Gemini Near-infrared Spectroscopy of Luminous z~6 Quasars: Chemical Abundances, Black Hole Masses, and MgII Absorption
Jul, 2007Citations per year
Abstract: (arXiv)
We present Gemini near-infrared spectroscopic observations of six luminous quasars at z=5.86.3. Five of them were observed using Gemini-South/GNIRS, which provides a simultaneous wavelength coverage of 0.9--2.5 m in cross dispersion mode. The other source was observed in 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_{\sun}, and a comparison with low-redshift observations shows no strong evolution in metallicity up to z6. The FeII/MgII ratio of the quasars is 4.9+/-1.4, consistent with low-redshift measurements. We estimate central BH masses of 10^9 to 10^{10} M_{\sun} and Eddington luminosity ratios of order unity. We identify two MgII 2796,2803 absorbers with rest equivalent width W_0^{\lambda2796}>1 \AA at 2.2Note:
- 33 pages (including 7 figures and 6 tables), AJ in press
- galaxies: active
- galaxies: high-redshift
- quasars: absorption lines
- quasars: emission lines
- quasars: general
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