Ultraviolet Fe ii emission in z∼ 2 quasars |
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| Authors: | H Sameshima J Maza Y Matsuoka S Oyabu K Kawara Y Yoshii N Asami N Ienaka Y Tsuzuki |
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| Institution: | Institute of Astronomy, University of Tokyo, 2-21-1, Osawa, Mitaka, Tokyo 181-0015, Japan;Departamento de Astronomia, Universidad de Chile, Casilla 36-D, Santiago, Chile;Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Kanagawa 229-8510, Japan;System Integration Service Department, Redfox Inc., 3-3-11, Kita-Aoyama, Minato-ku, Tokyo 107-0061, Japan |
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| Abstract: | We present spectra of six luminous quasars at z ～ 2 , covering rest wavelengths 1600?3200 Å. The fluxes of the UV Fe ii emission lines and Mg ii λ2798 doublet, the line widths of Mg ii and the 3000 Å luminosity were obtained from the spectra. These quantities were compared with those of low-redshift quasars at z = 0.06–0.55 studied by Tsuzuki et al. In a plot of the Fe ii (UV)/Mg ii flux ratio as a function of the central black hole mass, Fe ii (UV)/Mg ii in our z ～ 2 quasars is systematically greater than in the low-redshift quasars. We confirmed that luminosity is not responsible for this excess. It is unclear whether this excess is caused by rich Fe abundance at z ～ 2 over low-redshift or by non-abundance effects such as high gas density, strong radiation field and high microturbulent velocity. |
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| Keywords: | galaxies: abundances galaxies: active line: formation quasars: emission lines |
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