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Revisited Abundance...
Revisited Abundance Diagnostics in Quasars: Fe II/Mg II Ratios
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Verner, E. (författare)
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Bruhweiler, F. (författare)
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Verner, D. (författare)
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- Johansson, Sveneric (författare)
- Lund University,Lunds universitet,Astronomi - Genomgår omorganisation,Institutionen för astronomi och teoretisk fysik - Genomgår omorganisation,Naturvetenskapliga fakulteten,Lund Observatory - Undergoing reorganization,Department of Astronomy and Theoretical Physics - Undergoing reorganization,Faculty of Science
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Gull, T. (författare)
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(creator_code:org_t)
- 2003-06-26
- 2003
- Engelska.
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Ingår i: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 592:2, s. 59-62
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https://portal.resea... (primary) (free)
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http://dx.doi.org/10...
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https://lup.lub.lu.s...
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https://doi.org/10.1...
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Abstract
Ämnesord
Stäng
- Both the Fe II UV emission in the 2000-3000 Å region [Fe II(UV)]and resonance emission line complex of Mg II at 2800 Å areprominent features in quasar spectra. The observed Fe II(UV)/Mg IIemission ratios have been proposed as means to measure the buildup ofthe Fe abundance relative to that of the alpha-elements C, N, O, Ne,and Mg as a function of redshift. The current observed ratios show largescatter and no obvious dependence on redshift. Thus, it remainsunresolved whether a dependence on redshift exists and whether theobserved Fe II(UV)/Mg II ratios represent a real nucleosynthesisdiagnostic. We have used our new 830 level model atom for Fe+in photoionization calculations, reproducing the physical conditions inthe broad-line regions of quasars. This modeling reveals thatinterpretations of high values of Fe II(UV)/Mg II are sensitive not onlyto Fe and Mg abundance, but also to other factors such asmicroturbulence, density, and properties of the radiation field. We findthat the Fe II(UV)/Mg II ratio combined with Fe II(UV)/Fe II(optical)emission ratio, where Fe II(optical) denotes Fe II emission in 4000-6000Å band, can be used as a reliable nucleosynthesis diagnostic forthe Fe/Mg abundance ratios for the physical conditions relevant to thebroad-line regions of quasars. This has extreme importance for quasarobservations with the Hubble Space Telescope and also with the futureJames Webb Space Telescope.
Ämnesord
- NATURVETENSKAP -- Fysik -- Astronomi, astrofysik och kosmologi (hsv//swe)
- NATURAL SCIENCES -- Physical Sciences -- Astronomy, Astrophysics and Cosmology (hsv//eng)
Nyckelord
- Atomic Processes
- Line: Formation
- Methods: Numerical
- Galaxies: Quasars: Emission Lines
Publikations- och innehållstyp
- art (ämneskategori)
- ref (ämneskategori)
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