption from highly ionized transitions of , , , , , and probably . We found that only a power law type ionizing spectrum () is consistent with the observed sample of the line profiles, i.e. the system is definitely intrinsic. The relative metal abundances give almost the solar pattern and the metallicity of ~5 times solar. The system originates in a thin shell of the line-of-sight thickness pc. Two systems at = 1.674 ([C/H] ) and 1.602 ([O/H] ), arising in intervening halos, have linear sizes of 3–14 kpc and 17 kpc, respectively. Absorption systems at = 1.385 ([C/H] , 1.7–2.5 kpc) and = 1.667 ([C/H] ,  kpc) exhibit characteristics very similar to that observed in metal-enriched high velocity clouds in the Milky Way. These systems are probably embedded in extremely metal-poor halos with [C/H] (= 1.667) and [C/H] (= 1.385). We also found two additional extremely metal-poor Lyα systems at = 1.500 and 1.681 with, respectively, N() and  cm^-2  and [C/H] and , – an indication that the distribution of metals in the metagalactic medium is utterly patchy. Our results show that the ionization states in the analyzed absorbers, ranging from to 1.7, can be maintained by photoionization only and that the fraction of the shock-heated hot gas with temperature  K is negligible in these systems.