PHYSICAL AND DYNAMICAL PROPERTIES OF BLRs AS REVEALED THROUGH FE II EMISSION SPECTRA

AST-0607465 Verner铁（Fe）相对于α元素（如氧和镁）的富集是测量类恒星天体（QSO）年龄和探测星系形成时期核合成的一种方法。 这是因为类星体在紫外线中表现出突出的Fe II特征和Mg II共振双重态发射。 然而，必须确定铁II排放量如何随物理条件变化，然后才能将其用作丰度指标。 目前的研究人员已经开发出目前最复杂的铁原子模型，部分得到了NSF奖AST-0206150的支持。 由于该模型对类星体中的强辐射场敏感，因此它考虑了非丰度因素的强烈影响，如微湍流、电离通量和氢密度，这些因素在推导精确的丰度之前必须加以考虑。 将这些Fe II模型结果与多带通发射光谱测量相结合，该项目将评估模型的预测能力，并研究邻近类星体宽线区域的物理条件，特别是微湍流。 该项目还将考虑对推断的类星体紫外光谱能量分布的影响，以及对Fe/Mg比率测量的影响，该研究是国际性的多学科研究，结合了来自美国（建模）、欧洲（光谱学）和澳大利亚（观测）的主要理论、观测和实验小组。 由于Fe II在许多电离等离子体中很重要，该项目将对广泛的天体物理学研究产生影响。 牵头机构的外联工作覆盖了各种各样的人口，其中有大量代表性不足的群体。

AST-0607465VernerThe enrichment of iron (Fe) relative to the alpha-elements such as oxygen and magnesium (Mg) is a way to measure the ages of quasi-stellar objects (QSOs) and to probe nucleosynthesis in the galaxy formation epoch. This works because QSOs exhibit prominent Fe II features and Mg II resonance doublet emission in the ultraviolet. However, one must determine how Fe II emission varies with physical condition before it can be used as an abundance indicator. The present researchers have previously developed the most sophisticated model iron atom currently available, partially supported by NSF award AST-0206150. Because this model is sensitive to the strong radiation field in QSOs, it allows for the strong effect of non-abundance factors such as micro-turbulence, ionizing flux, and hydrogen density, which must be considered before any accurate abundance can be derived. Combining these Fe II model results with multi-bandpass emission spectrum measurements, this project will assess the predictive capabilities of the model, and study the physical conditions, especially micro-turbulence, in the Broad Line Regions of nearby quasars. The project will also consider the effects on the deduced spectral energy distribution of the QSO in the ultraviolet, and on the measurement of Fe/Mg ratios.The study is international and multi-disciplinary, combining leading theoretical, observational and experimental groups working on Fe II from the USA (modeling), Europe (spectroscopy), and Australia (observations). Since Fe II is important in many ionized plasmas, the project will have an impact on a wide range of astrophysical studies. Outreach work from the lead institution reaches a diverse population with a large number of under-represented groups.