Metal-enriched Neutral Gas Reservoir around a Strongly Lensed Low-mass Galaxy at z = 4 Identified by JWST/NIRISS and VLT/MUSE
Artikel i vetenskaplig tidskrift, 2023

Direct observations of low-mass, low-metallicity galaxies at z ≳ 4 provide an indispensable opportunity for detailed inspection of the ionization radiation, gas flow, and metal enrichment in sources similar to those that reionized the universe. Combining the James Webb Space Telescope (JWST), Very Large Telescope/MUSE, and Atacama Large Millimeter/submillimeter Array, we present detailed observations of a strongly lensed, low-mass (≈107.6 M ⊙) galaxy at z = 3.98 (also see Vanzella et al.). We identify strong narrow nebular emission, including C iv λ λ1548, 1550, He ii λ1640, O iii] λ λ1661, 1666, [Ne iii] λ3868, [O ii] λ3727, and the Balmer series of hydrogen from this galaxy, indicating a metal-poor H ii region (≲0.12 Z ⊙) powered by massive stars. Further, we detect a metal-enriched damped Lyα system (DLA) associated with the galaxy with the H i column density of N H I ≈ 1021.8 cm−2. The metallicity of the associated DLA may reach the supersolar metallicity (≳Z ⊙). Moreover, thanks to JWST and gravitational lensing, we present the resolved UV slope (β) map at the spatial resolution of ≈100 pc at z = 4, with steep UV slopes reaching β ≈ −2.5 around three star-forming clumps. Combining with low-redshift analogs, our observations suggest that low-mass, low-metallicity galaxies, which dominate reionization, could be surrounded by a high covering fraction of the metal-enriched, neutral-gaseous clouds. This implies that the metal enrichment of low-mass galaxies is highly efficient, and further supports that in low-mass galaxies, only a small fraction of ionizing radiation can escape through the interstellar or circumgalactic channels with low-column-density neutral gas.


Xiaojing Lin

Tsinghua University

Zheng Cai

Tsinghua University

Siwei Zou

Tsinghua University

Zihao Li

Tsinghua University

Zuyi Chen

University of Arizona

Fuyan Bian

European Southern Observatory Santiago

Fengwu Sun

University of Arizona

Yiping Shu

Chinese Academy of Sciences

Yunjing Wu

Tsinghua University

University of Arizona

Mingyu Li

Tsinghua University

Jianan Li

Tsinghua University

Xiaohui Fan

University of Arizona

J. Xavier Prochaska

Lick Observatory

University of Tokyo

D. Schaerer

Université de Genève

Stephane Charlot

Institut d 'Astrophysique de Paris

D. Espada

Universidad de Granada

M. Dessauges-Zavadsky

Université de Genève

Eiichi Egami

University of Arizona

Daniel Stark

University of Arizona

Kirsten Knudsen

Chalmers, Rymd-, geo- och miljövetenskap, Astronomi och plasmafysik

Gustavo Bruzual

Universidad Nacional Autónoma de México

Jacopo Chevallard

University of Oxford

Astrophysical Journal Letters

2041-8205 (ISSN) 2041-8213 (eISSN)

Vol. 944 2 L59


Analytisk kemi

Astronomi, astrofysik och kosmologi

Atom- och molekylfysik och optik



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