The Gas and Stellar Content of a Metal-poor Galaxy at z = 8.496 as Revealed by JWST and ALMA
Journal article, 2023
We present a joint analysis of the galaxy S04590 at z = 8.496 based on NIRSpec, NIRCam, and NIRISS observations obtained as part of the Early Release Observations program of the James Webb Space Telescope (JWST) and the far-infrared [C ii] 158 μm emission line detected by dedicated Atacama Large Millimeter/submillimeter Array (ALMA) observations. We determine the physical properties of S04590 from modeling of the spectral energy distribution (SED) and through the redshifted optical nebular emission lines detected with JWST/NIRSpec. The best-fit SED model reveals a low-mass (M ⋆ = 107.2-108 M ⊙) galaxy with a low oxygen abundance of 12 + log ( O / H ) = 7.16 − 0.12 + 0.10 derived from the strong nebular and auroral emission lines. Assuming that [C ii] effectively traces the interstellar medium, we estimate the total gas mass of the galaxy to be M gas = (8.0 ± 4.0) × 108 M ⊙ based on the luminosity and spatial extent of [C ii]. This yields an exceptionally high gas fraction, f gas = M gas/(M gas + M ⋆) ≳ 90%, though one still consistent with the range expected for low metallicity. We further derive the metal mass of the galaxy based on the gas mass and gas-phase metallicity, which we find to be consistent with the expected metal production from Type II supernovae. Finally, we make the first constraints on the dust-to-gas (DTG) and dust-to-metal (DTM) ratios of galaxies in the epoch of reionization at z ≳ 6, showing overall low mass ratios of logDTG < −3.8 and logDTM < −0.5, though they are consistent with established scaling relations and in particular with those of the local metal-poor galaxy I Zwicky 18. Our analysis highlights the synergy between ALMA and JWST in characterizing the gas, metal, and stellar content of the first generation of galaxies.
Author
K. E. Heintz
Niels Bohr Institute
Cosmic Dawn Center (DAWN)
C. Giménez-Arteaga
Cosmic Dawn Center (DAWN)
Niels Bohr Institute
S. Fujimoto
Cosmic Dawn Center (DAWN)
Niels Bohr Institute
The University of Texas at Austin
G. Brammer
Cosmic Dawn Center (DAWN)
Niels Bohr Institute
D. Espada
Universidad de Granada
S. Gillman
Technical University of Denmark (DTU)
Cosmic Dawn Center (DAWN)
J. González-López
Las Campanas Observatory
Diego Portales University
T. R. Greve
Cosmic Dawn Center (DAWN)
Technical University of Denmark (DTU)
Yuichi Harikane
University of Tokyo
B. Hatsukade
University of Tokyo
Kirsten Knudsen
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
Anton M. Koekemoer
Space Telescope Science Institute (STScI)
K. Kohno
Research Center for the Early Universe
University of Tokyo
V. Kokorev
University of Groningen
M. M. Lee
Technical University of Denmark (DTU)
Cosmic Dawn Center (DAWN)
Georgios E. Magdis
Cosmic Dawn Center (DAWN)
Niels Bohr Institute
Technical University of Denmark (DTU)
E. J. Nelson
University of Colorado at Boulder
F. Rizzo
Cosmic Dawn Center (DAWN)
Niels Bohr Institute
R. L. Sanders
University of California
D. Schaerer
University of Geneva
Institut de Recherche en Astrophysique et Planétologie (IRAP)
A. E. Shapley
University of California
V. B. Strait
Niels Bohr Institute
Cosmic Dawn Center (DAWN)
Sune Toft
Cosmic Dawn Center (DAWN)
Niels Bohr Institute
F. Valentino
Niels Bohr Institute
Cosmic Dawn Center (DAWN)
European Southern Observatory (ESO)
A. van der Wel
Ghent university
A. P. Vijayan
Cosmic Dawn Center (DAWN)
Technical University of Denmark (DTU)
D. Watson
Cosmic Dawn Center (DAWN)
Niels Bohr Institute
F. E. Bauer
Pontificia Universidad Catolica de Chile
Millennium Institute of Astrophysics
C. R. Christiansen
Niels Bohr Institute
Cosmic Dawn Center (DAWN)
S. N. Wilson
Niels Bohr Institute
Cosmic Dawn Center (DAWN)
Astrophysical Journal Letters
2041-8205 (ISSN) 2041-8213 (eISSN)
Vol. 944 2 L30Subject Categories
Astronomy, Astrophysics and Cosmology
Other Chemical Engineering
Metallurgy and Metallic Materials
DOI
10.3847/2041-8213/acb2cf