ALMA Lensing Cluster Survey: Physical Characterization of Near-infrared-dark Intrinsically Faint ALMA Sources at z = 2-4
Journal article, 2025
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 S1.2 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.
Author
Akiyoshi Tsujita
University of Tokyo
Kotaro Kohno
University of Tokyo
Research Center for the Early Universe
Shuo Huang
National Astronomical Observatory of Japan
Nagoya University
M. Oguri
Chiba University
Ken Ichi Tadaki
Hokkai Gakuen University
I. Smail
Durham University
H. Umehata
Nagoya University
California Institute of Technology (Caltech)
Zhen Kai Gao
Academia Sinica
National Central University
Wei Hao Wang
Academia Sinica
Fengwu Sun
University of Arizona
Harvard-Smithsonian Center for Astrophysics
S. Fujimoto
Cosmic Dawn Center (DAWN)
Niels Bohr Institute
University of Texas
T. Wang
Nanjing University
Ryosuke Uematsu
Kyoto University
D. Espada
Universidad de Granada
F. Valentino
European Southern Observatory (ESO)
Cosmic Dawn Center (DAWN)
Y. Ao
University of Science and Technology of China
Chinese Academy of Sciences
F. E. Bauer
Pontificia Universidad Catolica de Chile
Millennium Institute of Astrophysics
B. Hatsukade
University of Tokyo
The Graduate University for Advanced Studies (SOKENDAI)
National Astronomical Observatory of Japan
Fumi Egusa
University of Tokyo
Y. Nishimura
University of Tokyo
Anton M. Koekemoer
Space Telescope Science Institute (STScI)
D. Schaerer
Institut de Recherche en Astrophysique et Planétologie (IRAP)
University of Geneva
C. D. P. Lagos
Cosmic Dawn Center (DAWN)
ARC Centre of Excellence for All-sky Astrophysics (CAASTRO)
University of Western Australia
M. Dessauges-Zavadsky
University of Geneva
G. Brammer
Cosmic Dawn Center (DAWN)
Niels Bohr Institute
Karina I. Caputi
University of Groningen
Cosmic Dawn Center (DAWN)
Eiichi Egami
University of Arizona
J. González-López
Diego Portales University
Las Campanas Observatory
Jean Baptiste Jolly
Max Planck Society
Extragalactic Astrophysics
Kirsten Knudsen
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
V. Kokorev
Cosmic Dawn Center (DAWN)
Niels Bohr Institute
University of Groningen
Georgios E. Magdis
Niels Bohr Institute
Cosmic Dawn Center (DAWN)
Technical University of Denmark (DTU)
Masami Ouchi
National Astronomical Observatory of Japan
University of Tokyo
Sune Toft
Niels Bohr Institute
Cosmic Dawn Center (DAWN)
John F. Wu
Space Telescope Science Institute (STScI)
Johns Hopkins University
A. Zitrin
Ben-Gurion University of the Negev
Astrophysical Journal
0004-637X (ISSN) 1538-4357 (eISSN)
Vol. 989 1 115Subject Categories (SSIF 2025)
Atom and Molecular Physics and Optics
Other Physics Topics
Astronomy, Astrophysics, and Cosmology
DOI
10.3847/1538-4357/adb41d