The forbidden high ionisation line region of the type 2 quasar Q1131+16:
  a clear view of the inner face of the torus?
  We present spectroscopic observations of the type 2 quasar SDSS
J11311.05+162739.5 (Q1131+16 hereafter; z=0.1732), which has the richest
spectrum of forbidden high ionisation lines (FHIL, e.g. [Fe \textsc{vii}], [Fe
\textsc{x}], [Fe \textsc{xi}] and [Ne \textsc{v}]) yet reported for an AGN, as
well as unusually strong [O \textsc{iii}]$\lambda$4363 emission. The study of
this object provides a rare opportunity to investigate the physical conditions
and kinematics of the region(s) emitting the FHILs. By comparison with
photoionisation model results, we find that the FHIL region has high densities
(10$^{5.5}$ $<$ $n_H$ $<10^{8.0}$ cm$\textsuperscript{-3}$) and ionisation
parameters (-1.5 $<$ log[U] $<$ 0), yet its kinematics are similar to those of
the low ionisation emission line region detected in the same object (FWHM
$\sim$ 360$\pm$30 km/s), with no evidence for a significant shift between the
velocity centroid of the FHILs and the rest frame of the host galaxy. The
deduced physical conditions lie between those of the Broad-Line (n$_H$$>10^9$
cm$\textsuperscript{-3}$) and Narrow-Line Regions ($n_H$$<10^6$
cm$\textsuperscript{-3}$) of active galactic nuclei (AGN), and we demonstrate
that the FHIL regions must be situated relatively close to the illuminating AGN
(0.32 $<$ $r_{FHIL}$ $<$ 50pc). We suggest that the inner torus wall is the
most likely location for the FHIL region, and that the unusual strength of the
FHILs in this object is due to a specific viewing angle of the far wall of the
torus, coupled with a lack of dust on larger scales that might otherwise
obscure our view of the torus.
