Implications of Ca II emission for physical conditions in the broad-line region of active galactic nuclei
Implications of Ca II emission for physical conditions in the broad-line region of active galactic nuclei
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DOI：
10.1086/168156
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发表时间：
1989-12
期刊：
影响因子：
--
通讯作者：
G. Ferland;S. E. Persson
中科院分区：
文献类型：
--
作者：
G. Ferland;S. E. Persson
本文总结了活动星系核的Ca II发射观测结果，并讨论了它们对发射气体条件的影响。观测的钙II K和H，红外三重态，以及7300 A附近的禁戒线的汇编，给出一个标准的线比AGN与相对较强的Fe II的排放。一系列的光电离计算，检查所需的条件，以产生所观察到的发射。特别注意的是，由于自由和H（-）吸收过程耦合的近红外毫米连续发射气体加热列入。结果发现，无论密度或电离参数，薄云不能产生所观察到的钙II发射。半禁态C III 1909 A/C IV 1549 A的强度比不是一个很好的指标的电离参数为这个连续。具有大柱密度和电离参数的云在很大程度上再现了观测到的碳、钙和氢光谱。参考文献98篇。
This paper summarizes observations of Ca II emission from AGN and discusses their implications for conditions in the emitting gas. Observations of Ca II K and H, the infrared triplet, and the forbidden lines near 7300 A are compiled to give a standard set of line ratios for AGN with relatively strong Fe II emission. A series of photoionization calculations is presented which examines the conditions needed to produce the observed emission. Special attention is paid to the inclusion of heating due to free-free and H(-) absorption processes which couple the near-infrared to millimeter continuum with the emitting gas. It is found that, regardless of density or ionization parameters, thin clouds cannot produce the observed Ca II emission. The semiforbidden C III 1909 A/C IV 1549 A intensity ratio is not a good indicator of the ionization parameter for this continuum. Clouds with large column densities and ionization parameters largely reproduce the observed carbon, calcium, and hydrogen spectrum. 98 refs.