SCUBA-2 Ultra Deep Imaging EAO Survey (Studies). III. Multiwavelength Properties, Luminosity Functions, and Preliminary Source Catalog of 450 μm Selected Galaxies
Chen-Fatt Lim, Wei-Hao Wang, Ian Smail, Douglas Scott, Chian-Chou Chen, Yu-Yen Chang, James M. Simpson, Yoshiki Toba, Xinwen Shu, Dave Clements, Josh Greenslade, YiPing Ao, Arif Babul, Jack Birkin, Scott C. Chapman, Tai-An Cheng, Brian S. Cho, Helmut Dannerbauer, Ugnė Dudzevičiūtė, James Dunlop, Yu Gao, Tomotsugu Goto, Luis C. Ho, Li-Ting Hsu, Ho Seong Hwang, Woong-Seob Jeong, Maciej Koprowski, Chien-Hsiu Lee, Ming-Yi Lin, Wei-Ching Lin, Michał J. Michałowski, Harriet Parsons, Marcin Sawicki, Raphael Shirley, Hyunjin Shim, Sheona Urquhart, Jianfa Wang, Tao Wang
Abstract
Abstract We construct a SCUBA-2 450 μ m map in the COSMOS field that covers an area of 300 arcmin 2 and reaches a 1 σ noise level of 0.65 mJy in the deepest region. We extract 256 sources detected at 450 μ m with signal-to-noise ratios >4.0 and analyze the physical properties of their multiwavelength counterparts. We find that most of the sources are at z ≲ 3, with a median of . About of our sources are classified as starburst galaxies based on their total star formation rates (SFRs) and stellar masses ( M * ). By fitting the far-infrared spectral energy distributions, we find that our 450 μ m selected sample has a wide range of dust temperatures (20 K ≲ T d ≲ 60 K), with a median of K. We do not find a redshift evolution in dust temperature for sources with at z < 3. However, we find a moderate correlation where the dust temperature increases with the deviation from the SFR– M * relation. The increase in dust temperature also correlates with optical morphology, which is consistent with merger-triggered starbursts in submillimeter galaxies. Our galaxies do not show the tight IRX– β UV correlation that has been observed in the local universe. We construct the infrared luminosity functions of our 450 μ m sources and measure their comoving SFR densities (SFRDs). The contribution of the population to the SFRD rises dramatically from z = 0 to 2 (∝(1 + z ) 3.9±1.1 ) and dominates the total SFRD at z ≳ 2.