The role of infrared radiation pressure in shaping dusty winds in AGN

TL;DR

This paper develops a semi-analytical model to explore how infrared radiation pressure can drive dusty winds in active galactic nuclei, revealing complex wind structures influenced by radiation and gravity.

Contribution

It introduces a new semi-analytical model that simulates radiatively accelerated dusty winds in AGN, incorporating dust re-radiation and dynamics.

Findings

Dusty winds form a disk and hyperboloid polar outflow.

Wind morphology depends on Eddington ratio and dust column density.

Model aligns with high-resolution infrared observations of Seyfert AGN.

Abstract

The detection of dusty winds dominating the infrared emission of AGN on parsec scales has revealed the limitations of traditional radiative transfer models based on a toroidal distribution of dusty gas. A new, more complex, dynamical structure is emerging and the physical origin of such dusty winds has to be critically assessed. We present a semi-analytical model to test the hypothesis of radiatively accelerated dusty winds launched by the AGN and by the heated dust itself. The model consists of an AGN and an infrared radiating dusty disk, the latter being the primary mass reservoir for the outflow. We calculate the trajectories of dusty gas clumps in this environment, accounting for both gravity and the AGN radiation as well as the re-radiation by the hot dusty gas clouds themselves. We find that the morphology consists of a disk of material that orbits with sub-Keplerian velocities and a hyperboloid polar wind launched at the inner edge of the dusty disk. This is consistent with high-angular resolution infrared and sub-mm observations of some local Seyfert AGN. The strength of the wind and its orientation depend on the Eddington ratio and the column density of the dusty clumps, which is in agreement with proposed radiation regulated obscuration models developed for the X-ray obscuring material around AGN.