MID- AND FAR-INFRARED PROPERTIES OF A COMPLETE SAMPLE OF LOCAL ACTIVE GALACTIC NUCLEI

• Published in: The Astrophysical journal Vol. 754; no. 1; pp. 45 - 14
• Main Authors: Ichikawa, Kohei, Ueda, Yoshihiro, Terashima, Yuichi, Oyabu, Shinki, Gandhi, Poshak, Matsuta, Keiko, Nakagawa, Takao
• Format: Journal Article
• Language: English
• Published: United States 20.07.2012
• Subjects: Active galactic nuclei; ASTROPHYSICS; ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; Correlation; CORRELATIONS; Dust; Emission; ENERGY SPECTRA; FAR INFRARED RADIATION; GALAXIES; GALAXY NUCLEI; GAMMA ASTRONOMY; HARD X RADIATION; Infrared; INFRARED SPECTRA; INFRARED SURVEYS; INTERMEDIATE INFRARED RADIATION; KEV RANGE; LUMINOSITY; POLYCYCLIC AROMATIC HYDROCARBONS; TELESCOPES; X-RAY SPECTRA; X-rays
• ISSN: 0004-637X; 1538-4357
• DOI: 10.1088/0004-637X/754/1/45

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/Burst Alert Telescope (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 Infrared Astronomical Satellite and Wide-field Infrared Survey Explorer. Out of 135 non-blazer AGNs in the Swift/BAT nine-month catalog, we obtain the MIR photometric data for 128 sources either in the 9, 12, 18, 22, and/or 25 mu m band. We find good correlation between their hard X-ray and MIR luminosities over three orders of magnitude (42 < log [lambda]L sub([lambda])(9, 18 mu m) < 45), which is tighter than that with the FIR luminosities at 90 mu m. 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 mu m 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 polycyclic aromatic hydrocarbon emission feature, suggesting that their host galaxies have strong starburst activities.