Issue |
A&A
Volume 693, January 2025
|
|
---|---|---|
Article Number | L18 | |
Number of page(s) | 9 | |
Section | Letters to the Editor | |
DOI | https://doi.org/10.1051/0004-6361/202452604 | |
Published online | 24 January 2025 |
Letter to the Editor
Spectroscopic confirmation of a dust-obscured, possibly metal-rich dwarf galaxy at z ∼ 5
1
INAF, Istituto di Radioastronomia, Via Piero Gobetti 101, 40129 Bologna, Italy
2
Dipartimento di Fisica e Astronomia “G. Galilei”, Università di Padova, Via Marzolo 8, 35131 Padova, Italy
3
INAF-Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, 50125 Firenze, Italy
4
NSF’s National Optical-Infrared Astronomy Research Laboratory, 950 N. Cherry Ave., Tucson, AZ, 85719
USA
5
Astrophysics Science Division, NASA Goddard Space Flight Center, 8800 Greenbelt Rd, Greenbelt, MD, 20771
USA
6
INAF – Osservatorio Astronomico di Roma, via di Frascati 33, 00078 Monte Porzio Catone, Italy
7
Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA, 16802
USA
8
Institute for Computational and Data Sciences, The Pennsylvania State University, University Park, PA, 16802
USA
9
Institute for Gravitation and the Cosmos, The Pennsylvania State University, University Park, PA, 16802
USA
10
Centro de Astrobiología (CAB), CSIC-INTA, Ctra de Ajalvir km 4, Torrejón de Ardoz, 28850 Madrid, Spain
11
INAF–Osservatorio Astronomico di Padova, Vicolo dell’Osservatorio 5, I-35122 Padova, Italy
12
INAF-Osservatorio di Astrofisica e Scienza dello Spazio, via Gobetti 93/3, I-40129 Bologna, Italy
13
Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD, 21218
USA
14
Physics & Astronomy Department, University of Louisville, 40292 KY, Louisville, USA
15
INAF – Osservatorio Astronomico di Roma, via di Frascati 33, 00078 Monte Porzio Catone, Italy
16
Center for Astrophysics | Harvard & Smithsonian, 60 Garden St, Cambridge, MA, 02138
USA
17
Black Hole Initiative, Harvard University, 20 Garden St, Cambridge, MA, 02138
USA
18
Aix Marseille Univ, CNRS, CNES, LAM, Marseille, France
19
Astronomy Centre, University of Sussex, Falmer, Brighton, BN1 9QH
UK
20
Institute of Space Sciences and Astronomy, University of Malta, Msida, MSD 2080
Malta
21
Department of Astronomy, The University of Texas at Austin, Austin, TX, USA
22
Cosmic Frontier Center, The University of Texas at Austin, Austin, TX, USA
23
Laboratory for Multiwavelength Astrophysics, School of Physics and Astronomy, Rochester Institute of Technology, 84 Lomb Memorial Drive, Rochester, NY, 14623
USA
24
Department of Physics and Astronomy, Texas A&M University, College Station, TX, 77843-4242
USA
25
George P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy, Texas A&M University, College Station, TX, 77843-4242
USA
26
ESA/AURA Space Telescope Science Institute, USA
⋆ Corresponding author; laura.bisigello@inaf.it
Received:
14
October
2024
Accepted:
13
December
2024
We present the first spectroscopic confirmation of a dust-obscured dwarf galaxy, CEERS-14821. The analysis was performed by combining JWST NIRCam broadband photometry and NIRSpec/PRISM spectroscopic data. From the detection of multiple rest-frame optical lines, we derive that CEERS-14821 is located at z = 4.883 ± 0.003. Moreover, from a secure detection of the Hα and Hβ, we derive that the galaxy has a dust extinction ranging from AV = 2.2−0.6+0.5 to AV = 3.4−0.9+0.7, depending on the assumed reddening law. This value is extremely large given that we estimated a low stellar mass, that is, log10(M/M⊙) = 8.17−0.04+0.05 or log10(M/M⊙) = 8.65−0.05+0.06, based on two different dust extinction laws. Moreover, the combination of different metallicity tracers and the spectro-photometric fit suggests that the galaxy may also be metal-rich, with 12 + log10(O/H)> 8.3, but a low metallicity value cannot be totally ruled out. The high metallicity value would be above the expectation based on the mass-metallicity relation. Both metallicity estimations are above the expectations based on the fundamental mass-metallicity relation since CEERS-14821 is going through a burst of star formation. The constraints on a possible active galactic nucleus presence are limited and loose, but they point towards a possible non-dominant contribution (fAGN < 0.5 with respect to the total dust luminosity). Based on the rest-frame optical images, this source has a size compatible with galaxies of similar stellar masses and at similar redshifts. Finally, CEERS-14821 may be part of a larger galaxy overdensity, but there are no other galaxies closely interacting with it (within 30 Mpc).
Key words: galaxies: dwarf / galaxies: fundamental parameters / galaxies: ISM / galaxies: peculiar
© The Authors 2025
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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