  We estimate the relative contributions of the supermassive black hole (SMBH)
accretion disk, corona, and obscuring torus to the bolometric luminosity of
Seyfert galaxies, using Spizter mid-infrared (MIR) observations of a complete
sample of 68 nearby active galactic nuclei from the INTEGRAL all-sky hard X-ray
(HX) survey. This is the first HX-selected (above 15 keV) sample of AGNs with
complementary high angular resolution, high signal to noise, MIR data.
Correcting for the host galaxy contribution, we find a correlation between HX
and MIR luminosities: L_MIR L_HX^(0.74+/-0.06). Assuming that the observed MIR
emission is radiation from an accretion disk reprocessed in a surrounding dusty
torus that subtends a solid angle decreasing with increasing luminosity (as
inferred from the declining fraction of obscured AGNs), the intrinsic disk
luminosity, L_D, is approximately proportional to the luminosity of the corona
in the 2-300 keV energy band, L_C, with the L_D/L_C ratio varying by a factor
of 2.1 around a mean value of 1.6. This ratio is a factor of ~2 smaller than
for typical quasars producing the cosmic X-ray background (CXB). Therefore,
over three orders of magnitude in luminosity, HX radiation carries a large, and
roughly comparable, fraction of the bolometric output of AGNs. We estimate the
cumulative bolometric luminosity density of local AGNs at ~(1-3)x10^40
erg/s/Mpc^3. Finally, the Compton temperature ranges between kT_c~2 and ~6 keV
for nearby AGNs, compared to kT_c~2 keV for typical quasars, confirming that
radiative heating of interstellar gas can play an important role in regulating
SMBH growth.
