An extinction-free AGN census by 23 space-based infrared band SED fitting
Ting-Wen Wang1*, Tomotsugu Goto1, Seong Jin Kim1, Tetsuya Hashimoto1, Denis Burgarella2, Matthew Malkan3, Nagisa Oi4, Chien-Chang Ho1
1Institute of Astronomy, National Tsing Hua University, Hsinchu City, Taiwan
2Aix Marseille Univ. CNRS, CNES, LAM Marseille, France
3Department of Physics and Astronomy, UCLA, Los Angeles, CA, USA
4Tokyo University of Science, Tokyo, Japan
* Presenter:Ting-Wen Wang,
How active galactic nucleus (AGN) impact upon the total infrared (IR) luminosity is one of the critical issues to study galaxy-AGN coevolution. However, AGNs are often missed in optical, UV and soft X-ray observations. An mid-IR survey is one of the best ways to study AGNs because it is extinction-free. The uniqueness of AKARI enables us to search for hidden AGNs: the AKARI satellite performs continuous near- to mid-IR observation with 9 filters. WISE and SPITZER cannot separate star forming galaxy (SFG)-AGN well at certain redshift ranges due to the filter gaps in the mid-IR. In this work, we derive how much portion of the energy released from the active nucleus contributes to the total infrared luminosity of a galaxy. To decompose AGN emission from the whole energy distribution, we use the state-of-the-art modeling software based on the energy balance scheme between the obscured UV/optical and the reemitted IR emission by dust. There are 1955 sources in our AKARI sample; however, previously there were only 15 spectroscopically/X-ray classified AGNs. With our approach, 44 AGNs are recovered from the sample. Also, we found there is a redshift dependence of the AGN evolution, which implies more AGNs in the high-z universe. With the upcoming large IR surveys, e.g. JWST, we expect to find more AGNs and have a comprehensive understanding of the accretion history of supermassive black holes.

Keywords: galaxies: active, galaxies: infrared