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arXiv · 2211.01382

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
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Abstract

We present a study of the mass-metallicity relation (MZR) of 51 dwarf galaxies ($M_\star\approx 10^{6.5} - 10^{9.5}~M_\odot$) at $z = 2-3$ from the Abell 2744 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 $\approx$ 2.5 orders of magnitude as compared with previous studies. We find that the MZR has a shallower slope at the low-mass end ($M_\star<10^{9}~M_\odot$), with a slope turnover point of $\approx$ $10^9~M_\odot$. 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 $\approx0.09$ 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 anti-correlation between the SFR and metallicity of dwarf galaxies in the high-$z$ Universe.

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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. 2022-11-02. The Mass-Metallicity Relation of Dwarf Galaxies at Cosmic Noon from JWST Observations. https://doi.org/10.3847/2041-8213%2Facf470

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