Bibcode
Ramos-Almeida, C.; Levenson, N. A.; Alonso-Herrero, A.; Asensio-Ramos, A.; Rodríguez-Espinosa, J. M.; Pérez-García, A. M.; Packham, C.; Mason, R.; Radomski, J. T.; Díaz-Santos, T.
Bibliographical reference
Journal of Physics: Conference Series, Volume 372, Issue 1, pp. 012004 (2012).
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7
2012
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Description
We present near-to-mid-infrared spectral energy distributions (SEDs) for
21 Seyfert galaxies, using subarcsecond resolution imaging data. Our aim
is to compare the properties Seyfert 1 (Sy1) and Seyfert 2 (Sy2) tori
using clumpy torus models and a Bayesian approach to fit the infrared
(IR) nuclear SEDs. These dusty tori have physical sizes smaller than 6
pc radius, as derived from our fits. Active galactic nuclei (AGN)
unification schemes account for a variety of observational differences
in terms of viewing geometry. However, we find evidence that strong
unification may not hold, and that the immediate dusty surroundings of
Sy1 and Sy2 nuclei are intrinsically different. The Type 2 tori studied
here are broader, have more clumps, and these clumps have lower optical
depths than those of Type 1 tori. The larger the covering factor of the
torus, the smaller the probability of having direct view of the AGN, and
vice-versa. In our sample, Sy2 tori have larger covering factors
(CT = 0.95±0.02) and smaller escape probabilities than
those of Sy1 (CT = 0.5±0.1). Thus, on the basis of the
results presented here, the classification of a Seyfert galaxy may
depend more on the intrinsic properties of the torus rather than on its
mere inclination, in contradiction with the simplest unification model.
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