Bibcode
Ramos-Almeida, C.; Pereira-Santaella, M.; Hernán-Caballero, A.; García-González, J.; Alonso-Herrero, A.; Acosta-Pulido, J. A.; Díaz-Santos, T.; Esquej, P.; González-Martín, O.; Ichikawa, K.; López-Rodríguez, E.; Povic, M.; Roche, P. F.; Sánchez-Portal, M.
Bibliographical reference
Monthly Notices of the Royal Astronomical Society, Volume 458, Issue 4, p.4512-4529
Advertised on:
6
2016
Citations
16
Refereed citations
15
Description
We present far-infrared (FIR) 70-500 μm imaging observations obtained
with Herschel/Photodetector Array Camera (PACS) and Spectral and
Photometric Imaging REceiver (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 μm 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 μm emission has a
significant AGN contribution: (1) elevated 70/160 μm flux ratios, (2)
spatially resolved, high dust temperature gradient, (3) 70 μm excess
emission with respect to the fit of the FIR SEDs with a grey body, and
(4) excess of nuclear SFR obtained from 70 μm 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
˜40-70 per cent of their nuclear (r = 1-2 kpc) 70 μm emission
is contributed by dust heated by the AGN.