Chen-Fatt Lim(ASIAA/NTU); Wei-Hao Wang(ASIAA)
The majority of star formation in the Universe is obscured by dust and produces strong infrared and sub-millimeter radiation. Far-infrared or sub-millimeter observations are therefore required to fully understand the formation history of galaxies. In this talk, I will present the results of the SCUBA-2 Ultra Deep Imaging EAO Survey (STUDIES) project. STUDIES is a JCMT Large Project aiming at obtaining confusion limited 450-μm images in the COSMOS and SXDS regions, to detect the majority of the dusty galaxy population. By the end of 2018, ~ 60% of the total allocated integration of the COSMOS field has been obtained. This leads to a very deep 450-μm image with an area of ~300 arcmin2 with 1σ noise level of about 0.65 mJy in the map center. We conducted SED fitting on sources with multi-wavelength counterparts to estimate their physical properties, including infrared luminosities, star formation rates, dust temperatures, stellar masses, and dust attenuations. Because of the unprecedented depth of the STUDIES image, these analyses reached about 30 M⦿ yr-1 galaxies at z ~ 2. Our data provide new measurements of obscured SFR densities at z =0-4, without any assumptions in the faint-end slopes of the infrared luminosity function. We are also building a 450-μm-based machine-learning algorithm to identify the SMG candidates in the entire 1.77 deg2 COSMOS region. There will be roughly 8000 such machine-learning candidates and they will be used for clustering analyses and halo mass estimations for faint SMGs. All the above will advance our understanding of the typical members in the high-redshift dusty galaxy population.