The mid-infrared emission of Seyfert galaxies. A new analysis of ISOCAM data

Abstract

We present mid-infrared data of a sample of 57 AGNs obtained with the instrument ISOCAM on board the satellite ISO. The images were obtained through the LW2 (6.75 microns) and LW7 (9.62 microns) filters. This is a new analysis of Clavel et al. (2000) galaxy sample, which is divided into 26 type 1 (< or = 1.5) and 28 type 2 (> 1.5) Seyfert galaxies, plus three QSOs. The spatial resolution of the images allow us to separate the nuclear and the extended contributions to the total emission after decomposing the brightness profiles into different morphological components. The most common components are a central point source (identified as the active nucleus) and an exponential disk. In some cases a bulge, a bar or a ring are needed. The relative contribution of the nucleus to the total emission appears larger in Seyfert 1 than in Seyfert 2. This result confirms that both types of Seyfert galaxies are different in the mid-infrared and supports the existence of an structure which produces anisotropic emission in this wavelength range. We have also explored correlations between the mid-infrared and the radio and X-ray wavelength ranges. The well established radio/infrared correlation is mantained in our sample for the global emission of the galaxies. If only the nuclear infrared emission is considered then a non-linear correlation is apparent in the luminosity-luminosity scatter diagram. The ratio between the intrinsic hard X-ray and the nuclear mid-infrared emission presents large scatter and slightly larger values for type 2 Seyfert galaxies. These results seem to be consistent with the presence of a clumpy dusty torus surrounding the active nucleus.

28 pages, 10 figures, 3 tables. Published in AJ. Erratum added, 2 pages, 1 figure, accepted by AJ

References in corpus (4)

• Radiative Transfer Modeling of Three-Dimensional Clumpy AGN Tori and its Application to NGC 1068
• The Unified Model of Active Galactic Nuclei: I. Non-hidden Broad Line Region Seyfert 2 and Narrow Line Seyfert 1 Galaxies
• The small dispersion of the mid IR -- hard X-ray correlation in AGN
• Does the AGN Unified Model Evolve with Redshift? Utilizing the X-ray Background to Predict the Mid-Infrared Emission of AGN

Cited by in corpus (6)

• The Infrared Nuclear Emission of Seyfert Galaxies on Parsec Scales: Testing the Clumpy Torus models
• The mid IR -- hard X-ray correlation in AGN and its implications for dusty torus models
• Revisiting the relationship between 6 μm and 2-10 keV continuum luminosities of AGN
• The Complete Infrared View of Active Galactic Nuclei from the 70-month Swift/BAT Catalog
• The nuclear and extended mid-infrared emission of Seyfert galaxies
• Active Galactic Nuclei and their Role in Galaxy Evolution: The Infrared Perspective