Hypercubes of AGN Tori (HYPERCAT) -- I. Models and Image Morphology
  Near- and mid-infrared interferometers have resolved the dusty parsec-scale
obscurer (torus) around nearby active galactic nuclei (AGNs). With the arrival
of extremely large single-aperture telescopes, the emission morphology will
soon be resolvable unambiguously, without modeling directly the underlying
brightness distribution probed by interferometers today. Simulations must
instead deliver the projected 2D brightness distribution as a result of
radiative transfer through a 3D distribution of dusty matter around the AGN. We
employ such physically motivated 3D dust distributions in tori around AGNs to
compute 2D images of the emergent thermal emission using CLUMPY, a dust
radiative transfer code for clumpy media. We demonstrate that CLUMPY models can
exhibit morphologies with significant polar elongation in the mid-infrared
(i.e. the emission extends perpendicular to the dust distribution) on scales of
several parsecs, in line with observations in several nearby AGNs. We
characterize the emission and cloud distribution morphologies. The observed
emission from near- to mid-infrared wavelengths generally does not trace the
bulk of the cloud distribution. The elongation of the emission is sensitive to
the torus opening angle or scale height. For cloud distributions with a flat
radial profile, polar extended emission is realized only at wavelengths shorter
than ~18 micron, and shorter than ~5 micron for steep profiles. We make the
full results available through HYPERCAT, a large hypercube of resolved AGN
torus brightness maps computed with CLUMPY. HYPERCAT also comprises software to
process and analyze such large data cubes and provides tools to simulate
observations with various current and future telescopes.
