  Accreting supermassive black holes (SMBHs) located at the center of galaxies
are typically surrounded by large quantities of gas and dust. The structure and
evolution of this circumnuclear material can be studied at different
wavelengths, from the submillimeter to the X-rays. Recent X-ray studies have
shown that the covering factor of the obscuring material tends to decrease with
increasing Eddington ratio, likely due to radiative feedback on dusty gas. Here
we study a sample of 549 nearby (z<0.1) hard X-ray (14-195 keV) selected
non-blazar active galactic nuclei (AGN), and use the ratio between the AGN
infrared and bolometric luminosity as a proxy of the covering factor. We find
that, in agreement with what has been found by X-ray studies of the same
sample, the covering factor decreases with increasing Eddington ratio. We also
confirm previous findings which showed that obscured AGN typically have larger
covering factors than unobscured sources. Finally, we find that the median
covering factors of AGN located in different regions of the column
density-Eddington ratio diagram are in good agreement with what would be
expected from a radiation-regulated growth of SMBHs.
