The nuclear and integrated far-infrared emission of nearby Seyfert
  galaxies
  We present far-infrared (FIR) $70-500\,\mu$m imaging observations obtained
with Herschel/PACS and SPIRE of 33 nearby (median distance of 30 Mpc) Seyfert
galaxies from the Revised Shapley-Ames (RSA) catalogue. We obtain the FIR
nuclear ($r=1\,$kpc and $r=2\,$kpc) and integrated spectral energy
distributions (SEDs). We estimate the unresolved nuclear emission at 70 $\mu$m
and we fit the nuclear and integrated FIR SEDs with a grey body model. We find
that the integrated FIR emission of the RSA Seyferts in our sample is dominated
by emission from the host galaxy, with dust properties similar to those of
normal galaxies (non AGN). We use four criteria to select galaxies whose
nuclear $70\,\mu$m emission has a significant AGN contribution: (1) elevated
70/160 $\mu$m flux ratios, (2)spatially resolved, high dust temperature
gradient, (3) $70\,\mu$m excess emission with respect to the fit of the FIR
SEDs with a grey body, and (4) excess of nuclear SFR obtained from $70\,\mu$m
over SFR from mid-infrared indicators. 16 galaxies (48 per cent of the initial
sample) satisfy at least one of these conditions, whereas 10 satisfy half or
more. After careful examination of these, we select six bona fide candidates
(18 per cent of the initial sample) and estimate that $\sim 40-70$ per cent of
their nuclear ($r=1-2\,$kpc) $70\,\mu$m emission is contributed by dust heated
by the AGN.
