paper

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

arXiv:2211.01382 · doi:10.3847/2041-8213/acf470

Abstract

We present a study of the mass-metallicity relation (MZR) of 51 dwarf galaxies () at 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 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 (), with a slope turnover point of . This implies that the dominating feedback processes in dwarf galaxies may be different from that in massive galaxies. From to , the metallicity of the dwarf galaxies is enhanced by 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 . 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- Universe.

19 pages, 4 figures, 3 tables, Accepted for publication in the Astrophysical Journal Letters

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