New evidence for the ubiquity of prominent polar dust emission in AGN on
  tens of parsec scales
  The key ingredient of active galactic nuclei (AGN) unification, the dusty
obscuring torus was so far held responsible for the observed mid-infrared (MIR)
emission of AGN. However, the best studied objects with VLTI/MIDI show that
instead a polar dusty wind is dominating these wavelengths, leaving little room
for a torus contribution. But is this wind an ubiquitous part of the AGN? To
test this, we conducted a straightforward detection experiment, using the
upgraded VLT/VISIR for deep subarcsecond resolution MIR imaging of a sample of
nine [O IV]-bright, obscured AGN, all of which were predicted to have
detectable polar emission. Indeed, the new data reveal such emission in all
objects but one. We further estimate lower limits on the extent of the polar
dust and show that the polar dust emission is dominating the total MIR emission
of the AGN. These findings support the scenario that polar dust is not only
ubiquitous in AGN but also an integral part of its structure, processing a
significant part of the primary radiation. The polar dust has to be optically
thin on average, which explains, e.g., the small dispersion in the observed
mid-infrared--X-ray luminosity correlation. At the same time, it has to be
taken into account when deriving covering factors of obscuring material from
mid-infrared to bolometric luminosity ratios. Finally, we find a new tentative
trend of increasing MIR emission size with increasing Eddington ratio.
