Behind the dust veil: A panchromatic view of an optically dark galaxy at z = 4.82
Artikel i vetenskaplig tidskrift, 2025
Optically dark dusty star-forming galaxies (DSFGs) play an essential role in massive galaxy formation at early cosmic time; however, their nature remains elusive. Here, we present a detailed case study of all the baryonic components of a z = 4.821 DSFG, XS55. Selected from the ultra-deep COSMOS-XS 3 GHz map with a red SCUBA-2 450 μm/850 μm colour, XS55 was followed up with ALMA 3 mm line scans and spectroscopically confirmed to be at z = 4.821 via detections of the CO(5-4) and [CI](1-0) lines. JWST/NIRCam imaging reveals that XS55 is a F150W drop-out with a red F277W/F444W colour and a complex morphology: a compact central component embedded in an extended structure with a likely companion. XS55 is tentatively detected in X-rays with both Chandra and XMM-Newton, suggesting an active galactic nucleus nature. By fitting a panchromatic spectral energy distribution spanning from near-infrared to radio wavelengths, we reveal that XS55 is a massive main-sequence galaxy with a stellar mass of M∗ = (5 ± 1)×1010 M⊙ and a star formation rate of SFR = 540 ± 177 M⊙ yr- 1. The dust of XS55 is optically thick in the far-infrared with a surprisingly cold dust temperature of Tdust = 33 ± 2 K, making XS55 one of the coldest DSFGs at z > 4 known to date. This work unveils the nature of a radio-selected F150W drop-out, suggesting the existence of a population of DSFGs hosting active black holes embedded in optically thick dust.
Galaxies: active
Galaxies: ISM
Galaxies: general
Författare
Nikolaj B. Sillassen
Danmarks Tekniske Universitet (DTU)
Cosmic Dawn Center (DAWN)
S. Jin
Cosmic Dawn Center (DAWN)
Danmarks Tekniske Universitet (DTU)
Georgios E. Magdis
Cosmic Dawn Center (DAWN)
Danmarks Tekniske Universitet (DTU)
Niels Bohr Institute
J. Hodge
Universiteit Leiden
Raphael Gobat
Pontificia Universidad Católica de Valparaíso
Emanuele Daddi
Université Paris-Saclay
Kirsten Knudsen
Chalmers, Rymd-, geo- och miljövetenskap, Astronomi och plasmafysik
Alexis Finoguenov
Helsingin Yliopisto
E. Schinnerer
Max-Planck-Gesellschaft
Wei Hao Wang
Academia Sinica
Zhen Kai Gao
Academia Sinica
J. R. Weaver
University of Massachusetts
H. Algera
National Astronomical Observatory of Japan
Hiroshima University
Academia Sinica
Irham T. Andika
Max-Planck-Gesellschaft
Technische Universität München
Malte Brinch
Universidad de Valparaíso
C. C. Chen
Academia Sinica
R. Cochrane
University of Edinburgh
Columbia University
A. F.M. Enia
Istituto nazionale di astrofisica (INAF)
Universita di Bologna
A. Faisst
California Institute of Technology (Caltech)
S. Gillman
Cosmic Dawn Center (DAWN)
Danmarks Tekniske Universitet (DTU)
Carlos Gomez-Guijarro
Université Paris-Saclay
Ghassem Gozaliasl
Helsingin Yliopisto
Aalto-Yliopisto
Christopher C. Hayward
Flatiron Institute
V. Kokorev
University of Texas
Maya Merchant
Niels Bohr Institute
Cosmic Dawn Center (DAWN)
Francesca Rizzo
Rijksuniversiteit Groningen
Margherita Talia
Istituto nazionale di astrofisica (INAF)
Universita di Bologna
F. Valentino
Danmarks Tekniske Universitet (DTU)
Cosmic Dawn Center (DAWN)
David Blánquez-Sesé
Danmarks Tekniske Universitet (DTU)
Cosmic Dawn Center (DAWN)
Anton M. Koekemoer
Space Telescope Science Institute (STScI)
Benjamin Magnelli
Université Paris-Saclay
R. Michael Rich
University of California
Marko Shuntov
Cosmic Dawn Center (DAWN)
Niels Bohr Institute
Astronomy and Astrophysics
0004-6361 (ISSN) 1432-0746 (eISSN)
Vol. 693 A309The Origin and Fate of Dust in Our Universe
Knut och Alice Wallenbergs Stiftelse (KAW 2019.0443), 2020-06-01 -- 2023-05-31.
Knut och Alice Wallenbergs Stiftelse (KAW 2020.0081), 2021-07-01 -- 2026-06-30.
Ämneskategorier (SSIF 2025)
Annan fysik
Astronomi, astrofysik och kosmologi
DOI
10.1051/0004-6361/202452932