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 L30

Subject Categories

Astronomy, Astrophysics and Cosmology

Other Chemical Engineering

Metallurgy and Metallic Materials

DOI

10.3847/2041-8213/acb2cf

More information

Latest update

3/6/2023 2