Serendipitous discovery of an optically dark ultra-luminous infrared galaxy at <i>z</i> = 3.4

ABSTRACT 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$^{\prime \prime }$. From $^{12}$CO $J=4$–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, $z=3.386\pm 0.005$. This galaxy has a molecular mass $M_{\rm mol} \sim 10^{11}$ M$_\odot$ and a black hole mass $M_{\rm BH} \sim 10^{8}$ M$_\odot$, estimated from $^{12}$CO $J=4$–3 and archival Chandra X-ray data ($L_{\rm 2-10,keV} \sim 4 \times 10^{44}$ erg s$^{-1}$), respectively. We also estimate a total infrared luminosity of $L_{\rm FIR} = (2.8\pm {2.3}) \times 10^{12}$ L$_\odot$ and a stellar mass of $M_* \lesssim 10^{11}$ M$_{\odot }$, 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.

Authors

Institutions

Publication Details

Journal
Monthly Notices of the Royal Astronomical Society
Published
2025-09-29
DOI
https://doi.org/10.1093/mnras/staf1655
Primary Topic
Galaxies: Formation, Evolution, Phenomena
Type
article
Field-Weighted Citation Impact
0.00

Funders

Controls
|||
ALL TIME
JAN
FEB
MAR
APR
MAY
JUN
JUL
AUG
SEP
OCT
article

Serendipitous discovery of an optically dark ultra-luminous infrared galaxy at z = 3.4

C. Yang, Masahiro Nagashima, Natsuki H. Hayatsu, Nobunari Kashikawa et al.
Monthly Notices of the Royal Astronomical Society
Galaxies: Formation, Evolution, Phenomena
article

Serendipitous discovery of an optically dark ultra-luminous infrared galaxy at z = 3.4

C. Yang, Masahiro Nagashima, Natsuki H. Hayatsu, Nobunari Kashikawa, Zhi-Yu Zhang, Y. Nishimura, Chao‐Wei Tsai, R. J. Ivison, Ping Zhou, Katsuya Okoshi, Kotaro Kohno, Junfeng Wang, Denis Burgarella
article en

Abstract

ABSTRACT 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$^{\prime \prime }$. From $^{12}$CO $J=4$–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, $z=3.386\pm 0.005$. This galaxy has a molecular mass $M_{\rm mol} \sim 10^{11}$ M$_\odot$ and a black hole mass $M_{\rm BH} \sim 10^{8}$ M$_\odot$, estimated from $^{12}$CO $J=4$–3 and archival Chandra X-ray data ($L_{\rm 2-10,keV} \sim 4 \times 10^{44}$ erg s$^{-1}$), respectively. We also estimate a total infrared luminosity of $L_{\rm FIR} = (2.8\pm {2.3}) \times 10^{12}$ L$_\odot$ and a stellar mass of $M_* \lesssim 10^{11}$ M$_{\odot }$, 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.

Monthly Notices of the Royal Astronomical SocietyVol. 543(4)
Centre National de la Recherche Scientifique (FR), European Southern Observatory (DE), University of Tsukuba (JP), Waseda University (JP), Bunkyo University (JP), Tokyo University of Science (JP), Xiamen University (CN), Chinese Academy of Sciences (CN), Aix-Marseille Université (FR), Beijing Normal University (CN), Laboratoire d’Astrophysique de Marseille (FR), Astronomy and Space (AU), National Astronomical Observatory of Japan (JP), National Astronomical Observatories (CN), University of Chinese Academy of Sciences (CN), Chalmers University of Technology (SE), The University of Tokyo (JP), Nanjing University (CN)
National Science Foundation, National Aeronautics and Space Administration, California Institute of Technology, National Radio Astronomy Observatory, Deutsche Forschungsgemeinschaft, National Natural Science Foundation of China, Korea Astronomy and Space Science Institute, Centre National de la Recherche Scientifique, National Astronomical Observatory of Japan, Japan Society for the Promotion of Science, National Institutes of Natural Sciences
Openalex Percentile: Top 81%
Galaxies: Formation, Evolution, Phenomena
DOIOpen Access PDFOpenAlex
AI Navigator

Ask Laika to Summarize, Analyze, and Connect papers live on the map.

Summarize Papers & Methodologies

Extract key findings, datasets, and comparative methods across publications.

Benchmark Rankings & Visual Analytics

Rank top research institutions, authors, funders, topics, and journals by Field-Weighted Citation Impact (FWCI) and paper volume with instant charts.

Connect Distant Disciplines

Bridge topological clusters on the map to find hidden collaborative intersections.