Coronal-Line Forest AGN: the best view of the inner edge of the AGN torus?

Abstract

We introduce Coronal-Line Forest Active Galactic Nuclei (CLiF AGN), AGN which have a rich spectrum of forbidden high-ionization lines (FHILs, e.g. [FeVII], [FeX] and [NeV]), as well as relatively strong narrow ($\sim$300 km s${}^{-1}$) H$\alpha$ emission when compared to the other Balmer transition lines. We find that the kinematics of the CLiF emitting region are similar to those of the forbidden low-ionization emission-line (FLIL) region. We compare emission line strengths of both FHILs and FLILs to CLOUDY photoionization results and find that the CLiF emitting region has higher densities (10${}^{4.5}$ $<$ n${}_H$ $<$ 10${}^{7.5}$ cm${}^{-3}$) when compared to the FLIL emitting region (10${}^{3.0}$ $<$ n${}_H$ $<$ 10${}^{4.5}$ cm${}^{-3}$). We use the photoionization results to calculate the CLiF regions radial distances (0.04 $<$ R${}_{CLiF}$ $<$ 32.5 pc) and find that they are comparable to the dust grain sublimation distances (0.10 $<$ R${}_{SUB}$ $<$ 4.3 pc). As a result we suggest that the inner torus wall is the most likely location of the CLiF region, and the unusual strength of the FHILs is due to a specific viewing angle giving a maximal view of the far wall of the torus without the continuum being revealed.

22 pages, 14 Figures and 12 Tables. Resubmitted to MNRAS after minor corrections

References in corpus (5)

• The Host Galaxies and Classification of Active Galactic Nuclei
• The Toroidal Obscuration of Active Galactic Nuclei
• NTT, Spitzer and Chandra spectroscopy of SDSSJ095209.56+214313.3: the most luminous coronal-line supernova ever observed, or a stellar tidal disruption event ?
• A New Method for Measuring Extragalactic Distances
• The Circumnuclear Molecular Gas in the Seyfert Galaxy NGC4945

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