The Mass-Metallicity Relation of Dwarf Galaxies at Cosmic Noon from JWST Observations

Mingyu Li, Zheng Cai, Fuyan Bian, Xiaojing Lin, Zihao Li, Yunjing Wu, Fengwu Sun, Shiwu Zhang, Emmet Golden-Marx, Zechang Sun, Siwei Zou, Xiaohui Fan, Eiichi Egami, Stephane Charlot, Gustavo Bruzual, Jacopo Chevallard

Research output: Contribution to journalArticlepeer-review

22 Scopus citations

Abstract

We present a study of the mass-metallicity relation (MZR) of 51 dwarf galaxies (M ≈ 106.5-109.5 M ) at z = 2-3 from the A2744 and SMACS J0723-3732 galaxy cluster fields. These dwarf galaxies are identified and confirmed by deep JWST/NIRISS imaging and slitless grism spectroscopic observations. By taking advantage of the superior performance of JWST and the gravitational lensing effect, we extend the previous MZR relation at z = 2-3 to a much lower-mass regime down by ≈2.5 orders of magnitude as compared with previous studies. We find that the MZR has a shallower slope at the low-mass end (M < 109 M ), with a slope turnover point of ≈109 M . This implies that the dominating feedback processes in dwarf galaxies may be different from that in massive galaxies. From z = 3, to z = 2, the metallicity of the dwarf galaxies is enhanced by ≈0.09 dex for a given stellar mass, consistent with the mild evolution found in galaxies with higher mass. Furthermore, we confirm the existence of a fundamental metallicity relation (FMR) between the gas-phase metallicity, stellar mass, and star formation rate in dwarf galaxies at z = 2-3. Our derived FMR, which has no significant redshift evolution, can be used as a benchmark to understand the origin of the anticorrelation between the star formation rate and metallicity of dwarf galaxies in the high-z Universe.

Original languageEnglish (US)
Article numberL18
JournalAstrophysical Journal Letters
Volume955
Issue number1
DOIs
StatePublished - Sep 1 2023

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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