Gravitational microlensing of AGN dusty tori
  We investigated the gravitational microlensing of active galactic nucleus
dusty tori in the case of lensed quasars in the infrared domain. The dusty
torus is modeled as a clumpy two-phase medium. To obtain spectral energy
distributions and images of tori at different wavelengths, we used the 3D Monte
Carlo radiative transfer code SKIRT. A ray-shooting technique has been used to
calculate microlensing magnification maps. We simulated microlensing by the
stars in the lens galaxy for different configurations of the lensed system and
different values of the torus parameters, in order to estimate (a) amplitudes
and timescales of high magnification events, and (b) the influence of
geometrical and physical properties of dusty tori on light curves in the
infrared domain. We found that, despite their large size, dusty tori could be
significantly affected by microlensing in some cases, especially in the
near-infrared domain (rest-frame). The very long time-scales of such events, in
the range from several decades to hundreds of years, are limiting the practical
use of this method to study the properties of dusty tori. However, our results
indicate that, when studying flux ratios between the images in different
wavebands of lensed quasars, one should not disregard the possibility that the
near and mid-infrared flux ratios could be under the influence of microlensing.
