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arXiv · 1205.5032

Mid and Far Infrared Properties of a Complete Sample of Local AGNs

Kohei Ichikawa·Yoshihiro Ueda·Yuichi Terashima·Shinki Oyabu·Poshak Gandhi·Keiko Matsuta·Takao Nakagawa
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Abstract

We investigate the mid- (MIR) to far-infrared (FIR) properties of a nearly complete sample of local Active Galactic Nuclei (AGNs) detected in the Swift/BAT all sky hard X-ray (14-195 keV) survey, based on the cross correlation with the AKARI infrared survey catalogs complemented by those with IRAS and WISE. Out of 135 non-blazer AGNs in the Swift/BAT 9 month catalog, we obtain the MIR photometric data for 128 sources either in the 9, 12, 18, 22, and/or 25 um band. We find good correlation between their hard X-ray and MIR luminosities over 3 orders of magnitude (42< log lambda L_{lambda}(9, 18 um)< 45), which is tighter than that with the FIR luminosities at 90 um. This suggests that thermal emission from hot dusts irradiated by the AGN emission dominate the MIR fluxes. Both X-ray unabsorbed and absorbed AGNs follow the same correlation, implying isotropic infrared emission, as expected in clumpy dust tori rather than homogeneous ones. We find excess signals around 9 um in the averaged infrared spectral energy distribution from heavy obscured "new type" AGNs with small scattering fractions in the X-ray spectra. This could be attributed to the PAH emission feature, suggesting that their host galaxies have strong starburst activities.

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Kohei Ichikawa, Yoshihiro Ueda, Yuichi Terashima, Shinki Oyabu, Poshak Gandhi, Keiko Matsuta, Takao Nakagawa. 2012-05-22. Mid and Far Infrared Properties of a Complete Sample of Local AGNs. https://doi.org/10.1088/0004-637x/754/1/45

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