Serendipitous discovery of an optically dark ultra-luminous infrared galaxy at z = 3.4
Journal article, 2025
Dusty, submillimeter-selected galaxies without optical counterparts contribute a non-negligible fraction of the star formation in the early universe. However, such a population is difficult to detect through classical optical/UV-based surveys. We report the serendipitous discovery of such an optically dark galaxy, behind the quadruply lensed z = 2.56 quasar, H1413+117, offset to the north by 6″. From 12CO J = 4-3, J = 6-5, and part of the J = 13-12 transitions, which all spatially coincide with a compact submillimeter continuum emission, we determine an unambiguous spectroscopic redshift, z = 3.386 ± 0.005. This galaxy has a molecular mass Mmol ∼ 1011 M⊙ a black hole mass MBH ∼ 108 M⊙, estimated from 12CO J = 4.3 and archival Chandra X-ray data (L2-10, keV ∼-4 ∼ ×1044 erg s-1), respectively. We also estimate a total infrared luminosity of LFIR = (2.8 ± 2.3 ) × 1012 L⊙ a stellar mass of M∗ 1011 M⊙, from spectral energy distribution fitting. According to these simple mass estimations, this gas-rich and X-ray bright galaxy might be in a transition phase from starburst to quasar offering a unique case for studying galaxy-black hole co-evolution under extremely dusty conditions.
galaxies: high-redshift
galaxies: individual: (H1413+117)
methods: observational
submillimetre: galaxies
X-rays: galaxies
galaxies: distances and redshifts
Author
Natsuki H. Hayatsu
Waseda University
Z. Y. Zhang
Nanjing University
R. J. Ivison
European Southern Observatory (ESO)
Chao Wei Tsai
Beijing Normal University
Chinese Academy of Sciences
Ping Zhou
Nanjing University
Katsuya Okoshi
Tokyo University of Science
Chentao Yang
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
Y. Nishimura
University of Tokyo
University of Tsukuba
Kotaro Kohno
Research Center for the Early Universe
University of Tokyo
Nobunari Kashikawa
University of Tokyo
Masahiro Nagashima
Bunkyo University
Junfeng Wang
Xiamen University
Denis Burgarella
Laboratoire d'Astrophysique de Marseille
Monthly Notices of the Royal Astronomical Society
0035-8711 (ISSN) 1365-2966 (eISSN)
Vol. 543 4 3967-3974Subject Categories (SSIF 2025)
Atom and Molecular Physics and Optics
Astronomy, Astrophysics, and Cosmology
DOI
10.1093/mnras/staf1655