paper

A negative stellar massgaseous metallicity gradient relation of dwarf galaxies modulated by stellar feedback

arXiv:2504.17541 · doi:10.1051/0004-6361/202452978

Abstract

Baryonic cycling is reflected in the spatial distribution of metallicity within galaxies, yet gas-phase metallicity distribution and its connection with other properties of dwarf galaxies are largely unexplored. We present the first systematic study of radial gradients of gas-phase metallicities for a sample of 55 normal nearby star-forming dwarf galaxies (stellar mass ranging from to ), based on MUSE spectroscopic observations. We find that metallicity gradient shows a significant negative correlation (correlation coefficient ) with , in contrast to the flat or even positive correlation observed for higher-mass galaxies. This negative correlation is accompanied by a stronger central suppression of metallicity compared to the outskirts in lower-mass galaxies. Among the other explored galaxy properties-including baryonic mass, star formation distribution, galaxy environment, regularity of the gaseous velocity field, and effective yield of metals -only the velocity field regularity and show residual correlation with the metallicity gradient after controlling for , in the sense that galaxies with irregular velocity fields or lower tend to have less negative or more positive gradients. Particularly, a linear combination of and significantly improves the correlation with metallicity gradient () compared to alone. The lack of correlation with environment disfavors gas accretion as a dominant factor. Our findings imply that metal mixing and transport processes, including but not limited to feedback-driven outflows, are more important than in-situ metal production in shaping the metallicity distribution of dwarf galaxies.

19 pages, 13 figures, accepted for publication in A&A. The most important findings are shown in Figs 3, 12, and 13

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