SIMBAD references

2007AJ....134.1150J - Astron. J., 134, 1150-1161 (2007/September-0)

Gemini near-infrared spectroscopy of luminous z ∼ 6 quasars: chemical abundances, black hole masses, and mg II absorption.

JIANG L., FAN X., VESTERGAARD M., KURK J.D., WALTER F., KELLY B.C. and STRAUSS M.A.

Abstract (from CDS):

We present Gemini near-infrared spectroscopic observations of six luminous quasars at z=5.8 to ∼6.3. Five of them were observed using Gemini South GNIRS, which provides a simultaneous wavelength coverage of 0.9-2.5 µm in cross-dispersion mode. The other source was observed in the K band with Gemini North NIRI. We calculate line strengths for all detected emission lines and use their ratios to estimate gas metallicity in the broad-line regions of the quasars. The metallicity is found to be supersolar, with a typical value of ∼4 Z, and a comparison with low-redshift observations shows no strong evolution in metallicity up to z∼6. The Fe II/Mg II ratio of the quasars is 4.9±1.4, consistent with low-redshift measurements. We estimate central black hole masses of 109-1010 M and Eddington luminosity ratios of order unity. We identify two Mg II λλ2796, 2803 absorbers with rest equivalent width Wλ27960>1 Å at 2.2<z<3 and three Mg II absorbers with Wλ27960>1.5 Å at z>3 in the spectra, with the two most distant absorbers at z=4.8668 and 4.8823, respectively. The redshift number densities (dN/dz) of Mg II absorbers with Wλ27960>1.5 Å are consistent with no cosmic evolution up to z>4.

Abstract Copyright:

Journal keyword(s): Galaxies: Active - Galaxies: High-Redshift - Galaxies: Quasars: Absorption Lines - Galaxies: Quasars: Emission Lines - Galaxies: Quasars: General

Simbad objects: 7

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2023.01.31-00:55:56

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