The interplay between active galactic nuclei and star formation activities of type 1 active galactic nuclei probed by polycyclic aromatic hydrocarbon 3.3 mu m emission feature with AKARI

摘要

We investigate the connection between active galactic nucleus (AGN) and star formation activities of AGN host galaxies by studying the 3.3 mu m polycyclic aromatic hydrocarbon (PAH) emission feature of 79 type 1 AGNs using the AKARI space telescope. Utilizing the slitless spectroscopic capability of the AKARI Infrared Camera, we obtained the spectra in the wavelength range of 2-5 mu m from extended regions of the sample galaxies in order to measure star formation activity from the entire host galaxies. We detected the 3.3 mu m PAH emission feature from 18 sample galaxies and measured the luminosities of the feature (L-PAH3.3). We found that L-PAH3.3 is significantly correlated with AGN luminosities (L-AGN), such as 5100 angstrom monochromatic luminosity, and X-ray luminosity regardless of host galaxy morphology and radio-loudness. The correlation between L-PAH3.3 and L-AGN follows L-PAH3.3 proportional to L-AGN(0.9). Therefore we suggest that host galaxies with stronger AGN activities have stronger star formation activities. We also found that the ratios between L-PAH3.3 and the bolometric infrared luminosity (L-IR) of our sample galaxies are lower than for non-AGN galaxies due to increased L-IR. We suggest that this can be attributed to the contribution of AGN to L-IR.