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Extended Coronal Emission Lines in Active Galactic Nuclei

A. Rodriguez-Ardila·A. Prieto·S. M. Viegas
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Abstract

VLT and NTT spectra are used to examine the nuclear and extended coronal line emission in a sample of well-known Seyfert 1 and 2 galaxies. The excellent spatial resolution obtained with VLT allowed us to map [SiVI] 1.963 $μ$m and [SiVII] 2.48 $μ$m on scales of up to 20 pc. Coronal line emission, extended to distances of $\sim$100 pc, is detected in some of the lines analyzed, particularly in [FeX] 6374Å, [FeXI] 7891Å, and [SiVII] 2.48$μ$m. Most coronal lines are strongly asymmetric towards the blue and broader than low-ionization lines. This result is particularly important for Circinus, where previous observations had failed at detecting larger widths for high-ionization lines. Photoionization models are used to investigate the physical conditions and continuum luminosities necessary to produced the observed coronal emission. We found that an ionization parameter U> 0.10 is necessary to reproduce the observations, although the clouds should be located at distances < 30 pc.

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A. Rodriguez-Ardila, A. Prieto, S. M. Viegas. 2004-06-29. Extended Coronal Emission Lines in Active Galactic Nuclei. https://doi.org/10.1017/s1743921304002273

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