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arXiv · 1106.5501

Evidence for non-evolving FeII/MgII ratios in rapidly accreting z~6 QSOs

Gisella De Rosa·Roberto Decarli·Fabian Walter·Xiaohui Fan·Linhua Jiang·Jaron Kurk·Anna Pasquali·Hans-Walter Rix
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Abstract

[abridged] Quasars (QSOs) at the highest known redshift (z~6) are unique probes of the early growth of supermassive black holes (BHs). Until now, only the most luminous QSOs have been studied, often one object at a time. Here we present the most extensive consistent analysis to date of z>4 QSOs with observed NIR spectra, combining three new z~6 objects from our ongoing VLT-ISAAC program with nineteen 4 =-0.37 (Lbol/LEdd~0.43) with a scatter of 0.20 dex for the z>4 sample and the =-0.80 (Lbol/LEdd~0.16) with a scatter of 0.24 dex for the 0.35 4 sources are accreting significantly faster than the lower-redshift ones. We show that the derived FeII/MgII ratios depend sensitively on the performed analysis: our self-consistent, homogeneous analysis significantly reduces the FeII/MgII scatter found in previous studies. The measured FeII/MgII line ratios show no sign of evolution with cosmic time in the redshift range 4<z<6.5 [...]

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Gisella De Rosa, Roberto Decarli, Fabian Walter, Xiaohui Fan, Linhua Jiang, Jaron Kurk, Anna Pasquali, Hans-Walter Rix. 2011-06-27. Evidence for non-evolving FeII/MgII ratios in rapidly accreting z~6 QSOs. https://doi.org/10.1088/0004-637x/739/2/56

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