Oral Presentation

ALMA Lensing Cluster Survey: Full SED Analysis of Distant Galaxies Detected by Millimeter Observation

Author(s): Ryosuke Uematsu (Kyoto Univ.), Yoshihiro Ueda (Kyoto Univ.), Kohno Kotaro (The Univ. of Tokyo), Yoshiki Toba (NAOJ), Satoshi Yamada (RIKEN), Seiji Fujimoto (DAWN), Bunyo Hatsukade (The Univ. of Tokyo), Hideki Umehata (Nagoya Univ.)

Presenter: Ryosuke Uematsu (Kyoto University)

Sub-millimeter galaxies are a key population to elucidate galaxy evolution, because the majority of star formation at high redshifts occurred in galaxies deeply embedded by dust. To search for this population, our team have performed an extensive survey with ALMA, called the ALMA Lensing Cluster Survey (ALCS). This survey covers 134 arcmin^2 and detects 180 secure sources at z~0.5-6 with a flux limit of ~0.2 mJy at 1.2 mm (Fujimoto et al. in prep.). Here we report the results of multi-component SED analysis for the whole ALCS sample, utilizing the UV to millimeter photometries. We find that most of the ALCS sources are in the star-forming main sequence, while some of them show starburst activities. The ALCS sample contains dusty-obscured galaxies (IRX=logLIR/LUV>5) that are not detected in previous ALMA surveys. We also confirm the cosmological evolution of dust temperature across z=1-5 as reported in previous studies. Finally, we identify 20 AGN candidates that are not detected in the archival Chandra X-ray data. Their inferred AGN luminosity density shows an excess at z=2-3 compared with that determined from X-ray surveys by Ueda et al. (2014), suggesting that a significant fraction of AGNs in this epoch are Compton-thick and might be missed in previous X-ray observations below 10 keV.