The AGN fraction of submm-selected galaxies and contributions to the submm/mm-wave extragalactic background light
Im, M.; Kim, S.; Farrah, D.; Ibar, E.; Vaccari, M.; Negrello, M.; Chapman, S.; Wilson, G.; Dunne, L.; Dye, S.; Serjeant, S.; Aretxaga, I.; Pearson, C.; Takagi, T.; Jeong, W. -S.; Matsuhara, H.; Oyabu, S.; Wada, T.; Dunlop, J.; Mortier, A.; Hughes, D.; Clements, D.; Yun, M.; Austermann, J.; Lee, H. -M.
United Kingdom, Canada, United States, Mexico, South Korea, Japan, Italy
Abstract
We present a comparison of the SCUBA half degree extragalactic survey (SHADES) at 450 μm, 850 μm and 1100 μm with deep guaranteed time 15 μm AKARI FU-HYU survey data and Spitzer guaranteed time data at 3.6-24 μm in the Lockman hole east. The AKARI data was analysed using bespoke software based in part on the drizzling and minimum-variance matched filtering developed for SHADES, and was cross-calibrated against ISO fluxes. Our stacking analyses find AKARI 15 μm galaxies with ⪆200 μJy contribute >10% of the 450 μm background, but only <4% of the 1100 μm background, suggesting that different populations contribute at mm-wavelengths. We confirm our earlier result that the ultra-deep 450 μm SCUBA-2 cosmology survey will be dominated by populations already detected by AKARI and Spitzer mid-infrared surveys. The superb mid-infrared wavelength coverage afforded by combining Spitzer and AKARI photometry is an excellent diagnostic of AGN contributions, and we find that (23-52)% of submm-selected galaxies have AGN bolometric fractions fAGN > 0.3.