论文标题
$ z \ sim $ 3的窄线区域的多线评估$ 3射电星系
Multi-line assessment of narrow-line regions in $z \sim$ 3 radio galaxies
论文作者
论文摘要
在本文中，我们利用三个宽宽星系的高质量休息光谱在$ z \ sim $ 3中使用VLT/fors2观察到，以测量几条发射线的通量，包括相对较弱的线条，例如NIV] $λ$ 1486，OIIII III $λ$ 1663，以及[niiv] $λ$ 24242424 $ 2424。此外，我们从文献中收集了12 $ z \ sim $ 3宽射射线星系中微弱的静ul排放线的通量。以前，高$ z $活跃银河系核（AGN）的窄线区域（NLR）的物理和化学性质已大多仅通过仅使用强烈的REST-UV发射线（例如，NV $λ$ 1240，CIV $λ$λ$ 1549，HEII $ 1549，HEII $ 1640 $ 1640，以及CIII $ 1909）。由于可用的发射线约束数量的限制，这种强线诊断基于各种假设。在这项工作中，通过将详细的光电离模型拟合到测量的发射线通量来估计每个对象中NLR云的物理和化学特性。我们确认，$ z \ sim $ 3中NLR在AGN中的金属性是太阳或超极，而无需假设气体密度和电离参数，这要归功于微弱的发射线的约束。该结果表明，高$ z $射电星系已经以$ z \ sim $ 3的化学成熟。
In this paper, we utilize high-quality rest-UV spectra of three radio galaxies at $z \sim$ 3 observed with VLT/FORS2 to measure the flux of several emission lines including relatively faint ones, such as NIV]$λ$1486, OIII]$λ$1663, and [NeIV]$λ$2424. Additionally, we collect fluxes of faint rest-UV emission lines in 12 $z \sim$ 3 radio galaxies from the literature. Previously, physical and chemical properties of narrow-line regions (NLRs) in high-$z$ active galactic nuclei (AGNs) have been investigated mostly by using only strong rest-UV emission-lines (e.g., NV$λ$1240, CIV$λ$1549, HeII$λ$1640, and CIII]$λ$1909). Such strong-line diagnostics are based on various assumptions due to the limitation in the number of available emission-line constraints. In this work, both physical and chemical properties of NLR clouds in each object are estimated by fitting detailed photoionization models to the measured emission-line fluxes. We confirm that the metallicity of NLRs in AGNs at $z \sim$ 3 is solar or super-solar, without assuming the gas density and ionization parameter thanks to the constrains from the faint emission lines. This result suggests that high-$z$ radio galaxies are already chemically matured at $z \sim$ 3.
