The Prevalence of Narrow Optical Fe II Emission Lines in Type 1 Active Galactic Nuclei

Abstract

From detailed spectral analysis of a large sample of low-redshift active galactic nuclei (AGNs) selected from the Sloan Digital Sky Survey, we demonstrate---statistically for the first time---that narrow optical Fe II emission lines, both permitted and forbidden, are prevalent in type 1 AGNs. Remarkably, these optical lines are completely absent in type 2 AGNs, across a wide luminosity range, from Seyfert 2 galaxies to type 2 quasars. We suggest that the narrow FeII-emitting gas is confined to a disk-like geometry in the innermost regions of the narrow-line region on physical scales smaller than the obscuring torus.

arXiv commentThis Letter is separated from arXiv:0903.5020 (sumbitted to ApJ), with more tests on the robustness of the detection of narrow Fe II emission as well as more quantitative details and figures about narrow Fe II emission lines in AGNs. The implementation of the analytical narrow and broad Fe II templates in IDL is available at http://staff.ustc.edu.cn/~xbdong/Data_Release/FeII/Template/

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• Differences in Halo-Scale Environments between Type 1 and Type 2 AGNs at Low Redshift
• Panchromatic Properties of the Extreme FeII Emitter PHL 1092
• Deconstructing the narrow-line region of the nearest obscured quasar
• Local Active Galactic Nuclei with Large Broad-Hα Variability Reside in Red Galaxies
• A Multiwavelength Study of the Massive Cool Core Cluster MACS J1447.4+0827
• Wavelength-resolved Reverberation Mapping of quasar CTSC30.10: Dissecting MgII and FeII emission regions
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