Dust in the wind II: Polarization imaging from disk-born outflows

In this second research note of a series of two, we aim to map the polarized flux emerging from a disk-born, dusty outflow as it was prescribed by Elvis (2000). His structure for quasars was achieved to unify the emission and absorption features observed in active galactic nuclei (AGN) and can be used as an alternative scenario to the typical dusty torus that is extensively used to account for AGN circumnuclear obscuration. Using Monte Carlo radiative transfer simulations, we model an obscuring outflow arising from an emitting accretion disk and examine the resulting polarization degree, polarization angle and polarized flux. Polarization cartography reveals that a disk-born outflow has a similar torus morphology in polar viewing angles, with bright polarized fluxes reprocessed onto the wind funnel. At intermediate and edge-on inclinations, the model is rather close to a double-conical wind, with higher fluxes in the cone bases. It indicates that the optically thick outflow is not efficient enough to avoid radiation escaping from the central region, particularly due to the geometrically thin divergence angle of the outflow. As parametrized in this research note, a dusty outflow does not seem to be able to correctly reproduce the polarimetric behavior of an usual dusty torus. Further refinement of the model is necessary.

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Date added: Wed, 9 Oct 13