Kohei ICHIKAWA
(Kyoto University)
We present the mid-infrared (MIR) properties of a 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 matches with the AKARI, IRAS, and WISE infrared all-sky survey catalogs. Out of 135 non-blazar AGNs in the Swift/BAT 9-month catalog, we unambiguously identify the MIR photometric data of 128 sources. We find a good luminosity correlation between the hard X-ray and MIR band over three orders of magnitude (42 < log L_HX < 45). This suggests that MIR emission is suitable for estimating the AGN intrinsic power. 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 also find 9 um excess sign in the averaged infrared spectral energy distribution of a population of deeply buried ("new type") AGNs. This excess signal could originate from polycyclic aromatic hydrocarbon emission feature, suggesting that their host galaxies have strong starburst activities.