Oral Presentation

An extinction-free AGN census by 23 space-based infrared band SED fitting

Author(s): Ting-Wen Wang(NTHU), Tomotsugu Goto(NTHU), Seong Jin Kim(NTHU), Tetsuya Hashimoto(NTHU), Denis Burgarella(Aix Marseille Univ. CNRS), Matthew Malkan(UCLA), Nagisa Oi(Tokyo University of Science), Chien-Chang Ho(NTHU)

Presenter: Ting-Wen Wang (NTHU IoA)

Finding out how many galaxies have "active galactic nucleus(AGN)" is one of the important issues to understand the accretion history of supermassive black-holes (SMBHs) along with the history of the galaxies in the Universe, since the AGNs are powered by central SMBHs and feed back to the environments continuously. However, AGNs are often obscured by gas and dust, and those obscured AGNs are often missed in optical, UV and soft X-ray observations. An infrared(IR) survey is one of the best ways to study AGNs because it is extinction-free. Despite its advantage, it has been quite a big challenge. The mid-IR spectra of galaxies are normally mixtures of PAH emissions from star-forming regions and hot dust emission from AGNs. To tackle this problem, we take advantage of multi-wavelength photometric data. We include CFHT WIRCam, SPITZER IRAC, Herschel PACS and SPIRE, and the continuous 9 IR bands of AKARI. We construct physical modelings for various emission components based on the energy balance mechanism (e.g., CIGALE). The best-fitting model enables us to understand how AGNs contribute to the overall SEDs of galaxies. Also, we can take a statistical census of its evolution and dependencies as a function of redshift and luminosity.