The post-Herschel view of intrinsic AGN emission: constructing templates
  for galaxy and AGN emission at IR wavelengths
  Measuring the star-forming properties of AGN hosts is key to our
understanding of galaxy formation and evolution. However, this topic remains
debated, partly due to the difficulties in separating the infrared (i.e.
1--1000 $\mu$m) emission into AGN and star-forming components. Taking advantage
of archival far-infrared data from Herschel, we present a new set of AGN and
galaxy infrared templates, and introduce the spectral energy distribution
fitting code IRAGNSEP. Both can be used to measure infrared host galaxy
properties, free of AGN contamination. To build these, we used a sample of 100
local ($z$ < 0.3), low-to-high luminosity AGNs (i.e. $L_{\rm
bol}~\sim~10^{42--46}~\rm erg~s^{-1}$), selected from the 105-month Swift - BAT
X-ray survey, which have archival Spitzer - IRS spectra and Herschel
photometry. We first built a set of seven galaxy templates using a sample of 55
star-forming galaxies selected via infrared diagnostics. Using these templates,
combined with a flexible model for the AGN contribution, we extracted the
intrinsic infrared emission of our AGN sample. We further demonstrate that we
can reduce the diversity in the intrinsic shapes of AGN spectral energy
distributions down to a set of three AGN templates, of which two represent AGN
continuum, and one represents silicate emission. Our results indicate that, on
average, the contribution of AGNs to the far-infrared ($\lambda~\gtrsim$ 50
$\mu$m) is not as high as suggested by some recent work. We further show that
the need for two infrared AGN continuum templates could be related to nuclear
obscuration, where one of our templates appears dominated by the emission of
the extended polar dust.
