Exploring the inner parsecs of Active Galactic Nuclei using
  near-infrared high resolution polarimetric simulations with MontAGN
  Aims: In this paper, we aim to constrain the properties of dust structures in
the central first parsecs of Active Galactic Nuclei (AGN). Our goal is to study
the required optical depth and composition of different dusty and ionised
structures.
  Methods: We developed a radiative transfer code, MontAGN, optimised for
polarimetric observations in the infrared. With both this code and STOKES,
designed to be relevant from the hard X-ray band to near-infrared wavelengths,
we investigate the polarisation emerging from a characteristic model of the AGN
environment. For that purpose, we compare predictions of our models with
previous infrared observations of NGC 1068, and try to reproduce several key
polarisation patterns revealed by polarisation mapping.
  Results: We constrain the required dust structures as well as their
densities. More precisely, we find out that the electron density inside the
ionisation cone is about $2.0 \times 10^9$ m$^{-3}$ . With structures
constituted of spherical grains of constant density, we also highlight that the
torus should be thicker than 20 in term of K band optical depth to block direct
light from the centre. It should also have a stratification in density, with a
lesser dense outer rim with an optical depth at 2.2 {\mu}m typically between
0.8 and 4 for observing the double scattering effect previously proposed.
  Conclusions: We bring constraints on the dust structures in the inner parsecs
of an AGN model supposed to describe NGC 1068. When compared to observations,
this leads to optical depth of at least 20 in Ks band for the torus of NGC
1068, corresponding to $\tau_V \approx 170$, which is within the range of
current estimation based on observations. In the future, we will improve our
study by including non uniform dust structures and aligned elongated grains to
constrain other possible interpretations of the observations.
