ALMA Lensing Cluster Survey: Physical Characterization of Near-infrared-dark Intrinsically Faint ALMA Sources at z = 2–4

作者：Akiyoshi Tsujita, Kotaro Kohno, Shuo Huang, Masamune Oguri, Ken-ichi Tadaki, Ian Smail, Hideki Umehata, Zhen-Kai Gao, Wei-Hao Wang, Fengwu Sun, Seiji Fujimoto, Tao Wang, R. Uematsu, D. Espada, Francesco Valentino, Yiping Ao, F. E. Bauer, Bunyo Hatsukade, Fumi Egusa, Y. Nishimura, Anton M. Koekemoer, D. Schaerer, Claudia del P. Lagos, M. Dessauges‐Zavadsky, Gabriel Brammer, K. I. Caputi, Eiichi Egami, Jorge González-López, Jean-Baptiste Jolly, K. K. Knudsen, Vasily Kokorev, G. Magdis, Masami Ouchi, Sune Toft, John F. Wu, Adi Zitrin · 发表于：The Astrophysical Journal · 年份：2025 · DOI：10.3847/1538-4357/adb41d · 被引用次数：2 · 研究领域：Galaxies: Formation, Evolution, Phenomena、Astrophysics and Star Formation Studies、Astronomy and Astrophysical Research

Abstract We present results from Atacama Large Millimeter/submillimeter Array (ALMA) spectral line-scan observations at 3 mm and 2 mm bands of three near-infrared-dark (NIR-dark) galaxies behind two massive lensing clusters MACS J0417.5-1154 and RXC J0032.1+1808. Each of these three sources is a (sub)millimeter faint (delensed S 1.2 mm < 1 mJy) triply lensed system originally discovered in the ALMA Lensing Cluster Survey. We have successfully detected CO and [C i ] emission lines and confirmed that their spectroscopic redshifts are z = 3.652, 2.391, and 2.985. By utilizing a rich multiwavelength data set, we find that the NIR-dark galaxies are located on the star formation main sequence in the intrinsic stellar mass range of log ( M * / M ⊙ ) = 9.8–10.4, which is about 1 order of magnitude lower than that of typical submillimeter galaxies (SMGs). These NIR-dark galaxies show a variety in gas depletion times and spatial extent of dust emission. One of the three is a normal star-forming galaxy with gas depletion time consistent with a scaling relation, and its infrared surface brightness is an order of magnitude smaller than that of typical SMGs. Since this galaxy has an elongated axis ratio of ∼0.17, we argue that normal star-forming galaxies in an edge-on configuration can be heavily dust-obscured. This implies that existing deep WFC3/F160W surveys may miss a fraction of typical star-forming main-sequence galaxies due to their edge-on orientation.