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. [Fe VII], [Fe X] and [Ne V]), as well as relatively strong narrow (∼300 km s-1) Hα 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 (104.5 < nH < 107.5 cm-3) when compared to the FLIL emitting region (103.0 < nH < 104.5 cm-3). We use the photoionization results to calculate the CLiF regions radial distances (0.04 < RCLiF < 32.5 pc) and find that they are comparable to the dust grain sublimation distances (0.10 < RSUB < 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.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- April 2015
- DOI:
- 10.1093/mnras/stv113
- arXiv:
- arXiv:1501.02705
- Bibcode:
- 2015MNRAS.448.2900R
- Keywords:
-
- galaxies: active;
- quasars: emission lines;
- quasars: general;
- galaxies: Seyfert;
- Astrophysics - Astrophysics of Galaxies;
- Astrophysics - Cosmology and Nongalactic Astrophysics
- E-Print:
- 22 pages, 14 Figures and 12 Tables. Resubmitted to MNRAS after minor corrections