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Paper: An Infrared View of Local Universe AGN
Volume: 290, Active Galactic Nuclei: from Central Engine to Host Galaxy
Page: 445
Authors: Alonso-Herrero, A.
Abstract: In recent years, the advent of new infrared (IR) facilities (both space and ground-based) with superb spatial resolution and sensitivity has allowed us to make significant progress on the understanding of the IR properties of local universe AGN. In this talk I will summarize recent results obtained by our group on the IR properties of Seyfert and nearby radio galaxies. The IR emission in AGNs (Seyfert galaxies and radio quiet quasars) has often been interpreted as produced by a torus configuration where the dust is heated by the central source. However, until recently, the nuclear non-stellar IR continuum in Seyfert 2 galaxies had eluded us because of the dominance of the stellar emission shortward of 2 micron. From high resolution HST/NICMOS observations, we have now found that almost 100% of all Seyfert 1--1.9s and 50% of all Sy 2s show point sources at 1.6micron. This unresolved emission is variable in some of the Sy 2s and thus is presumably non-stellar emission (hot dust) associated with the central engine. We have put together non-stellar IR spectral energy distributions for a number of Seyfert and radio galaxies. Their modelling and the comparison between the infrared and hard X-ray properties of AGN has allowed us to demonstrate that the mid-IR emission (5-10micron) of local universe AGN is approximately an isotropic property, and thus it can be used as a good indicator of the AGN luminosity.
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