2003/04/01 by S. A. Levshakov, I. I. Agafonova, D. Reimers +2 · 1 citation
Chemistry · Physics and Astronomy · #Absorption spectroscopy #Astrophysics #Astrophysics and Star Formation Studies #Atomic physics #Chemistry #Galaxies: Formation, Evolution, Phenomena #Galaxy #Halo #Ion #Ionization #Metallicity #Milky Way #Optics #Photoionization #Physics #Quasar #Stars #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1051/0004-6361:20030493
published as Astron.Astrophys. 404 (2003) 449-464 · 16 pages, including 11 PostScript figures. Accepted for publication in A&A
arxiv created 2003/04/01 · openalex publication_date 2003/06/01 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
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.